Chitosan-Modified Biochars to Advance Research on Heavy Metal Ion Removal: Roles, Mechanism and Perspectives

The chitosan-modified biochars BC-CS 1-1, BC-CS 2-1 and BC-CS 4-1 were subjected to the synthetic application of biochar from agriculture waste and chitosan for the adsorption of Cu(II), Cd(II), Zn(II), Co(II) and Pb(II) ions from aqueous media. The results displayed a heterogeneous, well-developed surface. Additionally, the surface functional groups carboxyl, hydroxyl and phenol, determining the sorption mechanism and confirming the thermal stability of the materials, were present. The sorption evaluation was carried out as a function of the sorbent dose, pH, phase contact time, initial concentration of the solution and temperature. The maximum value of q(t) for Pb(II)-BC-CS 4-1, 32.23 mg/g (C-0 200 mg/L, mass 0.1 g, pH 5, 360 min), was identified. Nitric acid was applied for the sorbent regeneration with a yield of 99.13% for Pb(II)-BC-CS 2-1. The produced sorbents can be used for the decontamination of water by means of the cost-effective and high-performance method.

Automated summary

In this study, chitosan-modified biochars were synthesized and applied for the efficient adsorption of Cu(II), Cd(II), Zn(II), Co(II), and Pb(II) ions from aqueous media. The materials exhibited a heterogeneous, well-developed surface and demonstrated good thermal stability. The sorption mechanism was determined by the presence of carboxyl, hydroxyl, and phenol functional groups. The optimal sorption conditions were determined by varying the sorbent dose, pH, contact time, initial concentration, and temperature. The sorbents could be regenerated with nitric acid, achieving a high yield. This study provides a cost-effective and high-performance method for water decontamination.