Sustainable adsorbents: Metal oxide-biochar nanocomposites from Maize Stalks and Wild Tamarind residues for dye removal and phytotoxicity assessment

Environmental pollution arising from textile dye-based wastewater poses a significant concern within the industrial and scientific communities, given its profound impact on ecosystems. This study focuses on enhancing decontamination capabilities and broadening the scope of constructed wetlands. The study explores the potential of constructed wetland substrates that incorporate Wild Tamarind -mediated metal oxide-coated biochar for the removal of Reactive Golden Yellow-145 (RY-145) dye. Characterizations were conducted using Scanning Electron Microscopy, Brunauer–Emmett–Teller and Fourier Transform Infrared Spectroscopy . Optimization of various operational parameters were carried out. Results revealed that CuO-CBC (83.15 mg g −1 ), MgO-CBC (79.24 mg g −1 ), ZnO-CBC (69.20 mg g −1 ), MnO 2 -CBC (65.01 mg g −1 ), and CBC (54.72 mg g −1 ) demonstrated the highest adsorption capacities. The analysis included various isotherms, kinetics, and thermodynamic models. Maximum desorption was also achieved. The study also assessed the potential efficacy of nano-adsorbents in removing dye from real textile effluent and conducted phytotoxicity investigation on Pea seeds and Lemongrass to evaluate their environmental sustainability. Constructed wetlands exhibited higher removal efficiency compared to batch adsorption when incorporating green nano-biochar composites as substrates. Therefore, these promising green adsorbents hold significant potential for dye adsorption and serve as substrates for wetlands, contributing to the treatment of textile wastewater. • Maize Stalks and Wild Tamarind biochar mediated green substrates synthesis for RY-145 dye. • Highest adsorption capacities were achieved for CuO-CBC (83.15 mg g −1 ). • Highest percentage of desorption was achieved with NaOH (83.274 %–94.33 %). • Pea seeds germination (93.88 % − 78 % ) was increased in RY-145 dye treated solution. • Evaluating green nano-adsorbents in constructed wetlands for textile effluents.