摘要：

草甘膦是一种低毒高效的除草剂。我国普遍采用甘氨酸工艺生产草甘膦，生产过程中母液留存大量副产物，由此产生的废水具有COD和有机磷含量高等特点，直接排放会引起土壤板结和盐碱化。采用高温焚烧法处理草甘膦废水时成本较高，且会带来二次污染。采用CuO/NAC催化氧化-纳滤联合工艺处理草甘膦废水，探讨了CuO/NAC种类及用量、H₂O₂投加量、温度、时间等因素对COD去除率和磷酸盐生成率的影响。结果表明，处理100 mL废水，在以三聚氰胺为氮源的CuO/NAC用量为1.0 g、H₂O₂(质量分数为60%)用量为3 mL、120℃反应50 min时，COD去除率可达98.1%，磷酸盐生成率为142.6%。经纳滤膜过滤后〔产水通量10 L/(m²·h)〕，COD降为12 mg/L，磷酸盐 < 0.051 mg/L，符合《污水综合排放标准》(GB 8978—1996)的一级排放标准要求。

关键词: CuO/NAC催化剂, 草甘膦母液废水, 催化氧化, 纳滤

Abstract:

Glyphosate is an herbicide with low toxicity and high efficacy. Glycine process is widely used to produce glyphosate in China, and a large number of by-products are retained in mother liquid. The glyphosate mother liquid wastewater contains high concentrations of COD and organic phosphorus. Direct discharge of the glyphosate mother liquid wastewater will cause soil compaction and salinization. The cost of treating glyphosate mother liquid wastewater by high temperature incineration method is high and cause secondary pollution. A combined process of CuO/NAC catalytic oxidation and nanofiltration membrane separation was proposed to treat glyphosate mother liquid wastewater. The effects of the kinds and dosage of CuO/NAC catalysts, the dosage of H₂O₂, reaction temperature and time on the removal rate of COD and formation rate of phosphate were explored. The results showed that the COD removal rate was 98.1% and the phosphate formation rate was 142.6% under the condition of the dosage CuO/NAC with melamine as a nitrogen source 1.0 g, the dosage of 60%H₂O₂ 3 mL in 100 mL wastewater, reaction temperature 120℃, reaction time 50 min. Further, the nanofiltration was subsequently used after CuO/NAC catalytic oxidation process, in which the produced water flux was 10 L/(m²·h), COD in the wastewater was 12 mg/L and the concentration of PO₄^3- was less than 0.051 mg/L, which could meet the requirement of the first level standard in the Integrated Wastewater Discharge Standard(GB 8978-1996).

Key words: CuO/NAC catalyst, glyphosate mother liquid, catalytic oxidation, nanofiltration

中图分类号: 

• X703