碳羟基磷灰石对水中Cr(Ⅵ)的吸附性能研究

Study on adsorption properties of carbonate hydroxyapatite for Cr(Ⅵ) in simulative wastewater

利用废弃蛋壳为原材料,水热法合成碳羟基磷灰石(CHAP),并利用X射线衍射、扫描电镜、能谱分析手段对其结构进行了表征。将CHAP作为含铬废水的吸附剂,考察了pH、Cr(Ⅵ)初始浓度、吸附时间等对Cr(Ⅵ)吸附行为的影响。结果表明,初始质量浓度为50mg/L的Cr(Ⅵ)溶液,在常温(22±2)℃、溶液pH为3.0、CHAP用量为5g/L时,30min基本达到吸附平衡,Cr(Ⅵ)去除率为98.3%,饱和吸附容量达29.85mg/g。CHAP对Cr(Ⅵ)的吸附行为符合Langmuir吸附等温式和Freundlich吸附等温式,相关系数分别为0.9984和0.9226。通过10%(体积分数)H2SO4对吸附Cr(Ⅵ)的CHAP进行再生,再生率最高达95.8%。

The carbonate hydroxylapatite（CHAP） synthesized using abandoned eggshell was characterized by transmit selectron microscopy（TEM）,X-ray diffraction（XRD） and energy depressive spectroscopy（EDS）. Factors that might influent the adsorption performance were investigated,such as pH values,adsorption time,the initial concentration of chromium（Ⅵ） in simulative wastewater. The results showed that the rate of the remove of chromium（Ⅵ） by CHAP was increased to 98.3% and the maximum adsorption capacity was up to 29.85 mg/g when pH values was 3.0,adsorption time was 30 min,the dosage of CHAP was 5 g/L,the initial concentration of chromium（Ⅵ） in simulative wastewater was 50 mg/L,and room temperature.The adsorption isotherms for chromium（Ⅵ） could be well fitted by both Langmuir and Freundlich equation used to describe the adsorption behavior,their correlation coefficients were 0.998 4 and 0.922 6,respectively.After adsorption the CAHP could be regenerated quantificationally with 10% H2SO4 and microwave heating,the regeneration ratio reached upwards of 95.8%.