Bimetallic Cu/Ni-doped porous carbon fibers as high-performance adsorbents for organic dyes

The increasing amount of synthetic dye pollutants in industrial wastewater poses significant environmental and health concerns, creating an urgent need for efficient and sustainable remediation strategies. Herein, we report the fabrication of bimetallic Cu-Ni oxide-doped porous carbon nanofibers (Cu:Ni:PCFs) via block copolymer templating, electrospinning, and controlled pyrolysis. The hierarchical structures combined with uniformly dispersed copper and nickel oxide nanoparticles within the carbon matrix provided abundant active sites, enhanced surface charge modulation, and conferred multifunctional adsorption capabilities. The Cu:Ni:PCF adsorbent demonstrated excellent uptake of anionic MO and cationic MB, reaching Langmuir maximum monolayer adsorption capacities of 362 mg g^-1 for MO and 323 mg g^-1 for MB, showing enhanced localized single-point capacities under optimized pH environments. Rapid adsorption kinetics were observed, reaching equilibrium within 15 min. The kinetics data were best described by a pseudo-second-order model, indicating a strong adsorption interaction. The equilibrium data fit the Langmuir isotherm model, suggesting monolayer coverage on uniform adsorption sites. Notably, the adsorbent maintained its structural integrity and demonstrated high recyclability, retaining more than 90% of its initial adsorption capacity after five consecutive adsorption-desorption cycles. These findings underscore the potential of Cu:Ni:PCFs as a durable and efficient material for removing various dye contaminants from wastewater, representing a promising strategy for practical environmental remediation.