CN105664894A - Preparation method of purifying material for selectively removing positive trivalent arsenic from water body - Google Patents

Abstract

The invention belongs to the technical field of environment and discloses a preparation method of a purifying material for selectively removing positive trivalent arsenic from a water body.A nanocomposite with a magnetic separation function is prepared by arsenic (III) blotting and coating of ferroferric oxide nanoparticles according to an inverse emulsion crosslinking method.Environment friendliness of adopted materials is realized, the preparation method is simple, and the prepared composite material is high in adsorption rate of arsenic (III) in the water body and selective in arsenic removal, thereby being expected to be a novel environment-friendly water treatment material with selective arsenic (III) removal and magnetic separation functions.

Description

A kind of preparation method of the just arsenious scavenging material of selective removal water body

Technical field

The invention belongs to field of environmental technology, be specifically related to there is Magneto separate function and there is the technology of preparing of selective scavenging material.

Background technology

Arsenic is a kind of metalloid element being prevalent in nature, and different according to form, arsenic can be divided into inorganic arsenic and organo-arsenic. All the time, positive trivalent arsenic is well-known with its high toxicity. Arsenic element official confirmation was human carcinogen in 1980 by international cancer research institution. In recent years, due to the mankind's activity destruction to natural environment, the pollution of environment is on the rise by arsenic, especially the pollution to global water resources. Therefore, the purified treatment research of water body arsenic is extremely urgent.

In water body, arsenic mainly exists with the form of arsenious acid and arsenic acid, when natural environment pH, the general neutral of arsenious acid, and arsenic acid is electronegative, therefore in traditional water treatment procedure, first pass through pretreatment, arsenious acid oxidation is changed into arsenic acid, then passes through electrostatic adsorption and the arsenic in water is all removed. But this process is loaded down with trivial details, subsequent treatment bothers, and in water body, the existence of other ions can affect the removal of arsenic and causes inefficient. Therefore, a kind of high-efficiency environment friendly of preparation and there is selective arsenic (III) adsorbent have great importance.

Summary of the invention

It is an object of the invention to propose a kind of high-efficiency environment friendly and there is selective arsenic adsorbent, the preparation method that especially can remove the environmental protection water purification material of water body arsenic (III) simply and effectively.

The present invention comprises the following steps:

Comprise the following steps:

1) under stirring condition, by chitosan quaternary ammonium salt derivatives (HTCC) and Fe₃O₄Nanoparticle is distributed in arsenic (III) ion standard solution, obtains being loaded into the Fe of As (III)₃O₄/ HTCC mixed liquor;

2) adopt reversed-phase emulsion cross-linking method, be loaded onto the Fe of As (III)₃O₄/ HTCC mixed liquor is added drop-wise in the mixed solution being made up of liquid paraffin, Span 80 and ethyl acetate, and emulsifying obtains W/O emulsion;

3) W/O emulsion is warming up to 40^oAfter C, when rotating speed is 500r/min, adds formaldehyde, then be warming up to 50^oAdd glutaraldehyde after C, form mixed system;

4) with sodium hydrate aqueous solution regulating step 3) in the pH value of mixed system to 7.5～9, when rotating speed is 175r/min, stirring reaction is to terminating, more successively with petroleum ether, acetone, ethanol and secondary water washing, obtains composite;

5) remove free arsenic (III) ion in composite, lyophilization with eluant washing, obtain the just arsenious scavenging material of selective removal water body.

The present invention is with As (III) for imprinted templates, adopting a kind of chitosan quaternary ammonium salt derivatives biodegradable, eco-friendly is carrier material, prepare composite (As-IMHNPs) with conversed phase micro emulsion copolymerization method coated ferriferrous oxide nanoparticle, study it to the removal efficiency of water body arsenic (III), use condition and selective adsorption capacity. Gained trace composite (As-IMHNPs) can effectively remove water body arsenic (III), there is Magneto separate function, and compare with reference group (NIMHNPs), the selection absorbability of arsenic (III) is improved, is not substantially affected by water body cationic (Ca²⁺, Mg²⁺And Fe³⁺) and anion (SO₄ ^2?, Cl^?And NO₃ ^?, and the PO that concentration is relatively low₄ ^3-) impact, also reduce high concentration PO simultaneously₄ ^3-Impact.

The present invention overcomes existing arsenic removal material, and in particular for the deficiency that water body arsenic (III) arsenic removal material exists, preparation method is easy to be reliable, and experimental period is shorter, it is expected to produce in batches to be applied to the process of actual water.

Trace composite (As-IMHNPs) arsenic removal (III) efficiency obtained by the present invention is high, and removal efficiency is 93.8%; When pH value is 6, arsenic removal (III) is most effective; Ca²⁺、Mg²⁺、SO₄ ^2-、NO₃ ^-、Cl^-Do not affect the removal efficiency of arsenic (III), Fe³⁺Arsenic removal (III) efficiency of As-IMHNPs had minimal effect, only very high concentrations PO₄ ^3-Arsenic removal (III) efficiency of As-IMHNPs is affected relatively big, causes its arsenic removal (III) efficiency to reduce about 20% (under natural conditions, the phosphate concentration in subsoil water is general all very low); The existence of ferroso-ferric oxide makes it have Magneto separate function, it is simple to subsequent treatment. Research shows that As-IMHNPs can effectively get rid of or reduce the impact of coexisting ion, can be efficiently applied to the specific aim adsorption treatment of arsenic in natural water (III). As-IMHNPs is expected to become one and has the new green environment protection material of high selectivity arsenic removal (III) efficiency and Magneto separate function.

Further, the chitosan quaternary ammonium salt derivatives described in step 1) of the present invention and Fe₃O₄The mixing quality ratio of nanoparticle is 1: 1, to meet absorbability and the Magneto separate ability of material simultaneously. Supersound process is adopted during mixing.

In order to obtain desirable emulsifying effectiveness, step 2) in, it is loaded into the Fe of As (III)₃O₄The mixed volume ratio of/HTCC mixed liquor and mixed solution is 1: 1, and emulsification times is 0.5h.

Step 2) in, described Span 80 account for mixed solution percent by volume be 1.5%, experiment proves that the consumption of emulsifying agent is very few and is unfavorable for emulsifying, crosses and not easily cleans up at most, is unfavorable for the post processing of material; Ethyl acetate account for mixed solution percent by volume be 10%, ethyl acetate plays the effect of porogen, experiments show that under this ratio, adsorption effect is more preferably.

In mixed system described in step 3), the percent by volume of formaldehyde is 8%, and the percent by volume of glutaraldehyde is 4%. The effect of formaldehyde is short range crosslinking and glutaraldehyde is long-range crosslinking, cross-linking effect is used in combination more preferably, and relative to glutaraldehyde, formaldehyde lower in cost, it is possible to reduce industrial cost.

In step 5), described eluant is 0.1mol/L sodium hydrate aqueous solution. Arsenic (III) is easily soluble in sodium hydrate aqueous solution, it is simple to the eluting of template arsenic (III), and 0.1mol/L sodium hydroxide is enough to eluting arsenic (III) and can reduce the impact of adsorbent pattern.

Accompanying drawing explanation

Fig. 1 is Fe₃O₄SEM figure.

Fig. 2 is the SEM figure of As-IMHNPs.

Fig. 3 is the SEM figure of NIMHNPs.

Fig. 4 is the SEM figure of the As-IMHNPs after arsenic-adsorbing (III).

Fig. 5 is CS, HTCC, Fe₃O₄, As-IMHNPs and NIMHNPs FTIR figure.

Fig. 6 is Fe₃O₄Hysteresis curve figure with As-IMHNPs.

What Fig. 7 was pH on As-IMHNPs, NIMHNPs arsenic-adsorbing (III) respectively affects figure.

Fig. 8 is that As-IMHNPs arsenic-adsorbing (III) is affected figure by adsorbent amount.

Fig. 9 is the kinetic curve figure of As-IMHNPs arsenic-adsorbing at different temperatures (III).

Figure 10 is Ca²⁺, Mg²⁺And Fe³⁺Cation and SO₄ ^2?, NO₃ ^?, Cl^?And PO₄ ^3?When anion coexists, As-IMHNPs and NIMHNPs arsenic-adsorbing (III) affected figure.

Figure 11 is the PO of variable concentrations₄ ^3?As-IMHNPs and NIMHNPs arsenic-adsorbing (III) affected figure.

Figure 12 is the reusable adsorption efficiency figure of As-IMHNPs.

Detailed description of the invention

One, preparation technology:

1, synthesis chitosan quaternary ammonium salt derivatives (HTCC):

Taking chitosan (CS) and be dissolved in the acetum of 2wt%, be added dropwise over 1mol/L sodium hydroxide solution and make chitosan (CS) precipitate out, system pH is 9 ~ 10, soak 8h, sucking filtration, takes solid matter washing to neutral, obtains white flock chitosan.

0.5g white flock chitosan is dispersed in 15mL isopropanol, chitosan system in the pasty state after being uniformly dispersed. 2, the 3-epoxypropyltrimethylchloride chlorides (GTA) of 2.0g are dissolved in 5mL isopropanol, 80^oUnder C, 2h drips off and is slowly added dropwise to pasty state chitosan system, reacts 6h, makes precipitant with dehydrated alcohol and be precipitated out by product, through sucking filtration, dries, obtains chitosan quaternary ammonium salt derivatives HTCC.

2, preparation Fe₃O₄Nanoparticle:

Ferriferrous oxide nano-particle uses oxidation hydro-thermal method to prepare: weigh the ferrous sulfate heptahydrate of 0.009mol (2.502g), it is dissolved in the deionized water of 30mL, after adding 10mLPEG-200 solution, in 30 DEG C of waters bath with thermostatic control, magnetic agitation mixes, it is stirred continuously lower shifting liquid funnel dropping 30mL weak ammonia (being diluted to 30mL by the commercially available ammonia of 2.5mL), is 10 to solution ph so that ferrous ion is with Fe (OH)₂Form precipitate, solution presents blackish green. Then commercially available hydrogen peroxide 0.18mL it is slowly added dropwise so that part Fe (OH)₂It is oxidized to trivalent iron salt to solution and presents black, continue stirring 20 ~ 30min. Then, it is fully transferred in autoclave, 160 in Muffle furnace^oC insulation reaction 5h, obtains Fe₃O₄Nanoparticle.

3, trace composite (As-IMHNPs) is prepared:

1) by etc. the chitosan quaternary ammonium salt derivatives (HTCC) of quality and Fe₃O₄Nanoparticle is distributed in As (III) standard solution, and 30^oStir 24h under C, obtain being loaded into the Fe of As (III)₃O₄/ HTCC mixed liquor.

Prepared by the preparation method of arsenic (III) ion standard solution and the product made:

The preparation method of As (III) stock solution is as follows: by Powdered arsenic trioxide (0.25g, As₂O₃) be dissolved in sodium hydroxide solution (2.5mol/L), adjust volume with deionized water and regulate the pH value of this solution to 6.5 to 20mL and with the hydrochloric acid of 16mol/L and the sodium hydroxide of 2mol/L, add 0.2g sodium bicarbonate, finally with deionized water constant volume to 50mL. Seal up for safekeeping in reagent bottle, keep in Dark Place at 4 DEG C, during use, be diluted to variable concentrations as required. The solution sampling every time prepared preserves for calibrating, and uses atomic fluorescence spectrometry test fluorescence intensity, and standard deviation can use within 10%.

2) liquid paraffin, Span 80 and ethyl acetate are mixed, obtain that Span 80 accounts for 1.5%v/v, ethyl acetate accounts for the liquid paraffin of 10%v/v, Span 80 and ethyl acetate mixtures.

Adopt reversed emulsion polymerization, equal-volume ground by step 1) in mixed liquor be added drop-wise in liquid paraffin, Span 80 and ethyl acetate mixtures, emulsifying 0.5h, obtain W/O emulsion.

3) after W/O emulsion being warming up to 40 DEG C, when rotating speed is 500r/min, add formaldehyde (8%v/v) in 30min, then add glutaraldehyde (4%v/v) after being warming up to 50 DEG C, form mixed system.

In the mixed system made, formaldehyde accounting 8%v/v, glutaraldehyde accounting 4%v/v.

4) with sodium hydrate aqueous solution regulating step 3) pH value of mixed system that obtains is in 7.5～9 scopes, it is beneficial to being smoothed out of emulsification and cross linked reaction, when rotating speed is 175r/min, stirring reaction 3h, again successively with petroleum ether, acetone, ethanol and secondary water washing, obtain composite.

5) template ion in composite is removed with 0.1mol/L sodium hydroxide solution for eluant washing, process repeats no longer to find template ion and As (III) to filtrate, and lyophilization obtains trace composite (As-IMHNPs).

4, non-trace composite (NIMHNPs) is prepared:

Non-trace composite (NIMHNPs) is prepared in the same way, is different in that in example step 1) without template ion.

1) by chitosan quaternary ammonium salt derivatives (HTCC) and Fe₃O₄Nanoparticle is distributed in deionized water, stirs 24h, obtain Fe at 30 DEG C₃O₄/ HTCC mixed liquor;

2) liquid paraffin, Span 80 and ethyl acetate are mixed, obtain that Span 80 accounts for 1.5%v/v, ethyl acetate accounts for the liquid paraffin of 10%v/v, Span 80 and ethyl acetate mixtures.

Adopt reversed emulsion polymerization, by step 1) in mixed liquor be added drop-wise in liquid paraffin, Span 80 and ethyl acetate mixtures, emulsifying 0.5h, obtain W/O emulsion.

3) after W/O emulsion being warming up to 40 DEG C, when rotating speed is 500r/min, add formaldehyde (8%v/v) in 30min, then add glutaraldehyde (4%v/v) after being warming up to 50 DEG C, form mixed system.

4) with sodium hydrate aqueous solution regulating step 3) pH of mixed system that obtains is in 7.5～9 scopes, it is beneficial to being smoothed out of emulsification and cross linked reaction, when rotating speed is 175r/min, stirring reaction 3h, again successively with petroleum ether, acetone, ethanol and secondary water washing, obtain composite.

5) lyophilization obtains non-trace composite (NIMHNPs).

Two, the sign of composite:

Adopting model is that the scanning electron microscope (SEM) of S-4800II is to Fe₃O₄, As-IMHNPs and NIMHNPs and the As-IMHNPs after having adsorbed arsenic (III) characterized.

From figure 1 it appears that Fe prepared by hydro-thermal method₃O₄Nanoparticle presents cubical microscopic appearance, and size is comparatively homogeneous; With Fe₃O₄Comparing, the surface of As-IMHNPs (Fig. 2) and NIMHNPs (Fig. 3) is more coarse, and arrangement is more tight, and HTCC and Fe is described₃O₄Be coated with successfully, and due to the eluting of template ion, the surface of As-IMHNPs be more of a relatively loose, as seen from Figure 4: due to arsenic-adsorbing (III) ion, the surface of As-IMHNPs is more more coarse.

The nanoparticle made is characterized by fourier infrared spectrometer (FTIR) respectively that adopt model to be TENSOR27. Curve b and a, 1640cm in comparison diagram 5^?1The NH represented₂Stretching vibration peak strength reduction, and occur in that a new peak 1479cm^?1It is the stretching vibration peak of methyl; And HTCC and Fe₃O₄Characteristic peak can occur in the FTIR figure of As-IMHNPs and NIMHPs, 3716cm^?1(stretching vibration peak of OH), 3140cm^?1(stretching vibration peak of NH), 2309cm^?1(on HTCC main chain the stretching vibration peak of CH), 1592cm^?1(?NH₂Bending vibration peak), 1479cm^?1(?CH₂Stretching vibration peak), 1120cm^-1(stretching vibration peak of C O C), 572cm^?1And 472cm^?1(stretching vibration peak of Fe O), this result further illustrates HTCC and Fe₃O₄Successful crosslinking.

It is tested by the oscillation sample gaussmeter (VSM) adopting model to be EV7, shows Fe in Fig. 6₃O₄With hysteresis curve figure, the As-IMHNPs of As-IMHNPs, there is higher magnetic saturation intensity, for 85.65emu/g, illustrate that this composite can be separated by externally-applied magnetic field in water processes.

Three, the research of arsenic removal (III) efficiency of composite:

1, the impact of pH

The atomic fluorescence spectrophotometer adopting model to be AFS-3100 measures fluorescence intensity, thus calculating adsorption rate. As can be seen from Figure 7: when in water body to be clean, pH value is 6, arsenic removal (III) is most effective, and due to the effect of trace, the arsenic removal efficiency of As-IMHNPs is higher than NIMHNPs.

2, the impact of adsorbent amount

Adsorbent amount to the Adsorption Effect of arsenic (III) be fixing when in water body to be clean the initial concentration of As (III) 5mg/L, pH be 6, time of contact be 48h when, the consumption changing adsorbent finally calculates adsorption efficiency from 0.2 to 5g/L, and result is shown in Fig. 8.

As can be seen from Figure 8 along with the increase of adsorbent amount, the removal efficiency of arsenic ion increases 95.61% from 60.65%, and adsorption capacity is reduced to 0.96mg/g from 15.16, the removal efficiency of comprehensive arsenic, adsorption capacity and economic benefit consider, finally determine that adsorbent amount is 2g/L.

3, the impact of time of contact and temperature

Fig. 9 is the kinetic curve figure of As-IMHNPs arsenic-adsorbing at different temperatures (III). As can be seen from the figure 0.5h internal adsorption rate is attained by more than 40%, reaches absorption saturated in 11h, and when 313K, removal efficiency is the highest, and it is more strong that this is likely due to the more high Brownian movement of temperature, adds the contact probability of As (III) and adsorbent.

4, the performance of selective absorption arsenic (III)

The impact of As-IMHNPs and NIMHNPs arsenic-adsorbing (III) is tested by coexisting ion:

As shown in Figure 10, Ca²⁺、Mg²⁺、SO₄ ^2-、NO₃ ^-、Cl^-Do not affect the removal efficiency of arsenic (III), Fe³⁺Arsenic removal (III) efficiency of As-IMHNPs had minimal effect, the PO of high concentration₄ ^3-Arsenic removal (III) efficiency of As-IMHNPs is affected bigger.

Figure 11 is the PO of variable concentrations₄ ^3-Arsenic removal (III) efficiency of As-IMHNPs is affected figure, as seen from the figure, time concentration is lower than 20mg/L, arsenic removal (III) efficiency of As-IMHNPs is affected only small, increase along with phosphorus acid ion concentration, the arsenic removal of As-IMHNPs is affected more big, and under natural conditions, the phosphate concentration in subsoil water is general all very low; Compared with NIMHNPs, the anti-ion interference ability of As-IMHNPs is greatly improved, and illustrates that trace enhances the selective adsorption capacity of material.

5, regenerability

Figure 12 is the repeat performance of As-IMHNPs, and the As-IMHNPs having adsorbed arsenic ion is regenerated by 0.1mol/L sodium hydroxide solution. As it can be seen, after reusing 10 times, the arsenic removal efficiency of As-IMHNPs is maintained at more than 75%, illustrate that this material has good repeat performance.

Sum up:

By the research to composite arsenic removal (III) efficiency, As-IMHNPs has higher selectivity arsenic removal (III) effect, and there is good reusability, it is expected to become a kind of novel arsenic removal (III) green material with high selectivity, high removal efficiency and Magneto separate function.

Claims (6)

1. a preparation method for the just arsenious scavenging material of selective removal water body, comprises the following steps:

1) under stirring condition, by chitosan quaternary ammonium salt derivatives (HTCC) and Fe₃O₄Nanoparticle is distributed in arsenic (III) ion standard solution, obtains being loaded into the Fe of As (III)₃O₄/ HTCC mixed liquor;

2) adopt reversed-phase emulsion cross-linking method, be loaded onto the Fe of As (III)₃O₄/ HTCC mixed liquor is added drop-wise in the mixed solution being made up of liquid paraffin, Span 80 and ethyl acetate, and emulsifying obtains W/O emulsion;

3) after W/O emulsion being warming up to 40 DEG C, when rotating speed is 500r/min, adds formaldehyde, then add glutaraldehyde after being warming up to 50 DEG C, form mixed system;

4) with sodium hydrate aqueous solution regulating step 3) in the pH value of mixed system to 7.5～9, when rotating speed is 175r/min, stirring reaction is to terminating, more successively with petroleum ether, acetone, ethanol and secondary water washing, obtains composite;

5) remove free arsenic (III) ion in composite, lyophilization with eluant washing, obtain the just arsenious scavenging material of selective removal water body.

2. preparation method according to claim 1, it is characterised in that step 1) described in chitosan quaternary ammonium salt derivatives and Fe₃O₄The mixing quality ratio of nanoparticle is 1: 1, adopts supersound process during mixing.

3. preparation method according to claim 1, it is characterised in that step 2) in, it is loaded into the Fe of As (III)₃O₄The mixed volume ratio of/HTCC mixed liquor and mixed solution is 1: 1, and emulsification times is 0.5h.

4. preparation method according to claim 1 or 3, it is characterised in that step 2) in, described Span 80 account for mixed solution percent by volume be 1.5%, ethyl acetate account for mixed solution percent by volume be 10%.

5. preparation method according to claim 1, it is characterised in that in described step 3) described in mixed system in, the percent by volume of formaldehyde is 8%, and the percent by volume of glutaraldehyde is 4%.

6. preparation method according to claim 1, it is characterised in that step 5) in, described eluant is 0.1mol/L sodium hydrate aqueous solution.