Efficient Removal of Hexavalent Chromium with Novel Agro-Waste Biochar

The suitability of beechwood chip biochar(BC1) and garden green waste biochar (BC2) for Cr(VI) removal was explored in this study.Green waste biochar (BC2) was found to be the most effective for Cr(VI) removal (84.6 %) at room temperature at an adsorbent dose of 10 g L -1 at an optimum pH of 5.The Freundlich isotherm model exhibited the best fit, followed closely by the Langmuir model, suggesting a heterogeneous adsorption process with a potential contribution from monolayer adsorption, as supported by nine error functions.Adsorption kinetics was best explained by pseudo nth-order model (PNO).Gibbs free energy (G) was found to vary between -24.19 to -29.48 (BC1) and -24.18 to -28.39 483 kJ mol -1 (BC2), indicating a spontaneous reaction.Enthalpy (H) was 74.483 kJ mol -1 for BC1 and 59.51 483 kJ mol -1 for BC2, which indicates chemisorption in the current study.