CA1184853A - Agent and method for the treatment of production cycle and effluent water of the papermaking and related industries - Google Patents
Agent and method for the treatment of production cycle and effluent water of the papermaking and related industriesInfo
- Publication number
- CA1184853A CA1184853A CA000381497A CA381497A CA1184853A CA 1184853 A CA1184853 A CA 1184853A CA 000381497 A CA000381497 A CA 000381497A CA 381497 A CA381497 A CA 381497A CA 1184853 A CA1184853 A CA 1184853A
- Authority
- CA
- Canada
- Prior art keywords
- acid
- water
- clay
- adsorptive agent
- treatment
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F1/00—Wet end of machines for making continuous webs of paper
- D21F1/66—Pulp catching, de-watering, or recovering; Re-use of pulp-water
- D21F1/82—Pulp catching, de-watering, or recovering; Re-use of pulp-water adding fibre agglomeration compositions
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/28—Treatment of water, waste water, or sewage by sorption
- C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
- D21H17/63—Inorganic compounds
- D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
- D21H17/68—Water-insoluble compounds, e.g. fillers, pigments siliceous, e.g. clays
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Organic Chemistry (AREA)
- Dispersion Chemistry (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
- Paper (AREA)
- Water Treatment By Sorption (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
- Sealing Material Composition (AREA)
- Preventing Corrosion Or Incrustation Of Metals (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Saccharide Compounds (AREA)
Abstract
ABSTRACT
An automotive type fuel ignitor having an ignitor chamber continuously exposed to the engine combustion chamber temperatures and pressures for a first stage of compression of an air/fuel mixture thereon during the compression stage movement of the engine piston, a piston in the ignitor chamber being moved by a high pressure hydraulic force selectively applied thereto through a second stage of compression to raise the mixture charge pressure and temperature to the auto-ignition level, forcing the flame jet into the main combustion chamber, suitable inlet and outlet check valves controlling the supply of mixture charge to the ignitor chamber.
An automotive type fuel ignitor having an ignitor chamber continuously exposed to the engine combustion chamber temperatures and pressures for a first stage of compression of an air/fuel mixture thereon during the compression stage movement of the engine piston, a piston in the ignitor chamber being moved by a high pressure hydraulic force selectively applied thereto through a second stage of compression to raise the mixture charge pressure and temperature to the auto-ignition level, forcing the flame jet into the main combustion chamber, suitable inlet and outlet check valves controlling the supply of mixture charge to the ignitor chamber.
Description
i3 FIELD OF THE INVENTION
The invention relates to an agent and a method for the treatment of production cycle and effluent water of the papermaking and related industries for the purpose of remov-ing dissolved or colloidally dispersed organic substances.
BACKGROUND OF THE IN~EI~TION
The treatment of paper mill water circulations is effected today practically exclusively with sedimentation, flotation, or filtration pulp catchers, in part with the use of chemical flocculation aids.
In view of exceedingly high costs of effluent puri-fication and the atte~pt made for that reason to close the cycle - i.e. to reduce the specific effluent quantity - this procedure is obsolete. Possibilities of purification as pre-viously discussed in the waste water sector should be moved up into the cycle water so as to permit further narrowing of the water circulation and at the same time to reduce the load-ing of the residual waste water.
One of the greatest obstacles to further closin~ of the water circulation in the paper industry is the concentra-tion of dissolved or colloidally dispersed organic subs-ances in the cycle water, which because of their predominantly anionic nature cause considerable production disturbance and loss of product quality. These substances, therefore, should be removed from the cycle water to the extent possible, in order to close the water circulation completely in cases which are regarded to be impossible today. The second pro-blem, i.e. the concentration of the electrolytes, should ke reduced to simply a material problem, since it has been proven that production and product quality are not notably influenced by inorganic electrolytes.
~8~3 DESCRIPTION OF THE PRIOR ART
Solid adsorption agents in powder form have already been used for the treatment of paper mill water circulations.
~or example, the use of alkaline-activated bentonites for this purpose was disclosed in Wochenblatt fur Papierfabrikation, 105, 799-802 (1977). In the treatment of cycle water, how-ever, alkaline-activated bentonites must be added to the water in the form of a suspension and must therefore be re-moved subsequently by sedimentation or flotation. Direct filtration treatment is not possible because of the special properties of the alkaline-activated bentonites.
DE-AS 21 21 198 discloses a method for the recovery of fiber materials and fillers from effluents from the paper industry. According to this method a mixture of (a) swelled layer silicates transformed to the Na, K, NH4 and/or H form in the usu~l way and (b) water-soluble macromolecular com-pounds of filamentary molecule structure reacting with the layer silicates and possibly with the fiber materials and fillers is added to the effluent in a quantity sufficient for the formation of total flock. The formed sludge phase is returned to the papermaking process after separation is completed. This literature reference, therefore, aims at removing solid, undissolved substances from the effluent by flocculation and subsequent filtration, while according to this invention dissolved or colloidally dispersed organic substances are to be removed from the production effluent by adsorption. In the known methods, the use of the macromole-cular compounds of filamentary molecule structure is essen-tial, since without them recovery of fibrous and filler sub-stances by flocculation is not possible. The layer silicate, ~ 3ossibly transformed to the H form, is present in a swelled orm. Due to the mlld acid treatment, the layer structure is still largely preserved. In particular the layer lattice still contains practically the entire aluminum portion.
Accordingly, the sludge phase is contaminated by the macro-molecular compounds of filamentary molecule structures and is suitable only for the filling of paper or board of infer-ior quality. Further the effluent separated from the sludge phase e.g. by filtration still contains most of the dissolved or colloidally dispersed org~nic disturbance substances and therefore is unsuitable as cycle water. J. Weigl teaches in Elektrokinetische Grenzflachenvorgange9 Weinheim, New York:
Verlag-Chemie 1977, 156 - 157 that a specific asbestos type (chrysotile asbestos of high specific surface and positive zeta potential) has good adsorption properties for anionic organic substances.
I~ is also known that positively charged aluminum oxide is a good adsorption agent for anionic organic sub-stances. Industrially, this material is used in granulated form in adsorption towers, the laden adsorbent being regener-ated thermally (cf. Prog.Wat.Tech.10, 1978, ~9-96).
The cited :Literature references appear to suggest that adsorption ag~nts of high specific surface and positive zeta potential should be suitable for the treatment of paper-making cycle waters.
It was found, however, that under indus~rial con-ditions in the treatment of production cycle and effluent waters of the p~permaking and related industries, that the named adsorption agents gave unsatisfactory adsorption results, although in model experiments they had at first proved to be usable. Surprisingly, it was found that acid-activated clay minerals, which generally have a negakive zeta potential, gave in practice, better adsorption results.
SUMMARY OF THE INVE~TION
This invention provides a process for the treatment of process water containing organic waste materials, connected with the production of paper from wood pulp, which comprises the steps of:
A. adding an adsorptive agent, having a negatively charged surface to said process water, said adsorptive agent comprising:
1. an acid-treated silicate-layered clay, having a high surface area of at least 180 m2/gm and a high surface energy and whic~ contains a major portion of the original silicate layer in the form of free silicic acid and a minor portion of the original aluminous constituent of said clay and only residual amounts of the alkali and alkaline earth metals originally present in the clay; and B. separating the adsorptive agent from the process water.
This invention proposes, then, an agent for the treatment of production cycle and effluent waters of the papermaking and related industries for the purpose of re-moving dissolved or colloidally dispersed organic substances.
The agent is a negatively charged acid-treated clay. The clay prior to acid-treatment is of the silicate-layered type which includes the montmorillonite-beidellite series, the chlorite group and minerals with a series disorder, i.e.
mixed layer silicates. Of particular interest in this in-vention are the montmorillonite-beidellite series. The ~ 4 --,~ i silicate-layered clays are treated with acid such as hydro-chloric or sulfuric so that a major portion of the original silicate constituent is converted over to silicon dioxide and free silicic acid. A substantial portion of the original aluminous constituent is leached out by the acid treatment and essentially all of the alkali and alkaline earth metal constituents are removed by the treatment. The treatrnent is such that the original clay loses much of its original proper-ties and the silicate layer is converted over to a silicon dioxide layer containing a substantial amount of free silicic acid. The finished product has a high specific surface area of at least 180 m2/gm and more preferably a surface area in the range of 240-360 m2/gm. The surface has a 1early negative zeta potential and a high surface energy.
The finished product contains the siliceous constituent in the range of 60-75% by weight expressed a SiO2.
~a -., . , ) i3 The aluminous cons~ituent is present in the range of from 5-20~ expressed as A12O3 and the remainder consists essen-tially of compounds of iron, magnesium, and calciu~ in various proportions. The alkali and alkaline earth metal constituents are essentially completely removed by the acid -treatment. Only residual traces remain. The micro-pore volume of the pores having a pore diameter of <800A
is at least 0.3 ml/gm. The negatively charged acid-treated clay, having lost its original properties is added to the process water at one of two different points. The materials can be added to the water containing the pulp in suspension - so that upon separation of the pulp from the water the adsorptive agent, laden with the organic waste materials, remains with the pulp as a filler. The organic waste materials, which are either dissolved or colloidally dis-persed, include proteins, humic acids, lignins, synthetic retention aids, emulsifiers, dyes, and the like. In another embodiment of this invention, the adsorptive agen~s can be added to process water or to waste water prior to their discharge from the process cycle, and the adsorptive agent, after the proper processing time, is filtered from the water, which is then either recycled back to the process cycle or is discharged as essentially purified waste water.
The filter cake then can be collected and used as a filler in subsequent batches of paper or paper board.
DESCRIPTION OF THE PREFERRED EMBODI~NT
~ . . _ . . . . _ Acid-activated clay minerals are, per se, known as adsorption agents. Clay minerals belong to different structure types. Clay minerals of the kaolinite structure type are for example kaolinite, nacrite, dickite, anauxite and halloysite, as well as the serpentine minerals chrysotile, serpentine, antigorite and amesite. Another structure type comprises the mica-]ike layer silicates, which in turn are divided into minerals of the montmorillonite-beidellite series, vermiculate serles, illite series, and the mica minerals.
Especially important for the present purpose are the minerals of the montmorillonite-beidellite series. Suitable further are minerals of the chlorite group and minerals with species disorder (mixed layer silicates). A general summary of these clay minerals is found in "Ullmanns Encyklopadie der technis-chen Chemie", volume 17 ~1966), pages 583 to 597. The acid activation of these clay minerals is generally effected by treatment with hydrochloric or sulfuric acid. This treatment dissolves out the alkali and/or the alkaline earth component practically completely and also dissolves a large part, (pre-ferably at least 20 wt.%) of the aluminum and lron portion present in the octahedral layer of the mineral. There remains a product consisting predominantly of SiO2 with a high specific surface of at least 180 m2/g, (preferably 240 to 360 m2/g) a clearly negative zeta potential and a high surface energy.
Essentially, this product has lost the specific properties of the clay mineral employed as starting product. The silicic acid in the product consists in large part of free silicic acid soluble in weak alkali solution. The product has a micropore volume (800A) of a-t least 0.3 ml/g.
Acid activation of these clay materials is well known and suitable acid-activated clays have been described by the following: Carl-Ernst Hofstadt, et al, in U. S. Patent 3,901,826; Grant A Mickelson, et al, in U. S. Patent 2,981,697 (corresponding to German Patent 1,173,442); L. ~larbort, in U. S. Patent 3,293,060; Carl J. ~alble, in U. S. Patent ~b 3,557,023; L. Sugahara, in U. S. Patent 3,915,731 (corres-ponding to German patent 2,203,825); and Y. Sugahara, in U. S. Patent 3,787,330.
The especially good effect of the acid-activated clay minerals in the treatment of paper manufacture cycle waters is surprising because the properties of ~hese products in comparison to those mentioned before did not suggest such an effect. Due to their swelling power and the resulting special layered structure with possible formation of em-bedded compounds and special charge distribution at the crystalflakes (planes charged negatively, edges positively), alkaline-activated bentonites are known to be able to also adsorb negatively charged organic compounds. Clearly, however, the adsorption of positively charged compounds is preferred.
The above-named products chrysotile asbestos and aluminum oxide prove effective in the treatment of paper production cycle waters only if their zeta potential is positive at the prevailing pH value in the cycle water.
Evidently, there is a connection between the surface charge of the adsorbent and the charge of the organic substances to be adsorbed.
The acid-activated clay minerals of the invention, on the other hand, are employed in known applications for the treatment of vegetable oils and mineral oils, i.e. in a purely organic medium, while in aqueous medium they are employed only for the removal of positively charged proteins from bever-ages, mainly beer. The mechanism for the excellent adsorption -according to the present invention, i.e. adsorption of pre-dominantly negatively charged organic substances from aqueous paper mill circulation on negatively charged surface of the acid-activated clay minerals - is not fully understood.
The adsorbed organic substances, according to the invention which are either dissolved or colloidally dispersed "
~ 3 comprise, for example, proteins, humic acids, lignins, synthetic retention aids, emulsifiers, dyes, and the like.
The preferred agents according to the invention are acid-activated clay minerals of the montmorillonite ~ype.
The method according to the invention is carried out preferably by adding the acid-activated clay minerals to the mixture of substances present in aqueous suspension in the process water.
According to owr embodiment of this invention, the laden agent obtained in the treatment of the manufacturing cycle or effluent water is reused as a filler substance. This offers the rare case of a purification measure without the form-ation of solid waste materials which would have to be eliminated.
The efficacy of the agents of the invention and a comparison thereof with agents otherwise usable for such treatments is explained in the following examples in a non-~imiting manner. In Table I below, the properties of the agents used in the experiments are compared. The acid-acti-vated clay minera:Ls A to D according to the invention generally had a SiO2 content of about 66 to 72 wt.%, an A12O3 content of about 12 to 15 wt.%, and a loss on ignition of about 6 to 10 wt.%. The balance consisted essentially of Fe, Mg and Ca in varying amounts. The products A to D differ from one another essentially by their mean grain diameter and by the pH value. They were obtained by acid digestion of a calcium bentonite from the Moosburg area.
The comparison substances are generally commercial products. The chrysotile asbestos is of the HBB type; the two aluminum oxide types I and II differ primarily by their specific surface; the alkaline-activated bentonite is sold by Sud Chemie AG under the trademark "TIXOTON".
Table I. Properties of the test products.
Adsorption agent Spec. Mean Zeta potential mV Pore pH of the surface grainvol. 1% aqueous (BET) dia. pH SpH 7 1~ Hg/g suspension m /g /um Acid act. clay mineral A 260 2.5 -22 ~27 1.63 3.4 Acid act. clay mineral B 260 2.5 7.4 Acid act. clay mineral C 260 2.5 7.8 Acid act. clay mineral D 240 3.5 Chrysotile asbestos 55 - +32 +45 1.76 9.3 Aluminum oxide I 266 - +12 ~12 2.29 9.2 0 Aluminum oxide II 117 - +25 +20 0.67 5.1 Alkaline act. bentonite 46 * -20 -22 0.64 10.1 *Screen residue on 45 micron ~0.1%
The adsoprtion capacity of the substances listed on Table I was tested at first on lignin sulonic acid as model substance for anionic organic substances. Specifi-cally there was used as model ~ubstance calcium lignin suf-fonate, purified, mean molecular weight about 10,000. The adsorption measurements were made on solutions containing 50 mg~lignin sulfonat~ per liter of tap water and wi~h an ad~lltion of 1.0 g,adsorption agent per liter of solution.
Th~ contact time was 30 minutes; the separation was effected by centrifuging. The results are summarized in Table II~
.
Tal~,le II. Adsorption of lignin sulfonate.
Adsorption agentAdsorption in %, referred to the con-centration of the untreated solution Acid activated clay mineral A 5.4 Acid activatel clay mineral D 8.0 Chryfiotile asbestos 58~7 Aluminum oxide I 44.0 Aluminum oxide II 86.0 30 Alkaline activated bentonite 7.1 _g _ The results show clearly ~hac the anionic organic subs~ance can be ef~ectively adsorbed only by products with a positive surface charge. This is as expected.
However, as will be shown in the following examples, the manufacturing cycle waters occurring in industrial prac-tice surprisingly behave differently from the model substance lignin sulfonate.
Example__ In this example the adsorption of organlc substances from the cycle water of a paper mill is set forth, the con-tent of organic subs~ance being expressed by the Total Organic Carbon TOC in mg.C per liter. Corresponding results are found wi~h the use o~ other parameters for the contam-ination of water by organic substance, as for example chemi-cal oxygen requirement COR and biochemical oxygen require-ment BOR.
The results of th investigations are given in Table III.
Table III. Adsorption of organic substances from paper mill cycle water.
20 Adsorption agent Total organic carbon, TOC
_ _ mg.C/liter Decrease %
Untreated 210 Acid activated clay mineral A 80 62 Chrysotile asbestos 180 14 Aluminum oxide I 160 24 Aluminum oxide II 200 5 Alkaline-activated bentonite 140 13 For each of the measurements 1 liter of cycle water was treated with 10 g of the adsorption agen~ to be tested.
In each case the adsorption agent was pre-swelled ~or 2 ~ 3 hours with a little water, as the adsorption agents used are in part dependent in their action on the degree of preswelling. After addition of the preswelled adsorption agent, the cycle water was stirred wlth a vane agitator for 30 minutes, and then filtered through a glass fiber filter. The comparison sample (untreated) was likewise filtered through a glassfiber filter before the measure-ment.
With this type of treàtment, a large excess of adsorption agent is added to the water, so ~hat to some extent ~he maximum possible adsorption output for execu-tion of a one-stage ~reatment is measured.
The results clearly show that, contrary to expec-tation, the acid-activated clay mineral gives the best adsorption effect.
Example 2 In this example, the same investigations as in Example 1 were carried out on the cycle water of a plant for the production of mechanical wood pulp used as fiber material in papermaking. In such a plant, wood is de-fibered with addition of plenty of water, considerable portions of organic ~ubstances being released. As the resulting fiber paste is transferred to papermaking with a solids content of between 2 and lOV/o, depending on the technology, considerable amounts of the released organic substances get into the paper machine cycle.
The treatmen~s are carried out in analogy to Example 1. The results are given in Table IV.
Tab].e IV. Adsorption of organic substances from cycle water of the mechanical wood plllp department.
Adsorption agent Total organic carbon, TOC
m~C/lite~ Decrease %
. ., Untreated 510 Acid-activated clay mineral A 290 43 Chrysotile asb~stos 450 12 Aluminum oxide I 450 12 Aluminum oxide II 430 16 Alkaline-activated bentonite 410 20 _ .
Exactly the same result i5 found as in the treat-ment of paper machine cycle water~ although indubitably this water shows a distinctly different composition.
Example 3.
It had been noticed in the investigations accord-ing to Examples 1 and 2 that the treatment with the acid-activated clay mineral A had shifted the pH value of the treated sample from starting values of 6.0 in both cases to 3.8 (Example 1) and 4.2 (Example 2), respectively.
In view of the highly acid nature of the adsorption agent (Table I), this is not surprising. The other adsorption agents used for comparison, on the other hand, shift the pH value in both examples to values above 7~ It is logical to suspect that the excellent effect of the acid-activated clay mineral is caused by this pH displacement and could be obtained similarly also by combination of an acid with another adsorption agent. To check this assumption, inves-tigations were carried out on another paper mill cycle water with all four of the acid-activated clay minerals listed in Table I. The tests were carried out in the same manner as in Examples 1 and 2. The results are given in Table V.
3~3 Table V. Adsorption of organic substances from paper ~ill cycle water with consideratioh of the pH value.
Adsorption agent pH Total orga~ic carbon TOC
mg.C/liter Decre~se %
Untreated 6.1 220 Acid activated clay ~ineral A 4.0 140 36 Acid activated clay mineral B 7.2 150 32 Acid activated clay mineral C 7.4 150 32 Acid activated clay mineral D 4.1 145 34 Chrysotile asbestos 7.3 165 25 0 Aluminu~ oxide II 7.3 195 11 The results show clearly that the effect of the acid-activated clay mineral is not attributable to a pH
value displacement, since Products B and C, which were acid-activated but neutralized in subsequent processing, gave practically the same effect.
E~
It was to be xamined to what extent the acid-activated clay minerals actually absorb anionic organic substances, which are especially disturbing in papermaking.
The determina~ion of the anionic substances was effected by TOC measurement before and after a treatment of the water with a celL].ulose capable of anion exchange~
The difference G~TOC) indicates the C content of the quan-tity of anionic organic substances contained in the water.
The results are shown in Table VI.
3~
Table VI. Adsorption of anioni~ organic substances from cycle water of the ~echanical wood pulp department.
Adsorption agent pH Total organic carbon, Anionic organic substances, TOC measured on carbon content, mg,C/liter Decrease ~ ~TOC
_ mg.C/liter _ Decrease % __ Untreated 7.7 515 - 260 Acid act. clay A 5.5 310 40 125 52 Acid act. clay B 7.6 330 36 145 44 Chrysotile asb. 7.9 425 18 225 14 Aluminum oxide I 7.9 440 15 230 12 10 Aluminum oxide II 7.6 420 19 240 8 I~ is found that, surprisingly, the acid-activated clay minerals not only do absorb anionic substances, but that they absorb them in much greater measure than the positivély charged adsorption agents.
According to the invention, therefore, manufactur-ing cycle waters or waste waters of ~he papermaking industry and related branches of industry as well as waste waters of similar composition can be freed from disturbinu organic substances by addition of acid-activated clay minerals. The ~0 treatment according to the invention can be effect~d by one or both of the measures stated below:
1. Addition of the adsorption agent to tAle material present in aqueous suspension from which the prodl~ct (paper) is produced. The adsorption agent remains in the product together with the adsorbed organic substance. The water liberated in the production, which is re-used as cycle water or is discharged as waste water, contains fewer organic sub-stances than without addition of the adsorption agent~
The invention relates to an agent and a method for the treatment of production cycle and effluent water of the papermaking and related industries for the purpose of remov-ing dissolved or colloidally dispersed organic substances.
BACKGROUND OF THE IN~EI~TION
The treatment of paper mill water circulations is effected today practically exclusively with sedimentation, flotation, or filtration pulp catchers, in part with the use of chemical flocculation aids.
In view of exceedingly high costs of effluent puri-fication and the atte~pt made for that reason to close the cycle - i.e. to reduce the specific effluent quantity - this procedure is obsolete. Possibilities of purification as pre-viously discussed in the waste water sector should be moved up into the cycle water so as to permit further narrowing of the water circulation and at the same time to reduce the load-ing of the residual waste water.
One of the greatest obstacles to further closin~ of the water circulation in the paper industry is the concentra-tion of dissolved or colloidally dispersed organic subs-ances in the cycle water, which because of their predominantly anionic nature cause considerable production disturbance and loss of product quality. These substances, therefore, should be removed from the cycle water to the extent possible, in order to close the water circulation completely in cases which are regarded to be impossible today. The second pro-blem, i.e. the concentration of the electrolytes, should ke reduced to simply a material problem, since it has been proven that production and product quality are not notably influenced by inorganic electrolytes.
~8~3 DESCRIPTION OF THE PRIOR ART
Solid adsorption agents in powder form have already been used for the treatment of paper mill water circulations.
~or example, the use of alkaline-activated bentonites for this purpose was disclosed in Wochenblatt fur Papierfabrikation, 105, 799-802 (1977). In the treatment of cycle water, how-ever, alkaline-activated bentonites must be added to the water in the form of a suspension and must therefore be re-moved subsequently by sedimentation or flotation. Direct filtration treatment is not possible because of the special properties of the alkaline-activated bentonites.
DE-AS 21 21 198 discloses a method for the recovery of fiber materials and fillers from effluents from the paper industry. According to this method a mixture of (a) swelled layer silicates transformed to the Na, K, NH4 and/or H form in the usu~l way and (b) water-soluble macromolecular com-pounds of filamentary molecule structure reacting with the layer silicates and possibly with the fiber materials and fillers is added to the effluent in a quantity sufficient for the formation of total flock. The formed sludge phase is returned to the papermaking process after separation is completed. This literature reference, therefore, aims at removing solid, undissolved substances from the effluent by flocculation and subsequent filtration, while according to this invention dissolved or colloidally dispersed organic substances are to be removed from the production effluent by adsorption. In the known methods, the use of the macromole-cular compounds of filamentary molecule structure is essen-tial, since without them recovery of fibrous and filler sub-stances by flocculation is not possible. The layer silicate, ~ 3ossibly transformed to the H form, is present in a swelled orm. Due to the mlld acid treatment, the layer structure is still largely preserved. In particular the layer lattice still contains practically the entire aluminum portion.
Accordingly, the sludge phase is contaminated by the macro-molecular compounds of filamentary molecule structures and is suitable only for the filling of paper or board of infer-ior quality. Further the effluent separated from the sludge phase e.g. by filtration still contains most of the dissolved or colloidally dispersed org~nic disturbance substances and therefore is unsuitable as cycle water. J. Weigl teaches in Elektrokinetische Grenzflachenvorgange9 Weinheim, New York:
Verlag-Chemie 1977, 156 - 157 that a specific asbestos type (chrysotile asbestos of high specific surface and positive zeta potential) has good adsorption properties for anionic organic substances.
I~ is also known that positively charged aluminum oxide is a good adsorption agent for anionic organic sub-stances. Industrially, this material is used in granulated form in adsorption towers, the laden adsorbent being regener-ated thermally (cf. Prog.Wat.Tech.10, 1978, ~9-96).
The cited :Literature references appear to suggest that adsorption ag~nts of high specific surface and positive zeta potential should be suitable for the treatment of paper-making cycle waters.
It was found, however, that under indus~rial con-ditions in the treatment of production cycle and effluent waters of the p~permaking and related industries, that the named adsorption agents gave unsatisfactory adsorption results, although in model experiments they had at first proved to be usable. Surprisingly, it was found that acid-activated clay minerals, which generally have a negakive zeta potential, gave in practice, better adsorption results.
SUMMARY OF THE INVE~TION
This invention provides a process for the treatment of process water containing organic waste materials, connected with the production of paper from wood pulp, which comprises the steps of:
A. adding an adsorptive agent, having a negatively charged surface to said process water, said adsorptive agent comprising:
1. an acid-treated silicate-layered clay, having a high surface area of at least 180 m2/gm and a high surface energy and whic~ contains a major portion of the original silicate layer in the form of free silicic acid and a minor portion of the original aluminous constituent of said clay and only residual amounts of the alkali and alkaline earth metals originally present in the clay; and B. separating the adsorptive agent from the process water.
This invention proposes, then, an agent for the treatment of production cycle and effluent waters of the papermaking and related industries for the purpose of re-moving dissolved or colloidally dispersed organic substances.
The agent is a negatively charged acid-treated clay. The clay prior to acid-treatment is of the silicate-layered type which includes the montmorillonite-beidellite series, the chlorite group and minerals with a series disorder, i.e.
mixed layer silicates. Of particular interest in this in-vention are the montmorillonite-beidellite series. The ~ 4 --,~ i silicate-layered clays are treated with acid such as hydro-chloric or sulfuric so that a major portion of the original silicate constituent is converted over to silicon dioxide and free silicic acid. A substantial portion of the original aluminous constituent is leached out by the acid treatment and essentially all of the alkali and alkaline earth metal constituents are removed by the treatment. The treatrnent is such that the original clay loses much of its original proper-ties and the silicate layer is converted over to a silicon dioxide layer containing a substantial amount of free silicic acid. The finished product has a high specific surface area of at least 180 m2/gm and more preferably a surface area in the range of 240-360 m2/gm. The surface has a 1early negative zeta potential and a high surface energy.
The finished product contains the siliceous constituent in the range of 60-75% by weight expressed a SiO2.
~a -., . , ) i3 The aluminous cons~ituent is present in the range of from 5-20~ expressed as A12O3 and the remainder consists essen-tially of compounds of iron, magnesium, and calciu~ in various proportions. The alkali and alkaline earth metal constituents are essentially completely removed by the acid -treatment. Only residual traces remain. The micro-pore volume of the pores having a pore diameter of <800A
is at least 0.3 ml/gm. The negatively charged acid-treated clay, having lost its original properties is added to the process water at one of two different points. The materials can be added to the water containing the pulp in suspension - so that upon separation of the pulp from the water the adsorptive agent, laden with the organic waste materials, remains with the pulp as a filler. The organic waste materials, which are either dissolved or colloidally dis-persed, include proteins, humic acids, lignins, synthetic retention aids, emulsifiers, dyes, and the like. In another embodiment of this invention, the adsorptive agen~s can be added to process water or to waste water prior to their discharge from the process cycle, and the adsorptive agent, after the proper processing time, is filtered from the water, which is then either recycled back to the process cycle or is discharged as essentially purified waste water.
The filter cake then can be collected and used as a filler in subsequent batches of paper or paper board.
DESCRIPTION OF THE PREFERRED EMBODI~NT
~ . . _ . . . . _ Acid-activated clay minerals are, per se, known as adsorption agents. Clay minerals belong to different structure types. Clay minerals of the kaolinite structure type are for example kaolinite, nacrite, dickite, anauxite and halloysite, as well as the serpentine minerals chrysotile, serpentine, antigorite and amesite. Another structure type comprises the mica-]ike layer silicates, which in turn are divided into minerals of the montmorillonite-beidellite series, vermiculate serles, illite series, and the mica minerals.
Especially important for the present purpose are the minerals of the montmorillonite-beidellite series. Suitable further are minerals of the chlorite group and minerals with species disorder (mixed layer silicates). A general summary of these clay minerals is found in "Ullmanns Encyklopadie der technis-chen Chemie", volume 17 ~1966), pages 583 to 597. The acid activation of these clay minerals is generally effected by treatment with hydrochloric or sulfuric acid. This treatment dissolves out the alkali and/or the alkaline earth component practically completely and also dissolves a large part, (pre-ferably at least 20 wt.%) of the aluminum and lron portion present in the octahedral layer of the mineral. There remains a product consisting predominantly of SiO2 with a high specific surface of at least 180 m2/g, (preferably 240 to 360 m2/g) a clearly negative zeta potential and a high surface energy.
Essentially, this product has lost the specific properties of the clay mineral employed as starting product. The silicic acid in the product consists in large part of free silicic acid soluble in weak alkali solution. The product has a micropore volume (800A) of a-t least 0.3 ml/g.
Acid activation of these clay materials is well known and suitable acid-activated clays have been described by the following: Carl-Ernst Hofstadt, et al, in U. S. Patent 3,901,826; Grant A Mickelson, et al, in U. S. Patent 2,981,697 (corresponding to German Patent 1,173,442); L. ~larbort, in U. S. Patent 3,293,060; Carl J. ~alble, in U. S. Patent ~b 3,557,023; L. Sugahara, in U. S. Patent 3,915,731 (corres-ponding to German patent 2,203,825); and Y. Sugahara, in U. S. Patent 3,787,330.
The especially good effect of the acid-activated clay minerals in the treatment of paper manufacture cycle waters is surprising because the properties of ~hese products in comparison to those mentioned before did not suggest such an effect. Due to their swelling power and the resulting special layered structure with possible formation of em-bedded compounds and special charge distribution at the crystalflakes (planes charged negatively, edges positively), alkaline-activated bentonites are known to be able to also adsorb negatively charged organic compounds. Clearly, however, the adsorption of positively charged compounds is preferred.
The above-named products chrysotile asbestos and aluminum oxide prove effective in the treatment of paper production cycle waters only if their zeta potential is positive at the prevailing pH value in the cycle water.
Evidently, there is a connection between the surface charge of the adsorbent and the charge of the organic substances to be adsorbed.
The acid-activated clay minerals of the invention, on the other hand, are employed in known applications for the treatment of vegetable oils and mineral oils, i.e. in a purely organic medium, while in aqueous medium they are employed only for the removal of positively charged proteins from bever-ages, mainly beer. The mechanism for the excellent adsorption -according to the present invention, i.e. adsorption of pre-dominantly negatively charged organic substances from aqueous paper mill circulation on negatively charged surface of the acid-activated clay minerals - is not fully understood.
The adsorbed organic substances, according to the invention which are either dissolved or colloidally dispersed "
~ 3 comprise, for example, proteins, humic acids, lignins, synthetic retention aids, emulsifiers, dyes, and the like.
The preferred agents according to the invention are acid-activated clay minerals of the montmorillonite ~ype.
The method according to the invention is carried out preferably by adding the acid-activated clay minerals to the mixture of substances present in aqueous suspension in the process water.
According to owr embodiment of this invention, the laden agent obtained in the treatment of the manufacturing cycle or effluent water is reused as a filler substance. This offers the rare case of a purification measure without the form-ation of solid waste materials which would have to be eliminated.
The efficacy of the agents of the invention and a comparison thereof with agents otherwise usable for such treatments is explained in the following examples in a non-~imiting manner. In Table I below, the properties of the agents used in the experiments are compared. The acid-acti-vated clay minera:Ls A to D according to the invention generally had a SiO2 content of about 66 to 72 wt.%, an A12O3 content of about 12 to 15 wt.%, and a loss on ignition of about 6 to 10 wt.%. The balance consisted essentially of Fe, Mg and Ca in varying amounts. The products A to D differ from one another essentially by their mean grain diameter and by the pH value. They were obtained by acid digestion of a calcium bentonite from the Moosburg area.
The comparison substances are generally commercial products. The chrysotile asbestos is of the HBB type; the two aluminum oxide types I and II differ primarily by their specific surface; the alkaline-activated bentonite is sold by Sud Chemie AG under the trademark "TIXOTON".
Table I. Properties of the test products.
Adsorption agent Spec. Mean Zeta potential mV Pore pH of the surface grainvol. 1% aqueous (BET) dia. pH SpH 7 1~ Hg/g suspension m /g /um Acid act. clay mineral A 260 2.5 -22 ~27 1.63 3.4 Acid act. clay mineral B 260 2.5 7.4 Acid act. clay mineral C 260 2.5 7.8 Acid act. clay mineral D 240 3.5 Chrysotile asbestos 55 - +32 +45 1.76 9.3 Aluminum oxide I 266 - +12 ~12 2.29 9.2 0 Aluminum oxide II 117 - +25 +20 0.67 5.1 Alkaline act. bentonite 46 * -20 -22 0.64 10.1 *Screen residue on 45 micron ~0.1%
The adsoprtion capacity of the substances listed on Table I was tested at first on lignin sulonic acid as model substance for anionic organic substances. Specifi-cally there was used as model ~ubstance calcium lignin suf-fonate, purified, mean molecular weight about 10,000. The adsorption measurements were made on solutions containing 50 mg~lignin sulfonat~ per liter of tap water and wi~h an ad~lltion of 1.0 g,adsorption agent per liter of solution.
Th~ contact time was 30 minutes; the separation was effected by centrifuging. The results are summarized in Table II~
.
Tal~,le II. Adsorption of lignin sulfonate.
Adsorption agentAdsorption in %, referred to the con-centration of the untreated solution Acid activated clay mineral A 5.4 Acid activatel clay mineral D 8.0 Chryfiotile asbestos 58~7 Aluminum oxide I 44.0 Aluminum oxide II 86.0 30 Alkaline activated bentonite 7.1 _g _ The results show clearly ~hac the anionic organic subs~ance can be ef~ectively adsorbed only by products with a positive surface charge. This is as expected.
However, as will be shown in the following examples, the manufacturing cycle waters occurring in industrial prac-tice surprisingly behave differently from the model substance lignin sulfonate.
Example__ In this example the adsorption of organlc substances from the cycle water of a paper mill is set forth, the con-tent of organic subs~ance being expressed by the Total Organic Carbon TOC in mg.C per liter. Corresponding results are found wi~h the use o~ other parameters for the contam-ination of water by organic substance, as for example chemi-cal oxygen requirement COR and biochemical oxygen require-ment BOR.
The results of th investigations are given in Table III.
Table III. Adsorption of organic substances from paper mill cycle water.
20 Adsorption agent Total organic carbon, TOC
_ _ mg.C/liter Decrease %
Untreated 210 Acid activated clay mineral A 80 62 Chrysotile asbestos 180 14 Aluminum oxide I 160 24 Aluminum oxide II 200 5 Alkaline-activated bentonite 140 13 For each of the measurements 1 liter of cycle water was treated with 10 g of the adsorption agen~ to be tested.
In each case the adsorption agent was pre-swelled ~or 2 ~ 3 hours with a little water, as the adsorption agents used are in part dependent in their action on the degree of preswelling. After addition of the preswelled adsorption agent, the cycle water was stirred wlth a vane agitator for 30 minutes, and then filtered through a glass fiber filter. The comparison sample (untreated) was likewise filtered through a glassfiber filter before the measure-ment.
With this type of treàtment, a large excess of adsorption agent is added to the water, so ~hat to some extent ~he maximum possible adsorption output for execu-tion of a one-stage ~reatment is measured.
The results clearly show that, contrary to expec-tation, the acid-activated clay mineral gives the best adsorption effect.
Example 2 In this example, the same investigations as in Example 1 were carried out on the cycle water of a plant for the production of mechanical wood pulp used as fiber material in papermaking. In such a plant, wood is de-fibered with addition of plenty of water, considerable portions of organic ~ubstances being released. As the resulting fiber paste is transferred to papermaking with a solids content of between 2 and lOV/o, depending on the technology, considerable amounts of the released organic substances get into the paper machine cycle.
The treatmen~s are carried out in analogy to Example 1. The results are given in Table IV.
Tab].e IV. Adsorption of organic substances from cycle water of the mechanical wood plllp department.
Adsorption agent Total organic carbon, TOC
m~C/lite~ Decrease %
. ., Untreated 510 Acid-activated clay mineral A 290 43 Chrysotile asb~stos 450 12 Aluminum oxide I 450 12 Aluminum oxide II 430 16 Alkaline-activated bentonite 410 20 _ .
Exactly the same result i5 found as in the treat-ment of paper machine cycle water~ although indubitably this water shows a distinctly different composition.
Example 3.
It had been noticed in the investigations accord-ing to Examples 1 and 2 that the treatment with the acid-activated clay mineral A had shifted the pH value of the treated sample from starting values of 6.0 in both cases to 3.8 (Example 1) and 4.2 (Example 2), respectively.
In view of the highly acid nature of the adsorption agent (Table I), this is not surprising. The other adsorption agents used for comparison, on the other hand, shift the pH value in both examples to values above 7~ It is logical to suspect that the excellent effect of the acid-activated clay mineral is caused by this pH displacement and could be obtained similarly also by combination of an acid with another adsorption agent. To check this assumption, inves-tigations were carried out on another paper mill cycle water with all four of the acid-activated clay minerals listed in Table I. The tests were carried out in the same manner as in Examples 1 and 2. The results are given in Table V.
3~3 Table V. Adsorption of organic substances from paper ~ill cycle water with consideratioh of the pH value.
Adsorption agent pH Total orga~ic carbon TOC
mg.C/liter Decre~se %
Untreated 6.1 220 Acid activated clay ~ineral A 4.0 140 36 Acid activated clay mineral B 7.2 150 32 Acid activated clay mineral C 7.4 150 32 Acid activated clay mineral D 4.1 145 34 Chrysotile asbestos 7.3 165 25 0 Aluminu~ oxide II 7.3 195 11 The results show clearly that the effect of the acid-activated clay mineral is not attributable to a pH
value displacement, since Products B and C, which were acid-activated but neutralized in subsequent processing, gave practically the same effect.
E~
It was to be xamined to what extent the acid-activated clay minerals actually absorb anionic organic substances, which are especially disturbing in papermaking.
The determina~ion of the anionic substances was effected by TOC measurement before and after a treatment of the water with a celL].ulose capable of anion exchange~
The difference G~TOC) indicates the C content of the quan-tity of anionic organic substances contained in the water.
The results are shown in Table VI.
3~
Table VI. Adsorption of anioni~ organic substances from cycle water of the ~echanical wood pulp department.
Adsorption agent pH Total organic carbon, Anionic organic substances, TOC measured on carbon content, mg,C/liter Decrease ~ ~TOC
_ mg.C/liter _ Decrease % __ Untreated 7.7 515 - 260 Acid act. clay A 5.5 310 40 125 52 Acid act. clay B 7.6 330 36 145 44 Chrysotile asb. 7.9 425 18 225 14 Aluminum oxide I 7.9 440 15 230 12 10 Aluminum oxide II 7.6 420 19 240 8 I~ is found that, surprisingly, the acid-activated clay minerals not only do absorb anionic substances, but that they absorb them in much greater measure than the positivély charged adsorption agents.
According to the invention, therefore, manufactur-ing cycle waters or waste waters of ~he papermaking industry and related branches of industry as well as waste waters of similar composition can be freed from disturbinu organic substances by addition of acid-activated clay minerals. The ~0 treatment according to the invention can be effect~d by one or both of the measures stated below:
1. Addition of the adsorption agent to tAle material present in aqueous suspension from which the prodl~ct (paper) is produced. The adsorption agent remains in the product together with the adsorbed organic substance. The water liberated in the production, which is re-used as cycle water or is discharged as waste water, contains fewer organic sub-stances than without addition of the adsorption agent~
2. Treatment of the water liberated in the produc-tion, which is returned as cycle water or discharged as waste water, with the adsorption agent. Here the treatment is effected preferably in a con~inuous filtration process, in which an additional treatment step for the separation of the laden adsorption agent is obvia~ed. The laden adsorp-tion agent can be added as filler to the product produced or to another product produced in the same or an adjacent operation.
The method is characterized by ex~remely simple technical feasibility, low cost of technical means for its execution, and an ecologically beneficial treatment process without occurrence of solid waste materia~s and free of other polluting emissions.
The method is characterized by ex~remely simple technical feasibility, low cost of technical means for its execution, and an ecologically beneficial treatment process without occurrence of solid waste materia~s and free of other polluting emissions.
Claims (14)
EXCLUSIVE PROPERTY OR PRIVILEGE IS CLAIMED ARE
DEFINED AS FOLLOWS:
1. A process for the treatment of process water containing organic waste materials, connected with the production of paper from wood pulp, which comprises the steps of:
A. adding an adsorptive agent, having a negatively charged surface to said process water, said adsorptive agent comprising:
1. an acid-treated silicate-layered clay, having a high surface area of at least 180 m2/gm and a high surface energy and which contains a major portion of the original silicate layer in the form of free silicic acid and a minor portion of the original aluminous constituent of said clay and only residual amounts of the alkali and alkaline earth metals originally present in the clay; and B. separating the adsorptive agent from the process water.
2. A process for treatment of process water, as defined in Claim 1, in which the separated process water is returned to the process cycle.
3. A process for the treatment of process water, as defined in Claim l, in which the separated process water is dis-charged as waste water effluent from the system.
4. A process, a defined in Claim 1, in which:
A. said process water contains wood pulp in aqueous suspension; and B. the adsorptive agent laden with organic waste matter remains with the wood pulp upon separation of the water therefrom.
A. said process water contains wood pulp in aqueous suspension; and B. the adsorptive agent laden with organic waste matter remains with the wood pulp upon separation of the water therefrom.
5. A process, as defined in Claim 4, the improvement of adding an adsorptive agent, having a negatively charged surface to said separated process water, said adsorptive agent comprising:
A. an acid-treated silicate-layered clay, having a high surface area of at least 180 m2/gm and a high surface energy and which contains a major portion of the original silicate layer in the form of free silicic acid and a minor portion of the original aluminous constituent of said clay and only residual amounts of the alkali and alkaline earth metals, originally present in said clay;
B. the further step of filtering the adsorptive agent from said process water; and C. thereafter collecting the filtered adsorptive agent laden with organic waste materials, as a filler for use in the production of a subsequent batch of paper.
A. an acid-treated silicate-layered clay, having a high surface area of at least 180 m2/gm and a high surface energy and which contains a major portion of the original silicate layer in the form of free silicic acid and a minor portion of the original aluminous constituent of said clay and only residual amounts of the alkali and alkaline earth metals, originally present in said clay;
B. the further step of filtering the adsorptive agent from said process water; and C. thereafter collecting the filtered adsorptive agent laden with organic waste materials, as a filler for use in the production of a subsequent batch of paper.
6. A process, as defined in Claim 5, in which said filtered process water is returned to the process cycle of producing the paper pulp.
7. A process, as defined in Claim 5, in which the filtered process is discharged as waste effluent.
8. A process, as defined in Claim 1, in which said adsorptive agent has a negative zeta potential.
9. A process, as defined in Claim 1, in which said adsorptive agent contains micropores and in which the pore volume of micropores having a pore diameter >800.ANG. is at least 0.3 ml/gm.
10. A process, as defined in Claim 1, in which the acid clay is of the montmorillonite type.
11. A process, as defined in Claim 1, in which:
A. said siliceous constituent is present in the range of from 60-75% by weight, expressed as SiO2;
B. the aluminous constituent is present in the range of from 5-20%, expressed as Al2O3; and C. the remainder consists essentially of compounds of iron, magnesium and calcium in various quantities.
A. said siliceous constituent is present in the range of from 60-75% by weight, expressed as SiO2;
B. the aluminous constituent is present in the range of from 5-20%, expressed as Al2O3; and C. the remainder consists essentially of compounds of iron, magnesium and calcium in various quantities.
12. A process, as defined in Claim 5, in which said adsorptive agent contains micropores in which the pore volume of the pores having a pore diameter >800.ANG. is at least 0.3 ml/gm.
13. A process, as defined in Claim 5, in which the acid-treated clay is of the montmorillonite type.
14. A process, as defined in Claim 5, in which:
A. the silicate constituent of the acid-treated clay is present in the range of from 60-75% by weight, expressed as SiO2;
B. the aluminous constituent is present in the range of from 5-20%, expressed as Al2O3; and C. the remainder consists essentially of compounds of iron, magnesium and calcium in various quantities.
A. the silicate constituent of the acid-treated clay is present in the range of from 60-75% by weight, expressed as SiO2;
B. the aluminous constituent is present in the range of from 5-20%, expressed as Al2O3; and C. the remainder consists essentially of compounds of iron, magnesium and calcium in various quantities.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3026403A DE3026403C2 (en) | 1980-07-11 | 1980-07-11 | Means and processes for the treatment of manufacturing cycle water and waste water from the paper producing and allied industries |
| DEP3026403 | 1980-07-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1184853A true CA1184853A (en) | 1985-04-02 |
Family
ID=6107003
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000381497A Expired CA1184853A (en) | 1980-07-11 | 1981-07-10 | Agent and method for the treatment of production cycle and effluent water of the papermaking and related industries |
Country Status (10)
| Country | Link |
|---|---|
| EP (1) | EP0044058B1 (en) |
| JP (1) | JPS5753238A (en) |
| AT (1) | ATE6418T1 (en) |
| BR (1) | BR8104437A (en) |
| CA (1) | CA1184853A (en) |
| DE (2) | DE3026403C2 (en) |
| DK (1) | DK306181A (en) |
| ES (1) | ES503707A0 (en) |
| FI (1) | FI78056C (en) |
| MX (1) | MX158614A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| YU45903B (en) * | 1984-07-23 | 1992-09-07 | Smolčić, Vladislav | PROCEDURE FOR TREATMENT OF COLORED WASTEWATER |
| JPS6170097A (en) * | 1984-09-13 | 1986-04-10 | 水澤化学工業株式会社 | Filler for paper |
| DE4200479A1 (en) * | 1991-01-11 | 1992-07-16 | Sued Chemie Ag | Compsn. for cleaning heavily loaded esp. coloured waste water - contg. acid activated clay material, salt of aluminium or iron, lignite dust, calcium carbonate and opt. calcium hydroxide |
| AT401927B (en) * | 1993-10-08 | 1996-12-27 | Garuda Consulting & Holding Gm | Process for cleaning up works wastewaters from organic matter dissolved therein, in particular starch or wood pulp |
| IT1270118B (en) * | 1994-10-04 | 1997-04-28 | Italtraco Srl | COMPOSITION FOR THE TREATMENT OF POLAR WASTE CONTAINING COLLOIDAL DISPERSIONS CONSTITUTED BY SOLVED PARTICLES AND PROCEDURE FOR THE REMOVAL OF THESE SUBSTANCES USING THIS COMPOSITION |
| GB9623337D0 (en) | 1996-11-08 | 1997-01-08 | Markessinis Andreas | Water treatment process |
| US5883035A (en) * | 1997-11-05 | 1999-03-16 | Engelhard Corporation | Mesoporous silicoaluminate products and production thereof by controlled acid extraction of aluminum from calcium bentonite clay |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE258152C (en) * | ||||
| HU168869B (en) * | 1971-02-22 | 1976-07-28 | ||
| ES398161A1 (en) * | 1971-12-20 | 1974-08-16 | Vian Ortuno | Procedure for conditioning the wastewater of the manufacture of cellulosic pastes by alkaline method. (Machine-translation by Google Translate, not legally binding) |
| JPS4927380A (en) * | 1972-07-08 | 1974-03-11 | ||
| DE2300305A1 (en) * | 1973-01-04 | 1974-07-11 | Hans Heidenreich | Waste water treatment - by addn. of medium produced by reaction of hydrohalic acids with ternary clay minerals |
| JPS49128886A (en) * | 1973-04-17 | 1974-12-10 | ||
| GB1484671A (en) * | 1973-11-16 | 1977-09-01 | Alcan Res & Dev | Composition for treatment of waste waters and process for making same |
| DE2436498A1 (en) * | 1974-07-29 | 1976-02-12 | Karl Heinz Hartkorn | OXIDATION AND ADSORPTION PROCESS FOR THE REMOVAL OF INTERFERING SUBSTANCES IN LIQUIDS |
| FI752346A (en) * | 1974-09-13 | 1976-03-14 | Ciba Geigy Ag | |
| FR2359076A1 (en) * | 1976-07-22 | 1978-02-17 | Ouest Union Chimique Indle | Purificn. of aq. effluents e.g. contg. detergents esp. poly:amine(s) - by passing through cationic exchange resin or silicate |
| DE2727052C2 (en) * | 1977-06-15 | 1979-07-12 | Sued-Chemie Ag, 8000 Muenchen | Process for purifying high solids clay suspensions |
| DE2727053C2 (en) * | 1977-06-15 | 1982-11-25 | Süd-Chemie AG, 8000 München | Adsorptive silicate agent for binding alkaline earth ions |
-
1980
- 1980-07-11 DE DE3026403A patent/DE3026403C2/en not_active Expired
-
1981
- 1981-07-06 ES ES503707A patent/ES503707A0/en active Granted
- 1981-07-10 FI FI812184A patent/FI78056C/en not_active IP Right Cessation
- 1981-07-10 JP JP56107192A patent/JPS5753238A/en active Pending
- 1981-07-10 DK DK306181A patent/DK306181A/en unknown
- 1981-07-10 BR BR8104437A patent/BR8104437A/en unknown
- 1981-07-10 CA CA000381497A patent/CA1184853A/en not_active Expired
- 1981-07-11 EP EP81105422A patent/EP0044058B1/en not_active Expired
- 1981-07-11 AT AT81105422T patent/ATE6418T1/en not_active IP Right Cessation
- 1981-07-11 DE DE8181105422T patent/DE3162431D1/en not_active Expired
- 1981-07-13 MX MX188276A patent/MX158614A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DK306181A (en) | 1982-01-12 |
| DE3026403C2 (en) | 1982-07-01 |
| DE3162431D1 (en) | 1984-04-05 |
| MX158614A (en) | 1989-02-20 |
| EP0044058A1 (en) | 1982-01-20 |
| FI78056B (en) | 1989-02-28 |
| FI78056C (en) | 1989-06-12 |
| ES8205284A1 (en) | 1982-06-01 |
| JPS5753238A (en) | 1982-03-30 |
| BR8104437A (en) | 1982-03-30 |
| EP0044058B1 (en) | 1984-02-29 |
| ATE6418T1 (en) | 1984-03-15 |
| ES503707A0 (en) | 1982-06-01 |
| FI812184L (en) | 1982-01-12 |
| DE3026403A1 (en) | 1982-02-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Sanghi et al. | Review on decolorisation of aqueous dye solutions by low cost adsorbents | |
| US4415467A (en) | Agent for the purification of waste waters and process for its production | |
| CA2015256C (en) | Process for making acid activated bleaching earth using high susceptibility source clay and novel bleaching earth product | |
| Ugurlu et al. | Removal of phenolic and lignin compounds from bleached kraft mill effluent by fly ash and sepiolite | |
| CA2639513A1 (en) | Modified biogenic silica and method for purifying a liquid | |
| Li et al. | Cationic polyelectrolyte/bentonite prepared by ultrasonic technique and its use as adsorbent for Reactive Blue K-GL dye | |
| EP0228305B1 (en) | Process for acid treating clay for improved filtration | |
| Nwabanne et al. | Comparative study of lead (II) removal from aqueous solution using different adsorbents | |
| CN106554039A (en) | A kind of wastewater purificant and its preparation method and application | |
| CA1184853A (en) | Agent and method for the treatment of production cycle and effluent water of the papermaking and related industries | |
| CN110775985A (en) | Process for synthesizing analcite from red mud by hydrothermal alkaline method | |
| CN104001479A (en) | Inorganic mineral water treatment agent and preparation method thereof | |
| CN113244879B (en) | Application of iron phosphate microspheres in treatment of wastewater containing methylene blue | |
| Obiageli | ADSROPTION OF CATIONIC DYE ONTO LOW-COST ADSORBENT SYNTHESIZED FROM BENTONITE CLAY Part I. KINETIC AND THERMODYNAMIC STUDIES. | |
| JP2683225B2 (en) | Method for producing activated carbon and method for using the activated carbon for water treatment | |
| JPH0342096A (en) | Method for removing phosphate ion and sulfate ion in water | |
| US5043081A (en) | Method of chemically fixing liquid aqueous sludge by means of a pozzolanic reaction | |
| Bazrafshan et al. | Equilibrium and thermodynamics studies for decolorization of reactive black 5 by adsorption onto acid modified banana leaf ash | |
| JPH06279011A (en) | Expandable graphite composition for absorbing liquid and production thereof | |
| JP3766318B2 (en) | Method for producing porous material | |
| US3944687A (en) | Method of preparing purifying agents consisting of activated siliceous porous mineral substances | |
| JPH105750A (en) | Method of removing dye in dyeing waste liquor and dye removing agent | |
| US2903434A (en) | Decolorizing clays | |
| CN100366547C (en) | Production of water-purifying agent for papermaking sewage | |
| US1838621A (en) | Solid silicic acid containing bleaching agents and process of making the same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |