Abstract
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•Magnetic sorbent synthesis based on p-phenylenediamine, thiourea, formaldehyde (MpPDTF).•MpPDTF impregnation with Mo(VI) triples its sorption capacity towards As(V).•The sorption of As(V) by MpPDTF-Mo(VI) linearly increases with increasing the amount of loaded Mo(VI).•Temperature has two opposite effects on As(V) sorption on these sorbents.•The sorbents are very efficient for the recovery of As(V) from complex contaminated effluents.
The immobilization of Mo(VI) on magnetic poly p-phenylenediamine-thiourea-formaldehyde composite polymer (MpPDTF) (through an intermediary adsorption step) increased sorption of As(V) ions: retention capacity increased from 35.15mg As g−1 for MpPDTF to 99.04mg As g−1 for MpPDTF immobilized Mo(VI) at 298±1K. The impact of temperature and Mo(VI) immobilization on the kinetic and equilibrium constants of As(V) sorption on MpPDTF was evaluated. The thermodynamic study shows that Mo(VI) immobilization on MpPDTF changes the sorption process of As(V) on MpPDTF from exothermic associated with entropy decrease to endothermic associated with entropy increase. Also the impact of phosphate competition was studied. MpPDTF immobilized Mo(VI) was successfully tested for As(V) removal from the industrial effluents of insecticides manufacturing industry. NaHCO3 solution (0.5M) can be efficiently used for sorbent regeneration for at least 3 cycles with limited decrease in sorption performance.