铁锰复合氧化物的制备及其吸附除砷性能

Preparation of Fe-Mn bimetal oxide adsorbent and its adsorption characteristics of arsenic

采用共沉淀法制备了新型铁锰复合氧化物吸附剂,并对其表面特性及除砷性能进行了初步研究.ξ电位测试表明,铁锰复合氧化物pHzpc在6.0附近,SEM/EDX表征证明吸附剂表面Fe和Mn的相对摩尔比为3∶1;铁锰复合氧化物对As(V)和As(Ⅲ)均表现出很强的吸附能力,并且吸附速度快,在60min内即可达到平衡吸附容量的80%;该吸附剂在天然水环境pH范围内均有良好吸附除砷能力,磷酸根、硅酸根、碳酸根等阴离子对除砷效果有不同程度的影响,其余共存阴、阳离子及天然有机物在中性水环境中对除砷效果影响不大;采用Langmuir吸附等温线能较好地描述铁锰复合氧化物吸附As(V)的过程(R2=0.997),而Freundlich方程能较好地拟合As(Ⅲ)的吸附过程(R2=0.989),对As(V)与As(Ⅲ)的饱和吸附容量分别达到227mg·g-1和312mg·g-1.

Fe-Mn Bimetal Oxide Adsorbent （ FMO ）, a novel adsorbent for arsenic removal, was prepared by co - precipitation, The characteristics and adsorption properties of adsorbent were studied in detail. ξ potential characterization showed that pHzpc of FMO was near 6.0. SEM/EDX results indicated that the ratio of Fe to Mn on FMO surface was 3：1. FMO was proved to be effective to remove both arsenate and arsenite from water, and the adsorption capacity attained to almost 80% of equilibrium capacity within the first 60 minutes. FMO could be successfully applied for arsenic removal in natural pH ranges. The normally presented ions in natural environment had no obvious side effect on arsenic adsorption by FMO except for phosphate, silicate and carhormte. Langmuir isotherm was found to fit well with arsenate adsorption （R^2 = 0.997 ）, and Freundlich isotherm was employed to describe the experimental data for ar-pullite fairly well （R^2 = 0.989）. The maximum adsorption capacities for arsenate and arsenite were 227 mg·g^-1 and 312 mg·g^-1 respectively.