Evaluation of low-cost geo-adsorbents for As(V) removal

Four low-cost iron-bearing geo-adsorbents were tested for As(V) removal without pretreatment: Montanit300® (M), diatomite (D), pumice (P) and black sand (BS). The solids carefully characterized by different analytical techniques (SEM-EDX, TPD-pyridine, N2 Physisorption, XRD point of zero charge). adsorption was evaluated through isotherms kinetic studies (bottled water matrix, pH0=8,25 g/L solids), experiments addressing pH effect (pH0=3.6,7.5,11) the presence interfering anions (Cl?, SO42?, NO3?, PO43?). Experimental results fitted to Freundlich Langmuir sorption isotherms. Under employed conditions, P showed negligible adsorption, M D presented capacities around 0.02 mg/g and, in spite its lower surface area, BS displayed highest value (0.045 mg/g), which relates a higher density Fe species, samples easily regenerated (80%–100% desorption) basic treatment (0.01 NaOH) fast kinetics (1 h seconds M). slow (24 h) poor regeneration (only 50% desorption). Sample (natural zeolite) resulted promising option due remarkably kinetic, easy capacity suitable systems with relatively low As concentrations.