Institute on Membrane Technology, ITM-CNR, c/o University of Calabria via P. Bucci 17/C, I-87030 Rende, Cosenza, Italy.
Water Res. 2010 Jan;44(1):97-104. doi: 10.1016/j.watres.2009.09.007. Epub 2009 Sep 8.
Arsenic contamination of surface and groundwater is a worldwide problem in a large number of Countries (Bangladesh, Argentina, Italy, USA, New Zealand, etc.). In many contaminated areas a continuous investigation of the available arsenic removal technologies is essential to develop economical and effective methods for removing arsenic in order to meet the new Maximum Contaminant Level (MCL) standard (10microg/l) recommended by the World Health Organization (WHO). In this work the removal of pentavalent arsenic from synthetic water was studied on laboratory scale by using two commercial nanofiltration (NF) spiral-wound membrane modules (N30F by Microdyn-Nadir and NF90 by Dow Chemical). The influence of main operating parameters such as feed concentration, pH, pressure and temperature on the As rejection and permeate flux of both membranes, was investigated. An increase of pH and a decrease of operating temperature and As feed concentration led to higher As removal for both membranes, whereas higher transmembrane pressure (TMP) values slightly reduced the removal achievable with the N30F membrane. In both cases, the permeate flux increased with temperature and pressure and reached its maximum value at a pH of around 8. Among the parameters affecting the As rejection, feed concentration plays a key role for the production of a permeate stream respecting the limits imposed by WHO.
砷的地表和地下水污染是世界范围内许多国家（孟加拉国、阿根廷、意大利、美国、新西兰等）的一个普遍问题。在许多受污染地区，持续调查现有的除砷技术对于开发经济有效的除砷方法至关重要，以满足世界卫生组织（WHO）推荐的新的最大污染物水平（MCL）标准（10μg/l）。在这项工作中，使用两种商业纳滤（NF）螺旋缠绕膜组件（Microdyn-Nadir 的 N30F 和 Dow Chemical 的 NF90）在实验室规模上研究了从合成水中去除五价砷。考察了主要操作参数（进料浓度、pH 值、压力和温度）对两种膜的砷去除率和渗透通量的影响。pH 值的升高、操作温度和进料浓度的降低均导致两种膜的砷去除率升高，而跨膜压力（TMP）值的升高则略微降低了 N30F 膜的去除率。在这两种情况下，随着温度和压力的升高，渗透通量均升高，并在 pH 值约为 8 时达到最大值。在影响砷去除率的参数中，进料浓度对于生产符合 WHO 规定的渗透液流起着关键作用。
