KINETIC AND EQUILIBRIUM STUDIES OF ADSORPTION OF LEAD (II) IONS FROM AQUEOUS SOLUTION USING COIR DUST (Cocos nucifera L.) AND IT’S MODIFIED EXTRACT RESINS

摘要

Metal detoxification of waste water and industrial effluents are of increasing importance to industrialization in the twenty first century. The ability of coconut (cocos nucifera L) coir dust (CD), carbohydrate toluenediisocyanate resin (CTR) and sulphonated toluenediisocyanate resin (STR) to remove Pb(II) ions from aqueous solution by ion exchange was studied. Percentage ion exchange efficiency of the resins were found to increase in the order CD(65)> CTR(52) >STR(48). The extent of removal of Pb(II) was found to be dependent of contact time, temperature and initial metal concentration. The optimum time and pH were found to be 60 mins and 7.0 respectively for the three resins. The adsorption studied include both equilibrium adsorption isotherms and kinetics. Several isotherm models were investigated and the adsorption isotherm data were best represented by Freundlich and Flory-Huggins isotherms due to the observe high correction coefficient of 0.847, 0.944 and 0.902 for Frenudlich and 0.802, 0.963 for CD and CTR with Flory-Huggins model for the equilibrium studies. The kinetic data were well described by the pseudo-second order kinetic model as indicate by the high value of correlation coefficient R2 and rate constant K2 as 0.725, 0.94 and 0.858 for CD, CTR and STR. The result indicate that CD, CTR and STR could be employed as an alternative, low-cost adsorbent for the removal of Pb(II) ions from solutions and thus decontaminating industrial effluents.