Method for degrading subaqueous organochlorine pesticide in water by photocatalysis

Abstract

The invention relates to a method for degrading organochlorine pesticide in water through photocatalysis, which is characterized in that a porous ceramic flake carrying nickel-titanium composite oxideis used as a carrier catalyst; the carrier catalyst is placed in an aqueous solution to be treated; under the irradiation of ultraviolet light, the organochlorine pesticide in the water can be rapidly decomposed. The preparation method for the carrier catalyst comprises the following steps: a nanometer nickel-titanium composite oxide powder body after ultrasonic treatment is scattered in deionized water to form suspended mother liquor; the porous ceramic flake after silanization treatment is immersed in the suspended mother liquor and is kept stand; and the ceramic flake is directly dried, calcined and cooled, and then the carrier catalyst can be obtained. The method can be used for treating various species of wastewater containing the organochlorine pesticide, and can be used for degrading organochlorine pesticide residue in foods or Chinese herbal liquid medicine extracts.

Description

technical field [0001] The invention relates to a method for degrading pesticides, in particular to a method for photocatalytically degrading organochlorine pesticides in aqueous solution, and belongs to the technical field of catalysis. Background technique [0002] As we all know, chemical pesticides play an extremely important role in the production of agricultural products such as grain, vegetables, fruits, tea and Chinese medicinal materials, but the use of pesticides also brings many adverse consequences. For example: the wastewater generated during the production and use of pesticides will cause serious damage to the ecological environment, and the pesticides left in agricultural products seriously threaten people's health. Organochlorine pesticides, such as HCH and DDT, have broad-spectrum and high-efficiency killing effects on pests and diseases, and were used on a large scale in the early years. Due to their stable chemical properties, slow degradation speed, heat ...

AI Technical Summary

Problems solved by technology

At present, the degradation methods of common organochlorine pesticides all have some defects more or less: (1) The degradation selectivity by microorganisms is relatively high, but the cultivation of strains is very troublesome, and the strains have very strict requirements on temperature during degradation. Only at its optimum temperature can it have a high degradation rate, and it is difficult to use it on a large scale; (2) Ozone oxidation degradation has a broad spectrum, but it will also destroy the active ingredients at the same time, so it is more suitable for industrial wastewater treatment. It takes a long time to degrade, and the production cost of ozone is relatively high

(3) The use of mechanical ball milling for dechlorination is suitable for solid powder materials. Usually, CaO and drug-containing materials are mixed together in an argon atmosphere, and ball milled in a steel tank. After more than ten hours, the dechlorination in the material can be basically removed. Chlorine-containing pesticides, this method is time-consuming, expensive, and narrowly applicable; (4) The use of photocatalytic degradation technology has broad prospects. This method utilizes electron-hole pairs with redox capabilities produced by photocatalysts under the action of ultraviolet light Targets are effectively decomposed, and most of the literature uses nano-TiO 2 There are two main problems in the catalytic degradation of pesticides in water suspensions, one is that the catalytic materials are difficult to recycle and even cause secondary pollution, and the other is that the degradation selectivity of single nanomaterials is not high.