微波-柠檬酸浸出城市污泥中重金属

摘要

Citric acid was used as extractant to leach heavy metals which in the municipal sludge with microwave. Effects of heating rate,pH value,mixing time on leaching efficiency were investigated. The results showed that under the condition of heating rate at 15 t/min, pH value at 3, front-mixing time 30 min,radiation time at 2. 3 min with power of 170 W and after-mixing time at 3 h,the leaching rate of Zn,Cu,Ni and Pb in municipal sludge is 47. 84% ,11. 05% ,43. 83% ,25. 59% .respectively. The average leaching rate increased 50. 7% and the reaction time decreased 8 h compared with no microwave radiation. The content of heavy metals in the municipal sludge after treatment was far lower than the standard (GB 4284-84).%采用微波辅助柠檬酸浸出城市污泥中的重金属,考察了升温速率、pH值、搅拌时间等对浸出率的影响.结果表明,升温速率为15 ℃/min,pH值调至3,前搅拌30 min,170 W功率下微波2.3 min,再反应3h,污泥中Zn、Cu、Ni与Pb的浸出率分别达到了47.84％,11.05％,43.83％,25.59％,较无微波条件下,重金属浸出率平均提升了50.7％,反应时间缩短了8h.处理后污泥中重金属含量远低于《农用污泥中污染物控制标准》(GB 4284-84).