Tween-80对生物淋滤法去除垃圾焚烧飞灰中重金属的影响

通过接种氧化硫硫杆菌和序批式培养试验,研究了不同浓度表面活性剂Tween-80对飞灰生物淋滤过程中重金属溶出的影响.Tween-80的作用表现为:低质量浓度促进,高质量浓度抑制,最佳质量浓度约为1.5g/L.ρ(Tween-80)为1.5 g/L时可显著提高元素硫的生物氧化速率,加速飞灰浆液的酸化,从而提高飞灰中重金属的溶出(去除)率.但是当ρ(Tween-80)超过3.0 g/L时,将对硫杆菌的生长与增殖产生抑制甚至毒害效应,使生物淋滤反应不能顺利进行.结果表明:在常规的飞灰生物淋滤处理中添加1.5g/L的Tween-80,经过15 d的淋滤,Cd,Zn,Cu与Pb的去除率最高分别达到87.1%,81.8%,72.3%与31.9%;而不加Tween-80的对照组,4种重金属的去除率分别为84.0%,74.4%,67.5%与27.1%. 

Leaching Heavy Metals from MSWI Fly Ash by Using Acidithiobacillus thiooxidans in the Presence of a Surfactant Agent

The effect of a surfactant agent(Tween-80) on metal solubilization during the bioleaching of municipal solid waste incineration(MSWI) fly ash was studied in suspension-leaching experiments using Acidithiobacillus thiooxidans. Results showed that the addition of Tween-80 in an adequate amount(1.5 g/L) could enhance sulfur oxidation,fly suspension acidification and metal solubilization,but higher mass concentrations of Tween-80(>3.0 g/L) would interfere the normal growth and proliferation of Acidithiobacillus thiooxidans and thus inhibit metal solubilization.Result from batch experiments also demonstrated that supplementing 1.5 g/L Tween-80 led to the following metal removal efficiencies: Cd,87.1%;Zn,81.8%;Cu,72.3% and Pb,31.9% after 15 d of bioleaching.In contrast,only 84.0% of Cd,74.4% of Zn,67.5% of Cu and 27.1% of Pb were extracted from the control without Tween-80.