Novel hydrogel poly (GG- co-acrylic acid) for the sorptive removal of the color Rhodamine-B from contaminated water

Salma Jabeen; Sultan Alam; Luqman Ali Shah; Muhammad Zahoor; Muhammad Naveed Umar; Riaz Ullah

doi:10.1016/j.heliyon.2023.e19780

Novel hydrogel poly (GG- co-acrylic acid) for the sorptive removal of the color Rhodamine-B from contaminated water

Heliyon. 2023 Sep 3;9(9):e19780. doi: 10.1016/j.heliyon.2023.e19780. eCollection 2023 Sep.

Authors

Salma Jabeen¹, Sultan Alam¹, Luqman Ali Shah², Muhammad Zahoor³, Muhammad Naveed Umar⁴, Riaz Ullah⁵

Affiliations

¹ Department of Chemistry, University of Malakand, Chakdara Dir Lower, KPK, 18800, Pakistan.
² National Center of Excellence in Physical Chemistry (NCE), University of Peshawar, Pakistan.
³ Department of Biochemistry, University of Malakand, Chakdara Dir Lower, KPK, 18800, Pakistan.
⁴ Department of Chemistry, University of Liverpool, UK.
⁵ Department of Pharmacognosy, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia.

Abstract

Textile effluent's treatment is highly desired due to the presence of hazardous, water-soluble and non-biodegradable dyes that not only have harmful effect on the environment but on living beings as well. Treatment of these pollutants by sorption through biosorbents is considered to be a best method of choice due to greener nature of the processes. In this connection hydrogel sorbents might be an intriguing option due to its straightforward application, great efficacy, easy synthesis, rapid turnaround, and potential of recycling. Herein, novel hydrogel was prepared using Gellan Gum and acrylic acid (GG-co-AAc) which were then characterized by instrumental techniques like UV/visible and FTIR spectroscopy, SEM, EDX and XRD. The anionic hydrogel's adsorption capacity, swelling behavior, and sorption potential were determined using Rhodamine-B as potential environmental pollutant. The hydrogel exhibited an impressive adsorption capacity of 1250 mg/g. Swelling experiments were performed in Milli-Q distilled water at different pH levels, reaching maximum swelling of 3230% after 23 h as determined through Fickian diffusion. At pH 7, the anionic hydrogel's sorption potential was thoroughly studied in the subsequent experiments. The adsorption process was found to follow the Langmuir isotherm, indicating a monolayer adsorption mechanism supported by higher R² values compared to the Freundlich isotherm. Thermodynamic analysis revealed the exothermic nature of the adsorption process, with a negative enthalpy value of -11371 KJmol^-1 and negative entropy value of -26.39 Jmol^-1K^-1, suggesting a less ordered system. These findings provide valuable insights into the adsorption characteristics and potential applications of the synthesized anionic hydrogel.

Keywords: Adsorption; Hydrogel; Kinetics; Rhodamine B.