A review of synthesis strategies and applications of effective adsorbents for dye removal

ABSTRACT Graphical abstract illustrating dye wastewater treatment using composite adsorbents. The schematic begins with dye-contaminated wastewater flowing toward an adsorption process. Three major composite adsorbent categories are shown: metal oxide-based composites, biosorbent-based composites, and polymer-based composites. The workflow further highlights synthesis methods and environmental applications of the adsorbents for dye removal and wastewater remediation. The pervasive discharge of dye-laden wastewater poses a significant threat to environmental integrity and public health, with dyes containing toxic metals and functional groups inducing severe adverse effects on both aquatic life and human physiological systems. Adsorption technology has long been a cornerstone of dye removal; however, single-component adsorbents often exhibit limitations in achieving broad-spectrum and high-capacity removal of diverse dye pollutants. This review critically evaluates the emerging potential of composite adsorbents as a next-generation solution. By synergistically combining the properties of multiple materials, these composites offer enhanced selectivity, capacity, and overall performance compared with their single-component counterparts. This review provides an in-depth analysis of recent advancements in composite adsorbent design, highlighting novel synthesis methodologies and their impact on material properties. Key challenges and future perspectives for the large-scale application of these advanced materials in textile wastewater treatment are also discussed. This work aims to provide a comprehensive overview of the latest technical and scientific breakthroughs in dye removal and degradation, with a strong focus on the innovative use of composite adsorbents. This review assesses the synthesis trade-offs, recovery potential, and practical industrial implications of these composites.