A kind of preparation method of magnetic bio carbon-supported nanometer iron
Technical field
The invention belongs to Material Field, and in particular to a kind of preparation method of magnetic bio carbon-supported nanometer iron.
Background technology
Cr VI is a kind of poisonous heavy metal, and chromyl waste water is mainly derived from plating, metallurgy, mining, printing and dyeing
Deng industry.For trivalent chromium, Cr VI toxicity is more than 100 times of trivalent chromium greatly, and is easy to be absorbed by the body,
Human body can be invaded by alimentary canal, respiratory tract, skin and mucous membrane and can be accumulated in human body cohesion collection, it is excessive when containing in water
Cr VI when, have stronger lethal effect to aquatile, Cr VI is classified as among priority pollutant list by China.
For the processing method containing hexavalent chromium wastewater, mainly including chemical reduction method, electrochemical process, absorption method, ion-exchange etc.,
Industrially chemical reduction method and absorption method are processing waste water containing chrome more conventional methods, by hexavalent chrome reduction into trivalent chromium,
Handled, heavy metal precipitation is got off, to remove the chromium ion in water body by adding precipitating reagent or flocculant etc. again.But, this
Kind of method easily produces substantial amounts of sludge, and the processing in these sludge later stages and disposal are also one the problem of need solution.
In the last few years, zeroth order Nanoscale Iron is as reducing agent, removes the Cr VI in water body and receives and widely grinds both at home and abroad
Study carefully.Zeroth order Nanoscale Iron has the advantages that particle diameter is small, specific surface area is big, surface-active is high, reducing power is strong, still, zeroth order nanometer
Iron is due to stronger activity, it is easy to reacts and inactivates with oxygen in atmosphere, and due to huge ratio
Surface area, easily occurs to reunite and inactivate in water body.To solve the problem above existed when zeroth order Nanoscale Iron removes Cr VI,
Gradually paid close attention to using charcoal as the zeroth order of carrier Nanoscale Iron-biology carbon composite by people.Using charcoal as carrier,
The decentralization of metal nanoparticle can be improved, the reunion of metal nanoparticle is reduced, the activity of metal nanoparticle is kept.Separately
Outside, the magnetic zeroth order Nanoscale Iron-biology carbon composite prepared with reference to magnetic separation technique adds in the presence of magnetic field outside can be with
The quick separating of biological adsorption agent is realized, sewage disposal efficiency is improved, is a kind of new sorbing material.Due to magnetic material
Characteristic, after its reduction, Adsorption of Heavy Metals, can thoroughly be separated heavy metal with water body by magnetic separation technique, and
And magnetic material can also be recycled, cost is reduced.
Application of the magnetic separation technique in water process is more and more important, but currently, also there are problems that, such as,
Many magnetic materials have stronger saturation magnetization, and still, while its remanent magnetism or coercivity are also larger, water body passes through magnetic
After the processing of field, even if there be no externally-applied magnetic field, due to there is magnetic attraction between material so that be easy to reunite between material, than
Surface area is reduced, and influence material is active in itself.The small material of some saturation magnetizations, its remanent magnetism also very little, close to superparamagnetic
State, in the case of no externally-applied magnetic field, will not have magnetic or magnetic smaller, compared with the Van der Waals force between material,
Its size can be ignored, and what material can be stablized is dispersed in water body, its reactivity is kept, so in different water environments
In, it should according to specific circumstances, handled using suitable magnetic material.
Patent CN106362690 discloses a kind of magnetic bio charcoal sorbing material and preparation method thereof, biological by preparing
Charcoal, prepare ferric iron precursor liquid, solvent thermal reaction and obtain magnetic bio charcoal sorbing material.Patent CN105664854 discloses one
Plant the preparation method that charcoal loads Nanoscale Iron nickel bimetal material.At present, prior art also not publicly being capable of controlled material magnetic
Property strong and weak magnetic bio charcoal sorbing material preparation method.
The content of the invention
The technical problem to be solved in the present invention is to provide a kind of preparation method of magnetic bio carbon-supported nanometer iron, this method energy
The controllable of magnetic is enough realized, the magnetic bio charcoal of different magnetic can be prepared by controlling the molar concentration of Tea Polyphenols solution
Nanoscale Iron is carried, so as to suitable for different wastewater treatment environment;The magnetic bio carbon-supported nanometer iron material prepared can lead to
The abundant hydroxyl in surface, carboxyl functional group are crossed, occurs complexing with heavy metal ion, by complex in material
Surface.Magnetic bio carbon-supported nanometer iron material property stable in the air is high, when handling heavy metal water body, will not reunite
Phenomenon, with stronger reactivity, and can thoroughly be removed the heavy metal in water body by magnetic separation technique.
In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:
A kind of preparation method of magnetic bio carbon-supported nanometer iron, including:(1) modification biological charcoal;(2) ultrasonic immersing method is loaded
Molysite;(3) Tea Polyphenols is coated;(4) liquid phase reduction prepares charcoal and carries Nanoscale Iron;(5) magnetic method sub-argument goes out magnetic bio charcoal
Carry Nanoscale Iron;Wherein, the preparation-obtained magnetic green of control is reached by the molar concentration of Tea Polyphenols solution in rate-determining steps (3)
The purpose of the saturation magnetization of thing carbon-supported nanometer iron.
This method specifically includes following steps:
(1) modification of charcoal:Take charcoal, add concentrated nitric acid, immersion filtering, and rinsed to pH and no longer change with water,
Dry, obtain the charcoal of Nitric Acid Modified;
(2) load of molysite:Water-soluble trivalent ferric salt solution is prepared, the biology for the modification that step (1) is prepared is added
Then charcoal, ultrasonic immersing, suction filtration, drying weighs the sample after drying, it is warming up to 200 under inert atmosphere or nitrogen atmosphere~
250 DEG C, calcining obtains charcoal of the theoretical duty iron for 28%~32% load molysite, wherein theoretical duty iron
Calculation formula is (quality of the quality of iron ion/modification biological charcoal) × 100%;
(3) 0.002~0.008mol/L Tea Polyphenols solution is prepared, inert gas or nitrogen deoxygenation is passed through, step (2) is added
The charcoal of the load molysite prepared, the ratio between the quality of the load molysite charcoal of addition and the volume of Tea Polyphenols solution are
1:40~1:50g/mL, under inert gas or nitrogen atmosphere, stirring;
(4) sodium borohydride solution is prepared, is added into step (3) resulting solution, continues to stir, obtains biological carbon-supported nanometer
Iron slurries;
(5) go out magnetic bio carbon-supported nanometer iron with magnetic method sub-argument, wash, dry;
Reach that the preparation-obtained magnetic bio charcoal of control is carried by the molar concentration of Tea Polyphenols solution in rate-determining steps (3)
The purpose of the saturation magnetization of Nanoscale Iron,
When the concentration of Tea Polyphenols solution is more than or equal to 0.002mol/L, less than 0.004mol/L, the magnetic prepared
The saturation magnetization that charcoal carries Nanoscale Iron is less than or equal to 72.9emu/g, more than 36.5emu/g;
When the concentration of Tea Polyphenols solution is more than or equal to 0.004mol/L, less than 0.006mol/L, the magnetic prepared
The saturation magnetization that charcoal carries Nanoscale Iron is less than or equal to 36.5emu/g, more than 26.6emu/g;
When the concentration of Tea Polyphenols solution is more than or equal to 0.006mol/L, less than or equal to 0.008mol/L, prepare
The saturation magnetization of magnetic bio carbon-supported nanometer iron is less than or equal to 26.6emu/g, more than or equal to 5.2emu/g.
In step (3), the molar concentration of Tea Polyphenols solution is different, and magnetic strength that its final obtained material has is not yet
Together.Its relatively high magnetism when the molar concentration of Tea Polyphenols solution is 0.002mol/L, magnetic is weaker when concentration is 0.008mol/L.
It should be noted that the molecular weight Mr=281.36 of Tea Polyphenols of the present invention.
In step (1), the mass ratio of charcoal and concentrated nitric acid is 1:10~1:70.
In step (1), charcoal is weighed, is added after concentrated nitric acid, immersion 12h, centrifugal filtration, and with deionized water rinsing extremely
PH no longer changes (pH value is about 5-6), 70 DEG C of dryings, obtains the charcoal of Nitric Acid Modified.
In step (2), the theoretical duty iron of the charcoal of the load molysite prepared is 30%.
In step (2), water-soluble trivalent ferric salt is FeCl3、FeCl3·6H2O、Fe2(SO4)3In one or more, it is excellent
Elect FeCl as3;Drying temperature is 60~105 DEG C, preferably 70 DEG C.Indifferent gas is the one or more in helium, neon, argon, krypton, xenon,
It is preferred that argon gas.
In step (2), water-soluble trivalent ferric salt solution is prepared, the charcoal for the modification that step (1) is prepared is added, so
Ultrasonic immersing 8h, suction filtration, 70 DEG C of drying, then weigh the sample after drying in quartz boat, quartz boat are placed in into tube furnace afterwards,
Under argon atmosphere, 200 DEG C are risen to 5 DEG C/min heating rate, 3h is calcined, obtains loading the charcoal of molysite.
In step (3), the ratio between the quality of the load molysite charcoal of addition and the volume of Tea Polyphenols solution are 1:45g/mL.
Indifferent gas is the one or more in helium, neon, argon, krypton, xenon.
In step (4), the molar concentration of sodium borohydride solution is 0.005~0.014mol/L, preferably 0.007mol/L;
The volume ratio of Tea Polyphenols solution of the sodium borohydride solution of preparation with being prepared in step (3) is 1:6~1:10.Feed way can be with
It is to be added dropwise by constant pressure funnel or other conventional feed way.
In step (5), magnetic bio carbon-supported nanometer iron is gone out with magnetic method sub-argument, with water washing is distilled three times, is dried in vacuo
It can obtain charcoal and carry nano-iron material.Described magnetic method can be that magnet is placed in into container lower end, static a period of time
Afterwards, supernatant liquid is discharged.
The magnetic bio carbon-supported nanometer iron that above-mentioned preparation method is prepared is within protection scope of the present invention.
Above-mentioned magnetic bio carbon-supported nanometer iron applying in protection scope of the present invention in the Cr VI in removing water body
Within.
The magnetic bio carbon-supported nanometer iron 1g that the present invention is prepared, can apply to hexavalent chromium concentration for below 60mg/L
100mL waste water, the Cr VI in the waste water can be removed completely after 2d.
Beneficial effect:
(1) preparation method that provides of the present invention can prepare the magnetic green of different magnetic according to the power of required magnetic
Thing carbon-supported nanometer iron, so as to suitable for different wastewater treatment environment.
(2) the magnetic bio carbon-supported nanometer iron that the present invention is prepared, property is stable, and spontaneous combustion will not occur in atmosphere, and
Nanoscale Iron good dispersion, reactivity is higher, can quickly remove the Cr VI in waste water.
(3) the magnetic bio carbon-supported nanometer iron that the present invention is prepared, is respectively provided with magnetic, passes through Magneto separate skill afterwards before the reaction
Art, it is easy to separated with water body so that the separation of the material becomes simple possible.
Brief description of the drawings
Fig. 1 is the Technology Roadmap that synthesizing magnetic charcoal carries Nanoscale Iron;
Fig. 2 is that (SEM, left figure resolution ratio 100nm, right figure resolution ratio are 1 μ to magnetic bio carbon-supported nanometer iron scanning electron microscope (SEM) photograph
m);
Fig. 3 is charcoal, modification biological charcoal, magnetic bio carbon-supported nanometer iron Fourier infrared spectrum figure (FTIR);
Fig. 4 is charcoal, modification biological charcoal, magnetic bio carbon-supported nanometer iron X-ray diffractogram (XRD);
Fig. 5 is the magnetic bio carbon-supported nanometer iron UV-Vis scans figure (UV-VIS) that different Tea Polyphenols coat concentration;
Fig. 6 is the hysteresis curve (M-H) of the magnetic bio carbon-supported nanometer iron of different Tea Polyphenols cladding concentration;
Fig. 7 is the graph of a relation between Tea Polyphenols cladding concentration and saturation magnetization;
Fig. 8 is removal effect figure of the different Tea Polyphenols cladding concentration for Cr VI;
Fig. 9 is the graph of a relation between hexavalent chromium removal rate after hexavalent chromium solution initial concentration and 2d, 5d, 10d.
Embodiment
According to following embodiments, the present invention may be better understood.However, as it will be easily appreciated by one skilled in the art that real
Apply the content described by example and be merely to illustrate the present invention, without should be also without limitation on sheet described in detail in claims
Invention.
In addition to being defined, technical term used has universal with those skilled in the art of the invention in following examples
The identical meanings of understanding.Test reagent used, is routine biochemistry reagent unless otherwise specified in following examples;It is described
Experimental method, is conventional method unless otherwise specified.
The present invention is described in detail with reference to embodiment.
The preparation of embodiment 1, magnetic bio carbon-supported nanometer iron
A kind of preparation method of magnetic bio carbon-supported nanometer iron, comprises the following steps (as shown in Figure 1):
(1) modification of charcoal:2g charcoal is weighed in conical flask, is added after 100mL concentrated nitric acid, immersion 12h,
Centrifugal filtration, and no longer changed (pH value is about 5-6) with deionized water rinsing to pH, 70 DEG C are dried overnight, you can obtain nitric acid
Modified charcoal.
(2) load of molysite:Prepare Fe3+Ion molar concentration is 0.108mol/L ferric chloride solution, takes 50mL in burning
In cup, and the modification biological charcoal prepared in 1g above-mentioned (1) is added, then ultrasonic immersing 8h, suction filtration, 70 DEG C dried
At night, the sample after a certain amount of drying is then weighed in quartz boat, quartz boat tube furnace is placed in, under argon atmosphere, with 5
DEG C/min heating rate rises to 200 DEG C, 3h is calcined, obtains loading the charcoal of molysite.
(3) compound concentration is 0.002mol/L Tea Polyphenols (Mr=281.36) solution 45mL, is passed through nitrogen deoxygenation
40min, is placed in three-necked flask, centre insertion agitating paddle, the load molysite that then addition 1g above-mentioned (2) are prepared
Charcoal, under nitrogen atmosphere, 30min is stirred with 1000r/min.
(4) 0.007mol/L sodium borohydride solution 5mL is prepared, (3) resulting solution is then added dropwise to by constant pressure funnel
In, after being added dropwise to complete, continue to stir 30min with 1000r/min speed, you can obtain the slurries that charcoal carries Nanoscale Iron.
(5) gone out with magnetic method (magnet being placed in into there-necked flask lower end, after static a period of time, supernatant liquid is discharged) sub-argument
The magnetic bio carbon-supported nanometer iron, with water washing is distilled three times, vacuum drying can obtain magnetic bio carbon-supported nanometer iron.
Experimental result:
(1) Fig. 2 is scanning electron microscope (SEM) photograph (SEM, left figure resolution of the magnetic bio carbon-supported nanometer iron prepared in embodiment 1
Rate 100nm, right figure resolution ratio is 1 μm).It can be seen that charcoal has an abundant pore structure, thus its have compared with
Strong adsorption capacity, Nanoscale Iron is supported on charcoal, and its size is in 70nm or so, therefore the magnetic green that the present invention is prepared
Thing carbon-supported nanometer iron has great specific surface area and reactivity.
(2) Fig. 3 is charcoal, modification biological charcoal, magnetic bio carbon-supported nanometer iron Fourier infrared spectrum figure.Can from figure
To find out, modification biological charcoal is compared with the infrared figure of charcoal:In 3600cm-1There is stronger sharp peak at left and right, this is freely
Hydroxyl O-H stretching vibration absworption peak;In 1720cm-1There is the weak peak of C=O stretching vibrations at left and right, in 1320cm-1At left and right
There are C-O stretching vibration absworption peaks, after Nitric Acid Modified, biological carbon surface has the hydrophilic radicals such as carboxy hydroxy.Magnetic green
The infrared spectrum of thing carbon-supported nanometer iron is compared with Nitric Acid Modified charcoal:In 550cm-1, strong peak disappears, and may be iron and charcoal
The result of surface functional group interaction, also has some new peaks to occur, in 3000cm-1At left and right, there is the C-H on phenyl ring to stretch
Vibration, 1600~1450cm-1C=C skeletal vibrations, and 880~680cm-1There is more peak at place, is C-H out-of-plane bending vibrations,
Therefore there is phenyl ring, this is the functional group in Tea Polyphenols, illustrates that Tea Polyphenols has successfully been coated to the surface of charcoal.
(3) Fig. 4 is charcoal, modification biological charcoal, magnetic bio carbon-supported nanometer iron X-ray diffractogram (XRD).Can from figure
To find out, unmodified charcoal is similar with modified charcoal image, there is the wide diffraction maximum diffused at 23 ° or so, this
It is the diffraction maximum of charcoal, and shows that charcoal is not crystal.The magnetic bio carbon-supported nanometer iron material of synthesis is at 44.75 °
There is obvious diffraction maximum, corresponding to body-centred cubic α-Fe 110 diffraction, while also exist at 65.16 ° body-centred cubic α-
Fe 200 diffraction, it is known that, final obtained material is mutually present with the thing of α-Fe simple substance.
(4) Fig. 6 is that different Tea Polyphenols coat removal effect figure of the concentration for Cr VI.Wherein prepared by embodiment 1
The charcoal of 0.002mol/L Tea Polyphenols cladding carries Nanoscale Iron can be by concentration in 20mg/L hexavalent chromium solution after 1h
Cr VI remove completely.
The preparation of embodiment 2, magnetic bio carbon-supported nanometer iron
A kind of preparation method of magnetic bio carbon-supported nanometer iron, comprises the following steps:
(1) modification of charcoal:2g charcoal is weighed in conical flask, is added after 20mL concentrated nitric acid, immersion 12h,
Centrifugal filtration, and no longer changed (pH value is about 5-6) with deionized water rinsing to pH, 70 DEG C are dried overnight, you can obtain nitric acid
Modified charcoal.
(2) load of molysite:Prepare Fe3+Ion molar concentration is 0.101mol/L Fe2(SO4)3Solution, take 50mL in
In beaker, and the modification biological charcoal prepared in 1g above-mentioned (1) is added, then ultrasonic immersing 8h, suction filtration, 70 DEG C dried
At night, the sample after a certain amount of drying is then weighed in quartz boat, quartz boat tube furnace is placed in, under argon atmosphere, with 5
DEG C/min heating rate rises to 250 DEG C, 3h is calcined, obtains loading the charcoal of molysite.
(3) compound concentration is 0.002mol/L Tea Polyphenols (Mr=281.36) solution 50mL, is passed through nitrogen deoxygenation
20min, is placed in three-necked flask, centre insertion agitating paddle, the load molysite that then addition 1g above-mentioned (2) are prepared
Charcoal, under nitrogen atmosphere, 30min is stirred with 1000r/min.
(4) 0.014mol/L sodium borohydride solution 5mL is prepared, (3) resulting solution is then added dropwise to by constant pressure funnel
In, after being added dropwise to complete, continue to stir 30min with 1000r/min speed, you can obtain the slurries that charcoal carries Nanoscale Iron.
(5) the magnetic bio carbon-supported nanometer iron is gone out with magnetic method sub-argument, with water washing is distilled three times, vacuum drying can be obtained
To magnetic bio carbon-supported nanometer iron.
The 2h clearances of the Cr VI of the magnetic bio carbon-supported nanometer iron prepared are 100%.
The preparation of embodiment 3, magnetic bio carbon-supported nanometer iron
A kind of preparation method of magnetic bio carbon-supported nanometer iron, comprises the following steps:
(1) modification of charcoal:2g charcoal is weighed in conical flask, is added after 140mL concentrated nitric acid, immersion 12h,
Centrifugal filtration, and no longer changed (pH value is about 5-6) with deionized water rinsing to pH, 70 DEG C are dried overnight, you can obtain nitric acid
Modified charcoal.
(2) load of molysite:Prepare Fe3+Ion molar concentration is 0.115mol/L FeCl3·6H2O solution, takes 50mL
In beaker, and the modification biological charcoal prepared in 1g above-mentioned (1) is added, then ultrasonic immersing 8h, suction filtration, 70 DEG C of drying
Overnight, the sample after a certain amount of drying is then weighed in quartz boat, quartz boat is placed in tube furnace, under argon atmosphere, with 5
DEG C/min heating rate rises to 200 DEG C, 3h is calcined, obtains loading the charcoal of molysite.
(3) compound concentration is 0.002mol/L Tea Polyphenols (Mr=281.36) solution 40mL, is passed through nitrogen deoxygenation
40min, is placed in three-necked flask, centre insertion agitating paddle, the load molysite that then addition 1g above-mentioned (2) are prepared
Charcoal, under nitrogen atmosphere, 30min is stirred with 1000r/min.
(4) 0.005mol/L sodium borohydride solution 5mL is prepared, (3) resulting solution is then added dropwise to by constant pressure funnel
In, after being added dropwise to complete, continue to stir 30min with 1000r/min speed, you can obtain the slurries that charcoal carries Nanoscale Iron.
(5) the magnetic bio carbon-supported nanometer iron is gone out with magnetic method sub-argument, with water washing is distilled three times, vacuum drying can be obtained
To magnetic bio carbon-supported nanometer iron.
The 2h clearances of the Cr VI of the magnetic bio carbon-supported nanometer iron prepared are 100%.
Embodiment 4, choice of parameters experiment
According to the preparation method of embodiment 1, change important two preparation parameter in preparation process:Calcining heat and tea
The cladding concentration of polyphenol, prepares calcining heat for 150 DEG C respectively, 200 DEG C, 250 DEG C, 300 DEG C, 500 DEG C, 600 DEG C, and tea is more
Phenol cladding concentration is respectively 0mol/L, 0.002mol/L, 0.004mol/L, 0.006mol/L, 0.008mol/L, 0.01mol/L,
0.012mol/L magnetic bio carbon-supported nanometer iron, and iron load capacity by magnetic bio carbon-supported nanometer iron and 100mL
20mg/L hexavalent chromium removals test to select optimal parameter.
The assay method of iron load capacity is:It is 1 that concentrated nitric acid, which is configured, with concentrated sulfuric acid volume ratio:3 nitration mixture, as digestion solution,
80ml is taken in digestion tube;0.1g magnetic bio carbon-supported nanometer iron is weighed, adds in digestion tube, is cleared up at a temperature of 150 DEG C
To solution clarification, then with atomic absorption spectrophotometry, the content of the iron in measurement digestion solution.Experimental result is shown in Table 1, its
In, the Nanoscale Iron load capacity described in the present embodiment refers to Nanoscale Iron actual negative carrying capacity, is (quality/magnetic of zeroth order Nanoscale Iron
Charcoal carries Nanoscale Iron gross mass) × 100%.
Table 1
From result, two important preparation parameters change can have a certain impact to material overall performance,
When calcining heat is too low (200 DEG C of <), its Nanoscale Iron load capacity can be very low, when its reason is that calcining heat is too low, iron ion
Can not firmly it be bonded with the functional group on charcoal, it is substantial amounts of when later stage liquid phase prepares magnetic bio carbon-supported nanometer iron
Iron ion meeting dissolution, causes certain loss so that its load capacity is relatively low.When temperature is too high (250 DEG C of >), in inert atmosphere
Under, charcoal can serve as reducing agent, cause the loss of charcoal, and be possible to collapse the hole in charcoal, under load factor
Drop.Therefore 200 DEG C~250 DEG C are the optimum temperatures calcined in preparation process.
Tea Polyphenols concentration influences little to Nanoscale Iron load capacity, and has large effect to the clearance of Cr VI, when not having
When having cladding Tea Polyphenols, its clearance is relatively low, and less than the clearance of blank charcoal, reason is that Nanoscale Iron activity is too strong,
With oxygen reaction in air before being tested, aoxidized, activity is too low when causing reaction, and the Nanoscale Iron loaded is occupied
The pore structure of charcoal, causes charcoal specific surface area to decline, and adsorption capacity is also accordingly reduced.And when cladding concentration is excessive
When, due to Existential Space steric effect, there is resistance in Cr VI and Nanoscale Iron or charcoal haptoreaction, and electron transmission also can be by
Resistance, causes the ability reduction of removal Cr VI.Therefore it can be prepared when Tea Polyphenols concentration is 0.002mol/L~0.008mol/L
Preferably magnetic bio carbon-supported nanometer iron.
Test example 1, the influence experiment of Tea Polyphenols concentration
It is respectively 0.002mol/L, 0.004mol/L, 0.006mol/L to change Tea Polyphenols concentration according to embodiment 1,
0.008mol/L, prepares the magnetic bio carbon-supported nanometer iron of different magnetic, and with deionized water and 0.002mol/L Tea Polyphenols
Solution is control, carries out ultraviolet sedimentation experiment, comprises the following steps that:
It is respectively 0.002mol/L, 0.004mol/L, 0.006mol/L to change Tea Polyphenols concentration according to embodiment 1,
0.008mol/L, prepares the magnetic bio carbon-supported nanometer iron of different magnetic.
Take 0.5g to be dissolved in 50mL glass centrifuge tube respectively, cover and 10min is had children outside the state plan after plug, shaken well, then will
Centrifuge tube is placed on magnet 10 seconds, and upper solution 0.5mL is pipetted with liquid-transfering gun, is added in 50mL colorimetric cylinders, is added water to quarter
Spend at line, shake up, be subsequently poured into the cuvette that light path is 1cm, scan 190nm-800nm ultraviolet-visible absorption situation,
Using wavelength as abscissa, absorbance is ordinate, mapping.Simultaneously using deionized water and 0.002mol/L Tea Polyphenols solution as
Control.
Experimental result:
Fig. 5 is the ultravioletvisible absorption figure that different Tea Polyphenols concentration are coated.As shown in Figure 5, obtained magnetic bio charcoal is carried
Nanoscale Iron supernatant has absorption at 206nm and 295nm or so place, and Tea Polyphenols only has obvious absorption at 206nm, therefore can
With the characteristic absorption wavelength using 295nm or so as the magnetic bio carbon-supported nanometer iron material.As shown in Figure 5, it is dense with coating
The increase of degree, its absorbance also increases, and positive correlation is presented in absorbance and the concentration of the material, so cladding concentration is bigger, its
The more not free settling under magnetic fields.Therefore select Tea Polyphenols as covering, the magnetic size of material prepared can be controlled.
Test example 2, the magnetic bio carbon-supported nanometer ferromagnetism size of various concentrations Tea Polyphenols cladding compare
It is respectively 0mol/L, 0.001mol/L, 0.002mol/L, 0.003mol/ to change Tea Polyphenols concentration according to embodiment 1
L, 0.004mol/L, 0.005mol/L, 0.006mol/L, 0.007mol/L, 0.008mol/L, 0.009mol/L, 0.01mol/
L, the charcoal for preparing different magnetic carries Nanoscale Iron.By obtained solid material with SQUID VSM magnetometers to the magnetic prepared
Charcoal carries Nanoscale Iron and applies AC magnetic field, obtains the M-H hysteresis curves (see Fig. 6) of magnetic bio carbon-supported nanometer iron, and analyzes
The magnetic size of each magnetic bio carbon-supported nanometer iron.The remanent magnetization (Mr) and saturation magnetization (Ms) of each material
It is shown in Table 2.The relation that Tea Polyphenols is coated between concentration and saturation magnetization is shown in Fig. 7.
Table 2
It can be obtained by hysteresis curve and its obtained remanent magnetization and saturation magnetization data analysis, when low concentration
Tea Polyphenols to charcoal carry Nanoscale Iron coat when, its saturation magnetization is higher, and remanent magnetization is also larger, with compared with
Good ferromagnetism.When the concentration rise of Tea Polyphenols, its saturation magnetization and remanent magnetization are all reduced, the magnetic of material
Die down.It therefore, it can regulate and control by the concentration of Tea Polyphenols the magnetic size of the magnetic bio carbon-supported nanometer iron.
As shown in Figure 7:
When the concentration of Tea Polyphenols solution is more than or equal to 0.002mol/L, less than 0.004mol/L, the magnetic prepared
The saturation magnetization that charcoal carries Nanoscale Iron is less than or equal to 72.9emu/g, more than 36.5emu/g, it is adaptable to not by magnetic
Handling process processing does not have magnetic waste water.
When the concentration of Tea Polyphenols solution is more than or equal to 0.004mol/L, less than 0.006mol/L, the magnetic prepared
The saturation magnetization that charcoal carries Nanoscale Iron is less than or equal to 36.5emu/g, more than 26.6emu/g, it is adaptable to which weak magnetic handles work
Skill or with faint magnetic water body;
When the concentration of Tea Polyphenols solution is more than or equal to 0.006mol/L, less than or equal to 0.008mol/L, prepare
The saturation magnetization of magnetic bio carbon-supported nanometer iron be less than or equal to 26.6emu/g, more than or equal to 5.2emu/g, it is adaptable to have compared with
The water body of strong magnetic treatment technique or relatively high magnetism.
Test example 3, the experiment of water body hexavalent chromium removal
It is respectively 0mol/L, 0.001mol/L, 0.002mol/L, 0.003mol/ to change Tea Polyphenols concentration according to embodiment 1
L, 0.004mol/L, 0.005mol/L, 0.006mol/L, 0.007mol/L, 0.008mol/L, 0.009mol/L, 0.01mol/
L, the charcoal for preparing different magnetic carries Nanoscale Iron, and using modification biological charcoal as blank, carries out hexavalent chromium removal in water body real
Test, comprise the following steps that:
It is respectively 0mol/L, 0.001mol/L, 0.002mol/L, 0.003mol/ to change Tea Polyphenols concentration according to embodiment 1
L, 0.004mol/L, 0.005mol/L, 0.006mol/L, 0.007mol/L, 0.008mol/L, 0.009mol/L, 0.01mol/
L, the charcoal for preparing different magnetic carries Nanoscale Iron.
A certain amount of potassium bichromate is weighed, 20mg/L hexavalent chromium solution is prepared, pH to 6 is adjusted.Take 100mL 20mg/L
Cr VI as reaction solution add reaction bulb in.And the 1g materials are taken, it is added in reaction bulb, is put into vibration case, with
180r/min, 25 DEG C of vibrations, respectively in 5min, 10min, 20min, 30min, 45min, 60min, 90min, 120min samplings,
Filter membrane, measures the Cr (VI) of supernatant concentration.
Experimental result:
Fig. 8 is removal effect figure of the different Tea Polyphenols cladding concentration for Cr VI.It can be seen that cladding
The material of 0.002mol/L Tea Polyphenols solution can all remove Cr VI in 2h, with the increase of cladding concentration, remove
Efficiency is also slightly reduced.Different Tea Polyphenols coat Cr VI of the concentration for 20mg/L and are shown in Table 3 in 2h clearance.
Table 3
The data in table 3, magnetic bio carbon-supported nanometer iron prepared by embodiment 1 can be whole by Cr VI in 1h
Remove, the Cr VI in the degraded water body that it can be rapidly and efficiently, in 1h and 2h, its clearance is more or less the same the charcoal of blank,
Illustrate charcoal already close to adsorption equilibrium.The material of Tea Polyphenols is not coated, its clearance is minimum, reason one is due to not have
The cladding of Tea Polyphenols, Nanoscale Iron property is not sufficiently stable, and has been oxidized before the test, reactivity reduction;Two be that Nanoscale Iron is occupied
The pore structure of charcoal, causes the reduction of its specific surface area, and adsorption capacity is deteriorated.The magnetic bio of remaining Tea Polyphenols concentration cladding
Carbon-supported nanometer iron, has part lifting to the removal effect of Cr VI, particularly when cladding concentration is 0.002-0.008mol/L
When, its 1h clearance can reach more than 85%, 2h clearances more than 90%.Therefore the material can be quick, efficiently
Remove the Cr VI in water body.
Its partial results is fitted with pseudo-first-order dynamics and pseudo-second order kinetic equation,
Pseudo-first-order kinetics equation:DC/dt=-kC,
Pseudo-second order kinetic equation:
Its reactive kinetics parameters fitting result is shown in Table 4.
Table 4
As can be seen from Table 4, the reaction is not high to first _ order kinetics equation degree of fitting, and cladding Tea Polyphenols concentration is low
Its one-level Kinetics Rate Constants By Using highest of charcoal.The reaction is higher for second-order kinetic equation degree of fitting, illustrates reaction point
For two stages of fast response and long response time, the material for coating Tea Polyphenols, it starts based on quick adsorption, and the later stage is main
For the reaction of iron and Cr VI.When cladding concentration is low, its removal rate is higher, and its main cause is probably the sky due to Tea Polyphenols
Between steric hindrance hinder the quick adsorption of charcoal, and also cause contact of the Cr VI with Nanoscale Iron by certain limit
System.But the presence of Tea Polyphenols make it that the property of Nanoscale Iron is relatively stable, not easy in inactivation, therefore in practical application, can root
The concentration of Tea Polyphenols is prepared according to concrete condition.
Test example 4, the experiment of water body hexavalent chromium removal
Compound concentration is 20mg/L, 40mg/L, 60mg/L, 80mg/L, and 100mg/L hexavalent chromium solution adjusts pH to 6,
The above-mentioned solution of 100mL is taken to add in reaction bulb respectively, and the magnetic bio carbon-supported nanometer for respectively taking 1g to be prepared according to embodiment 1
Iron is separately added into above-mentioned reaction bulb, and reaction bulb is put into vibration case, with 180r/min, 25 DEG C of vibrations, respectively at vibration 2
My god, 5 days, after 10 days, take supernatant, the content of Cr VI in supernatant is measured with diphenyl carbazide spectrophotometry, and is counted
Calculate clearance of the magnetic bio carbon-supported nanometer iron to Cr VI in water body.Experimental result is shown in Table 5, hexavalent chromium solution initial concentration
And the relation after 2d, 5d, 10d between hexavalent chromium removal rate is shown in Fig. 9.
Table 5
The magnetic bio carbon-supported nanometer iron that the 1g present invention is prepared it can be seen from experimental result table 5, Fig. 9, Ke Yiying
For the 100mL waste water that hexavalent chromium concentration is below 60mg/L, the Cr VI in the waste water can be removed completely after 2d.