Dynamic and Equilibrium Studies on the sorption of Basic dye (Basic Brown 4) onto Multi-walled Carbon Nanotubes Prepared from Renewable Carbon Precursors

The main objective of this research was to evaluate the adsorption mechanism of Multi-walled carbon nanotubes synthesized from Pine oil, methyl ester of Jatropha curcas oil and methyl ester of Pongamiya pinnata oil in comparison with commercial Activated Carbon for the removal of Basic dye (Basic brown 4). The Multi-walled nanotubes synthesized from respective precursors by spray pyrolysis method were used as adsorbent. The sorbent properties of these materials for the removal of Basic brown 4 dye from aqueous solution was studied. The effect of variables such as temperature, initial concentration, solution pH on the sorbent property of the materials in a batch mode contact time process was investigated. The influences of different factors on the adsorption of Basic brown 4 on these adsorbents were explained in terms of electrostatic fields on the Basic brown 4 dye molecule and on the surface of adsorbents. The specific rate constant measurements confirming the applicability of pseudo second order rate expression for the process. Thermodynamic parameters such as free energy change, enthalpy change and entropy change were calculated. The negative value of free energy change indicates that the Basic Brown dye adsorption process is spontaneous and the positive value of enthalpy change shows the endothermic in nature. The kinetic measurements enabled to propose possible mechanism of adsorption involved in this process.