FeOOH-MnO_(2)修饰海泡石纤维及其对As(Ⅴ)的吸附性能

Sepiolite fibers decorated with FeOOH-MnO_(2) and their adsorption properties for As(Ⅴ)

为提高海泡石对废水中重金属离子砷As(Ⅴ)的吸附效能,以海泡石为基体,以KMnO_(4)、 MnCl_(2)、 FeCl_(2)为金属源,以尿素为沉淀剂,采用水热法制备纳米棒状结构羟基氧化铁-二氧化锰(FeOOH-MnO_(2))修饰的海泡石纤维样品;采用XRD、 SEM、 TEM、 BET、 XPS等对样品进行表征,并进行样品对As(Ⅴ)的吸附性能实验研究;讨论样品的合成与吸附机理。结果表明:FeOOH-MnO_(2)呈短棒状均匀负载在海泡石纤维上;样品比表面积最高可达77.4 m^(2)/g;当pH为7、室温条件下,对As(Ⅴ)的最大吸附容量为124.3 mg/g;样品对As(Ⅴ)的吸附是化学吸附,遵循Freundlich等温吸附模型;该吸附剂表现出良好的吸附循环性能,第5次循环后As(Ⅴ)去除率保持在90%左右。

In order to improve adsorption efficiency of sepiolite for heavy metal ion As(Ⅴ) in wastewater, nano rod-shaped sepiolite samples modified by hydroxyl iron oxide-manganese dioxide(FeOOH-MnO_(2)) were prepared by hydrothermal method with sepiolite as matrix, KMnO_(4), MnCl_(2)and FeCl_(2)as metal source and urea as precipitant. The samples were characterized by XRD, SEM, TEM, BET and XPS and adsorption properties of As(Ⅴ) were studied experimentally. The synthesis and adsorption mechanism of samples were discussed. The results show that FeOOH-MnO_(2)is uniformly loaded on sepiolite fiber in the form of short rod. The maximum specific surface area of the sample can reach 77.4 m^(2)/g. When pH is 7, the maximum adsorption capacity of As(Ⅴ) is 124.3 mg/g at room temperatm. The adsorption of As(Ⅴ) by sample is chemical adsorption, which follows Freundlich isothermal adsorption model. The adsorbent show good adsorption cycle performance because the removal rate of As(Ⅴ) remains about 90% after the fifth cycle.