Adsorption efficiency of chitosan obtained from <i>Schistocerca gregaria</i> for Fe²⁺ and Zn²⁺ metals

Abstract

A number of technologies for wastewater treatment have been developed  and used over the years, but adsorption comes into  prominence and gained  wide recognition due to its simple handling, flexibility in design, high  efficiency, reversible nature for multiple  uses, high-quality treatment, and  adsorbent availability. Chitosan obtained from desert locust (S. gregaria)  exoskeleton emerged as best  candidate as a sorbent for heavy metals  removal via adsorption process in aqueous solution. Isolation of chitosan  involved three  main stages, includes demineralization, deprotenization and  deacetylation. Chitosan was characterized using Fourier Transform Infrared  Spectroscopy (FTIR) and X-ray diffraction (XRD). The affinity of chitosan for  Fe (II) and Zn (II) ions solutions adsorbed under different  conditions was  evaluated using atomic adsorption spectroscopy. And the result showed that  the equilibrium percentage adsorption of  Fe²⁺ was 95 %, 95 %, 96 %, 96.2  %, and 95.8 % and the quantity of Fe²⁺ adsorbed was 5.98, 5.96, 6, 6.1 and  5.98 (mg/g) while the  equilibrium percentage adsorption of Zn²⁺ was 78 %,  83 %, 86 %, 87 %, and 89 % and the quantity of Zn²⁺ adsorbed was 5, 5.2,  5.3, 5.4  and 5.6 (mg/g) at contact time 10, 20, 30, 40 and 50 mins. The effect of adsorbent dose and contact time were studied, as the result  revealed that increment of adsorbent dosage which provides more binding  sites used for metal adsorption, leads to the increase in  quantity of Fe²⁺ and  Zn²⁺ adsorbed and their percentage removal.