CN103586088B - A kind of preparation method of degradation selectivity hydroquinones composite photo-catalyst - Google Patents

Abstract

The invention discloses a kind of preparation method of degradation selectivity hydroquinones composite photo-catalyst, comprise the following steps: TiO ₂the Hydrothermal Synthesis of semi-conducting material; TiO ₂microparticle surfaces modification; The preparation of molecularly imprinted polymer; Utilize surface molecule print technology, select suitable polymerization, template molecule and function monomer are changed the immobilized surface to semiconductor light-catalyst according to suitable proportioning by crosslinked initiation method, leave the hole matched with template molecule at polymer surfaces after wash-out, thus achieve have template molecule selective, specialty identifies then to the circulating system of its catalytic degradation, and then reaches collaborative and the object of promotion selective photocatalysis degraded target contaminant.Effectively can realize target contaminant Selective recognition, adsorb and the object of catalytic degradation, improve the efficiency of the effective degraded to target substance, there is the advantage of stronger selective processing environment pollutant waste water.

Description

A kind of preparation method of degradation selectivity hydroquinones composite photo-catalyst

Technical field

The present invention relates to the preparation of a kind of material and environmental pollution treatment technology, in particular a kind of preparation method of degradation selectivity hydroquinones composite photo-catalyst.

Background technology

Hydroquinones is a kind of typical industrial chemicals, the main black-and-white development agent being used as photographic film, also the raw material producing anthraquinone dye, azo dyes is used as, also for the preparation of stabilizing agent, the antioxidant and polymerization inhibitor etc. of coating lacquer, thus very easily entered environment, pollutes environment especially water body.The toxicity of hydroquinones is very large, once enter human body, all can cause damage to liver, kidney, central nervous system; In addition, hydroquinones is easily oxidized to benzoquinone, easily and DNA react larger harm produced to human body, have carcinogenic with cause mutagenicity.Therefore, the removing of the hydroquinones pollutant in environment is very important.At present, photocatalysis technology has been called the technology being widely used in wastewater treatment in environment.People carry out modification to semiconductor and composite semiconductor and carry out processing environment pollution and obtain good effect, but do not have selective, are difficult in the Complex water body coexisted at multiple pollutant, target contaminant be removed.In order to improve the selective of photocatalysis technology, be combined by molecular imprinting with photocatalysis technology, in the system that can coexist at multi-pollutant, prioritizing selection removes target contaminant.

The frontier branch of science that molecular engram is the branch superiorities such as collection Polymer Synthesizing, molecular recognition, bionical bioengineering and grows up is the technology that preparation has recognition function material.Due to have can be predetermined the advantage such as selective, identity, molecularly imprinted polymer (molecular imprinted polymer, MIP) is applied to the aspects such as chromatography, environment trace analysis, UF membrane, chiral material fractionation, biology sensor and receives much attention.

Molecular imprinting is the covalently or non-covalently effect utilized between template molecule and monomer, polymer is formed through cross-linked polymeric, and then with eluent, template molecule is eluted from polymer, just define the hole matched with polymer so in the polymer, these holes have selective and affine performance to template molecule.Surface molecule print technology is the engram technology type more having application prospect grown up on molecular imprinting basis, have stronger selective with polymer prepared by the method, more recognition site, and material Transfer and adsorption dynamics adsorption kinetics faster.In photocatalytic process, it has specific recognition performance to target substance, and then reaches the object of preferential degradation target substance.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art, provide a kind of preparation method of degradation selectivity hydroquinones composite photo-catalyst, achieve the process of target contaminant first being adsorbed again to catalytic degradation, and then effectively utilize light source to reach the object of hydroquinones pollutant waste water in environment of effectively degrading.

The present invention is achieved by the following technical solutions, the present invention includes following steps:

(1) TiO ₂the Hydrothermal Synthesis of semi-conducting material

First by Ti (OC ₄h ₉) ₄mix 1:1.25 ~ 4 in mass ratio with absolute ethyl alcohol, be uniformly mixed, distilled water is added in whipping process, joined by mixed liquor in reactor, total liquor capacity is no more than 80% of reactor volume, isothermal reaction 12 ~ 36h at 120 ~ 160 DEG C, at room temperature naturally cool after reaction terminates, the product obtained uses distilled water and absolute ethyl alcohol to replace washing 2 ~ 5 times, dry under 50 ~ 70 DEG C of vacuum after centrifugation, obtains the TiO of uniform particle sizes ₂semiconductor micron ball;

(2) TiO ₂microparticle surfaces modification

By the TiO of Hydrothermal Synthesis gained ₂semiconductor micron ball is distributed in the methanol solution containing o-phenylenediamine, TiO ₂being 6:1 ~ 3:1 with the mass ratio of o-phenylenediamine, under room temperature, making o-phenylenediamine molecule fully be connected to TiO by stirring ₂the surface of material, achieves at TiO ₂surface grafting active group;

(3) preparation of molecularly imprinted polymer

By template molecule hydroquinones and function monomer α-methacrylic acid in mass ratio 1:4 ~ 1:15 be dissolved in glutaraldehyde solution, the volume ratio of α-methacrylic acid and glutaraldehyde solution is 1:20 ~ 1:40, stirring 2 ~ 8h at ambient temperature makes it fully be polymerized, then crosslinking agent EGDMA and initiator A IBN that mass ratio is 1:1 ~ 1:5 is added, the volume ratio of crosslinking agent EGDMA and mixed solution is 1:30 ~ 1:50, the volume ratio of initiator A IBN and mixed solution is 1:60 ~ 1:100, and 2 ~ 10mL methyl alcohol is as pore-foaming agent, the volume ratio of pore-foaming agent and mixed solution is 1:40 ~ 1:60, finally add the TiO that in step (2), o-phenylenediamine is modified ₂semi-conducting material is as the carrier of imprinted polymer, and said mixture is polymerisation 10 ~ 30h at water bath with thermostatic control 40 ~ 80 DEG C, the solid powder substance obtained is crossed 200 mesh sieves after grinding, then the template molecule of apparatus,Soxhlet's in temperature 70 ~ 80 DEG C of water-bath wash-out imprinted polymers is used, eluent is methyl alcohol and acetic acid, the volume ratio of methyl alcohol and acetic acid is 9:1 ~ 7:3, until can't detect hydroquinones in eluent.

As one of preferred embodiment of the present invention, in described step (1), the liner of reactor is that polytetrafluoroethylene (PTFE) is made.

As one of preferred embodiment of the present invention, described stirring means is magnetic agitation.

Synthesize blank imprinted polymer in the same way, in step (2), do not add template molecule hydroquinones.For contrasting.

Utilize surface molecule print technology, select suitable polymerization, template molecule and function monomer are changed the immobilized surface to semiconductor light-catalyst according to suitable proportioning by crosslinked initiation method, leave the hole matched with template molecule at polymer surfaces after wash-out, thus achieve have template molecule selective, specialty identifies then to the circulating system of its catalytic degradation, and then reaches collaborative and the object of promotion selective photocatalysis degraded target contaminant.

The present invention has the following advantages compared to existing technology: the Photocatalytic Degradation Process of molecularly imprinted polymer photochemical catalyst of the present invention effectively can realize target contaminant Selective recognition, adsorb and the object of catalytic degradation, improve the efficiency of the effective degraded to target substance, there is the advantage of stronger selective processing environment pollutant waste water.

Accompanying drawing explanation

Fig. 1 is the infrared spectrogram of molecular imprinted polymer on surface and the blank imprinted polymer photochemical catalyst of contrast;

Fig. 2 is the solid UV-Vis spectrogram of trace and blank imprinted polymer photochemical catalyst.

Detailed description of the invention

Elaborate to embodiments of the invention below, the present embodiment is implemented under premised on technical solution of the present invention, give detailed embodiment and concrete operating process, but protection scope of the present invention is not limited to following embodiment.

Embodiment 1

(1) TiO ₂the Hydrothermal Synthesis of semi-conducting material

First by Ti (OC ₄h ₉) ₄with absolute ethyl alcohol 1:1.25 mixing in mass ratio, stir 5h at constant speed lower magnetic force and make both fully mixing, appropriate distilled water is added in whipping process, mixed liquor is joined in teflon-lined reactor, total liquor capacity is no more than 80% of reactor volume, 30h is reacted at constant temperature 160 DEG C, at room temperature naturally cool after reaction terminates, the product obtained uses distilled water and absolute ethyl alcohol to replace washing 5 times, centrifugation, last dry under 70 DEG C of vacuum, finally obtain the TiO2 semiconductor micron ball of uniform particle sizes;

(2) TiO ₂microparticle surfaces modification

By the TiO of Hydrothermal Synthesis gained ₂semi-conducting material is distributed in a certain amount of methanol solution of o-phenylenediamine, makes TiO ₂be 6:1 with the thing mass ratio of o-phenylenediamine, under room temperature condition, with constant speed magnetic agitation 10h, enable o-phenylenediamine molecule fully be connected to TiO ₂the surface of material, achieves at TiO ₂surface grafting active group, obtains the TiO through o-phenylenediamine modification ₂microballoon;

(3) preparation of molecularly imprinted polymer

By template molecule hydroquinones and function monomer α-methacrylic acid in mass ratio 1:4 ~ 1:15 be dissolved in glutaraldehyde solution, the volume ratio of α-methacrylic acid and glutaraldehyde solution is 1:20 ~ 1:40, stirring 2 ~ 8h at ambient temperature makes it fully be polymerized, then crosslinking agent EGDMA and initiator A IBN that mass ratio is 1:1 ~ 1:5 is added, the volume ratio of crosslinking agent EGDMA and mixed solution is 1:30 ~ 1:50, the volume ratio of initiator A IBN and mixed solution is 1:60 ~ 1:100, and 2 ~ 10mL methyl alcohol is as pore-foaming agent, the volume ratio of pore-foaming agent and mixed solution is 1:40 ~ 1:60, finally add the TiO that in step (2), o-phenylenediamine is modified ₂semi-conducting material is as the carrier of imprinted polymer, and said mixture is polymerisation 10 ~ 30h at water bath with thermostatic control 40 ~ 80 DEG C, the solid powder substance obtained is crossed 200 mesh sieves after grinding, then the template molecule of apparatus,Soxhlet's in temperature 70 ~ 80 DEG C of water-bath wash-out imprinted polymers is used, eluent is methyl alcohol and acetic acid, the volume ratio of methyl alcohol and acetic acid is 9:1 ~ 7:3, until can't detect hydroquinones in eluent, namely pattern of descriptive parts molecule is removed completely from imprinted polymer,

As a comparison, synthesize blank imprinted polymer in the same way, except not adding template molecule hydroquinones in the course of the polymerization process;

(4) sample getting preparation in 75mg step (3) carries out photocatalytic degradation test in photochemical reaction instrument, record this photochemical catalyst and in 60min, reach 88% more than to the antibiotic degradation rate of hydroquinones under visible ray causes, this surface molecule print photochemical catalyst has stronger photocatalytic activity.

The method of photocatalytic activity evaluation is: carry out in photo catalysis reactor (light source is purchased from Zhong Jiaojin source, Beijing CEL-S500 solar simulated xenon source), the hydroquinones simulated wastewater of 100mL variable concentrations to be added in reactor and to measure its initial value, then 0.5g/L is added respectively, 1.0g/L, 1.5g/L, 2.0g/L, the molecularly imprinted polymer of 2.5g/L and blank polymer photochemical catalyst, magnetic agitation and open aerator pass into air keep catalyst be in suspension or afloat, oxygen in photocatalytic process can be provided, at interval of 10min sample analysis in During Illumination, supernatant liquor is got at ultraviolet-visible spectrophotometer λ after centrifugation _max=289nm place measures absorbance, and degradation rate DC is obtained by following formula:

DC=[(A ₀-A _i)/A ₀]×100%

Wherein A ₀the absorbance of quinol solution during for reaching adsorption equilibrium, A _ifor the absorbance of the quinol solution of different time sampling and measuring.

As shown in Figure 1, Fig. 1 is the infrared spectrogram of molecular imprinted polymer on surface and the blank imprinted polymer photochemical catalyst of contrast, and a, b, c, d are respectively through the modified TiO of o-phenylenediamine ₂before the non-eluted template molecule of hydroquinones molecularly imprinted polymer, infrared spectrogram after blank imprinted polymer and imprinted polymer eluted template molecule, as can be seen from the figure in printing process, hydroquinones and methacrylic acid disappear the characteristic peak of some functional groups because of polymerization, after wash-out removes template molecule, these characteristic peaks occur again.

Fig. 2 is the solid UV-Vis spectrogram of trace and blank imprinted polymer photochemical catalyst, and as can be seen from the figure, the optical absorption intensity of the photochemical catalyst after molecular engram polymerization is better than the TiO of non-trace ₂material, molecular imprinted polymer on surface photochemical catalyst has the absorbability preferably to Uv and visible light, and the absorption in the photochemical catalyst sample after trace is to the trend of visible region movement, illustrate that the polyalcohol catalyst after trace has stronger visible light-responded scope.

Embodiment 2

Weigh the different templates molecule of equal in quality and the different molecular trace photochemical catalyst of function monomer proportioning, visible light photocatalytic degradation 5mg L ^-1quinol solution, other embodiments are identical with embodiment 1, result shows when the mass ratio of hydroquinones and methacrylic acid is 1:8, its photocatalytic degradation hydroquinones is most effective, so, select the imprinted polymer photochemical catalyst of this proportioning to examine or check the selective contrast of itself and blank imprinted polymer.

Embodiment 3

(1) solution of the hydroquinones of variable concentrations, catechol, phloroglucin is first adsorbed separately with the imprinted polymer of synthesis and blank polymer catalyst.According to following formulae discovery polymer to the adsorption capacity of different plant species:

Q=(C ₀-C _e)*V/m

Wherein Q is adsorption capacity (the mg g of adsorbent ^-1), C ₀, C _econcentration (mg L before being respectively hydroquinones absorption and after adsorption equilibrium ^-1), V is the concentration (L) of quinol solution, and m is the quality (g) of adsorbent.

(2) hydroquinones of imprinted polymer and blank polymer Catalyst Adsorption same concentrations and the mixed solution of interfering material is used respectively, through identical adsorption time, centrifugation aaerosol solution, measure the concentration of supernatant, calculate catalyst to the adsorption capacity of different plant species, then calculate its adsorptive selectivity to different material.Result shows imprinted polymer photochemical catalyst to the adsorption capacity of hydroquinones apparently higher than the adsorption capacity to catechol and phloroglucin, and blank imprinted polymer is little to the adsorption capacity difference of three, illustrates and improve the adsorption capacity of imprinted polymer to hydroquinones in printing process.

Embodiment 4

(1) by changing the consumption 0.5g L of molecular engram photochemical catalyst ^-1, 1.0g L ^-1, 1.5g L ^-1, 2.0g L ^-1, 2.5g L ^-1, examine or check the impact of catalyst amounts on photocatalytic degradation, result shows that at catalyst amount be 1.5g L ^-1time, it is the highest to the degradation efficiency of hydroquinones, can reach more than 88%.So the catalyst amount selected in experiment is 1.5g L ^-1.

(2) with the quinol solution of catalytic degradation variable concentrations under molecularly imprinted polymer photochemical catalyst visible ray, examination when variable concentrations molecular engram photochemical catalyst to the degradation kinetics of hydroquinones, by calculate and matching kinetics equation is known, the process of molecular engram photocatalyst for degrading hydroquinones meets pseudo-first-order kinetic model, when hydroquinones initial concentration is 5mgL ^-1time, it is 0.052min to the average degradation rate of hydroquinones ^-1.

Embodiment 5

Use the hydroquinones of imprinted polymer and blank polymer photocatalyst for degrading same concentrations and the mixed solution of interfering material (as catechol, phloroglucin etc.) respectively, by calculating the degradation efficiency of different material and then calculating its selectivity factor to different material.

$E\%=\frac{C_0-C_e}{C_0}\×100\%$

$D=\frac{(C_0-C_e)V}{C_{e}W}$

$\mathrm{\α}=\frac{D_{\mathrm{QUI}}}{D_M}$

${\mathrm{\α}}_{\mathrm{\β}}=\frac{{\mathrm{\α}}_i}{{\mathrm{\α}}_n}$

Wherein C ₀, C _ebe respectively concentration (the mg L after the degraded of hydroquinones initial sum ^-1); D is distribution coefficient, D _qUI, D _mbe respectively the distribution coefficient of hydroquinones and interfering material; α is selectivity factor, α _i, α _nbe respectively the selectivity factor of trace and blank polymer photochemical catalyst, α _βit is relative selectivity coefficient.

Experimental result shows, the material that imprinted polymer photochemical catalyst contrasts apparently higher than other degradation efficiency of hydroquinones, selectivity factor is also all greater than other interfering materials, and relative selectivity coefficient shows that imprinted polymer photochemical catalyst has good degradation efficiency than blank polymer photochemical catalyst to hydroquinones.The molecularly imprinted polymer photochemical catalyst of explanation the method synthesis has selective preferably to hydroquinones, thus achieves the object of degrading to the selective catalysis of target substance.

Claims (4)

1. a preparation method for degradation selectivity hydroquinones composite photo-catalyst, is characterized in that, comprises the following steps:

(1) TiO ₂the Hydrothermal Synthesis of semi-conducting material

First by Ti (OC ₄h ₉) ₄mix 1:1.25 ~ 4 in mass ratio with absolute ethyl alcohol, be uniformly mixed, distilled water is added in whipping process, joined by mixed liquor in reactor, total liquor capacity is no more than 80% of reactor volume, isothermal reaction 12 ~ 36h at 120 ~ 160 DEG C, at room temperature naturally cool after reaction terminates, the product obtained uses distilled water and absolute ethyl alcohol to replace washing 2 ~ 5 times, dry under 50 ~ 70 DEG C of vacuum after centrifugation, obtains the TiO of uniform particle sizes ₂semiconductor micron ball;

(2) TiO ₂microparticle surfaces modification

By the TiO of Hydrothermal Synthesis gained ₂semiconductor micron ball is distributed in the methanol solution containing o-phenylenediamine, TiO ₂being 6:1 ~ 3:1 with the mass ratio of o-phenylenediamine, under room temperature, making o-phenylenediamine molecule fully be connected to TiO by stirring ₂the surface of material, achieves at TiO ₂surface grafting active group;

(3) preparation of molecularly imprinted polymer

By template molecule hydroquinones and function monomer α-methacrylic acid in mass ratio 1:4 ~ 1:15 be dissolved in glutaraldehyde solution, the volume ratio of α-methacrylic acid and glutaraldehyde solution is 1:20 ~ 1:40, stirring 2 ~ 8h at ambient temperature makes it fully be polymerized, then crosslinking agent EGDMA and initiator A IBN that mass ratio is 1:1 ~ 1:5 is added, the volume ratio of crosslinking agent EGDMA and mixed solution is 1:30 ~ 1:50, the volume ratio of initiator A IBN and mixed solution is 1:60 ~ 1:100, and 2 ~ 10mL methyl alcohol is as pore-foaming agent, the volume ratio of pore-foaming agent and mixed solution is 1:40 ~ 1:60, finally add the TiO that in step (2), o-phenylenediamine is modified ₂semi-conducting material is as the carrier of imprinted polymer, and said mixture is polymerisation 10 ~ 30h at water bath with thermostatic control 40 ~ 80 DEG C, the solid powder substance obtained is crossed 200 mesh sieves after grinding, then the template molecule of apparatus,Soxhlet's in temperature 70 ~ 80 DEG C of water-bath wash-out imprinted polymers is used, eluent is methyl alcohol and acetic acid, the volume ratio of methyl alcohol and acetic acid is 9:1 ~ 7:3, until can't detect hydroquinones in eluent.

2. the preparation method of a kind of degradation selectivity hydroquinones composite photo-catalyst according to claim 1, is characterized in that, in described step (1), the liner of reactor is that polytetrafluoroethylene (PTFE) is made.

3. the preparation method of a kind of degradation selectivity hydroquinones composite photo-catalyst according to claim 1, it is characterized in that, described stirring means is magnetic agitation.

4. the preparation method of a kind of degradation selectivity hydroquinones composite photo-catalyst according to claim 1, is characterized in that, synthesize blank imprinted polymer in the same way, in step (2), do not add template molecule hydroquinones.