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.