ABSTRACT
Major causes of water pollution in the ecosystem are pollutants such as dyes which are noxious. The present study was based on the synthesis of the green nano-biochar composites from cornstalk and green metal oxide resulting in Copper oxide/biochar, Zinc oxide /biochar, Magnesium oxide/biochar, Manganese oxide/biochar, biochar for removal of dyes combined with the constructed wetland (CW). Biochar Augmentation in constructed wetland systems has improved dye removal efficiency to 95% in order of copper oxide/biochar > Magnesium oxide/biochar > Zinc oxide/biochar > Manganese oxide/biochar > biochar > control (without biochar) respectively in wetlands. It has increased the efficiency of pH by maintaining pH 6.9-7.4, while Total Suspended Solids (TSS) removal efficiency and Dissolved oxygen (DO) increased with the hydraulic retention time of about 7 days for 10 weeks. Chemical oxygen demand (COD) and colour removal efficiency increased with the hydraulic retention time of 12 days for 2 months and there was a low removal efficiency for total dissolved solids (TDS) from control (10.11%) to Copper oxide /biochar (64.44%) and Electrical conductivity (EC) from control (8%) to Copper oxide /biochar (68%) with the hydraulic retention time of about 7 days for 10 weeks. Colour and chemical oxygen demand removal kinetics followed second and first-order kinetic. A significant growth in the plants were also observed. These results proposed the use of agricultural waste-based biochar as part of a constructed wetland substratum can provide enhanced removal of textile dyes. That can be reused.
