氧化淋洗联合修复氰化物污染土壤技术及工程实践  

Process study and project practice on restoring cyanide-contaminated soil with joint techniques of oxidation and flushing

作　　者：袁珊珊[1,2] 宋震宇 巢军委[1,2] 李野 杨伟[1,2] YUAN Shanshan;SONG Zhenyu;CHAO Junwei;LI Ye;YANG Wei(Tianjin Eco-City Environmental Protection Ltd.Co.,Tianjin 300480,China;Tianjin Contaminated Site Remediation Technology Engineering Center,Tianjin 300480,China)

机构地区：[1]天津生态城环保有限公司,天津300480 [2]天津市污染场地治理修复技术工程中心,天津300480

出　　处：《环境工程学报》2020年第11期3192-3200,共9页Chinese Journal of Environmental Engineering

摘　　要：以天津某氰化物污染场地污染土壤为研究对象,采用氧化淋洗联合使用的工艺方法,研究在不同氧化剂用量和淋洗次数条件下氰化物形态转变与修复效果之间的关系。利用氰化物的还原性和较高的溶解度,通过氧化分解和溶解作用实现对土壤中氰化物的去除。结果表明:在氧化条件下,随着氧化剂用量的增加,土壤中总氰化物呈现下降的趋势,土壤中氰化物的形态从络合态向易释放态转变,土壤浸提液中总氰化物的浓度呈现先升高后降低的趋势;当氧化剂用量为5%时,总氰化物浓度从51.2 mg·kg-1降低至9.23 mg·kg-1,满足总量的修复目标;而土壤浸提液浓度从初始的1.6 mg·L-1降低至0.79 mg·L-1,未能达到修复目标;在振荡淋洗条件下对土壤淋洗5次,随着淋洗次数的增加,土壤中总氰化物呈现下降的趋势,而氰化物易释放态逐渐减少,土壤浸提液中总氰化物浓度呈现快速下降的趋势;在淋洗3次时,土壤浸提液浓度从初始的1.6 mg·L-1降低至0.04 mg·L-1,达到修复目标,而土壤总氰化物含量从51.2 mg·kg-1降低至10.2 mg·kg-1,未能达到修复目标;氧化技术和淋洗技术联合使用时,在氧化剂用量为3%,淋洗1次条件下,工程实践表明土壤氰化物可以满足总量(9.86 mg·kg-1)和浸出(0.1 mg·L-1)的双重修复目标。本研究所提出的氧化淋洗联合修复技术应用于氰化物污染土壤修复是可行的。In this study, the cyanide-polluted soil was taken as the research object, the joint process of oxidation and flushing techniques was used to restore it. The relationship between the cyanide form transformation and remediation effects was investigated at different oxidant dosages and flushing times. Due to the reducibility and high-solubility, the cyanide in soil was removed by means of oxidative decomposition and dissolution. The results showed that the total cyanide in soil decreased, the cyanide changed from complexing form into easyrelease one, and the total cyanide content in soil leaching solution increased firstly and then decreased with the increase of oxidant dosage under the oxidation conditions. At the oxidant dosage of 5%, the total cyanide concentration decreased from 51.2 mg·kg-1 to 9.23 mg·kg-1 which met the remediation target. However, the total cyanide concentration in soil leaching solution decreased from initial 1.6 mg·L-1 to 0.79 mg·L-1 which could not meet the remediation target. When the soil was flused for 5 times under shaking conditions, the total cyanide in soil decreased, and the easy-release cyanide form also gradually decreased, and the total cyanide in soil leaching soultion decreased rapidly with the increase of the elution times. After three times-elution, the total cyanide concentraion in soil leaching solution decreased from 1.6 mg·L-1 to 0.04 mg·L-1 which met the remediation target. However, the total cyanide concentration in soil decreased from 51.2 mg·kg-1 to 10.2 mg·kg-1 which could not meet the remediation target. When oxidation and flushing techniques were jointly used, the dual remediation targets of total amount of 9.86 mg·kg-1 and leaching amount of 0.1 mg·L-1 were met in the actual project with the oxidant dosage of 3% and one time-elution. The joint oxidation and flushing techniques in this study was feasible to restore the cyanide-contaminated soil.

关 键 词：污染土壤 氰化物 氧化 淋洗 

分 类 号：X53[环境科学与工程—环境工程]