木醋液改性羟基磷灰石对溶液中Cd2+的吸附特性

水体中存在Cd²⁺会危害人体健康,Cd²⁺污染的去除是一个需要解决的问题。以羟基磷灰石(HAP)和低成本的木醋液(WV)为原料,通过水浴搅拌制备了木醋液改性羟基磷灰石(WV-HAP),并将其应用于去除溶液中Cd²⁺的研究。利用XRD、FT-IR、SEM、BET对WV-HAP进行了表征,通过吸附试验探究溶液初始pH、初始离子浓度、接触时间和温度对WV-HAP对Cd²⁺吸附特性的影响。结果表明:在吸附剂添加量2 g/L、温度298 K、Cd²⁺初始浓度100 mg/L、pH=5、吸附时间4 h时,WV-HAP的平衡吸附容量为46.43 mg/g;WV-HAP对Cd²⁺的吸附过程符合Langmuir等温吸附模型和准二级动力学模型;热力学研究表明吸附过程是吸热的;通过对吸附Cd²⁺前后的WV-HAP进行表征,发现吸附机制主要是表面吸附、孔道吸附和离子交换。WV-HAP表现出优于HAP的对溶液中Cd²⁺的吸附能力,是一种潜在的Cd²⁺吸附材料。

Adsorption Characteristics of Cd2+ in Solution by Hydroxyapatite Modified with Wood Vinegar

The presence of Cd²⁺in water endangers human health,and the removal of Cd²⁺pollution is a problem that needs to be solved.Wood vinegar modified hydroxyapatite(WV-HAP)was prepared by water bath stirring with hydroxyapatite(HAP)and low cost wood vinegar(WV),and it was used to remove Cd²⁺from solution.WV-HAP was characterized by XRD,FT-IR,SEM and BET.The effects of initial pH,initial ion concentration,contact time and temperature on the adsorption characteristics of WV-HAP were investigated through adsorption experiments.The results show that the equilibrium adsorption capacity of WV-HAP is 46.43 mg/g under the conditions of adsorbent dosage of 2 g/L,temperature 298 K,initial concentration of Cd²⁺100 mg/L,pH=5 and adsorption time 4 h.The adsorption process of Cd²⁺by WV-HAP conform to Langmuir isothermal adsorption model and quasi-second-order kinetic model.Thermodynamic study shows that the adsorption process is endothermic.Through the characterization of WV-HAP before and after Cd²⁺adsorption,it is found that the adsorption mechanisms are mainly surface adsorption,pore adsorption and ion exchange.The adsorption capacity of WV-HAP to Cd²⁺in solution is better than that of HAP,and WV-HAP is a potential Cd²⁺adsorption material.