KR20150033327A - Production and application of sodium salt of naphthalene sulfonate polymerized with formaldehyde compound as a flocculating and dehydrating aid - Google Patents

Abstract

The present invention provides a reticulated structure of naphthalenesulfonic acid-formalin polymer exhibiting high coagulation assistant efficiency in a low residual monomer, wherein the molar ratio of the naphthalenesulfonic acid-formalin polymer is controlled by controlling the molar ratio and the remaining monomer is stabilized by using organic acid and hydrogen peroxide The monomers were minimized and the amount of sodium hydroxide and potassium hydroxide in the neutralization process was controlled to produce a network structure suitable for use as a dehydrating aid.

Description

Preparation and application of coagulation and dehydration auxiliaries using naphthalenesulfonic acid-formaldehyde polymer (Preparation and application of sodium salt of naphthalene sulfonate polymerized with formaldehyde compound as a flocculating and dehydrating aid)

The present invention relates to the preparation and application of coagulation and dehydration auxiliaries using naphthalenesulfonic acid-formalin polymers and more particularly to the use of naphthalene and naphthalene as residual coagulants to utilize well-known naphthalenesulfonic acid- A method of producing a naphthalenesulfonic acid-formalin polymer in a form containing a small amount of residual monomer by removing formalin and a method of producing a sludge having a viscosity in a sludge itself such as a highly concentrated sludge and an excess sludge in a sludge, , Food and waste wastewater due to its own acid fermentation process, it does not have surface charge among the sludge and sludge which have low pH and high specificity, so there is no charge that can be combined with the flocculant in the general flocculation process, Like bad sludge In order to prevent the aggregation and dehydration efficiency from being deteriorated by this special situation factor, the naphthalenesulfonic acid-formalin polymer polymerized by the technique of the present invention is utilized to improve the efficiency.

A conventional technique for producing naphthalenesulfonic acid-formalin polymer and a technique for using the same are disclosed in JP-A-52-932, which discloses a technique for polymerizing and polymerizing naphthalenesulfonic acid and formalin. Japanese Patent Application Laid- 58-84160 discloses a technique of polymerizing alkylnaphthalenesulfonic acid and formalin, and JP-A-55-71656 discloses a technique in which naphthalene and alkylnaphthalene are sulfonated and then polymerized with formalin have.

The role of naphthalenesulfonic acid-formalin polymer in this conventional technique is that the ion is converted into anion and calcium cation of sulfonic acid in the polymer in water and exhibits a strong anionic activity. The naphthalenesulfonic acid-formalin polymer adsorbs on the surface of the particles and electrostatically repels and disperses And it plays a role of securing fluidity and separating water and air from each other to improve its fluidity. The functional groups applicable to this role are highly hydrophilic functional groups such as sulfonic acid group (-SO ₃ H), sulfuric acid ester group (-OSO ₃ H) and amine group (-NH ₂ ).

In Korea, a new copolymer obtained by copolymerizing a naphthalenesulfonic acid-formalin polymer with a saccharide or an oxide thereof in a Korean patent 10-0055392 patent of Ssangyong Cement Co., Ltd. is used to further reduce slump loss and improve workability, A novel copolymer has been developed which improves strength without adversely affecting physical properties such as coagulation, hardening and strength even when added in an excessive amount.

The preparation process is to convert sulfonated naphthalene into sulfonated naphthalene through the sulfonation reaction as shown in the chemical reaction formula 1 by adding sulfuric acid to the naphthalene and convert it into a structure capable of polymerization by injecting formalin (HCHO) into naphthalenesulfonic acid as shown in the chemical reaction formula 2, n is about 6 to 20.

[Sulfonation reaction of naphthalene]

[Condensation reaction of naphthalenesulfonic acid with formalin]

In this process, formalin is excessively injected and therefore remains in the process, which indicates a limitation in application to sludge treatment. The chemical reaction formula 3 is formed through a neutralization process in the form of a single chain structure or a network structure.

[Formation of chain structure by neutralization process]

However, most of these conventional techniques are limited to techniques for improving the efficiency as a fluidizing agent by adding other chemicals during the production of naphthalenesulfonic acid-formalin polymer, and the naphthalene-based polymer thus prepared is used as a flocculant It has a problem such as a high content of residual monomers and there is a limitation in coagulating the cohesive flock when it is structurally chain type when it is applied as a dehydrating auxiliary agent. Dialogue is easy.

Japanese Patent Laid-Open Publication No. 52-932 Japanese Patent Laid-Open Publication No. 58-84160 Japanese Patent Application Laid-Open No. 55-71656 Korean Patent Registration 10-0055392

Accordingly, it is an object of the present invention to overcome the above-mentioned problems and provide a method of manufacturing and applying coagulation and dehydration aids using naphthalenesulfonic acid-formalin polymer.

Accordingly, the inventors of the present invention have made efforts to solve the above-mentioned problems, and as a result, they have found that a method for minimizing formalin, which is a residual monomer in the preparation thereof, and a method for imparting functionality capable of coordinating flocs during agglomeration, It is possible to minimize the monomers by controlling the molar ratio during condensation and exhausting the residual monomers by using organic acid and hydrogen peroxide, and by adjusting the amount of sodium hydroxide and potassium hydroxide in the neutralization process, Lt; / RTI >

According to the manufacturing method of the present invention, it is possible to manufacture a reticulated structure exhibiting high coagulation assist efficiency in a low residual monomer by complementing the disadvantage that improvement in cohesion efficiency due to high environmental properties and chain structure due to high residual monomers when using existing products is insufficient can do.

The naphthalenesulfonic acid-formalin polymer produced by the present invention has an ionic cross-linking between a reticular structure having an anionic group and a polymer flocculant, so that flocculation and sedimentation efficiency can be improved with respect to sludge which is difficult to coagulate and dehydrate as a general flocculant, In particular, it is possible to reduce the processing cost by improving the compaction property.

Fig. 1 shows the results of experiments in which pH was adjusted to 4.55, 5.61 and 6.63 from the upper left in the photograph, and 7.58, 8.60 and 10.02 from the lower left.
FIG. 2 shows the pH of the wastewater after flocculation (pH 4.55, 5.61, and 6.63 from the upper left in the photograph) and 7.58, 8.60 and 10.02 As shown in Fig.

Hereinafter, the present invention will be described in detail.

In order to minimize the monomeric naphthalene and formalin in the preparation of coagulation and dehydration auxiliaries using the naphthalenesulfonic acid-formalin polymer of the present invention, formalin is excessively added during the condensation reaction of naphthalenesulfonic acid and formalin so that naphthalene can be minimized during the condensation reaction The amount of formalin added is in the range of 1.1 to 1.2 mol, preferably 10 to 20%, so that the conversion to naphthalenesulfonic acid is maximized to not less than 99.9%. As a result, the reaction of naphthalene The residual concentration can be minimized, but with the opposite effect, residual formalin remains.

The remaining formalin is added with sulfuric acid to adjust the pH to 4 ~ 5 and then the ascobic acid, which is an organic acid as a reducing agent, is added to the residual formalin at a molar ratio to react the unstable structure of the ascorbic acid in aqueous solution with the formalin Ferric chloride (FeCl ₃ ) and hydrogen peroxide (H ₂ O ₂ ) are also added at a molar ratio to remove them by conversion to formic acid (HCOOH).

The residual amount after the reaction can be removed to 0.05% or less, and the amount of the above-mentioned reagents for reducing the residual monomer is not specified, but it is preferably adjusted to 3 to 5 times by the molar ratio, So that the influence of the residual monomer can be minimized.

When the amount of the ascorbic acid used in the monomer consumption process is in the range of 1 mol%, the removal rate is less than 1 mol%. If the amount of the ascorbic acid is less than 3 mol%, an unnecessary amount is added to decrease the economical efficiency. In the case of ferric chloride and hydrogen peroxide The same phenomenon appears.

In particular, when the hydrogen peroxide solution is added in excess, the OH radical reacts with the structure itself to cause a change over time, so that the amount is preferably less than 1 mol%.

The structure of the naphthalenesulfonic acid-formalin polymer can be prepared as a crosslinked structure of the formula (2) and a reticular structure of the formula (3) by controlling the amount and the reaction amount of sodium hydroxide and calcium hydroxide in the neutralization step after the condensation reaction.

In the case of the linear structure, there is a limit in the cross-linking action of the polymer coagulant and the coagulation reaction with each other. However, since the coagulation structure itself is formed in the form of a network in the coagulation process in the form of a network, The dehydration efficiency can be improved.

When the amount of sodium hydroxide required for neutralization of the sulfonic acid in the structure is 100%, except for the amount of the neutralizing agent to remove residual sulfuric acid during the condensation reaction, 10 to 90% of sodium hydroxide is firstly added The neutralization reaction of the linear structure is terminated by substituting sodium (Na) in some sulfonic acid groups in the linear structure, and the remaining amount of calcium hydroxide is added to introduce crosslinked structures through crosslinking with divalent ions And a neutralizing agent which is added while adjusting the charging ratio of sodium hydroxide and calcium hydroxide as neutralizers is sequentially changed to be added, thereby making the structure as a network-like structure having a complex structure as shown in Formula (3).

In the characteristics of the structure, crosslinking type rather than linear type, and reticular type rather than crosslinking type are more effective as coagulation assistant, but naphthalenesulfonic acid-formalin polymer can be used as coagulation and dehydration auxiliary irrespective of its structure.

[Linear structure of naphthalenesulfonic acid-formalin polymer]

[Example of crosslinked structure of naphthalenesulfonic acid-formalin polymer]

[Example of a reticular structure of naphthalenesulfonic acid-formalin polymer]

The physical properties of the naphthalenesulfonic acid-formalin polymer prepared from the network-like low monomer structure as described above can be changed according to the preparation process. Therefore, the solid content of the naphthalenesulfonic acid-formalin polymer is about 35 to 45% , The optimum viscosity is in the range of 150 to 250 cps, the pH is in the range of 7 to 10 in 1% aqueous solution, and the specific gravity is in the range of 1.10 to 1.25 Lt; / RTI >

As described above, the present invention can impart eco-friendliness and functionality to a naphthalenesulfonic acid-formalin polymer by reducing the residual monomer and making it into a reticular structure. When the new structure manufactured according to the present invention is used to coagulate the wastewater and sludge in general and there is no surface charge of the particulate pollutants therein, the concentration of the sludge is high or the sludge particles have a mucus component, Can be used for the preparation of coagulation and dehydration auxiliaries which can be applied to wastewater treatment wastewater and sludge such as wastewater which causes an abnormal aggregation form, and solid-liquid separation, concentration and dehydration processes of various wastewater and sludge.

The method of applying the network-type naphthalenesulfonic acid-formaldehyde polymer of the present invention as an adjuvant may be applied before the coagulation process by a pretreatment method such as the other coagulation and dehydration aid, but it is more effective to treat the coagulation agent after the addition of the coagulant. The coagulant aid of the present invention optimizes the efficiency while neutralizing the viscosity and the charge remaining by the coagulant, and unlike other coagulants, a post treatment method can be easily applied.

The use of naphthalenesulfonic acid-formalin polymer produced by the present invention as a water-soluble anionic structure as an auxiliary agent for flocculation and dehydration is limited to the types and properties of wastewater and the types and applications of coagulants and other water treatment chemicals. Hereinafter, the present invention will be described in detail with reference to Examples.

Examples for producing the coagulation assistant of the present invention are described in detail below, but the present invention is not limited to this embodiment.

[Example]

(21.1 mol) of sulfuric acid was added to 2575 g (20.1 mol) of naphthalene and sulfonation reaction was carried out to obtain 4184 g (20.1 mol) of naphthalenesulfonic acid while minimizing residual naphthalene. To 4059 g (18.5 mol) of naphthalenesulfonic acid, The amount of naphthalenesulfonic acid-formalin polymer was minimized by the condensation reaction in the presence of excess amount of 2.95 mol. In the neutralization process, the pH was adjusted to 7.5 during the final neutralization so that the sodium hydroxide and the calcium hydroxide were alternately injected in 5 mol increments to increase the degree of crosslinking. To remove residual formalin, sulfuric acid was additionally added to adjust the pH to 4 ~ 5. Ascorbic acid, which is an organic acid, was added as a reducing agent to 3.5 mol of residual formalin in an amount of 3.5 mol, and ferric chloride (FeCl ₃ ) And hydrogen peroxide (H ₂ O ₂ ) were also added at 2 mol to minimize the residue.

The coagulation assistant solution prepared by diluting the coagulant aid and water prepared in this Example with a certain ratio (10%) to prepare a flocculant adjuvant solution, and adjusting the ratio of the coagulant aid solution to the sludge storage tank prior to the centrifugal dewatering process The water content after dehydration was measured. The wastewater used for the dehydration is collected from each household, and after removing the particles after grinding, it is applied to the process of concentration and dehydration. The pH of the wastewater is 3 to 5 in summer and acid fermentation occurs in the summer. To 7, the extent of acid fermentation and decay varies depending on the ambient temperature.

The solid content of the wastewater sludge was in the range of 3 to 10%. In this experiment, the experimental sludge of the dehydration process was 8.49% and the floating sludge was 7.06%. In this experiment, the naphthalenesulfonic acid- The flocculation efficiency of the experimental group and the control group was evaluated while adjusting the amount and pH of the formalin polymer (hereinafter referred to as 'OC-512').

The pH of the raw wastewater was 4.55, and sodium hydroxide was used to adjust the pH to 10 as shown in Table 1, and the flocculation size before and after the application of OC-512 was evaluated in mm.

C-810EL manufactured by OCI-SNF was applied to the coagulant, and the amount of the coagulant was set to 480 mg / l through preliminary evaluation.

Cohesion efficiency evaluation test result by OC-512 application Change condition pH change 4.55 5.61 6.63 7.58 8.60 10.02 Coagulant C-810EL Same as left input 480 mg / l Same as left Coagulation state - - - ≪ D1 D2 D2 OC-512 500 mg / l Same as left Coagulation state - D3 D5 D8 D10 > D10 Dehydration rate experiment After 5 seconds, g 0.32 28.74 33.00 52.99 102.15 83.52 After 10 seconds, g 0.35 42.37 51.60 74.60 135.85 111.01 After 20 seconds, g 0.41 59.99 70.23 96.61 140.40 131.74 After 30 seconds, g 1.16 72.70 83.64 106.14 140.65 136.37

In the above table, the coagulation state indicates the diameter of the produced flock, and D10 means a 10 mm sized flock.

As shown in Table 1, when the pH of the food wastewater was 4.55, there was no change before and after the addition of the dehydrating aid OC-512, which was prepared according to the present invention, and when the pH was adjusted to 10.02 And a flaky state in which dehydration could not be normally performed with a flaked size of 2 mm or less (see Fig. 1).

After applying the aid OC-512, the size and strength of the pre-injection was improved as shown in FIG. 2, and when the pH was 5.60 or more, the size of the coagulated flock was improved. When the pH was 8.60, , And at pH 5.61 or higher, dehydration - capable flocs were formed.

Results of application of dehydration of raw wastewater before and after application of OC-512 Experiment Item Dehydrator inflow Removed from the dehydration process
Suspended suspension concentration Removal rate existing
(Coagulant alone) 8.49% 3.21% 37.8% change
(OC-512 application) 5.83% 68.7% Improvement rate 81.6% more removed

Results of application of cohesion injury before and after application of OC-512 Experiment Item Flotation process inflow Removed from the flotation process
Suspended suspension concentration Removal rate existing
(Coagulant alone) 7.06% 2.89% 71.9% change
(OC-512 application) 3.78% 94.0% Improvement rate 30.8% more removed.

As shown in Table 2 and Table 3, OC-512 was applied to the flocculation dewatering process and flotation process in the food wastewater treatment plant. As a result, the dewatering process improved about 81% in the case of flocculant alone application and 30.8% The results were derived.

As described above, the naphthalenesulfonic acid-formalin polymer produced by the production method of the present invention is produced as a network structure with little monomer, and is applied together with the flocculant to improve flocculation efficiency. Therefore, Can be usefully used for agglomeration.

Claims (5)

Coagulation and dehydration auxiliaries containing a network of naphthalenesulfonic acid-formalin polymers. Characterized in that after the formalin condensation with naphthalene sulfonic acid is carried out, sodium hydroxide and calcium hydroxide are used as a neutralizing agent to prepare a reticulated structure. The method according to claim 2, wherein the residual monomers naphthalene and formalin are reduced by applying ascorbic acid, ferric chloride and hydrogen peroxide solution. A flocculation method comprising flocculating and dehydrating auxiliaries after the flocculant is added thereto, and then flocculating the flocculant and dehydrating auxiliaries in a post treatment system. The method of claim 4, wherein the flocculant is a cationic polymer flocculant.

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