ADSORPTION OF CHROMIUM(VI) AND COPPER(II) IONS FROM WELL WATER IN CHALLAWA INDUSTRIAL AREA USING PECTIN-CHITOSAN POLYELECTROLYTE COMPLEX

Abstract

The aim of the research was to carryout adsorption study of the removal of chromium(vi) and copper(ii) ions from well water using pectin-chitosan polyelectrolyte complex as adsorbent. The optimum pH and ratio of pectin/chitosan was determined and the chitosan/pectin complex was characterized by using FTIR, BET, XRD, and SEM. Finally, removal efficiency of the PEC for chromium and copper was studied under optimum conditions. I.e. 0.4 g adsorbent mass, 1.221 and 0.12 mg/L of initial copper and chromium concentration respectively, 60 oC temperature and 30 mins of time. Result shows that the optimum pectin/chitosan ratio and pH of the medium required to produce PEC with high removal efficiency was pH: 4 and pectin/chitosan ratio: 1:3. The active groups identified from FTIR are NH2 group and OH group from carboxylate group, with particle size 2 nm and surface area was 377 m2/g from BET. When the optimum temperature was 60 ℃, adsorption time of 30mins and the amount of adsorbent was 0.4g, the results showed that the adsorption capacities of the PEC of Cu2+ and Cr6+ were 333.33 and 270.27 mg/g respectively when the initial concentration was 1.221 and 0.12 mg/L respectively. The fitting results of Langmuir isothermal model, the pseudo second order kinetic model and the copper and chromium’s ∆Gowhich had negative values and ∆Ho of 53.39 and 51.67KJ.mol-1 respectively and ∆So of 0.163 and 0.167 J.mol-1K-1 respectively of thermodynamics data of the ions adsorption process show that the adsorption of heavy metal ions of Cu2+ and Cr6+ by the PEC is a spontaneous process of single-layer chemisorption.