title: Removal of Cd2+ from contaminated water by nano-sized aragonite mollusk shell and the competition of coexisting metal ions.
abstract: The potential of using nano-sized aragonite mollusk shell (nano-Bio-ARA) to remove Cd(2+) from contaminated water was investigated by comparing the sorption kinetics and isotherms with the nano-sized calcite-type mollusk shell (nano-Bio-CAL) and nano-sized geological calcite (nano-Geo-CAL). Nano-Bio-ARA displayed extremely high sorption capacity to Cd(2+) (8.91mmol/g), much higher than nano-Bio/Geo-CAL, and many other natural or engineered materials. The results of thermodynamic experiments indicated that the sorption of Cd(2+) on the nano-ARA was a spontaneous and endothermic process. The coexisting metals in the solution displayed competition effect to the sorption of Cd(2+) on nano-Bio-ARA in the following order: Cu(2+)>Cr(3+)>Pb(2+)>Zn(2+)>Ca(2+). EDTA impeded the sorption of Cd(2+) on nano-Bio-ARA due to its strong chelating capacity to Cd(2+) in the solution. The results demonstrate that nano-Bio-ARA is a potential high-effective material to treat Cd(2+) contaminated water.
authors: College of Environmental Science and Engineering, Tianjin Key Laboratory of Urban Ecology Environmental Remediation and Pollution Control, Ministry of Education, Nankai University, Tianjin 300071, PR China.
authors: Yang
authors: Y
authors: Du
authors: Lingyan
authors: L
authors: Zhu
authors: Guoqiang
authors: G
authors: Shan
mesh_terms: D000327:Adsorption; D000818:Animals; D002104:Cadmium / Q000302:isolation & purification*; D002119:Calcium Carbonate / Q000737:chemistry*; D007477:Ions / Q000302:isolation & purification; D008670:Metals / Q000302:isolation & purification; D008974:Mollusca / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: D007477:Ions; D008670:Metals; D014874:Water Pollutants, Chemical; D002104:Cadmium; D002119:Calcium Carbonate