Preparation method of composite heterojunction photocatalyst and application thereof

Abstract

The invention discloses a preparation method of a composite heterojunction photocatalyst and an application thereof, and belongs to the field of resource utilization and environment purification. Thecomposite heterojunction photocatalyst comprises 5-30 parts of high-iron red mud and 5-30 parts of a reducing agent. The preparation method comprises the following steps: uniformly mixing the high-iron red mud and the reducing agent, and molding under the pressure of 0.5-3MPa; calcining the obtained mixture at the temperature of 200 to 400 DEG C; and finally, taking out the mixture, grinding and sieving to obtain the photocatalyst. According to the method, Fe2O3 in the high-iron red mud is partially converted into magnetic Fe3O4 in a biomass pyrolysis mode, so that the catalyst has magnetism and is convenient to recycle; in the calcining process, silicon-aluminum minerals of the high-iron red mud are combined with Fe2O3 and TiO2, so that Fe2O3 and TiO2 generate heterojunctions; the pyrolysis product carbon is combined with catalyst particles, so that the adsorption and conductivity of the catalyst are improved; the degradation efficiency of the catalyst is favorably improved; accordingto the method, the low-molecular pollutants which are not thoroughly degraded can be adsorbed to the surface of the catalyst to be degraded again, secondary pollution is prevented, the whole degradation process is easy to operate, and the self-cleaning purpose is effectively achieved. The adopted raw materials are easily available and economically feasible.

Description

technical field [0001] The invention belongs to the technical field of resource utilization of industrial solid waste and environmental purification, and specifically relates to a self-cleaning, high-conductivity and easy-to-recover composite heterojunction photocatalyst and a preparation method thereof. Background technique [0002] High-iron red mud is a strong alkaline industrial solid waste discharged during the production of alumina by the Bayer process. With the development of the alumina industry, the discharge of high-speed iron red mud is increasing day by day. In 2018, the discharge of high-speed iron red mud in my country has exceeded 40 million tons, but its resource utilization rate is only about 4%. The high-speed iron red mud is disposed of in the open air or by dams, which not only occupies a large amount of land, but also causes serious pollution to the environment. Therefore, how to improve the resource utilization rate of high-speed iron red mud and broad...

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Problems solved by technology

The above-mentioned patents all use red mud to prepare photocatalysts or photocatalyst carriers, but due to the influence of the catalyst's non-magnetic properties, low electrical conductivity and poor adsorption performance, it cannot be effectively recovered at present.

At the same time, the photocatalytic efficiency is low and there may be secondary pollution in the process of degrading organic pollutants. In addition, the processing technology for reuse is complex, energy-consuming, not environmentally friendly, and high in cost. As a result, the preparation of photocatalysts from red mud cannot be promoted and widely used. application

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