ISOTHERMAL AND KINETIC STUDIES ON THE ADSORPTION OF CATIONIC (MB) AND ANIONIC DYE (MO) BY OIL SEED RESIDUE OF Guizotia scabra

Abstract

Agricultural products are not only beneficial to man for food, its waste or residue is seen to be helpful in the chemical circle in producing low cost adsorbents. This research is aimed at studying the isothermal and kinetic mechanism on the adsorption of methylene Blue (MB) and methyl orange (MO) which are cationic and anionic dyes respectively by the residue of the oil seed of Guizotia scabra. The sample was impregnated with Phosphoric acid and carbonized at 450OC for 45minutes. UV /visible spectrophotometer was used to obtain the absorbance of the dyes. Series of experiments were conducted, the results revealed the effect of contact time, adsorbent dosage, pH, and initial dye concentration. The percentage removal of adsorbate of MB ranged from 82.58 to 98.37% while MO was 69.85 to 96.14% for adsorbent dose that varied from 0.05 to 0.20g.The percentage removal of MB ranged from 10.86 to 21.03% while MO was 43.70% to 72.96% for contact time that varied from 10 to 40 minutes. The percentage removal of MB ranged from 91.72 to 99.36% while MO was 24.76% to 9.90% for change in pH from 2 to 11. The percentage removal for MB ranged from 39.21 to 99.48% while MO was 87.62 to 73.41% for dye initial concentrations varied from 10 to 40mg/L. Equilibrium parameter analyzed found that Langmuir and Freundlich isotherm fit for all material but Langmuir fit better for M.B (R2=0.9997) than for MO. Freundlich fit better for MB (R2=0.9583) than for MO (R2=0.8319). The adsorption kinetics study shows MB (R2 = 0.9979) fit better for pseudo -first- order kinetics mechanism than MO (R2=0.8602) and MO (R2=0.995) fit better for pseudo-second–order kinetics mechanism than MB ((R2=0.7405).