阅读说明：本技术 一种铜铁双金属掺杂改性粉煤灰-分子筛复合催化剂及其制备方法和应用 (Copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst and preparation method and application thereof ) 是由 徐东彦 戴萍 黄丽鑫 汪传生 于 2019-10-19 设计创作，主要内容包括：本发明涉及一种铜铁双金属掺杂改性粉煤灰-分子筛复合催化剂及其制备方法和在降解煤化工喹啉废水中的应用。本发明是将粉煤灰加入到氢氧化钠溶液中,在微波辐照下辅助碱熔,然后加入含有铜和铁的前驱体盐溶液以及十六烷基三甲基溴化铵,再置于水热反应釜中晶化,最后经洗涤、过滤、干燥和焙烧后得到铜铁双金属掺杂的改性粉煤灰-分子筛复合催化剂。本发明催化剂制备工艺简单,制备过程中无废料产生,利用得到的复合催化剂活化H<Sub>2</Sub>O<Sub>2</Sub>降解煤化工喹啉废水具有优良的催化活性和稳定性。(The invention relates to a copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst, a preparation method thereof and application thereof in degradation of quinoline wastewater in coal chemical industry. The invention adds fly ash into sodium hydroxide solution, assists alkali fusion under microwave irradiation, then adds precursor salt solution containing copper and iron and cetyl trimethyl ammonium bromide, then puts into hydrothermal reaction kettle for crystallization, finally obtains modified fly ash-molecular sieve composite catalyst doped with copper and iron bimetal through washing, filtering, drying and roasting. The catalyst of the invention has simple preparation process, no waste material is generated in the preparation process, and the obtained composite catalyst is utilized to activate H 2 O 2 The degradation of quinoline wastewater in coal chemical industry has excellent catalytic activity and stability.)

1. A preparation method of a copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst is characterized by comprising the following steps: the method specifically comprises the following steps:

(1) adding the fly ash into a sodium hydroxide solution with the mass concentration of 10-30% to obtain a suspension A;

(2) transferring the suspension A into a microwave reactor, assisting alkali fusion under microwave irradiation, and then adjusting the pH value to about 9 by using an HCl solution to obtain a suspension B, wherein the suspension B consists of insoluble modified fly ash and a solution containing a silicon element and an aluminum element;

(3) weighing hexadecyl trimethyl ammonium bromide, dissolving the hexadecyl trimethyl ammonium bromide in water, and adding the hexadecyl trimethyl ammonium bromide into the suspension B with the well adjusted pH value under the stirring condition;

(4) weighing Fe (NO)₃)₃·9H₂O and Cu (NO)₃)₂·3H₂Preparing a metal precursor salt solution from O, adding the solution into a suspension B containing hexadecyl trimethyl ammonium bromide, carrying out ultrasonic treatment for 40min, and then stirring for 2h to obtain a suspension C;

(5) transferring the suspension C dispersed with the metal precursor into a hydrothermal reaction kettle lined with polytetrafluoroethylene, putting the hydrothermal reaction kettle into an oven for hydrothermal crystallization, wherein the crystallization temperature is 60-100 ℃, and the time is 12-24 hours;

(6) and after the crystallization reaction is finished, filtering and washing the metal-doped modified fly ash-molecular sieve compound to be neutral, drying and then transferring the compound into a muffle furnace for roasting for 3 hours.

2. The preparation method of the copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst according to claim 1, which is characterized by comprising the following steps of: the mass ratio of the fly ash to the sodium hydroxide in the step (1) is 1: 1.2.

3. The preparation method of the copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst according to claim 1, which is characterized by comprising the following steps of: in the step (2), the microwave power is 160-320W, and the irradiation time is 15-30 min.

4. The preparation method of the copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst according to claim 1, which is characterized by comprising the following steps of: the mass ratio of the hexadecyl trimethyl ammonium bromide to the fly ash in the step (3) is 1: 6-8.

5. The preparation method of the copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst according to claim 1, which is characterized by comprising the following steps of: in the step (4), the mass ratio of copper to iron in the metal precursor salt solution is 1:1.

6. The preparation method of the copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst according to claim 1, which is characterized by comprising the following steps of: the roasting temperature in the step (6) is 300-500 ℃.

7. The copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst prepared by the preparation method of any one of claims 1 to 6.

8. The use of the copper-iron bimetallic doped modified fly ash-molecular sieve composite catalyst of claim 7 in the degradation of quinoline wastewater in coal chemical industry.

9. The application of the copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst in degrading quinoline wastewater in coal chemical industry according to claim 8 is characterized in that: the oxidant jointly used by the copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst in the process of degrading quinoline wastewater is H₂O₂。

Technical Field

The invention belongs to the field of waste recycling, and particularly relates to a copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst, and a preparation method and application thereof.

Background

The fly ash is mainly a product formed by burning coal dust in coal-fired power plants, smelting, chemical industries and other industries at high temperature, and is one of industrial solid wastes with the largest discharge amount in China. The building material industry is the most main comprehensive utilization field of the fly ash in China, and once the fly ash disposal problem caused by the rapid growth of the thermal power industry is greatly relieved. However, as the economic development of China enters a new normal state, the requirements of the building industry and infrastructure on traditional building materials such as cement and concrete are further reduced, and the fly ash treatment and utilization of China face more severe challenges.

Based on the self-properties and chemical components of the fly ash (containing more than 70 percent of Al)₂O₃And SiO₂) The preparation of high value-added products by proper modification is of more realistic significance. In the existing research, people modify fly ash by acid-base modification, synthesis of molecular sieve and loading of metal oxide to improve activity. Wherein, acid-base modification can generate liquid waste, and has limited effect of improving the activity of the fly ash; the process of synthesizing the molecular sieve is complicated and complicated, and the yield is low; the way of loading metal is mostly stopped in the dipping method, the steps are more, and the dispersion of the metal is not facilitated. Therefore, there is a need to develop an environmentally friendly and efficient improved method for treating fly ash and expanding its application range.

Disclosure of Invention

The invention aims to provide a preparation method of a copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst and application of the copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst in degradation of quinoline wastewater in coal chemical industry. By utilizing the technical scheme of the invention, the problems of complex process, harsh modification conditions and uneven metal dispersion in other methods for preparing the molecular sieve by utilizing the fly ash can be solved, the purposes of preparing the modified fly ash catalyst with more stable structure, higher metal dispersion degree and better catalytic effect are realized, and the preparation process is simple.

In order to realize the purpose of the invention, the invention adopts the following technical scheme to realize:

the invention provides a preparation method of a copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst, which specifically comprises the following steps:

(1) adding the fly ash into a sodium hydroxide solution with the mass concentration of 10-30% to obtain a suspension A;

(2) transferring the suspension A into a microwave reactor, assisting alkali fusion under microwave irradiation, and then adjusting the pH value to about 9 by using an HCl solution to obtain a suspension B, wherein the suspension B consists of insoluble modified fly ash and a solution containing a silicon element and an aluminum element;

(3) weighing hexadecyl trimethyl ammonium bromide, dissolving the hexadecyl trimethyl ammonium bromide in water, and adding the hexadecyl trimethyl ammonium bromide into the suspension B with the well adjusted pH value under the stirring condition;

(4) weighing Fe (NO)₃)₃·9H₂O and Cu (NO)₃)₂·3H₂Preparing a metal precursor salt solution from O, adding the solution into a suspension B containing hexadecyl trimethyl ammonium bromide, carrying out ultrasonic treatment for 40min, and then stirring for 2h to obtain a suspension C;

(5) transferring the suspension C dispersed with the metal precursor into a hydrothermal reaction kettle lined with polytetrafluoroethylene, putting the hydrothermal reaction kettle into an oven for hydrothermal crystallization, wherein the crystallization temperature is 60-100 ℃, and the time is 12-24 hours;

(6) and after the crystallization reaction is finished, filtering and washing the metal-doped modified fly ash-molecular sieve compound to be neutral, drying and then transferring the compound into a muffle furnace for roasting for 3 hours.

Further: the mass ratio of the fly ash to the sodium hydroxide in the step (1) is 1: 1.2.

Further: in the step (2), the microwave power is 160-320W, and the irradiation time is 15-30 min.

Further: the mass ratio of the hexadecyl trimethyl ammonium bromide to the fly ash in the step (3) is 1: 6-8.

Further: in the step (4), the mass ratio of copper to iron in the metal precursor salt solution is 1:1.

Further: the roasting temperature in the step (6) is 300-500 ℃.

The invention also provides the copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst prepared by the preparation method.

The invention also provides application of the copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst in degradation of quinoline wastewater in coal chemical industry.

Further: the copper-iron bimetal doped modified fly ash-moleculeThe combined oxidant of the sieve composite catalyst in the process of degrading quinoline wastewater is H₂O₂。

Compared with the prior art, the invention has the advantages and beneficial effects that:

the invention adopts a microwave irradiation auxiliary alkali fusion method to modify the fly ash, simultaneously obtains a solution containing silicon element and aluminum element, adds a template agent and a metal precursor salt solution after adjusting the pH value, and obtains the modified fly ash-molecular sieve composite catalyst with highly dispersed metal by one step of hydrothermal crystallization. The catalyst has simple preparation process and mild conditions, does not need to add a silicon source or an aluminum source, and has high utilization rate of the fly ash.

The copper-iron bimetal doped modified fly ash-molecular sieve composite catalyst prepared by the invention is used for H₂O₂Has good activation effect and can efficiently degrade quinoline in the coal chemical industry wastewater.

Drawings

FIG. 1 is a TEM image of the Cu-Fe bimetal doped modified fly ash-molecular sieve composite catalyst prepared in example 1 of the present invention.

FIG. 2 shows the efficiency of the catalysts prepared in examples 1-3 of the present invention and comparative example 1 for degrading quinoline wastewater.

Detailed Description

The technical solutions of the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments, and the present invention is not limited to these embodiments.

The fly ash used in the examples of the present invention has the following chemical composition:

components	SiO2	Al2O3	Fe2O3	CaO	SO3	CuO	Others
								Composition (wt%)	41.07	17.69	8.58	13.44	7.72	0.05	11.45