CN108529754B

CN108529754B - Polyvinyl alcohol-zinc oxide composite microsphere and preparation method and application thereof

Info

Publication number: CN108529754B
Application number: CN201710119030.8A
Authority: CN
Inventors: 李文; 邓靖; 汤建新; 邱卫; 何军; 周庆华; 贾明玺
Original assignee: HUNAN NEW WELLFUL CO Ltd; Hunan University of Technology
Current assignee: HUNAN NEW WELLFUL CO Ltd; Hunan University of Technology
Priority date: 2017-03-02
Filing date: 2017-03-02
Publication date: 2019-12-27
Anticipated expiration: 2037-03-02
Also published as: CN108529754A

Abstract

The invention discloses a polyvinyl alcohol-zinc oxide composite microsphere and a preparation method and application thereof, wherein the preparation method of the PVA-ZnO composite microsphere comprises the following steps: dissolving polyvinyl alcohol in deionized water to obtain a polyvinyl alcohol solution with the mass percent of 5-15%, and marking as a solution A; dissolving polyvinylpyrrolidone in dimethylformamide to obtain a solution B, wherein the mass ratio of the polyvinylpyrrolidone to the dimethylformamide is 20: 0.02-0.1; uniformly mixing the solution A and the solution B in equal volume to obtain a mixed solution, dropwise adding the mixed solution into acetone to obtain microspheres, immersing the microspheres into a glutaraldehyde crosslinking agent for crosslinking, and drying the crosslinked microspheres; the obtained microspheres are dipped into a zinc oxide solution for more than 12 hours, and then taken out and dried to obtain the polyvinyl alcohol-zinc oxide composite microspheres. The PVA-ZnO composite microspheres bear COD degrading bacteria, can degrade slaughter wastewater, effectively inhibit the growth of escherichia coli, and improve the COD degradation rate.

Description

Polyvinyl alcohol-zinc oxide composite microsphere and preparation method and application thereof

Technical Field

The invention relates to a polyvinyl alcohol-zinc oxide composite microsphere and a preparation method and application thereof, belonging to the field of water treatment preparations.

Background

With the social progress and the rapid development of the industry, the global water resource condition is gradually worsened. On the one hand, the demand of human beings for water resources is rapidly increasing; on the other hand, increasingly serious water pollution is gradually creating available water resources for predators. With the improvement of the social living standard, the market of meat products is rapidly expanded, the slaughtering and processing amount of livestock and poultry is also rapidly increased, the proportion of slaughter wastewater generated in the processes in an organic pollution source is rapidly increased, and the treatment of the wastewater becomes one of the problems to be solved urgently in the slaughtering industry at present. At present, many countries are vigorously developing environmental science research works, and research and development of low-pollution and pollution-free technologies are carried out, so that the problem of environmental pollution is well solved within a certain range.

The carrier method is the most studied and commonly used method, and the carrier and the microorganism are mutually adsorbed to provide a relatively stable growth environment for the microorganism, so that the microorganism can resist adverse factors, and the microorganism treatment method is more stable.

Disclosure of Invention

The invention aims to provide a carrier material suitable for processing slaughter wastewater by a carrier method, which is used for improving the processing effect of slaughter wastewater and reducing the processing cost.

The technical scheme of the invention is to provide a preparation method of polyvinyl alcohol-zinc oxide composite microspheres, which comprises the following steps:

(1) dissolving polyvinyl alcohol in deionized water to obtain a polyvinyl alcohol solution with the mass percent of 5-15%, and marking as a solution A; dissolving polyvinylpyrrolidone in Dimethylformamide (DMF) to obtain a solution B, wherein the mass ratio of the polyvinylpyrrolidone to the dimethylformamide is 20: 0.02-0.1;

(2) uniformly mixing the solution A and the solution B in equal volume to obtain a mixed solution, dropwise adding the mixed solution into acetone to obtain microspheres, immersing the microspheres into a glutaraldehyde crosslinking agent for crosslinking, and drying the crosslinked microspheres;

(3) and (3) dipping the microspheres dried in the step (2) into a zinc oxide solution for more than 12 hours, and taking out and drying to obtain the polyvinyl alcohol-zinc oxide composite microspheres.

Preferably, in the step (3), the mass fraction of the zinc oxide solution is 0.5% -1.5%.

Preferably, the glutaraldehyde crosslinking agent consists of glutaraldehyde, hydrochloric acid and acetone in a mass ratio of 5:1: 94.

Preferably, the zinc oxide solution is obtained by dissolving nano zinc oxide in deionized water by ultrasonic treatment.

Preferably, in step (3), the time for immersion is 20 to 30 hours.

Preferably, in step (2), the mixture is added dropwise to acetone, and the resulting microspheres are kept immersed in acetone for 6-10 hours.

The invention further provides the polyvinyl alcohol-zinc oxide composite microspheres obtained by the preparation method.

The invention also provides the application of the polyvinyl alcohol-zinc oxide composite microspheres in wastewater, in particular slaughter wastewater.

The invention adopts polyvinyl alcohol solution with certain concentration and polyvinyl pyrrolidone solution to be dripped into acetone solution, microspheres are formed, and after being soaked, the microspheres are filtered and placed into glutaraldehyde crosslinking agent for crosslinking. Taking out after crosslinking, and drying at room temperature (20-30 ℃) to obtain the polyvinyl alcohol microspheres with stable forms. Soaking the microspheres into a nano ZnO solution to enable the microspheres to adsorb nano ZnO, taking out and drying to obtain the polyvinyl alcohol-zinc oxide microspheres. The synthesized polyvinyl alcohol-zinc oxide (PVA-ZnO) composite microspheres are materials with mesoporous structures, have uniform pore structures on the surfaces, have larger specific surface areas, are favorable for the attachment and growth of degradation bacteria, and improve the COD degradation rate of sewage. Meanwhile, the surface is adsorbed with nano ZnO, which has a certain inhibiting effect on the growth of escherichia coli.

The invention uses the polyvinyl alcohol-zinc oxide (PVA-ZnO) composite microspheres to bear COD degrading bacteria, can carry out degradation treatment on slaughter wastewater, is green and environment-friendly, has low cost and simple operation, and the microspheres have stable shapes and can be recycled.

Detailed Description

The present invention will be further described with reference to the following examples.

Preparation of carrier microsphere

1. Preparing PVA microspheres: dissolving 10g of PVA in 90ml of deionized water, stirring for 40min at 85 ℃, and completely dissolving to obtain 10% PVA solution, namely solution A;

2. dissolving a proper amount of PVP in DMF (the mass ratio of the PVP to the PVP is =20: 0.05) to obtain a solution B, mixing the solution A and the solution B in equal volume uniformly, and standing and defoaming for later use;

3. dropwise adding the raw materials into an acetone solution, soaking for 8h, filtering out the microspheres, soaking into a glutaraldehyde crosslinking agent (glutaraldehyde: hydrochloric acid: acetone =5:1: 94) for crosslinking, and finally naturally drying the crosslinked microspheres at room temperature to obtain the porous PVA microspheres.

4. Dissolving 1g of nano ZnO in 100ml of deionized water, and dissolving the ZnO by ultrasonic oscillation for 30 min. And (3) soaking the porous PVA microspheres in a ZnO solution for 24 hours, taking out and drying to obtain the PVA-ZnO composite microspheres.

Secondly, the carrier microspheres bear the simulation effect of degrading bacteria on slaughter wastewater treatment

1. Inhibition of growth of Escherichia coli by carrier microspheres

0g (blank control group) and 0.1g (experimental group) of PVA-ZnO composite microspheres were added to 50ml of E.coli culture solution, and cultured by shaking at 32 ℃ respectively. After 12h, the turbidity of the liquid in the culture bottle without the carrier composite microspheres is greatly increased, and the turbidity of the liquid before and after culture is basically unchanged or slightly changed in the culture bottle with the carrier composite microspheres. The detection is carried out under an ultraviolet spectrophotometer with the wavelength of 600nm, and the OD value of the blank control group liquid is far higher than that of the experimental group liquid. This indicates that the growth of Escherichia coli can be normally achieved in the culture solution without the addition of the composite microspheres, while the growth of Escherichia coli is significantly inhibited in the culture solution with the addition of the microspheres.

2. Carrier microsphere for carrying COD degrading bacteria

In the load-bearing experiment, 0g (control group) and 0.1g (experimental group) of PVA-ZnO composite microspheres are respectively added into 50ml of LB culture solution, 100 mul of common-Rou COD degrading bacteria (purchased from common-Rou biotechnology, Co., Ltd.) are simultaneously inoculated, and the turbidity is respectively 0.205 and 0.201 by using an ultraviolet spectrophotometer with the wavelength of 600 nm;

after 5h incubation, the turbidity was again measured with a 600nm UV spectrophotometer at 0.546 and 0.413 respectively. The decrease in the increase in OD value in the experimental group relative to the control group was approximately considered to be the supported portion, and therefore the support ratio was calculated to be 37.82%. The carrier composite microspheres have good bearing effect on COD degrading bacteria.

3. COD degradation Effect

The ammonium sulfate with the concentration of 0.3g/100ml is selected to replace the waste water, so that a more accurate numerical value can be better determined by dripping. Under the aseptic condition, a control group (0 g of carrier) and an experimental group (0.1 g) of carriers are respectively inoculated into LB culture solution containing ammonium sulfate (the specific proportioning method is that 0.3g of ammonium sulfate, 10 ml of degradation bacterium solution, 65 ml of sterile water and 25 ml of LB culture solution), and the constant temperature shaking culture is carried out in a shaking table at 37 ℃. Sampling is carried out after 24h, COD in the culture solution is measured by a potassium permanganate method, and the degradation rate is calculated. The degradation rate of the control group is 10.74 percent, the degradation rate of the experimental group is 17.84 percent, and the degradation efficiency of the carrier bacteria is about 1.66 times of that of the free bacteria.

According to the tests, the PVA-ZnO composite microsphere-based loaded degradation bacteria is used for slaughter wastewater treatment, and is low in cost, simple and effective in operation, green and environment-friendly; the prepared carrier microspheres have obvious inhibition effect on escherichia coli, and the PVA-ZnO composite microspheres bear degrading bacteria, so that the degrading efficiency is improved.

Claims

1. A preparation method of polyvinyl alcohol-zinc oxide composite microspheres is characterized by comprising the following steps:

(1) dissolving polyvinyl alcohol in deionized water to obtain a polyvinyl alcohol solution with the mass percent of 5-15%, and marking as a solution A; dissolving polyvinylpyrrolidone in dimethylformamide to obtain a solution B, wherein the mass ratio of the polyvinylpyrrolidone to the dimethylformamide is 20: 0.02-0.1;

(3) dipping the microspheres dried in the step (2) into a zinc oxide solution for more than 12 hours, and then taking out and drying to obtain polyvinyl alcohol-zinc oxide composite microspheres;

in the step (3), the mass fraction of the zinc oxide solution is 0.5-1.5%.

2. The method of claim 1, wherein the glutaraldehyde cross-linking agent consists of glutaraldehyde, hydrochloric acid, and acetone in a mass ratio of 5:1: 94.

3. The preparation method of claim 1, wherein the zinc oxide solution is obtained by dissolving nano zinc oxide by ultrasonic treatment in deionized water.

4. The method according to claim 1, wherein in the step (3), the immersion time is 20 to 30 hours.

5. The method of claim 1, wherein in the step (2), the mixture is added dropwise to acetone, and the resulting microspheres are further immersed in acetone for 6 to 10 hours.

6. Polyvinyl alcohol-zinc oxide composite microspheres obtained by the production method according to any one of claims 1 to 5.