title: Adsorption of Cd(II) and Cu(II) from aqueous solution by carbonate hydroxylapatite derived from eggshell waste.
abstract: Carbonate hydroxylapatite (CHAP) synthesized by using eggshell waste as raw material has been investigated as metal adsorption for Cd(II) and Cu(II) from aqueous solutions. The effect of various parameters on adsorption process such as contact time, solution pH, amount of CHAP and initial concentration of metal ions was studied at room temperature to optimize the conditions for maximum adsorption. The results showed that the removal efficiency of Cd(II) and Cu(II) by CHAP could reach 94 and 93.17%, respectively, when the initial Cd(II) concentration 80 mg/L and Cu(II) 60 mg/L and the liquid/solid ratio was 2.5 g/L. The equilibrium sorption data for single metal systems at room temperature could be described by the Langmuir and Freundlich isotherm models. The highest value of Langmuir maximum uptake, (b), was found for cadmium (111.1mg/g) and copper (142.86 mg/g). Similar Freundlich empirical constants, K, were obtained for cadmium (2.224) and copper (7.925). Ion exchange and surface adsorption might be involved in the adsorption process of cadmium and copper. Desorption experiments showed that CaCl2, NaCl, acetic acid and ultrasonic were not efficient enough to desorb substantial amount of metal ions from the CHAP. The results obtained show that CHAP has a high affinity to cadmium and copper.
authors: College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China.
authors: Wei
authors: W
authors: Zheng
authors: Xiao-ming
authors: XM
authors: Li
authors: Qi
authors: Q
authors: Yang
authors: Guang-ming
authors: GM
authors: Zeng
authors: Xiang-xin
authors: XX
authors: Shen
authors: Ying
authors: Y
authors: Zhang
authors: Jing-jin
authors: JJ
authors: Liu
mesh_terms: D000327:Adsorption; D002104:Cadmium / Q000302:isolation & purification*; D002254:Carbonates; D003300:Copper / Q000302:isolation & purification*; D017886:Durapatite; D004531:Eggs; D052918:Environmental Restoration and Remediation; D007220:Industrial Waste; D014874:Water Pollutants, Chemical; D018508:Water Purification
chemical_list: D002254:Carbonates; D007220:Industrial Waste; D014874:Water Pollutants, Chemical; D002104:Cadmium; D003300:Copper; D017886:Durapatite