Vacuum membrane distillation for purifying waters containing arsenic

In this work, the potentialities of Vacuum Membrane Distillation (VMD) for treating water containing arsenic, both in the trivalent and pentavalent form, were analyzed, with the aim of producing a purified permeate working at low feed temperatures (20 °C-40 °C). Experimental tests were carried out on a commercial flat membrane module varying the arsenic concentration, the arsenic form (trivalent or pentavalent), the membrane,the operating temperatures and flow-rates. Long-term tests were also performed. The membrane area was of 180 cm2 and the vacuum pressure was fixed at 10 mbar. In all tests, no arsenic was detected in the permeate and the highest flux ranged between 3 and 12.5 kg/hm2 at 20 °C and 40 °C, respectively.