A highly efficient biomass-based adsorbent fabricated by graft copolymerization: Kinetics, isotherms, mechanism and coadsorption investigations for cationic dye and heavy metal.

Natural biomass materials are endowed with good potential for pollutant remediation due to low cost, environment friendliness and easy accessibility. In this work, an efficient biomass-based adsorbent named g-PS was fabricated by free radical graft copolymerization of peanut shell with methacrylic acid and N,N'-methylenebis(acrylamide). The structural and morphological properties of g-PS were characterized and analyzed. The effectiveness of g-PS as adsorbent to remove cationic dye and heavy metal pollutants (i.e. methylene blue (MB), basic red 46 (BR) and Cd(II)) from water was evaluated. The batch adsorption tests indicated that g-PS showed rapid removal rates for MB, BR and Cd(II), with the adsorption equilibriums achieved within 30 min. The adsorption processes of three compounds were more suitable to be described by Langmuir and pseudo-second-order models. The maximum adsorption capacities were 538.34 mg/g for MB, 687.52 mg/g for BR and 62.01 mg/g for Cd(II) at 298 K. The coadsorption experiments in the mixed system indicated that g-PS was still effective for simultaneous removal of both BR and Cd(II). Additionally, g-PS exhibited satisfactory removal performance even after seven repeated uses. The as-prepared g-PS can be used as a promising adsorbent candidate to dispose wastewater containing cationic dyes and heavy metals.