Engineering and Technology Journal

Industrial and agricultural discharges have been shown as important sources for a wide range of contaminants like heavy metals. This study focused on the assessment of the toxic effect of heavy metals and illustrates some methods of eliminating or avoiding these contaminants. In certain methods, heavy metals (Cu, Zn, Cr, Ni, Pb, Hg, and Cd) are recovered, and range of absorbents are tested. A number of studies have reported the complex interaction of polymers with metal ions with the polymers for eliminating heavy metals (e.g. cellulose, chitosan, and chitin. Metal ions are absorbed by these polymers by the amine and hydroxyl groups. They have unique features that incorporate polyxysalt arrangement, capacity to frame films, optical underlying qualities, and chelates metal particles. Chemical bonds, pH, crystallinity, and deacetylation are controlling the mechanism and performance of the absorption. Some methods increase the efficiency, selectivity, and quality of chitosan: the first is through chemical modification employing grafting and crosslinking, and the second by physical modification, such as manufacturing gel granules and reducing crystallization. This study aims to investigate the removal of heavy metals from water by the sorption method and to study and analyze literature dealing with this topic using chitosan hydrogel.

Plant wastes have been successfully applied as biosorbent materials of several heavy metal ions from industrial wastewater due to the obvious capability of removing significant quantities of heavy metal ions. In the current work, banana peel powder was constrained by calcium alginate for polymerization and bead formation and subjected to both biosorption and recovery processes of Zn, Cr and Ni ions from untreated wastewater, collected from general state electrical manufacturing company in Baghdad-Iraq, using designed laboratory treatment unite. It has been found that the capacity of immobilized banana peel was significantly higher in bioremoving Zn, Cr and Ni ions than that of calcium alginate where mean biosorption capacities of Zn, Cr and Ni ions was 74.0 ± 2.3 mg/l, 83.0 ± 0.0 mg/l and 71.0 ± 1.8 mg/l respectively while in case of calcium alginate, these values were 25.0 ± 2.2 mg/l for Zn 34.0 ± 1.3 mg/l for Cr and 19.0 ± 0.9 mg/l for Ni. This study has found that biosorption capacities of heavy metal ions by immobilized banana beads, used in laboratory treatment unite, from industrial wastewater was much efficient where this lab designed unite had shown significant capacity of such beads in bioremoving all examined heavy metal ions by giving higher biosorption capacities which were 86.6 % in case of Zn ions and 100% for both Cr and Ni ions. In the recovery of these heavy metal ions from biosorbent immobilized banana beads, it was found that the percentages of recovered metal ions, from these beads used in laboratory unite, were very high ranging from 88.0 % in case of Cr ions to 90.5% for Zn ions while this recovery percentage was 88.7% for Ni ions.