An all-biomass adsorbent: competitive removal and correlative mechanism of Cu 2+ , Pb 2+ , Cd 2+ from multi-element aqueous solutions

It is imperative to develop adsorbents, which have the virtue of cost-effective, eco-friendly and degradable. In this paper , the bio-adsorbent beads were prepared via cross-linking between sodium alginate (SA) and ionic-modified sodium carboxymethyl cellulose (CMC-z) , of which CMC-z is modified by introducing sulfobetaine as function group. It was employed to eliminate Cu 2+ , Pb 2+ and Cd 2+ in multi-element aqueous medium. The concentrations of heavy metal ions were determined by the 5100 ICP-OES. The maximum adsorption capacities of Cu 2+ , Pb 2+ , Cd 2+ was 212 mg/g, 255 mg/g, 123 mg/g, respectively ( C 0 = 300 mg/L, T = 278 K). The strength of the attraction between the heavy metal ions and the SA/CMC-z hydrogel beads will be the sequence of Pb 2+ > Cu 2+ > Cd 2+ > Ca 2+ . The XPS peaks of Ca 2+ became pitiable in the competitive system, the C=O, C–O/C–N groups would be involved in the metal gelation process. Strong electron donating ability of functional groups in adsorbents would capture Pb 2+ , Cu 2+ and Cd 2+ ions. The second-order kinetic model ( R 2 > 0.99) pointed to interactions between heavy metal ions and SA/CMC-z gel beads that occurred via various types of binding sites and SA/CMC-z beads have heterogeneous surface nature. The heavy metal ions have a high affinity toward the SA/CMC-z hydrogel beads, which can be increased randomness at solution/adsorbent interface during adsorption. The adsorption efficiency in a multicomponent competitive system could be having antagonism effects. After four reaction cycles, the reusability performance exhibited excellent. This study offers a highly promising candidate for the treatment of wastewater contaminated with a mixture of heavy metal.