Nanoflltration Membrane Process for the Removal of Arsenic from Drinking Water

摘要

The removal of arsenic from drinking water by nanoflltration membranes was investigated.Experiments were conducted with tap water to which arsenate and arsenite were added.Two types of nanoflltration membranes,i.e.,NF-90 and NF-200,have been tested.The effect of various operating conditions,e.g.,applied pressure,feed concentration,pH and temperature,were also investigated.The pH and arsenic concentration in the feed and the operating temperature are found to be decisive factors in determining the arsenic concentration remaining in the permeate.The level of removal of As(V) was higher than 98 % for both membranes,but that of As(III) was much lower.It can be concluded that by controlling the operating parameters,source water containing As(V) may be recovered as drinking water to EPA maximum contaminant level quality standards,but that water containing As(III) must undergo a pre-oxidation treatment before passing through the nanoflltration membrane in order to maintain drinking water quality.