Montmorillonite-silica Nanocomposite for Dye Removal from Solution
Dyes are used in various industries such as pharmaceutical, cosmetic, paper, leather, food stuff, plastics, and textile etc. The dye effluents are discharged into environment by either water or land. The discharge of these effluents into the receiving environments results in hazardous health problems as most of these dyes have carcinogenic effects on the living organisms. Congo red was removed on Montmorillonite-silica nanocomposite from solution by adsorption process. The adsorption parameters studied were adsorbent dose, initial concentration and contact time. The optimum adsorption parameters were found to be 2 mg/L, 1.5 g and 40 minutes for initial concentration, adsorbent dose and contact time respectively with removal percentage of 84.10%. Pseudo first and second order kinetics were used for the studies. Pseudo second order best fit the adsorption process with R²= 1 than the Pseudo first order which has R²= 0.933. Experimental data were best fitted by the Langmuir Isotherm with R²=0.9024 other than the Freundlich Isotherm, R²=0.568. The RL of 0.994 of the Langmuir isotherm shows the favourability of the adsorption process. The maximum adsorption capacity by Langmuir isotherm was found to be 172. 40 mg/g. The adsorption process of Congo red was carried out using Montmorilonite silica nanocomposite. From the experimental data the percentage removal of 84.10% obtained at an optimum initial concentration of 2 mg/l, an optimum adsorbent dose of 1.5 g and optimum contact time of 40 minutes. Experimental data were best fitted by the Langmuir Isotherm with R²=0.9024 other than the Freudlich Isotherm, R²=0.568. The pseudo second order kinetic with R²= 1 best fit the adsorption process other than the pseudo second order kinetics, R²=0.933. Therefore, montmorillonite-silica nanocomposite obtained from montmorillonite clay and Rice husk ash can serve as a cost-effective adsorbent in the removal of Congo red dye.
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