title: Experimental study of arsenic removal by direct contact membrane distillation.
abstract: Arsenite (As(III)) and arsenate (As(V)) removal by direct contact membrane distillation (DCMD) were investigated with self-made polyvinylidene fluoride (PVDF) membranes in the present work. Permeability and ion rejection efficiency of the membrane were tested before the arsenic removal experiments. A maximum permeate flux 20.90 kg/m(2)h was obtained, and due to the hydrophobic property, the PVDF membrane had high rejection of inorganic anions and cations which was independent of the solution pH and the temperature. The experimental results indicated that DCMD process had higher removal efficiency of arsenic than pressure-driven membrane processes, especially for high-concentration arsenic and arsenite removal. The experimental results indicated that the permeate As(III) and As(V) were under the maximum contaminant limit (10 microg/L) until the feed As(III) and As(V) achieved 40 and 2000 mg/L, respectively. The 250 h simultaneous DCMD performance of 0.5mg/L As(III) and As(V) solution was carried out, respectively. The permeate arsenic was not detected during the process which showed the PVDF membrane had stable arsenic removal efficiency. Membrane morphology changed slightly after the experiments, however, the permeability and the ion rejection of the membrane did not change.
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, The Chinese Academy of Sciences, P.O. Box 2871, 100085 Beijing, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Qu
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Deyin
authors.initials: D
authors.lastname: Hou
authors.forename: Zhaokun
authors.initials: Z
authors.lastname: Luan
authors.forename: Bin
authors.initials: B
authors.lastname: Fan
authors.forename: Changwei
authors.initials: C
authors.lastname: Zhao
mesh_terms: D001151:Arsenic / Q000302:isolation & purification*; D018053:Arsenites / Q000302:isolation & purification*; D005374:Filtration; D007477:Ions; D008567:Membranes, Artificial; D010539:Permeability; D011145:Polyvinyls; D014874:Water Pollutants, Chemical / Q000302:isolation & purification; D005465:Fluorocarbon Polymers
chemical_list: D001151:Arsenic; D018053:Arsenites; D007477:Ions; D008567:Membranes, Artificial; D011145:Polyvinyls; D014874:Water Pollutants, Chemical; C024865:polyvinylidene fluoride; D005465:Fluorocarbon Polymers; C015001:arsenite