Chitosan-blended membranes for heavy metal removal from aqueous systems: A review of synthesis, separation mechanism, and performance.

The environmental pollution caused by heavy metal ions has become a serious global environmental issue. Heavy metal contaminants released from industrial effluents, agricultural runoff, and human activities, can enter into water resources. The toxicity of these heavy metal ions even at trace concentrations presents a substantial hazard to both aquatic systems and human well-being.

Optimization of process using carboxymethyl chitosan for the removal of mixed heavy metals from aqueous streams.

This paper highlights the efficacy of carboxymethyl chitosan (CMCh), a bio-degradable water-soluble derivative of chitosan for the separation of a mixture of heavy metal ions such as copper, nickel, zinc and lead from aqueous streams, as they constitute, the major industrial pollutants present in wastewater. The experimental studies are conducted using commercially available ultrafiltration module using synthetic solutions of the contaminants. The design of experiments was performed by Response Surface Methodology (RSM) with split-plot D-optimal design.

Removal and recovery of heavy metals through size enhanced ultrafiltration using chitosan derivatives and optimization with response surface modeling.

N‑N‑N‑triethylammonium chitosan (TEAC) and carboxymethyl chitosan (CMCh), the two water-soluble chitosan derivatives were utilized for the removal and recovery of heavy metals by size enhanced ultrafiltration (SEUF). The strong positive quaternary ammonium [-N(CH)] cation in TEAC interacts with Cr(VI), which exists as a strong chromate anion thereby enabling the efficient removal of chromate through ultrafiltration. CMCh consists of COOH and NH moieties, which facilitate interactions with heavy metals such as Cu(II) and Ni(II).