In 2019, the <i>Agency for Toxic Substances and Disease Registry</i> (ATSDR) prioritized arsenic as the most prevalent substance with the highest potential for human exposure at National Priorities List (NPL) sites. In addition to its prevalence at NPL sites, arsenic contaminates private wells used for drinking water. Reverse osmosis (RO) membranes are a technology recommended by the US EPA for the physical treatment of arsenic-contaminated well water. Typically, membranes with high water productivity have low contaminant removal and vice versa. Here we investigate a new membrane modification method aimed at overcoming this performance tradeoff.  We hypothesize that membranes modified with solvent exposure followed by additional polymerization have improved As(III) removal and equal or higher water productivity.  We modified three types of commercially available membranes with the proposed modification method. We tested the contaminant removal and water productivity of membranes in a filtration system that mimics the conditions of a house-hold RO unit.  Initial results show that two modified membranes had ~4 percentage points better As(III) removal and 10-23% higher water productivity than unmodified membranes for one commercial membrane type. Additionally, the new modification method affected As(III) removal more than NaCl removal for all three types of commercial membranes. The proposed modification method resulted in a subset of membranes with better As(III) removal and higher water productivity, on average, than unmodified membranes. Our results highlight that including specific contaminants-of-interest can bring a dimension to the performance analysis that one might miss if only model contaminants like NaCl are used.

New reverse osmosis membrane modification method may result in better arsenic removal and higher water productivity than unmodified counterparts

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.