ADSORPTION CAPACITY OF CARBONIZED TITONIA DIVERSIFOLIA TOWARDS Cd2+ AND CU2+ UNDER DIFFERENT pH, ADSORPTION CAPACITY AND CONCENTRATION

Abstract

Adsorption studies were performed to investigate the adsorption capacity of carbonized Tithonia diversifolia towards heavy metal ions (Cd2+ and Cu2+) under different pH, contact time, concentration and temperature conditions. Cadmium metal concentrations at; 25 ppm, 50 ppm, 75 ppm, 100 ppm, 150 ppm and 200 ppm of metal solutions were prepared and the pH was adjusted to 5. The uptake of copper (II) increases as the pH of the solution increases; at pH 1, pH 2, pH 3, pH 4 and pH 5, percentage metal bound were 20.59, 48.47, 94.26 and 94.08% respectively, at pH 5 and pH 6, percentage metal bound dropped to 93.26, 92.62% respectively. The increase in the removal of copper as pH increases is attributed to the decrease in competition between proton and Cu2+ ion for the surface site. Cadmium study showed that the optimum binding pH is 5 while at pH 1, pH 2, pH 3, pH4 and pH 6, percentage bound were 25.59, 59.12, 96.76, 96.14 and 98.31% respectively. The percentage removal for cadmium (II) ion is low at pH 1 and remains high and almost constant at pH 6. The high binding power of cadmium (II) ion at the initial stage is attributed to the biomass having maximum binding sites available for interaction. Our findings showed that the amount of Cu+2 and Cd2+ adsorbed was found to vary with the initial solution pH, adsorbent dosage and concentration.