Chromium-Sorbed Maize Stalk Biochar and Its Power Benefited Disposal: An Effective Power Generation Method for Removal of Chromium

This study examined Cr(VI) removal efficiency of maize stalk biochar (MSB) from waste water. Equilibrium isotherm results were examined by Langmuir, Freundlich, and Temkin isotherms. The adsorption was found to fit well with the Freundlich and Temkin isotherm models, with R-2 values of 0.994 and 0.909, respectively. Temkin indicates the process to be exothermic. The values of the thermodynamic parameter ( ?G(0)) suggested that the adsorption was reasonable and natural. The FT-IR bands were recorded to explore the functional groups available to bind Cr(VI) ions). The SEM-EDS and TEM results show the morphology of the studied adsorbent and C/O ratio present in MSB. XRD and XPS analyses of the adsorbents before and after the reaction indicate that co-precipitation occurred during adsorption. Brunauer, Emmett, and Teller (BET) were recorded for MSB to understand the nature of the surface and pore space present. Thus, MSB has the potential to remove hexavalent chromium ions from wastewater, and removal efficiency is 81%. Microbes present in the soil effectively assisted the desorption of chromium ions from MSB's active sites with concurrent power generation of 359 mV in microbial fuel cells.

Automated summary

This study investigated the efficiency of maize stalk biochar (MSB) in removing Cr(VI) from wastewater. Equilibrium isotherm results were analyzed using Langmuir, Freundlich, and Temkin isotherms. Freundlich and Temkin isotherm models exhibited good fit, with R-2 values of 0.994 and 0.909, respectively. The FT-IR bands revealed functional groups involved in binding Cr(VI) ions. SEM-EDS and TEM results provided insights into the morphology of the adsorbent and C/O ratio in MSB. XRD and XPS analyses indicated co-precipitation during adsorption. BET measurements characterized the surface and pore space of MSB. MSB showed a removal efficiency of 81% for hexavalent chromium ions in wastewater, and microbial fuel cells facilitated desorption with concurrent power generation of 359 mV.