modified zero valent iron (zvi) nanoparticles for removal of manganese from water

manganese is one of the significant raw materials for various industries and most difficult element to remove from water because of its high solubility. the treatment of mn (ii) contained wastewater is stringent for environmental preservations. in the present study adsorption of mn2+ on zero-valent iron nanoparticles synthesized by chemical reduction process and modified with phosphate coating was investigated. synthesized nanoparticles were characterized by scanning electron microscopy (sem), energy dispersive x-ray spectrometry (eds), x-ray diffraction (xrd) and fourier transform infrared spectra (ftir).the effects of contact time, adsorbent dose, mn (ii) initial concentration, ph and temperature were investigated. the maximum adsorption occurred after 5 hrs and maximum removal (92.45%) of mn(ii) took place at a ph of 9. the removal rates of mn (ii) decreased from 93.11% to 68.82% as the initial concentration was increased from 2 to 9% (approximately) when zvi nanoparticles were used. on the other hand the removal rate is almost steady when modified zvi nanoparticles with phosphate ion were used. the equilibrium data fits well to langmuir adsorption isotherm, suggests monolayer adsorption. the adsorption followed the pseudo second order kinetics. the effect of other metal ions present in water on the removal of mn (ii) has been also investigated.