Heavy metal removal by ambient-temperature argon plasma modified polyethylene terephthalate (PET) fibers with surface acrylic acid grafting

Abstract

This study utilized the capability of ambient-temperature plasma in modifying the surface properties of materials to activate the nonwoven polyethylene terephthalate (PET) fiber surfaces. The effects of different plasma treatment parameters (such as plasma power, treatment time) and grafting parameters (such as grafting temperature, acrylic acid monomer concentration, grafting time) on the activation and grafting of the PET fibers were studied. The feasibility of applying ambient-temperature plasma combined with grafting technology for the preparation of ion exchangers in the wastewater treatment was evaluated. The results showed that the optimal modification effect of PET fibers by Argon plasma and the highest hydrophilicity was achieved at a plasma power of 800 W and treatment time of 10 s. During the grafting procedure, the optimal grafting yield of 4.45% was observed at a grafting temperature of 90°C, an acrylic acid monomer concentration of 6 M, and a reaction time of 5 h. The above surface modification and acrylic acid grafting conditions were used to prepare the ion exchangers for the investigation of subsequent adsorption behaviors. Suitable adsorption performance was achieved at a solution pH of 6, with the adsorption of Copper ion of 0.073 mmole Cu/g-polymer, Lead ion of 0.037 mmole Pb/g-polymer, and Nickel ion of 0.012 mmole Ni/g-polymer. After calculation, the reaction heat was found to be 13.74 kJ/mol, indicating that the adsorption was an endothermic reaction. Key words: Ambient-temperature plasma, polyethylene terephthalate (PET) fibers, acrylic acid grafting, heavy metal removal.