阅读说明：本技术 一种多孔磁性半导体复合光催化剂的制备方法 (Preparation method of porous magnetic semiconductor composite photocatalyst ) 是由 李慧芝 赵蔚琳 赵可贤 于 2020-04-10 设计创作，主要内容包括：本发明公开了一种多孔磁性半导体复合光催化剂的制备方法,其特征在于,以兔毛为碳源,氯化锌和硫脲为溶剂水热法制备水溶性锌、硫掺杂碳量子点；采用锌、硫掺杂碳量子点修饰磷酸氢二钠,滴加硝酸银溶液,制备得量子点修饰磷酸银；在反应器中,分别加入,去离子水：60~66%,蛋白粉：6~10%,刺槐豆胶：3~6%,搅拌溶解,量子点修饰磷酸银：18~22%,氨基化三氧化二铁磁性纳米颗粒：4~6%,超声分散20 min,得粘稠悬浮液,挤压成球体,于5%的氯化镁溶液中固化12 h,固液分离,洗涤,冷冻干燥,制得多孔磁性半导体复合光催化剂。本发明具有制备方法简单,稳定性好、可降解等特点；催化剂容易回收,催化活性高。(The invention discloses a preparation method of a porous magnetic semiconductor composite photocatalyst, which is characterized in that water-soluble zinc and sulfur-doped carbon quantum dots are prepared by a hydrothermal method by taking rabbit hair as a carbon source and zinc chloride and thiourea as solvents; modifying disodium hydrogen phosphate by adopting zinc and sulfur doped carbon quantum dots, and dropwise adding a silver nitrate solution to prepare quantum dot modified silver phosphate; in the reactor, deionized water: 60-66%, protein powder: 6-10%, locust bean gum: 3-6%, stirring and dissolving, and modifying the silver phosphate by the quantum dots: 18-22%, aminated iron sesquioxide magnetic nanoparticles: 4-6 percent of the porous magnetic semiconductor composite photocatalyst is ultrasonically dispersed for 20 min to obtain a viscous suspension, the viscous suspension is extruded into a sphere, the sphere is solidified in a 5 percent magnesium chloride solution for 12 h, and the porous magnetic semiconductor composite photocatalyst is prepared by solid-liquid separation, washing and freeze drying. The invention has the characteristics of simple preparation method, good stability, degradability and the like; the catalyst is easy to recover and has high catalytic activity.)

1. A preparation method of a porous magnetic semiconductor composite photocatalyst is characterized by comprising the following process steps:

(1) preparing zinc and sulfur doped carbon quantum dots, namely adding 84-88 mass percent of 2.0 mol/L zinc chloride and 4-8 mass percent of thiourea into a reaction kettle with a polytetrafluoroethylene lining, stirring and dissolving, pretreating rabbit hair powder, covering a sealing cover, placing the rabbit hair powder into a constant temperature box, keeping the temperature at 120 +/-2 ℃, reacting for 8 hours to obtain colorless transparent liquid, dialyzing, and drying to obtain water-soluble zinc and sulfur doped carbon quantum dots, wherein the sum of the mass percent of the components is one hundred percent;

(2) preparing quantum dot modified silver phosphate, namely adding 83-88 mass percent of deionized water, 4-8 mass percent of disodium hydrogen phosphate and 0.5-2.0 mass percent of zinc and sulfur doped carbon quantum dots into a reactor, stirring and dissolving, dropwise adding 5-9 mass percent of 12 mol/L silver nitrate solution, keeping the sum of the mass percent of the components at one hundred percent, stirring and reacting for 18 hours in a dark place, carrying out solid-liquid separation, washing and drying to obtain the quantum dot modified silver phosphate;

(3) preparing a porous magnetic semiconductor composite photocatalyst: adding deionized water into a reactor according to the following composition by mass percent: 60-66%, protein powder: 6-10%, locust bean gum: 3-6%, stirring and dissolving, and modifying the silver phosphate by the quantum dots: 18-22%, aminated iron sesquioxide magnetic nanoparticles: 4-6 percent of the porous magnetic semiconductor composite photocatalyst is obtained by ultrasonic dispersion for 20 min, wherein the sum of the mass percentages of the components is one hundred percent, a viscous suspension is obtained, the viscous suspension is extruded into a sphere, the sphere is solidified in a 5 percent magnesium chloride solution for 12 hours, and the porous magnetic semiconductor composite photocatalyst is obtained by solid-liquid separation, washing and freeze drying.

2. The preparation method of the porous magnetic semiconductor composite photocatalyst according to claim 1, wherein the pre-treated rabbit hair powder in step (1) is prepared by washing rabbit hair with water to remove impurities, drying, pulverizing, sieving with a 100-mesh sieve, soaking the rabbit hair powder in 10% hydrogen peroxide solution by mass for 6h according to a solid-to-liquid ratio of 1: 40m L, boiling for 5min, cooling, washing with deionized water, performing solid-liquid separation, and drying.

3. The method for preparing the porous magnetic semiconductor composite photocatalyst according to claim 1, wherein the molar ratio of disodium hydrogen phosphate to silver nitrate in step (2) is 1: 3-3.2.

4. The method for preparing the porous magnetic semiconductor composite photocatalyst according to claim 1, wherein in the step (3), the extruded sphere has a particle size of 0.5-2.0 mm.

5. The porous magnetic semiconductor composite photocatalyst prepared by the method for preparing the porous magnetic semiconductor composite photocatalyst according to claim 1.

Technical Field

The invention relates to the technical field of preparation of supported catalysts, in particular to a preparation method of a porous magnetic semiconductor composite photocatalyst and application of the porous magnetic semiconductor composite photocatalyst in degradation of organic pollutants.

Background

The environmental pollution problem is one of the major problems to be solved urgently by human beings nowadays. The photocatalytic oxidation method has the advantages of low energy consumption, mild purification conditions, no secondary pollution and the like for treating environmental pollution, so the photocatalytic oxidation method is concerned as a green chemical process. Conventional semiconductor photocatalysts such as TiO₂And ZnO, which has a wider forbidden band width and can only absorb 3% -5% of solar energy. Bi-based and Ag-based semiconductors have the problems of narrow visible light absorption range, strong light corrosivity and the like, and the recombination rate of photon-generated carriers of most semiconductors is high, so that the potential application of semiconductor photocatalysts is limited. Therefore, an increasing amount of research is being conducted to widen the visible light absorption range of the photocatalyst and to promote the separation efficiency of carriers to improve the photocatalytic activity and stability thereof.

A Carbon Quantum Dot (CQDs) is a novel Carbon nano material with outstanding fluorescence recently discovered, consists of quasi-discrete spherical Carbon nano particles with the size less than 10 nm, and is an environment-friendly material with excellent water solubility, high biocompatibility and low toxicityElectron transport performance, can effectively transfer and store photoproduction electrons in the catalyst, achieves the effect of improving charge separation efficiency, and the photoproduction electrons and O adsorbed on the surface of the photoproduction electrons₂The combination can form superoxide radical to realize multi-site catalysis, the ④ pi-pi conjugated structure is favorable for the adsorption of organic pollutants on the surface of the photocatalyst, ⑤ can prevent the catalyst from dissolving and effectively prevent the photo corrosion after forming a core-shell structure on the CQDs layer and the CQDs layer, and the like, so the CQDs is compounded with the semiconductor and is an important way for improving the performance of the photocatalyst.

According to the preparation method, rabbit hair is used as a carbon source, zinc oxide and thiourea are used as solvents to prepare zinc and sulfur doped carbon quantum dots, then the semiconductor photocatalyst silver phosphate is modified, protein powder and magnetic particles are added into locust bean gum, and the porous magnetic semiconductor composite photocatalyst is prepared by freeze drying.

Disclosure of Invention

The invention aims to provide a preparation method of a porous magnetic semiconductor composite photocatalyst.

A preparation method of a porous magnetic semiconductor composite photocatalyst is characterized by comprising the following process steps:

(1) preparing zinc and sulfur doped carbon quantum dots, namely adding 84-88 mass percent of 2.0 mol/L zinc chloride and 4-8 mass percent of thiourea into a reaction kettle with a polytetrafluoroethylene lining, stirring and dissolving, pretreating rabbit hair powder, covering a sealing cover, placing the rabbit hair powder into a constant temperature box, keeping the temperature at 120 +/-2 ℃, reacting for 8 hours to obtain colorless transparent liquid, dialyzing, and drying to obtain water-soluble zinc and sulfur doped carbon quantum dots, wherein the sum of the mass percent of the components is one hundred percent;

(2) preparing quantum dot modified silver phosphate, namely adding 83-88 mass percent of deionized water, 4-8 mass percent of disodium hydrogen phosphate and 0.5-2.0 mass percent of zinc and sulfur doped carbon quantum dots into a reactor, stirring and dissolving, dropwise adding 5-9 mass percent of 12 mol/L silver nitrate solution, keeping the sum of the mass percent of the components at one hundred percent, stirring and reacting for 18 hours in a dark place, carrying out solid-liquid separation, washing and drying to obtain the quantum dot modified silver phosphate;

(3) preparing a porous magnetic semiconductor composite photocatalyst: adding deionized water into a reactor according to the following composition by mass percent: 60-66%, protein powder: 6-10%, locust bean gum: 3-6%, stirring and dissolving, and modifying the silver phosphate by the quantum dots: 18-22%, aminated iron sesquioxide magnetic nanoparticles: 4-6 percent of the porous magnetic semiconductor composite photocatalyst is obtained by ultrasonic dispersion for 20 min, wherein the sum of the mass percentages of the components is one hundred percent, a viscous suspension is obtained, the viscous suspension is extruded into a sphere, the sphere is solidified in a 5 percent magnesium chloride solution for 12 hours, and the porous magnetic semiconductor composite photocatalyst is obtained by solid-liquid separation, washing and freeze drying.

The pre-treatment rabbit hair powder in the step (1) is prepared by washing rabbit hair with water to remove impurities, drying, crushing, sieving with a 100-mesh sieve, soaking the rabbit hair powder in a hydrogen peroxide solution with the mass percentage concentration of 10% according to the solid-to-liquid ratio of 1: 40m L for 6h, boiling for 5min, cooling, washing with deionized water, carrying out solid-liquid separation, and drying.

The molar ratio of the disodium hydrogen phosphate to the silver nitrate in the step (2) is 1: 3-3.2.

Extruding into a sphere in the step (3), wherein the particle size of the sphere is 0.5-2.0 mm.

The invention also aims to apply the porous magnetic semiconductor composite photocatalyst to analysis and evaluation of catalytic degradation of methyl orange, rhodamine B, azo dyes, bisphenol A, tetracycline, organic pollutants and the like in wastewater.

The invention has the beneficial effects that:

(1) according to the porous magnetic semiconductor composite photocatalyst provided by the application, water-soluble zinc and sulfur-doped carbon quantum dots are synthesized by a solvothermal method with rabbit hair as a carbon source and zinc chloride and thiourea as solvents, silver phosphate is modified by the quantum dots, and then the catalyst is immobilized in a biological magnetic porous material, so that the porous magnetic semiconductor composite photocatalyst is more green, economic and environment-friendly compared with the traditional process. The rabbit hair is widely distributed, has short growth cycle, and is cheap and easily available as a carbon source raw material.

(2) The porous magnetic semiconductor composite photocatalyst prepared by adopting a solvothermal method is simple to operate, adopts quantum dots to modify silver phosphate, then is immobilized in a biomagnetic porous material, has uniformly dispersed particles, has the characteristics of being porous, large in specific surface area, high in catalytic efficiency, light in weight, low in price, good in stability, degradable, environment-friendly and the like, is a renewable resource, has good physicochemical stability and excellent mechanical stability, and can widen the absorption range of the catalyst to sunlight; the material has up-conversion photoluminescence characteristics, and can excite a semiconductor to form more photo-generated electron-hole pairs; the visible light catalysis efficiency is high.

(3) The porous magnetic semiconductor composite photocatalyst prepared by the solvothermal method has magnetism and is easy to separate.

Detailed Description