猪场沼液/稻草腐解液模拟原位柱淋洗修复铬污染土壤效果研究

实验室模拟原位柱淋洗工艺,以猪粪源沼液、腐解稻草中溶解性有机质(DOM)提取液为淋洗剂,探究其对铬污染土壤洗脱效果,优化了淋洗速度、淋洗液用量及淋洗方式等影响洗因子,并研究了土柱中残留铬浓度纵向分布和洗脱机制.结果表明:猪粪源沼液和腐解稻草中DOM提取液均为修复铬污染土壤的高效绿色淋洗剂,其中猪粪源沼液修复效果更佳.最...

Effect of Simulated In-Situ Column Elution with Pig Manure Biogas Slurry/Straw Decomposing Solution on Remediation of Chromium-Contaminated Soil

The in-situ column leaching process was simulated in the laboratory.The biogas slurry of pig manure and dissolved organic matter(DOM)extracted from decomposable straw were used as leaching agent,the leaching agent effect on chromium contaminated soil was investigated,and the leaching factors such as leaching speed,dosage of leaching agent and leaching method were optimized.The longitudinal distribution and elution mechanism of residual chromium concentration in soil column were studied.The results showed that pig manure biogas slurry and DOM extract solution of decomposed straw both were efficient green eluent for the restoration of chromium contaminated soil,and the remediation effect of pig manure biogas slurry was better.The optimum conditions were:leaching speed 1.5 min·L^-1,continuous leaching of 10 pore volumes.Under this condition,with the total original chromium content of 121.54 mg·kg^-1in soil(the hexavalent chromium content 119.9 mg·kg^-1),the removal rates of total chromium and hexavalent chromium were 56.25%and 56.91%respectively when the pig manure biogas slurry as eluent,and that were 42.79%and 42.94%respectively when the straw DOM as eluent.When the total chromium content in soil was 941.9 mg·kg^-1(hexavalent chromium 856.9 mg·kg^-1),the removal rates of total chromium and hexavalent chromium were 94.99%and 95.17%respectively when the pig manure biogas slurry as eluent,while that were 92.01%and 92.64%respectively when the straw DOM as eluent.The longitudinal distribution of residual chromium concentration in soil column varied with depth and reached its maximum value at 1/5 from the bottom of soil column.The pig manure biogas slurry and DOM extract of decomposed rice straw contained a large number of carboxyl,hydroxyl,phenolic and electron groups,and it had detoxification effect on residual hexavalent chromium in soil column while eluting chromium from soil.