Graphene-Based Nanomaterials for Dye Removal from Wastewater: A Review

Among those, the release of synthetic dyes from textile, paper, leather, and cosmetic industries into water bodies poses a serious environmental problem because of their toxicity, non-biodegradability, and carcinogenic nature. In many cases, conventional wastewater treatment technologies have shown limited abilities to remove such a complex organic pollutant; therefore, the pursuit for advanced materials is under way. Graphene-based nanomaterials including graphene oxide, reduced graphene oxide, and their composites have emerged as promising adsorbents and catalysts for dye removal due to their ultra-high surface area, tunable surface chemistry, and robust mechanical strength. Generally, the main dye sequestration mechanisms involve: π-π stacking, electrostatic interaction, and hydrogen bonding. This review will cover in detail dye classification, conventional removal methods, the synthesis and functionalization of GBNs, their application, the dominating removal mechanisms, factors affecting efficiency, adsorption kinetics, and isotherms. Comparative studies between the prepared GBNs and some other adsorbents prove the superior performance of GBNs. Finally, the critical challenges related to scalability, environmental fate, and ecotoxicity are discussed in this review; it also proposes future research directions that could help the practical application of these nanomaterials in sustainable remediation.