Chemical modified bark for Cu (II) sorption from aqueous solution

In present study the removal of Copper ions from aqueous solution containing 100-800 mg/lit, using chemically modified Acacia bark was performed on laboratory scale. The chemical modification was done by treating grinded bark with formaldehyde in acidic medium. The Cu (II) is exchanged against protons on the modified bark that contain carboxyl groups in both pectin and tannin compounds. The effects of different parameters such as effect of pH, effect of bark doses, effect of temperature, effect of time and effect of metal ion concentration have been investigated. The efficiency of copper removal increases to maximum to about 45% at around pH 5 with only 0.2 gram material. The study also revealed that the rate of sorption increase with increase in the quantity of material. The sorption copper ions are more in initial time of sorption process but the rate decreases with contact time increase. It is noted that with increasing temperature the absorption capacity of copper ions also increases indicating endothermic nature of adsorption. The equilibrium data for copper ion follow the Langmuir and Freundlich isotherms. It has been observed that interaction of copper ion on bark material follow a cation exchange mechanism which is supported by elution process in which recovery of about 90% of copper take place with 0.1N HCl solution.