Zr(IV) functionalized graphene oxide anchored sand as potential and economic adsorbent for fluoride removal from water

• Published in: Diamond and related materials 2020-11, Vol.109, p.108081, Article 108081
• Main Authors: Prathibha, C., Biswas, Anjana, Chunduri, L.A. Avinash, Reddy, Shiva Konda, Loganathan, Paripurnanda, Kalaruban, Mahatheva, Venkatarmaniah, Kamisetti
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; Carbon; Defluoridation; Drinking water; Endothermic reactions; Fluoride; Fluorides; Graphene; Graphene oxide; Reaction kinetics; Regeneration; Sand; Zirconium impregnated graphene oxide; Zirconium oxides
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2020.108081

Excessive fluoride (F) in drinking water is a major problem affecting human health in many parts of the world. Cost-effective adsorbents are required for the defluoridation of drinking water. A carbon-based adsorbent, graphene oxide coated sand was produced from very inexpensive materials, sugar and river sand and impregnated with zirconium (Zr) for defluoridation of water. F adsorption by Zr impregnated graphene oxide coated sand (ZIGCS) at pH 4.0 satisfactorily fitted to Langmuir and Freundlich adsorption models with a Langmuir maximum adsorption capacity of 6.12 mg/g which is one of the highest values among the other carbon-based economic adsorbents reported for defluoridation. The adsorption of F on to ZIGCS (point of zero charge of pH 4.5) increased from pH 2 to 4 and then decreased up to 12. However, considerable adsorption capacity was observed throughout this pH range. Pseudo-second order model successfully described the adsorption reaction kinetics. Fluoride adsorbed on to ZIGCS was effectively desorbed using 0.1 M NaOH and the regenerated adsorbent maintained approximately 75% of the original F adsorption capacity even after five regeneration cycles. Thermodynamic data revealed that the adsorption process was endothermic and spontaneous with increase in randomness at the solid/solution interface. [Display omitted] •ZIGCS, a product of Zirconium Impregnated Graphene oxide, anchored on Sand is a low cost adsorbent for defluoridation of water.•The adsorbent is produced from inexpensive materials: table sugar and sand.•Quick and rapid removal of fluoride is possible with ZIGCS.•It could retain 75% of its F− removal capacity even after five regeneration cycles.