Novel chitosan/polyurethane/anatase titania porous hybrid composite for removal of metal ions waste

BACKGROUNDFor almost three decades, heavy metal pollution has been studied and several treatment techniques have been proposed. Nevertheless, this contamination in wastewater is still a severe problem. In our study, Cd (II), Pb (II) and Al (III) metal ions removal was evaluated, using a chitosan-TiO2-polyurethane based composite. Composite synthesis variations in composition and temperature were studied; morphology characterization was conducted by SEM, EDS-STEM and X-ray micro-CT. Wastewater samples in different pH solutions, and in static and dynamic systems were analyzed by ICP-MS. Also, the photo-degradation of azo dyes in these systems was studied by UV-vis spectrophotometry. A dynamic removal system was built as possible water treatment plant prototype. RESULTSMorphology results showed porosity dependence on synthesis temperature and interconnected pores. Cd (II) and Pb (II) ions best removals were 64.9% and 70.5%, respectively; improving removal in highly acidic solutions compared with other TiO2/chitosan proposals that dissolve or have no significant removal percentages at this pH. Azo dyes degradation was achieved at 27.6%, which allows the material to be used with double function in wastewater treatment. CONCLUSIONSThese findings are novel because they show good performance of the material on different wastewater samples, including multicomponent mixtures with highly acidic media. These efforts will allow wastewater treatment without previous water conditioning in a dynamic removal system; additionally, dye degradation could be possible in the same system. (c) 2016 Society of Chemical Industry