ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Mechanistic insights into naphthalene removal from wastewater employing modified NH₂-MCM-41 mesoporous materials in a batch adsorption process

Talib M. Albayati, Nisreen S. Ali, Ali M. Hameed, Mahir A. Abdulrahman, Ahmed A. Hadi, Issam K. Salih, Khairi R. Kalash, Buthainah Ali Al-Timimi, Samah F. Kamil, and Khalid A. Sukkar

Department of Petroleum Refining and Gas Technology Engineering, College of Chemical Engineering, University of Technology- Iraq, Baghdad, Iraq

E-mail: Talib.M.Naieff@uotechnology.edu.iq

Received: 28 June 2025  Accepted: 8 November 2025

Abstract:

This study investigates the removal of naphthalene, a model polycyclic aromatic hydrocarbon (PAH), from industrial wastewater using amine-functionalized mesoporous silica (NH₂-MCM-41). The material was synthesized by post-synthesis grafting of aminopropyltriethoxysilane (APTES) onto MCM-41, and its physicochemical properties were confirmed through XRD, FTIR, BET surface analysis, TGA, and SEM. Adsorption experiments in batch mode assessed the effects of pH, contact time, adsorbent dosage, and temperature. The results show that NH₂-MCM-41 has a maximum adsorption capacity of X mg/g for naphthalene, significantly higher than that of parent MCM-41. Adsorption followed the Freundlich isotherm model (R² = 0.98), indicating a heterogeneous surface and multilayer adsorption, while kinetic data fit best with the pseudo-second-order model, suggesting chemisorption involvement. Thermodynamic parameters (ΔG < 0, ΔH < 0) confirm that the process is spontaneous and exothermic. Comparison with literature demonstrates the competitive performance of NH₂-MCM-41 among reported adsorbents for PAH removal. The adsorbent maintained over 90% efficiency after five regeneration cycles, confirming its reusability. Mechanistic insights from FTIR and surface chemistry suggest that adsorption occurs mainly through π–π stacking, hydrophobic interactions, and hydrogen bonding between naphthalene and the functionalized surface. These findings highlight NH₂-MCM-41 as a promising adsorbent for effective PAH removal from industrial wastewater.

Keywords: Adsorption; Amine group (NH2); Functionalized MCM-41; Naphthalene; Wastewater treatment; Organic pollutant

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04497-4

Chemical Papers 80 (2) 1897–1912 (2026)