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

Sustainable hydrogel for simultaneous dye removal from real water: foam-stabilized salep–montmorillonite

Faezeh Pourebrahim, Mehdi Pourahmadi, Ruhollah Shaali, and Mohammad Mahdi Doroodmand

Department of Chemistry, College of Sciences, Shiraz University, Shiraz, Iran

E-mail: doroodmand@shirazu.ac.ir

Received: 6 August 2023  Accepted: 7 October 2023

Abstract:

In this contribution, a highly efficient adsorption–desorption-based method was developed for the simultaneous removal of methylene blue (%removal = 98%) and methyl violet (%removal = 93.5%) from real water media. In this regard, a foam-stabled salep-montmorillonite hydrogels were prepared as a high throughput and ultra-reusable adsorbent for the simultaneous removal of organic dyes. The adsorbent is environment-friendly with facile reusability without needing for applying any external separator such as a centrifuge or magnetic field. Optimization of effective parameters on removal efficiency including pH, contact time, adsorbent amount, adsorbent composition (based on salep–montmorillonite content), and temperature was performed by the one-factor-at-a-time-optimization method. The adsorption equilibrium was studied by Langmuir, Freundlich, and Temkin isotherm models indicating that the Freundlich isotherm efficiently represented both MB and MV adsorption data. Kinetic models were employed to investigate the data corresponding to the adsorption of MB and MV on the surface of the as-prepared adsorbent. The results revealed that the adsorption of MV and MB on the as-prepared hydrogels follows pseudo-second-order and pseudo-first-order kinetics, in order. The maximal adsorption capacity for MB and MV was calculated at about 83.3 mg g⁻¹ and 53.8 mg g⁻¹, respectively. The reusability studies exhibited that the as-prepared adsorbent saved 53% and 63% of its initial yield for removal efficiency of MV and MB, in order, after 7 operational cycles. Finally, the method was applied for practical application by removing organic dyes from real water media, including tap, lake, river, industrial, and pool water samples.

Keywords: Simultaneous dye removal; Methylene blue; Methyl violet; Foam-stabled salep–montmorillonite; Ease-to-recovery adsorbents

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-03149-9

Chemical Papers 78 (2) 1103–1115 (2024)