Temperature Effects and Thermodynamic Adsorption of Flouride on Activated Coconut Shell Carbon, Activated Montmorillonite Clay and Rice Husk Ash
Danbature Lamayi Wilson* , Shehu Zaccheus, Fai Frederick Yirankinyuki, Pipdok Solomon Kwarson
Citation :Danbature Lamayi Wilson et.al., Temperature Effects and Thermodynamic Adsorption of Flouride on Activated Coconut Shell Carbon, Activated Montmorillonite Clay and Rice Husk AshInternational Journal of Advanced Research in Chemical Science 2017,4(9) : 21-27.
The temperature dependency and thermodynamic properties adsorption of fluoride by activated coconut shell carbon, and activated rice husk ash were investigated. The studies were carried out at various temperatures of 303,313,323 & 333K (30deg;c to 60°c). The maximum removal percentages were found at the maximum temperature of the study which is 60°C for each adsorbent. Thus, the removal percentage of fluoride increases with the increase in temperature. And the maximum removal percentage were found to be 83.5, 81.7 and 73.1 % for activated coconut shell carbon, activated montmorillonite and activated rice husk ash respectively. The value of the enthalpy change (ΔH) calculated from the slope were -28808.01, -19388.25, and -31335.47 (KJ/mole) for activated coconut shell carbon, activated montmorillonite and activated rice husk ash respectively. The negative values of (ΔH) indicate the exothermic nature of the process. The values of the entropy change, (ΔS) were found to be 123.62, 91.62 and 120.07 (KJ/mole/K) for activated coconut shell carbon, activated montmorillonite and activated rice husk ash respectively. The positive values of entropy change suggest an increased randomness at the solid/liquid interface during the sorption of fluoride into the adsorbents. The average calculated Gibbs free (ΔG) were found to be -67891.92, -48523.4 and - 69517.73 (kJ/mole). The negative values of Gibbs free energy suggests the spontaneous and feasibility of the process