Agricultural biomass wastes, which may pollute the environment yet are inefficiently managed worldwide, can be recycled into biochar, which is subsequently used to remediate salt-affected environments. This creates value- added or dual benefits of treating the wastes while reclaiming saline water/soil for sustainable development. Nevertheless, a lack of knowledge about the linkage between biochar characteristics and sodium adsorption capacity may restrict the wastes from being recycled. The current study aimed to examine physicochemical, nano/microstructural, and functional-group characteristics of biochar and to assess its sodium isothermal adsorption properties. Four biochars made from rice husk (RH-BC), corn stalks (CS-BC), longan branch (LA- BC), and coconut coir (CC-BC) were used for an isothermal-adsorption experiment. Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Brunauer-Emmett-Teller surface area (BET area), pore size distribution, and Fourier Transform Infrared spectroscopy (FTIR) were used to characterize biochars, which were additionally analyzed for 9 parameters. RH-BC had the highest BET area (151 m2 g-1) and porosity, whereas LA- BC exhibited the lowest BET area (10.6 m2 g-1), and LA-BC was more condensed. Functional groups, necessary for cation adsorption, were found in biochars. The maximum adsorption capacity of RH-BC (33.9 mg g-1), estimated by the Langmuir isotherm model, was the highest while that of CC-BC (15.5 mg g-1) was the lowest. The Dubinin-Radushkevich isotherm model showed that the Na adsorption mechanism was dominantly a physical process. The current study provides a feasible value-added and sustainable strategy of recycling agricultural biomass wastes with dual benefits of waste treatment and salt-affected environment remediation, applicable worldwide.
ⓒ 2026 BICE | Biochar-based Integrated Circular Economy for Paddy Rice.
