阅读说明：本技术 一种高效铝酸锌/钼酸铋异质结紫外光催化剂及其制备方法和应用 (Efficient zinc aluminate/bismuth molybdate heterojunction ultraviolet light catalyst and preparation method and application thereof ) 是由 田庆文 房桂干 丁来保 邓拥军 沈葵忠 施英乔 盘爱享 韩善明 焦健 李红斌 梁 于 2019-09-27 设计创作，主要内容包括：本发明公开了一种高效铝酸锌/钼酸铋异质结紫外光催化剂,所述的催化剂是所述的光催化剂是由ZnAl<Sub>2</Sub>O<Sub>4</Sub>和Bi<Sub>2</Sub>MoO<Sub>6</Sub>组合形成的异质结催化剂,其中ZnAl<Sub>2</Sub>O<Sub>4</Sub>与Bi<Sub>2</Sub>MoO<Sub>6</Sub>质量比为1:3~500。本发明制备方法简便,价格低廉,催化性能高。在紫外光的照射下,该异质结光催化剂对于亚甲蓝印染废水的去除率高达86.36%和桉木化机浆生化废水的COD去除率为50.88%,在印染、造纸和林化等工业废水等领域具有广阔的前景。(The invention discloses a high-efficiency zinc aluminate/bismuth molybdate heterojunction ultraviolet light catalyst, wherein the catalyst is prepared from ZnAl 2 O 4 And Bi 2 MoO 6 In combination, form a heterojunction catalyst in which ZnAl is present 2 O 4 And Bi 2 MoO 6 The mass ratio is 1:3 ~ 500. the invention has simple preparation method, low cost and high catalytic performance, and the heterogeneous material is irradiated by ultraviolet lightThe removal rate of the photocatalyst on methylene blue printing and dyeing wastewater reaches 86.36 percent, the removal rate of COD (chemical oxygen demand) of eucalyptus chemi-mechanical pulp biochemical wastewater is 50.88 percent, and the photocatalyst has wide prospects in the fields of industrial wastewater such as printing and dyeing, papermaking, forestry and the like.)

1. The high-efficiency zinc aluminate/bismuth molybdate heterojunction ultraviolet photocatalyst is characterized by comprising ZnAl₂O₄And Bi₂MoO₆In combination, form a heterojunction catalyst in which ZnAl is present₂O₄And Bi₂MoO₆The mass ratio is 1:3 ~ 500.

2. The method for preparing the high-efficiency zinc aluminate/bismuth molybdate heterojunction ultraviolet photocatalyst as claimed in claim 1, which is characterized by comprising the following steps:

(1) preparation of ZnAl₂O₄Powder;

(2) preparation of ZnAl₂O₄/Bi₂MoO₆Photocatalyst: ZnAl is put into₂O₄And molybdate are dissolved in distilled water and added into the bismuth salt solution at a certain speed, NaOH is added to adjust the pH of the solution, the solution is stirred uniformly by ultrasound and is placed in a hydrothermal kettle, and the product after the reaction is washed by water and alcohol and dried in vacuum, thus obtaining ZnAl₂O₄/Bi₂MoO₆A heterojunction photocatalyst.

3. The method according to claim 2, wherein the molar ratio of bismuth salt to molybdate is 3:1 ~ 2: 3.

4. The method of claim 2, wherein the solution pH is adjusted to 4 ~ 8 with NaOH solution.

5. The preparation method of claim 2, wherein the reaction conditions in the hydrothermal kettle are 140 ~ 200 ℃ for 12 ~ 36 h.

6. The preparation method according to claim 2, wherein in the step (2), the bismuth salt is any one or two of bismuth nitrate, bismuth sulfate, bismuth chloride and bismuth acetate; the molybdate-containing salt is any one of sodium molybdate, ammonium molybdate, potassium molybdate or cerium molybdate.

7. The production method according to claim 2, wherein in the step (2), the dropping rate is 1 ~ 10 ml/min.

8. The use of the high efficiency zinc aluminate/bismuth molybdate heterojunction uv catalyst of claim 1 in the treatment of wastewater under uv light.

9. The use according to claim 8, wherein the wastewater is any one of printing and dyeing, papermaking and forestry chemical wastewater.

Technical Field

The invention relates to the field of photocatalytic materials and industrial wastewater treatment, in particular to industrial wastewater which is difficult to biodegrade, such as printing, papermaking, forestry and the like, and specifically relates to ZnAl₂O₄/Bi₂MoO₆A preparation method of the photocatalyst and application thereof.

Background

With the rapid development of printing and dyeing, pulping and papermaking and forest chemical industry, the industrial wastewater pollution problem increasingly draws high attention all over the world. In consideration of the cost of wastewater treatment, industrial wastewater is generally treated by organisms such as aerobic and anaerobic organisms. However, the wastewater after biochemical treatment has a heavy color, and contains part of residual macrocyclic refractory organics such as refractory COD, toxic phenols and the like, and trace pollutants, so that the wastewater must be further treated to reach the standard of safe discharge. Therefore, advanced treatment technology for industrial wastewater has become one of the hot spots and important points of wastewater treatment research. The main techniques are as follows: coagulation technology, adsorption technology, membrane separation technology, advanced oxidation technology, biological treatment technology, combined treatment of various technologies and the like. At present, most of the treatment research on industrial wastewater by the technologies mainly stays in the exploration stage, and the problems of high operation cost, harsh operation conditions and the like still exist. The advanced treatment technology which has been applied to engineering is only a FENTON oxidation method, and although the advanced treatment technology can meet the new discharge requirement, the advanced treatment technology has the defects of high operation cost, large amount of used chemicals, large amount of raw sludge which is complicated to operate and ineffective treatment. The environmental protection pressure of enterprises is generally increased, and the market competitiveness of the enterprises is seriously weakened. Research and development of brand-new low-cost high-efficiency advanced treatment technology are urgent requirements of advanced wastewater treatment engineering. Ultraviolet light catalytic oxidation technology has become a hot spot of great interest in recent years.

Bi₂MoO₆Because of the advantages of low price, high efficiency, no toxicity, stable chemical property and the like, the photocatalyst is widely applied to the field of photocatalysis. Chinese patent (CN108311135A) discloses a preparation method of a bismuth molybdate photocatalyst, which has good adsorption performance on heavy metal wastewater containing mercury and also has strong catalytic reduction degradation capability on heavy metal mercury. The Chinese invention patent (CN105498751A) provides a preparation method of hollow spherical nano gamma-bismuth molybdate, which has good photocatalytic performance and can degrade the concentration of methyl orange solution from 1g/L to 0.01g/L under the irradiation of visible light for 30 min. However,the photocatalyst has the defects of high combination rate of photoproduction electrons and holes, low quantum efficiency and the like, and the photocatalytic performance of the photocatalyst is seriously influenced. Thus, construction of Bi₂MoO₆The base heterojunction photocatalyst can obviously improve the photocatalytic performance. Wang et al prepared Bi by hydrothermal method_3.64Mo_0.36O_6.55/Bi₂MoO₆The heterojunction catalyst has pure Bi for degrading rhodamine B solution₂MoO₆1.98 times of and Bi_3.64Mo_0.36O_6.554.88 times (Journal of Alloys and Compounds, 766(2018) 1037-. ZnAl₂O₄Has the advantages of strong photoresponse, stable structure, various compositions, narrow band gap and the like, and is widely applied to the field of environmental protection. Chaudhary et al prepared ZnAl by sol-gel method₂O₄Nanopowders, which were systematically studied on dyeing wastewater such as Eosin B (EB), Congo Red (CR), Chicago Sky Blue (CSB), Methyl Orange (MO) and Methylene Blue (MB), were found to have degradation rates higher than 90% (Materials Science)&Engineering B227 (2018) 136-144). According to the reference of the literature, ZnAl is not seen temporarily₂O₄/Bi₂MoO₆The preparation and application of the heterojunction photocatalyst are reported.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to solve the problems of high recombination property of photoproduction holes and electrons, low quantum efficiency, poor catalytic performance and the like in a photocatalyst and the problems of high industrial wastewater treatment cost, large sludge amount, large pollution and the like, and provides an efficient ZnAl₂O₄/Bi₂MoO₆A preparation method and application of a heterojunction ultraviolet photocatalyst.

The technical scheme is as follows: in order to realize the technical purpose, the invention provides an efficient ZnAl₂O₄/Bi₂MoO₆The heterojunction ultraviolet photocatalyst is made of ZnAl₂O₄And Bi₂MoO₆In combination, form a heterojunction catalyst in which ZnAl is present₂O₄And Bi₂MoO₆The mass ratio of ZnAl to ZnAl is 1: 3-500₂O₄Is added according to 0.2 wt% to 30 wt%In the reaction.

The invention further provides the high-efficiency ultraviolet ZnAl₂O₄/Bi₂MoO₆The preparation method of the photocatalyst comprises the following steps:

(1) preparation of ZnAl₂O₄Powder;

(2) preparation of ZnAl₂O₄/Bi₂MoO₆Photocatalyst: ZnAl is put into₂O₄And molybdate are dissolved in distilled water and added into the aqueous solution of bismuth salt at a certain speed, NaOH is added to adjust the pH of the solution, the solution is stirred uniformly by ultrasound and is placed in a hydrothermal kettle, and the product after the reaction is washed by water and alcohol and dried in vacuum, thus obtaining ZnAl₂O₄/Bi₂MoO₆A heterojunction photocatalyst.

Wherein the molar ratio of bismuth salt to molybdate is 3: 1-2: 3, the pH of the solution is adjusted to 4-8 by using NaOH solution, and the reaction is carried out in a hydrothermal kettle under the reaction condition of 140-200 ℃ for 12-36 h.

Specifically, in the step (2), the bismuth salt is any one or two of bismuth nitrate, bismuth sulfate, bismuth chloride and bismuth acetate; the molybdate-containing salt is any one of sodium molybdate, ammonium molybdate, potassium molybdate or cerium molybdate.

Preferably, in the step (2), the dropping speed is 1-10 ml/min.

The invention further provides ZnAl₂O₄/Bi₂MoO₆The application of the heterojunction ultraviolet catalyst is that the heterojunction ultraviolet catalyst is used for treating chemical wastewater of printing and dyeing, papermaking and forest industry under ultraviolet light.

Has the advantages that: compared with the prior art, the invention has the following advantages:

(1) ZnAl prepared by the method of the invention₂O₄/Bi₂MoO₆The material has excellent catalytic performance, stable chemical structure and reusability, and has good effect on treatment of industrial wastewater of printing and dyeing, papermaking, forest chemical industry and the like;

(2) ZnAl prepared by the invention₂O₄/Bi₂MoO₆The photocatalyst belongs to the field of heterojunction, and can inhibit the generation of lightThe combination of electrons and holes improves the performance of photocatalytic reaction.

Drawings

FIG. 1 shows Bi₂MoO₆,ZnAl₂O₄And ZnAl₂O₄/Bi₂MoO₆XRD patterns of the heterojunctions, wherein ZB1-ZB6 correspond to 0.2 wt% ZnAl₂O₄/Bi₂MoO₆、0.5wt％ZnAl₂O₄/Bi₂MoO₆、 1wt％ZnAl₂O₄/Bi₂MoO₆、3wt％ZnAl₂O₄/Bi₂MoO₆、5wt％ZnAl₂O₄/Bi₂MoO₆And 30 wt% ZnAl₂O₄/Bi₂MoO₆；

FIG. 2 shows Bi₂MoO₆And 0.5 wt% ZnAl₂O₄/Bi₂MoO₆(ZB2) wherein (a) is Bi₂MoO₆And 0.5 wt% ZnAl₂O₄/Bi₂MoO₆(ZB2) and (b) to (f) are high-resolution XPS spectra of Bi, Mo, O, Zn and Al elements, respectively;

FIG. 3 is SEM, HRTEM and EDS images of the prepared catalyst, wherein (a) is Bi₂MoO₆SEM picture of (1); (b) is 5 wt% ZnAl₂O₄/Bi₂MoO₆SEM picture of (1); (c) is 5 wt% ZnAl₂O₄/Bi₂MoO₆A TEM image of (B); (d) is 5 wt% ZnAl₂O₄/Bi₂MoO₆Selecting an electron diffraction pattern; (e) is 5 wt% ZnAl₂O₄/Bi₂MoO₆EDS spectrum of (a);

catalyst 5 wt% ZnAl prepared in FIG. 4 position₂O₄/Bi₂MoO₆The TEM-EDX scanning spectrum of (a), wherein, the pictures (b) to (f) are Mapping pictures of corresponding Bi, Mo, O, Zn and Al elements respectively.

Detailed Description

The invention provides a high-efficiency ZnAl₂O₄/Bi₂MoO₆A heterojunction photocatalyst byThe method comprises the following steps:

(1) preparation of ZnAl₂O₄Powder: preparation of ZnAl by using existing technique₂O powders, e.g. as referred to (microporouus and Mesoporous Materials 163(2012)29-33)

(2) Preparation of ZnAl₂O₄/Bi₂MoO₆Photocatalyst: ZnAl is put into₂O₄Dissolving bismuth salt and molybdate in distilled water, adding into molybdate water solution at a certain speed, adding NaOH to adjust pH of the solution, ultrasonically stirring, placing in a hydrothermal kettle, washing the product with water and alcohol, and vacuum drying to obtain ZnAl₂O₄/Bi₂MoO₆A heterojunction photocatalyst.

The technical solution of the present invention is further illustrated by the following examples.