title: Remediation of cadmium-contaminated soil by extraction with para-sulphonato-thiacalix[4]arene, a novel supramolecular receptor.
abstract: Batch extractions were conducted to evaluate the performance of para-sulphonato-thiacalix[4]arene (STC[4]A), a novel supramolecular receptor, for removing cadmium (Cd) from soil. The extraction mechanism was investigated by determination of the conditional stability constants (log K) of the STC[4]A-Cd complex. The influences of various variables were examined, including pH, contact time, and extractant concentration. The Cd extraction efficiency increased with increasing pH, reaching the maximum at pH 11 and then declining at higher pH values. This pH dependence was explained by the variation in the log K value of the STC[4]A-Cd complex along with pH change. When the STC[4]A dose was increased to an STC[4]A:Cd molar ratio of 2.5:1, Cd was exhaustively removed (up to 96.8%). The comparison experiment revealed that the Cd extraction performance of STC[4]A was almost equivalent to that of EDTA and significantly better than that of natural organic acids. STC[4]A extraction could efficiently prevent co-dissolution of soil minerals.
authors.affiliation: Key Laboratory of Regional Environment and Eco-Remediation (Ministry of Education), Shenyang University, Shenyang 110044, PR China.
authors.forename: Yushuang
authors.initials: Y
authors.lastname: Li
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Hu
authors.forename: Xueying
authors.initials: X
authors.lastname: Song
authors.forename: Tieheng
authors.initials: T
authors.lastname: Sun
mesh_terms: D002104:Cadmium / Q000032:analysis / Q000737:chemistry*; D005591:Chemical Fractionation; D004492:Edetic Acid / Q000737:chemistry; D052918:Environmental Restoration and Remediation / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D010636:Phenols / Q000737:chemistry; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry
chemical_list: D010636:Phenols; D012987:Soil; D012989:Soil Pollutants; D013440:Sulfides; C500450:thiacalix(4)arene; D002104:Cadmium; D004492:Edetic Acid