A novel amphoteric adsorbent derived from biomass materials: Synthesis and adsorption for Cu(II)/Cr(VI) in single and binary systems

A novel amphoteric resin derived from wheat straw (WS) was created. Its physicochemical properties as well as biosorption properties in single and binary systems for Cu(II) and Cr(VI) were discussed in depth. The characteristics of the products indicated that the required binding sites (amine and carboxyl groups) have been grafted onto the agricultural residue biomass. The adsorption capacities for Cu(II) and Cr(VI) are 73.53 and 227.3 mg g−1, respectively, which can be in competition with other similar adsorbents. In binary systems, the two ions exhibited competitive adsorption and the interference of Cu(II) with Cr(VI) was much more obviously attributed to the higher affinity and selectivity for Cr(VI) onto wheat straw amphoteric adsorbent (WSAA).