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

High-efficiency protein adsorption from aqueous media using copper-LDH functionalized clinoptilolite: a dual-step modification approach

Hamed Karimzadeh, Hossein Hazrati, Reza Alizadeh, and Nava Pourbakhsh

Faculty of Chemical Engineering, Sahand University of Technology, Tabriz, Iran

E-mail: h.hazrati@sut.ac.ir

Received: 6 June 2025  Accepted: 5 September 2025

Abstract:

Water pollution remains a critical environmental concern, necessitating the development of efficient and sustainable treatment technologies. Proteins, as abundant macromolecules in natural and industrial effluents, require effective removal strategies. In this study, a novel adsorbent was synthesized using natural clinoptilolite, activated with nitric acid and subsequently modified with copper-based layered double hydroxides (LDHs). The structural and surface characteristics of the synthesized material were examined via SEM, FTIR, XRD, EDX, XRF, and BET analyses. The effects of key operational parameters including initial protein concentration, adsorbent dosage, solution pH, and temperature were systematically investigated. Kinetic modeling revealed that the pseudo-second-order model provided the best fit (R² = 0.979), while isotherm analysis indicated strong agreement with the Freundlich model (R² = 0.999), yielding a maximum adsorption capacity of 806.45 mg/g. The optimized adsorption conditions were found to be an initial protein concentration of 500 mg/L, an adsorbent dosage of 0.03 g/L, and a pH of 4. The results demonstrate the high potential of modified clinoptilolite as a cost-effective and environmentally friendly adsorbent for protein removal from aqueous media.

Keywords: Surface adsorption; Proteins; Clinoptilolite; Dual-layer hydroxide; Kinetics; Adsorption isotherm

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-04369-x

Chemical Papers 79 (12) 9037–9056 (2025)