Preparation of straw carbon film electrode and the validation study on the effect of electrochemical removal of heavy metal cadmium

The accelerating pace of global industrialization and urbanization has intensified the conflict between finite natural resources and expanding populations. Within this context, agricultural residues like rice straw are significant yet underutilized carbon-rich biomass present untapped potential for circular economy applications. Despite its abundance, systematic research on valorizing this lignocellulosic waste into advanced functional materials remains scarce. Our study pioneers an integrated biorefinery approach transforming rice straw into two synergistic high-value products: (1) hierarchically porous conductive biochar fabricated through optimized single-step pyrolysis, and (2) ethyl cellulose biopolymer synthesized via a solvent-efficient pathway in our specially engineered high-pressure reactor system.These two components were subsequently combined to create electrode materials for heavy metal removal from wastewater. The results demonstrated that cadmium removal efficiency improved with increasing pH values and extended treatment duration. Specifically, an impressive removal efficiency of 88.1% was achieved at pH 9 with 10 hours of treatment. The removal mechanisms were elucidated through various analytical methods including SEM, FTIR, and XRD. This research highlights the potential of high-value straw derivatives in effectively treating heavy metal-containing wastewater, offering a sustainable strategy to address environmental pollution through renewable resources like rice straw.