Novel comprehensive pretreatment method of albendazole high-concentration sulfur-containing wastewater

Abstract

The invention relates to a novel comprehensive pretreatment method of high-concentration sulfur-containing wastewater in albendazole production and aims to solve the problem that high-concentration sulfur-containing wastewater in albendazole production is high in treatment cost and harsh in treatment condition. Albendazole high-concentration sulfur-containing wastewater mainly contains sulfur-containing compounds like sodium sulfide (Na2S), sodium thiosulfate (Na2S2O3), sodium thiocyanate (NaSCN), sodium sulfite (Na2SO3) and sodium sulfate (Na2SO4), sodium bromide (NaBr) and a small amount of organic impurities. The method includes: adding a fixed quantity of ferrous sulfate into the high-concentration sulfur-containing wastewater, and filtering after reaction to obtain byproducts ferrous sulfide and filtrate 1; adding copper sulfate into the filtrate 1, and filtering after reaction to obtain byproducts cuprous thiocyanate and filtrate 2; cooling the filtrate 2 to 0-10 DEG C, crystallizing to obtain filtrate 3 and filter residue 3 which mainly contains sodium sulfate (Na2SO4), and recrystallizing to obtain a byproduct anhydrous sodium sulfate, and entering wastewater after bromine is recycled, wherein the filtrate 3 mainly contains bromide ions and recyclable bromine. The pretreatment method is mild in reaction condition, low in equipment requirement, good in treatment effect, simple and convenient to operate, capable of recycling byproducts, low in treatment cost and convenient for industrial application.

Description

technical field [0001] The invention belongs to the technical field of sulfur-containing wastewater treatment, and in particular relates to a novel comprehensive pretreatment method for high-concentration albendazole-containing sulfur-containing wastewater. Background technique [0002] Albendazole is a high-efficiency broad-spectrum anthelmintic, which has a significant control effect on pinworms, nematodes, roundworms and other parasites in warm-blooded animals such as dogs and sheep. Insect disease, low toxicity to human body and animals, and small side effects. At present, o-nitroaniline is mainly synthesized with o-nitroaniline as a starting material at home and abroad, that is, o-nitroaniline undergoes thiocyanation reaction, alkylation reaction, reduction reaction, and ring reaction. Albendazole is prepared by the combination reaction, but there is a large amount of sulfur-containing wastewater in the sodium sulfide reduction step, and the pressure on environmental pr...

AI Technical Summary

Problems solved by technology

[0004] The sulfur-containing wastewater produced by albendazole production has a large amount of water, complex components, high sulfur content in sulfide, serious pollution to the surrounding environment, and difficult treatment. At present, the methods for treating sulfur-containing wastewater at home and abroad mainly include oxidation method and alkali absorption method. , steam stripping method, precipitation method, Claus method, membrane separation method and biochemical method, etc., but these methods have high energy consumption, a large demand for chemicals, a large investment in equipment, and the need to reprocess end products such as sediment, so the cost is relatively high. Therefore, it is an urgent problem to be solved today to find a comprehensive pretreatment method for high-concentration sulfur-containing wastewater that is efficient, economical, fast, and has low requirements on equipment and processes, and to effectively recover by-products.

[0005] The purpose of the present invention is to solve the problems of high treatment cost and harsh treatment conditions of high-concentration sulfur-containing wastewater in the production of albendazole, and provide a kind of high-efficiency, fast, low requirements on equipment and process, high removal efficiency, effective recovery of by-products, Comprehensive pretreatment method for high-concentration sulfur-containing wastewater to avoid secondary pollution