Thermodynamic Function of Adsorption Methylene blue on Nanocellulose Synthesized from Corn cobs

Abstract

In this work, the use of nanocellulose (NC) prepared from one of the useless agricultural waste, corncobs, was used to remove pollution in one of the organic dyes, namely, methylene blue dye. NC known to have interesting characteristics such as nano scale dimensions, high surface area, optical properties, rigidness, strength, rheology and crystalline structure Adsorption isotherms are carried out by three isothermal mathematical models; Langmuir, Freundlich and Temkin. It is clear that the adsorption process on NC corn cobs is fitted very well with isotherm models. The efficiency of NC to remove Methylene Blue dye (MB) was also studied at different temperatures to measure the efficiency of the NC to remove pollutants from environment. It was found that excellent removal process occurred by using NC as adsorbent for MB dye. The measured adsorption quantity of MB dye by NC was noticed to be decreased with the increasing of temperature, besides that, the adsorption quantity of MB on NC nanofibers has been found to be higher than of adsorption quantity of nanoparticles NC. The thermodynamic study of adsorption isotherm was accomplished and investigated. The Gibbs free energy change (∆Gο), entropy change (∆Sο) and enthalpy change (∆Hο) were revealed. The negative sign of ∆Gο indicated that adsorption of MB dye on the surface of prepared NC was spontaneous process, in other hand, the negative values of ∆H ο signified that the adsorption is exothermic process and the negative values of ∆Sο reflect that decrease in randomness in the solid- liquid surface during the adsorption was undertaken