title: Citric-acid preacidification enhanced electrokinetic remediation for removal of chromium from chromium-residue-contaminated soil.
abstract: Electrokinetic experiments were conducted on chromium-residue-contaminated soils collected from a chemical plant in China. Acidification-electrokinetic remediation technology was proposed in order to solve the problem of removing inefficient with ordinary electrokinetic. The results showed that electrokinetic remediation removal efficiency of chromium from chromium-contaminated soil was significantly enhanced with acidizing pretreatment. The total chromium [Cr(T)] and hexavalent chromium [Cr(VI)] removal rate of the group acidized by citric acid (0.9 mol/L) for 5 days was increased from 6.23% and 19.01% in the acid-free experiments to 26.97% and 77.66% in the acidification-treated experiments, respectively. In addition, part of chromium with the state of carbonate-combined will be converted into water-soluble state through acidification to improve the removal efficiency. Within the appropriate concentration range, the higher concentration of acid was, the more chromium was released. So the removal efficiency of chromium depended on the acid concentration. The citric acid is also a kind of complexing agent, which produced complexation with Cr that was released by the electrokinetic treatment and then enhanced the removal efficiency. The major speciation of chromium that was removed from soils by acidification-electrokinetics remediation was acid-soluble speciation, revivification speciation and oxidation speciation, which reduced biological availability of chromium.
authors.affiliation: a Chinese Research Academy of Environmental Sciences , Beijing , People's Republic of China.
authors.forename: Fansheng
authors.identifier: http://orcid.org/0000-0002-4395-8927
authors.initials: F
authors.lastname: Meng
authors.affiliation: a Chinese Research Academy of Environmental Sciences , Beijing , People's Republic of China.|b College of Water Sciences , Beijing Normal University , Beijing , People's Republic of China.
authors.forename: Hao
authors.initials: H
authors.lastname: Xue
authors.affiliation: c China National Environmental Monitoring Centre , Beijing , People's Republic of China.
authors.forename: Yeyao
authors.initials: Y
authors.lastname: Wang
authors.affiliation: a Chinese Research Academy of Environmental Sciences , Beijing , People's Republic of China.|b College of Water Sciences , Beijing Normal University , Beijing , People's Republic of China.
authors.forename: Binghui
authors.initials: B
authors.lastname: Zheng
authors.affiliation: a Chinese Research Academy of Environmental Sciences , Beijing , People's Republic of China.
authors.forename: Juling
authors.initials: J
authors.lastname: Wang
mesh_terms: D002681:China; D002857:Chromium / Q000032:analysis / Q000737:chemistry*; D019343:Citric Acid / Q000737:chemistry*; D004563:Electrochemistry; D052918:Environmental Restoration and Remediation / Q000379:methods*; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000737:chemistry*
chemical_list: D012987:Soil; D012989:Soil Pollutants; D002857:Chromium; C074702:chromium hexavalent ion; D019343:Citric Acid
keywords: Electrokinetic remediation; chromium residue; citric acid; complexation; speciation