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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