Sorption of Lead to Slurry Trench Cutoff Wall Backfills Comprised of SHMP-Amended Ca-Bentonite
This study investigated effects of phosphate dispersant on lead(typical heavy metal)sorption capacity of the sand/Ca-bentonite backfill for slurry trench cutoff walls.Several series of batch sorption tests were conducted using backfills consisting of sand and 20%Ca-bentonite with/without dispersant,as well as amended/un-amended Ca-bentonite alone.First,amended/un-amended backfills and amended Ca-bentonite were prepared.Next,aqueous solutions with 0 to 40,000 mg/L Pb concentration were prepared.Finally,the backfills and the Ca-bentonites were mixed with the solution in liquids to solid ratio of 10 and shaken for 24 h.The mixture was then centrifuged,and the supernatant was separated and analyzed for Pb concentration.The results show that the relationship between the amount of sorption and equilibrium concentration of Pb was well quantified by Langmuir and Freundlich isotherm models.Phosphate dispersant significantly increased Pb sorption capacity of both the sand/Ca-bentonite backfill and Ca-bentonite.The sorption process of the Pb onto the backfills or Ca-bentonites was found to be favorable.Overall,phosphate dispersant is shown to be a promising additive to sand/Ca-bentontie backfill in slurry trench cutoff wall construction for effective containment of Pb-laden groundwater.
Calcium bentonite Slurry walls Sorption Lead
Yu-Ling Yang Krishna R.Reddy Yan-Jun Du Ri-Dong Fan
Jiangsu Key Laboratory of Urban Underground Engineering and Environmental Safety,Institute of Geotec Department of Civil and Materials Engineering,University of Illinois at Chicago,Chicago,IL 60607,USA
国际会议
The 8th International Congress on Environmental Geotechnics(第八届国际环境土工大会)
杭州
英文
537-543
2018-10-28（万方平台首次上网日期，不代表论文的发表时间）