Efficacy of nanochitosan impregnated polyurethane foam in removing phosphate from aqueous solutions

Abstract

A novel potential adsorbent was developed by impregnating chitosan nanoparticles on polyurethane foam (PFC) for the reduction of phosphate in aqueous solutions. The emergence of nanoparticles was first confirmed by the ultraviolet-visible (UV-Vis) spectroscopy. The mean size of chitosan nanoparticles between 56 nm and 112 nm was provided by the field emission scanning electron microscopy (FESEM). The presence of specific elements (C, O, P) in PFC before and after treatment was determined by energy dispersive X-ray (EDX) spectroscopy. The interplay between amino groups in PFC and phosphate ions during adsorption was identified by the Fourier transform infrared (FTIR) spectroscopy. X-ray diffraction (XRD) analysis of PFC showed nearly the same pattern before and after treatment, indicating the stability of sorbent. The point of zero charge experiment described the positive surface charge of PFC below pH 7.4. The experimental studies showed that phosphate removal efficiency by PFC increases from 35.04% to 69.78% with the decrease of influent phosphate concentration from 150 mg/L to 3 mg/L at contact time 6 h and pH 6.5. Hence PFC can be considered as an effective sorbent for removing phosphate at lower concentrations.