化学沥浸与硫化钠钝化联合处理猪粪中重金属

Treatment of heavy metal in pig manure by chemical leaching and sodium sulfide passivation

利用柠檬酸浸提猪粪中重金属,减少总量,再利用硫化钠钝化经柠檬酸浸提后的猪粪残渣,降低猪粪中剩余重金属的生物可利用性。柠檬酸浸提实验表明:0.2 mol·L-1柠檬酸与猪粪按固液比1:5混合,反应24 h,对猪粪中Cu、Zn、Mn的浸出率为18.10%、66.16%、43.85%;硫化钠投加量5%,钝化7 d,猪粪中离子交换态Cu、Zn、Mn的浓度由酸浸后的14.08、116、81.75 mg·kg^(-1)降为8.77、12.04、21.02 mg·kg^(-1),硫化钠对酸浸后猪粪中Cu、Zn的钝化率为52.00%、63.72%,猪粪残渣中离子交换态Mn所占全量的比例由对照组的30.22%降到7.77%;柠檬酸酸浸和硫化钠钝化对猪粪中Cu、Zn、Mn总处理效率为73.00%、61.44%、29.90%。重金属分离技术和钝化技术联合处理猪粪中重金属,可以有效减少猪粪中Cu、Zn、Mn的总量并降低其生物可利用性。

Citric acid was used to extract heavy metal in pig manure to reduce the total amount of heavy metals.After the extraction, sodium sulfide was used to passivate heavy metals to reduce their bioavailability in pig manure residue. Results show when 0.2 mol·L^-1 citric acid and pig manure were mixed at 1：5 for 24 h, the extraction rate of Cu, Zn and Mn was 18.10%, 66.16% and 43.85%, respectively. The concentration of Cu, Zn and Mn in ion exchange state was 8.77, 12.04 and 21.02 mg·kg^-1 after 7 days passivation with 5% sodium sulfide. The passivation rate of Cu and Zn in the pig manure was 52.00% and 63.72%,respectively. The proportion of total ion exchange Mn was7.77% after passivating compared with 30.22% in the control. The total treatment efficiency of acid leaching and passivation of Cu, Zn and Mn in pig manure was 73.00%, 61.44% and 29.90%, respectively. The combination of chemical leaching and passivation can reduce the total amount of Cu, Zn and Mn in pig manure and reduce their bioavailability at the same time.