摘要
通过室外模拟淹水实验研究纳米Ti O_2对土壤重金属迁移转化的影响,分析了两种纳米Ti O_2对三峡水库典型消落区土壤中Cr、Zn、Pb、Cu和Cd释放和形态变化的影响.结果表明,淹水两个月后,添加4 g·kg^(-1)金红石和锐钛矿颗粒处理均导致约30%的Cr释放到水中,主要促进可氧化态和残渣态Cr的溶出,从而促进土壤Cr的活化,大大提高其生态风险;另外,添加4 g·kg^(-1)金红石颗粒处理导致酸可交换态和可氧化态Pb含量分别下降25.92%和33.09%,增强其迁移性;但添加锐钛矿颗粒处理促进土壤中可氧化态Zn的生成,含量提高约30%,有利于Zn的固定;此外,两种纳米Ti O_2颗粒对Cu和Cd的形态均没有明显的影响.因此,纳米Ti O_2对土壤中Cr释放和形态变化影响最大,其次是Pb和Zn,在进行重金属污染土壤的修复及其风险评估时需要特别注意.
The effects of nano-Ti O2 on migration and transformation of heavy metals in soil were investigated by outdoor flooding simulation experiments. Cr,Pb,Zn,Cd and Cu contents of different forms were determined in soil of typical fluctuating zone of Three Gorges Reservoir. The results showed that,after flooding months,both addition of 4 g·kg^-1of rutile and anatase particles resulted in the release of about 30% Cr into the water. Nano-Ti O2 particles mainly promoted the dissolution of oxidizable residual Cr,and elevated its ecological risk. Thus nano-Ti O2 promoted the activation of chromium and improved the mobility of chromium in soil. 4 g·kg^-1of rutile particles caused the decrease of acid exchangeable lead by 25. 92% and oxidizable lead by 33. 09%,and enhanced the mobility of Pb. However,anatase particles caused the increase of oxidizable zinc by 30% in soil,which facilitated fixing of zinc. In addition,two types of nano-Ti O2 particles had no significant effect on the speciation changes of Cu and Cd. Therefore,the effect of nano-Ti O2 on release and transformation of Cr in soil was the largest,followed by Pb and Zn. This needs special attention when using nano-Ti O2 to remediate heavy metals contaminated soil and assessing its environmental risk.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2016年第5期1946-1952,共7页
Environmental Science
基金
国家重点基础研究发展规划(973)项目(2013GB430004)
国家自然科学基金项目(41173116)
中央高校基本业务费专项(XDJK2015C124)
四川省大学生创新创业训练计划项目(X201319)
关键词
纳米二氧化钛
土壤
重金属
形态
转化
nano-TiO2
soil
heavy metal
speciation
transformation
