Biochar based Nanocomposite derived from Watermelon Rinds as a Novel Adsorbent for Removal of Acid Red 27 Dye: Reusability and Phytotoxicity Assessment

Centre for Plant and Environmental Biotechnology, Amity Institute of Biotechnology, Amity University Uttar Pradesh, Noida - 201313, Uttar Pradesh, India

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Published online: 21 January 2026

Abstract

Water pollution emerges as a pressing global problem due to rise in population, urbanization, industrialization, and agricultural intensification. Dye contamination in water resources is a serious threat for environment and public health, thus effective strategies are needed to solve the problem. The watermelon fruit rind wastes were used as a raw material for synthesis of biochar nanocomposite for Acid red 27 (AR27) dye removal from aqueous solution. Adsorption has gained attention as a promising technique for AR27 dye removal due to its simplicity, flexibility, cost-effectiveness, and ease of operation etc. The batch study was executed to analyze performance of synthesized watermelon fruit rind biochar (WMR) and MnO₂/WMR biochar nanocomposite as sorbent for AR27 dye elimination from aqueous medium. Experimental findings reported that MnO2/WMR biochar nanocomposite increased AR27 dye elimination in comparison to WMR biochar. AR27 dye removal (80 mg L^-1) was recorded 85% at pH 5 by 0.3 g MnO₂/WMR biochar nanocomposite. Reusability test reported that WMR biochar and MnO2/WMR biochar nanocomposite can be used up to five consecutive cycles. Thus, application of MnO2/WMR biochar nanocomposite is a renewable resource with high AR27 dye adsorption efficiency, thus can be applied for dye polluted wastewater treatment and environment protection.