Development and Application of Chitosan Extracted from Crab Shell for Water Purification

Abstract

The properties of chitosan enable it to attach itself to a variety of organic contaminants (bacteria, algae, urea and sweat), minerals metals and oils. Chitosan, therefore, drastically increases the effectiveness of filtration systems, being sand or decent ridges which normally cannot capture fine particles and dissolved pollutants. Crab shell was collected from Rivers State in the southern part of Nigeria and characterized using XRF and Chitosan was extracted from it using the conventional method of pretreatment, demineralization, HCl deproteinization and NaOH deacetylation and also the chitosan was characterized using XRF, SEM, and FTIR. Results obtained from XRF show that CaO is in a high percentage of 88.74%, CeO₂ in low percent of 0.01% and Al₂O₃ 0f 2.2% in crab shell after the Chitosan characterized Al₂O₃ increases to 7.7% while CaO decreases to 85.49%. The FTIR spectra of the chitosan gave characteristic bands 0f 3433.41 cm^-1 for –NH2 and 1647. 41cm^-1 for the carbonyl group and the SEM shows nonsmooth space in the morphology of the chitosan indicating a high degree of deacetylation. The prepared chitosan was used at different dosages and contact times in Gubi Dam raw water treatment some physical, chemical, and microbial properties of the water were analyzed before and after purification and was found to be a good coagulant/ flocculant aid and disinfectant.