重金属螯合剂TMT-15处理高含汞气田废水

Treatment of Gas Field Wastewater with High Mercury Concentration Using Heavy Metal Chelator TMT-15

选用重金属螯合剂TMT-15处理高含汞气田废水（COD=1 560 mg/L,SS=210 mg/L,pH=2.5～3.0,汞质量浓度为340 mg/L）,考察了TMT-15投加量,废水pH,与氢氧化物、硫化物联用等因素对汞去除效果的影响,分析了TMT-15与汞的螯合产物的稳定性.实验结果表明：TMT-15能与汞强力螯合并沉淀,投加量低,pH适用范围广;絮凝剂聚合硫酸铝与TMT-15的联用可提高除汞效果,但作用有限;TMT-15与氢氧化物联用时的汞的去除效果提升显著,在氢氧化钠、三聚硫氰酸、汞元素的摩尔比为0.5：0.5：1和废水pH为3.0的条件下,汞去除率可达99.99％,剩余汞浓度低于GB 8978-1996中规定的汞排放浓度;螯合产物具有很高的热稳定性,且在较高浓度的酸碱环境中溶解率低,对环境造成二次污染的风险小.

The gas filed wastewater with high mercury concentration （COD=1560 mg/L, SS=210 mg/L, pH=2.5- 3.0, ρ （Hg）=340 mg/L）was treated using heavy metal chelator TMT-15. The factors affecting mercury removal were studied, such as TMT-15 dosage, wastewater pH, hydroxide, sulfide and so on, and the stability of the chelation product was analyzed. The experimental results show that： TMT- 15 can chelate and precipitate with mercury under low dosage and wide pH range; The combination of flocculant PAS and TMT-15 has limited effect on mercury removal; When TMT-15 is used with hydroxide, the mercury removal rate is increased significantly; Under the conditions of mole ratio of sodium to trithiocyanuric acid to mercury 0.5 ： 0.5 ： 1 and wastewater pH 3.0, the mercury removal rate reaches 99.99%, and the residual mercury concentration is below the mercury emission standard of GB 8978-1996; The chelation product has high thermal stability and low dissolution rate in high-concentration acid/base environment, which indicates that it has low risk of secondary environmental pollution.