A systematic literature review on adsorption of potentially toxic elements from aquatic systems by sugarcane and corn residues

Potentially toxic elements (PTE) pose environmental concerns due to their persistence, toxicity, and accumulation in living organisms. Their effective removal from waters and effluents is crucial for preserving aquatic ecosystems, human health, and biodiversity. Conventional treatment methods face challenges like waste generation and harmful substances. In this context, adsorption using agro-industrial residues emerges as a sustainable, low-cost, and environmentally friendly alternative. This is especially relevant in countries like Brazil, the United States, India, China, Argentina, and Thailand, where sugarcane and corn residues are abundantly available. This systematic literature review aims to provide a comprehensive overview of the adsorption of PTE from aquatic systems using sugarcane and corn residues, contributing to the identification of trends, gaps, and future directions in this field. Sugarcane bagasse and corncobs are highlighted as the most commonly used residues. The most frequently reported experimental conditions include grinding as treatment, batch mode adsorption, adsorbate concentration of 50 mg L−1, adsorbent concentration of 10 mg L−1, temperature of 25 °C, and a contact time of 60 min. Specific details such as particle size (0.25 mm for sugarcane, 0.15 mm for corn), main PTE (Pb for sugarcane, Cd for corn), and optimal pH (5 for sugarcane, 6 for corn) were also identified. However, research gaps remain, such as the use of sugarcane and corn leaves, the biological modification of residues, and the study of less-explored PTEs like Fe and Mn. These gaps provide opportunities for future investigations and advances in water treatment technologies.Graphical abstract