Adsorption of phosphate ions from water using a novel cellulose-based adsorbent

A novel cellulose-based adsorbent, iron(III)-coordinated amino-functionalised poly(glycidylmethacrylate)-grafted cellulose [Fe(III)-AM-PGMACell] was developed for the removal of phosphate from water and wastewater. The scanning electron micrograph showed that AM-PGMACell has a rougher surface than cellulose and the adsorption of Fe(III) on AM-PGMACell made the surface even rougher. Infrared spectroscopy revealed that amino groups on the surface of AM-PGMACell complexed with Fe(III) played an important role in the removal of phosphate from solutions. X-Ray diffraction patterns showed a decrease in crystallinity after graft copolymerisation onto cellulose. The effects of contact time, initial sorbate concentration, pH, agitation speed, dose of adsorbent and temperature on the removal process were investigated. Maximum removal of 99.1% was observed for an initial concentration of 25mg center dot L -1 at pH 6.0 and an adsorbent dose of 2.0g center dot L -1. A two-step pseudo-first-order kinetic model and Sips isotherm model represented the measured data very well. Complete removal of 11.6mg center dot L -1 phosphate from fertiliser industry wastewater was achieved by 1.6g center dot L -1 Fe(III)-AM-PGMACell. The adsorbent exhibited very high reusability for several cycles. Overall, the study demonstrated that Fe(III)-AM-PGMACell can be used as an efficient adsorbent for the removal and recovery of phosphate from water and wastewater.