Zheng Wei, Li Xiao-ming, Yang Qi, Zeng Guang-ming, Shen Xiang-xin, Zhang Ying, Liu Jing-jin
College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China.
J Hazard Mater. 2007 Aug 17;147(1-2):534-9. doi: 10.1016/j.jhazmat.2007.01.048. Epub 2007 Jan 19.
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.
以蛋壳废料为原料合成的碳酸羟基磷灰石（CHAP）已被研究用于从水溶液中吸附镉（II）和铜（II）等金属。在室温下研究了接触时间、溶液pH值、CHAP用量和金属离子初始浓度等各种参数对吸附过程的影响，以优化最大吸附条件。结果表明，当初始镉（II）浓度为80 mg/L、铜（II）浓度为60 mg/L且液固比为2.5 g/L时，CHAP对镉（II）和铜（II）的去除效率分别可达94%和93.17%。室温下单金属体系的平衡吸附数据可用朗缪尔和弗伦德里希等温线模型描述。镉（111.1mg/g）和铜（142.86 mg/g）的朗缪尔最大吸附量（b）最高。镉（2.224）和铜（7.925）的弗伦德里希经验常数K相似。离子交换和表面吸附可能参与了镉和铜的吸附过程。解吸实验表明，氯化钙、氯化钠、乙酸和超声波对从CHAP中解吸大量金属离子的效率不够高。所得结果表明，CHAP对镉和铜具有很高的亲和力。
