MIL-125(Ti)/Bagasse nanocomposite for efficient adsorption of Rhodamine B from aqueous solution

In this research, the adsorption properties of a new nanocomposite including Titanium-based metal-organic framework (MIL-125(Ti)) and bagasse towards adsorption of rhodamine B (a cationic dye) was investigated. Herein, terephthalic acid as an organic linker and titanium isopropoxide as a metal source used to synthesize MIL-125(Ti). Various syntheses with different weight percentages of MIL-125 and Bagasse have been performed to enhance the dye adsorption properties. XRD s pattern and SEM images were used to verify the synthesis of the nano-composite material. The data showed that MIL/Bagasse nanocomposite has XRD s pattern and SEM images as same as pure MIL which represents that the structure of MIL-125 did not change during the synthesis. The high surface area properties of the nano-composite material were extracted from the BET result. The adsorption power of removal rhodamine B from aqueous solution was investigated. It was also determined that the MIL/Bagasse with 30 % weight percent of bagasse could remove almost 100 % of the dye at 25 ° C in 40 minutes. The desorption capacity of the as-synthesized composite was also investigated with the selected solvents such as Methanol, Ethanol, HCl and also different ratios of them. As an important result, it was observed that a 1:1 mixture of HCl and Methanol could display desorption of dye around 97 %. In addition, adsorption kinetics was investigated carefully. For this purpose, pseudo-first-order and pseudo-second-order models were investigated. The obtained data show that the removal of the dye kinetics was followed the pseudo-second-order with R2=0.99. To achieve the adsorption isotherm, Langmuir and Freundlich s models were investigated and the results demonstrated that the adsorption isotherm follows the Langmuir model. In addition, adsorption thermodynamics was investigated carefully and the obtained data represent that the reaction is exothermic and will be accompanied by the rise of entropy.

کلیدواژه ها:

Titanium-based metal-organic frameworks ، MIL-125 ، Bagasse ، Rhodamine B ، Adsorption ، Desorption