Aqua (Jun 2024)

Synthesis, utilization, and recycling of graphene oxide-based nanohybrid biopolymeric hydrogels for purification of dye wastewater

  • Omera Sarwar,
  • Ruba Munir,
  • Nageen Mushtaq,
  • Hina Ambreen,
  • Muhammad Zeeshan Bashir,
  • Maryam Sana,
  • Amna Muneer,
  • Murtaza Sayed,
  • Saima Noreen

DOI
https://doi.org/10.2166/aqua.2024.033
Journal volume & issue
Vol. 73, no. 6
pp. 1228 – 1256

Abstract

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Wastewater from industries contributes significantly to pollution. Adsorption of acidic dye using nanohybrid biopolymeric hydrogels has evolved as one of the viable techniques. Graphene oxide (GO)/chitosan (CS)–polyvinyl alcohol (PVA), GO/starch–PVA, and GO/agar–PVA hydrogels were synthesized. The results revealed that the following are the ideal values: GO/CS–PVA: 3 pH (8.251 mg g−1), 0.05 g/50mL dosage (8.251 mg g−1), 90 min (8.251 mg g−1), 12 ppm dye concentration (8.251 mg g−1), and 30 °C (8.251 mg g−1); for GO/starch–PVA: 2 pH (7.437 mg g−1), 0.05 g/50 mL dosage (7.437 mg g−1), 90 min (7.437 mg g−1), 12 ppm dye concentration (7.437 mg g−1), and 30 °C (7.437 mg g−1); and for GO/agar–PVA; 3 pH (6.142 mg g−1), 0.05 g/50 mL dosage (6.142 mg g−1), 90 min (6.142 mg g−1), 12 ppm dye concentration (6.142 mg g−1), 30 °C (6.142 mg g−1). GO/CS–PVA outperformed the other hydrogels. The Langmuir model suited GO/CS–PVA data, while GO/starch–PVA and GO/agar–PVA hydrogels followed Freundlich isotherm models. The adsorption capacity data followed a pseudo-second-order model. Negative value of Gibbs free energy and enthalpy showed that the reactions were spontaneous and exothermic in nature. The presence of heavy metals, electrolytes, and detergents/surfactants affected the dye adsorption. Entropy changes positive values implied randomness at the solid/solution contact. The desorption (60, 55, and 58%) of GO/CS–PVA, GO/starch–PVA, and GO/agar–PVA hydrogels was obtained using 0.5 N NaOH. Scanning electron microscope, X-ray diffraction, and Fourier transform infrared (FT-IR) were used for characterization. HIGHLIGHTS Nanohybrid biopolymeric hydrogels are effective for textile wastewater treatment.; Prepared hydrogels are based on graphene oxide (GO) and biopolymers. GO was made using Hummer's technique.; Synthesized GO/chitosan–polyvinyl alcohol (PVA), GO/starch–PVA, and GO/agar–PVA nanohybrid biopolymeric hydrogels.; Physiochemical and postexperimental analysis were performed to determine efficient elimination of Acid Red 97 dye.;

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