Comparative Studies of Sorption of Copper (II) ions from Aqueous Solution Using Synthetic Hematite, Activated Carbon and Composite

Abstract

Hematite nanoparticles, activated carbon and composite were used for the removal of copper (II) ions from aqueous solution. The effects of contact time, adsorbent dosage, pH and temperature on the adsorption of Copper (II) ions were studied. The results show that the adsorption of Cu (II) was time, adsorbent dosage, temperature and pH dependent. The thermodynamic studies show that the adsorption process was exothermic in nature. The results obtained show that the uptake of Cu(II) ions onto hematite and activated carbon best fitted the Langmuir isotherm with R² values of 0.9557 and 0.9614 respectively while that of composite best fitted the Freundlich isotherm with R² value of 0.9616. The hematite has the highest adsorption capacity of 21.5 mg Cu(II)/g of adsorbent, activated carbon has higher adsorption capacity of 15.4mg Cu(II) /g of adsorbent while that of composite was 14.6mg Cu(II)/g. Kinetic studies show that pseudo-second-order reaction model best described the adsorption process for all three adsorbents with R² value in the range 0.8755-0.9647 indicating a chemisorption process.  The thermodynamic results reveal the spontaneity of the reaction for hematite and composite.