Multi-walled carbon nanotubes/TiO2/Chitosan nanocomposite for efficient removal of malachite green dye from aqueous system: A comprehensive experimental and theoretical investigation

Zeeshan Ahamad; Fouzia Mashkoor; Abu Nasar; Changyoon Jeong

doi:10.1016/j.ijbiomac.2025.139461

Multi-walled carbon nanotubes/TiO₂/Chitosan nanocomposite for efficient removal of malachite green dye from aqueous system: A comprehensive experimental and theoretical investigation

Int J Biol Macromol. 2025 Jan 6:295:139461. doi: 10.1016/j.ijbiomac.2025.139461. Online ahead of print.

Authors

Zeeshan Ahamad¹, Fouzia Mashkoor², Abu Nasar³, Changyoon Jeong⁴

Affiliations

¹ Department of Applied Chemistry, Faculty of Engineering and Technology, Aligarh Muslim University, Aligarh 202 002, India.
² School of Mechanical Engineering, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Republic of Korea.
³ Department of Applied Chemistry, Faculty of Engineering and Technology, Aligarh Muslim University, Aligarh 202 002, India. Electronic address: abunasaramu@gmail.com.
⁴ School of Mechanical Engineering, Yeungnam University, Gyeongsan, Gyeongbuk 38541, Republic of Korea. Electronic address: yoonni22@yu.ac.kr.

PMID: 39778841
DOI: 10.1016/j.ijbiomac.2025.139461

Abstract

This study presents the preparation, characterization, and application of a novel Multi-walled carbon nanotubes/TiO₂/chitosan (MWCNT/TiO₂/CS) nanocomposite, prepared using a hydrothermal method, for the removal of malachite green (MG) dye from aqueous solutions. Adsorption studies revealed optimal dye removal within 15 min of adsorption equilibrium time, with maximum removal efficiency of 98.53 % at pH 7.0, dose 0.4 g/L and 298 K. Isotherm studies showed the Langmuir model best described the adsorption equilibrium data with maximum monolayer adsorption (q_m) value was found to be 269.98 mg/g at 298 K. Kinetic analyses favored the pseudo-second-order model with q_cal value was found to be 201.6 mg/g at C_o = 100 mg/L. Thermodynamic investigations indicated an exothermic, spontaneous adsorption process. Seven successful adsorption-desorption cycles were achieved using HCl as an eluent (97.65 % desorption). Theoretical reactivity parameters derived from DFT calculations corroborated experimental findings, elucidating the molecular-level mechanisms underlying the efficient adsorption of MG onto the MWCNT/TiO₂/CS surface. The strong electrophilic nature and electron-accepting character of the MG molecule, along with its ability to form electronic interactions, explain its high adsorption affinity. These findings demonstrate the potential of MWCNT/TiO₂/CS nanocomposite as an effective and sustainable solution for MG dye removal from aqueous environments.

Keywords: Adsorption; MWCNT/TiO(2)/Chitosan; Malachite green.