Crosslinking of chitosan with glutaraldehyde for removal of dyes and heavy metal ions from aqueous solutions

ABSTRACT

Crosslinking of chitosan with glutaraldehyde in acidic medium has been studied. Factors affecting the crosslinking reaction including, reaction time [5-30 min] and temperature [40-80°C], as well as concentration of glutaraldehyde [0.5-1%] were studied. The efficiency of the crosslinking reaction was determined through measuring nitrogen content of the crosslinked chitosan. Utilization of glutaraldehyde crosslinked chitosan in the removal of different kinds of dyes has also been studied. Dyes used were acid, reactive, direct and basic dyes. Results obtained show that chitosan was effectively crosslinked when using 2% glutaraldehydc based on weight of chitosan at temperature 80°C for 10 min, Application was also made of highly crosslinked chitosan in dye and heavy metal ions removal. Results obtained disclosed that 100% [dye concentration, lg/l] acid dye and reactive dye adsorption could he achieved when the treatment was allowed to proceed for 2 hr. This was against 68% adsorption in case of the direct dye. On the other hand, crosslinked chitosan exhibited low affinity to basic dyes. It was also found that the adsorption capacity of the crosslinked chitosan was 85% and 75% for the copper ions and chromate ions, respectively