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

Controlled removal of textile azo dye Congo red from aqueous system using PEG-ZnO/rGO composite

Jamil A. Buledi, Amber R. Solangi, Arfana Mallah, Madeeha Batool, Zia-ul-hassan Shah, and Syed Tufail Sherazi

National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, Pakistan

E-mail: ambersolangi@gmail.com

Received: 24 August 2023  Accepted: 6 June 2024

Abstract:

Water pollution is a pressing global concern due to the uncontrolled discharge of organic pollutants into aquatic environments without adequate treatment. One significant contributor is the release of organic dyes, notably Congo red (CR) dye, from industrial effluents, posing environmental and health risks. In response, a highly effective 2D porous material, the PEG-ZnO/rGO composite, has been developed for the removal of CR dye from water systems. The composite was thoroughly characterized using XRD, FTIR, SEM, AFM and EDX analytical techniques to assess its crystalline nature, functionalities, surface morphology, 3D structure and elemental composition. Under optimized conditions (pH 3, 3 mg adsorbent dose and 0.5 mM CR dye concentration), the PEG-ZnO/rGO composite demonstrated a remarkable 94% removal efficiency of CR dye from aqueous solutions, with an adsorption capacity of 97.462 mg/g. Various isotherm models, including Langmuir, Freundlich, D-R, and Temkin, were applied to determine the adsorption capacity, with the Langmuir model showing the best fit (R² = 0.9809), indicating a homogeneous surface for CR dye adsorption. The practical utility of the composite was validated through testing in both river and synthetic water samples, yielding recovery values within acceptable limits, affirming its potential for commercial-scale application in CR dye removal.

Keywords: PEG-ZnO/rGO; Graphene oxide; Congo red; Cationic dyes; Water pollution and environmental pollution

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-024-03552-w

Chemical Papers 78 (11) 6531–6543 (2024)