Adsorption efficiency of chitosan obtained from Schistocerca gregaria 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.