Adsorption of Zn(II) and Pb(II) Ions from Aqueous Solution Using Chitosan Cross-Linked Formaldehyde Adsorbent to Protect the Environment

Abstract

Synthesis of chitosan cross-linked formaldehyde was successfully prepared from shrimp chitosan. Characterization of the adsorbent using functional properties such as Fourier transform infrared spectroscopy and scanning electron microscope shows the present of amide and hydroxyl groups at their respective position, also the morphological structure of the adsorbent. Adsorption study of the above adsorbent was carry out for the removal of Zn(II) and Pb(II) from aqueous solution. The effect of cross-linked chitosan dosage, initial concentration, contact time, temperature and pH of the solution for the removal of Zn(II) and Pb(II) were discussed. The optimum dosage required for the removal of Zn(II) and Pb(II) were found to be at 0.4 g at the maximum temperature of 25 °C and the percentage removal were 20.34 and 13.54% respectively. The time required for equilibrium to be reached was 50 min. Effectiveness of the cross-linked adsorbent was observed to increase by increase in contact time. Further studies were also done on isotherms and kinetics of Zn(II) and Pb(II) removal from aqueous solution using chitosan cross-linked formaldehyde. Adsorption Isotherm study conducted from the cross-linked absorbent, shows that the Langmuir plot for the removal of Zn(II) was best fitted with R2 value of 0.9934, and the adsorption process follows the pseudo second order kinetics with an R2 value of 0.996. This adsorption process was established to be reversible with an RL values of zinc (0.8232) and lead (0.8853) respectively. Therefore this implies a successfully reduction in the adsorption of zinc and lead ions from cross-linked formaldehyde solution to protect our environment.