Facile synthesis of novel pH-sensitive grafted guar gum for effective removal of mercury (II) ions from aqueous solution

Abstract

Acrylamide and acrylic acid was grafted on guar gum via microwave-assisted technique without using any initiator to prepare a new pH-sensitive adsorbent for mercury (II) ions removal from aqueous solution. The fabricated adsorbent [GG-g-poly(Am-co-AA)] was characterized via SEM, FT-IR, XRD, and TGA analytical techniques to confirm the grafting of acrylamide and acrylic acid on guar gum. The influence of numerous procedure parameters like adsorption dose, pH, time, concentration, and temperature was investigated to achieve the maximum mercury (II) ions removal from water. The maximum mercury (II) ions removal (95%) was observed at dose (30 mg), temperature (30 °C), pH (6), time (40 min) with 100 ppm mercury concentration. The mercury adsorption on [GG-g-poly(Am-co-AA)] was confirmed by zeta potential SEM- EDX and XPS study. The adsorption isotherm and adsorption kinetics were studied to know the pattern of adsorption. The mercury ions adsorption isotherm data can be explained by Langmuir adsorption isotherm while kinetic data of adsorption was found to the suitable for the Elovich model. The present investigation provides important evidence beyond doubt to prove that GG-G-poly(Am-co-AA) has the potential to effective removal of Hg (II) ions from aqueous streams.