Multifunctional carbon composites derived from biomass for water treatment and battery applications

Communities worldwide face two urgent environmental challenges: rising water pollution and the need for cleaner, more sustainable energy. Industrial wastewater often contains harmful substances such as heavy metals, dyes, and pharmaceutical residues that are difficult to remove. At the same time, conventional batteries rely on non-local, non-renewable materials, creating environmental strain throughout their entire lifecycle.

This PhD research investigates how locally available renewable biomass can be converted into advanced carbon-based materials that simultaneously address two critical challenges: water purification and sustainable energy storage. Using techniques such as catalytic pyrolysis, metal-organic framework (MOF) integration, surface charge modification, cellulose nanofiber impregnation, and hydrothermal carbonisation, the study develops carbon composites with tailored structures and high porosity. These engineered materials are designed to capture a wide range of water pollutants and to function as high-performance components in sodium-ion batteries, highlighting the potential of biomass as a versatile and sustainable solution for cleaner water and greener energy technologies.

This research produced several biomass-derived carbon materials that demonstrated outstanding performance in removing diverse impurities. For water treatment, these materials effectively removed heavy metals, dyes and pharmaceutical residues. One composite captured copper and manganese in continuous-flow systems with saturation capacities of 5.97 mg/g (Cu2⁺) and 4.84 mg/g (Mn2⁺). Another achieved high methylene blue removal of 106 mg/g and 71.14 mg/g in batch and column modes, respectively, alongside a 93% reduction in total organic carbon. Additional composites exhibited strong dye removal, up to 263 mg/g for methylene blue and 278 mg/g for Congo Red, while a zirconium-based hybrid composite showed exceptional diclofenac sodium uptake of 384.6 mg/g. In energy storage, a biomass-based carbon–MOF composite demonstrated excellent performance as a sodium-ion battery anode, delivering an initial capacity of 348.5 mAh/g, stable cycling over 600 cycles, and Coulombic efficiency over 98%. Collectively, these results highlight biomass-derived carbon as a powerful and sustainable platform for advancing both clean water and clean energy technologies.