The present study investigated the influence of ferric iron (Fe (III)) and organic matter (OM) on arsenite (As (III)) rejection from a synthetic contaminated water by direct contact membrane distillation (DCMD). Two different pore sizes (0.22 μm and 0.45 μm) of hydrophobic membranes made of Polytetrafluoroethylene (PTFE) were used at
different feed temperature (40, 50 and 60 oC). The operating temperatures, the feed solution Fe (III) and OM concentration have been varied during the study to follow pollutants rejection efficiency and flux behavior. Fe (III) and OM concentration in the solution did not affect negstively As(III) rejection; both membranes used had high rejection efficiency and permeate arsenic (As) concentration was lower than recommended 10 μg/L. As (III)
concentration was below detection limit in many permeates. Fe(III) and OM contributed to higher rejection of As(III) and better transmembrane flux. Conductivity and As(III) was rejected up to 99%. In presence of Fe(III) and at feed temperature of 40 and 50 oC, As(III) was non-detectable in the permeate.