Dithiocarbamate-Functionalized Cellulose for High-Efficiency Separation of Critical Metals from Organic Effluents

The effective separation of critical metals (CMs) from organic solvent waste streams represents a formidable challenge in industrial environmental management, primarily because conventional aqueous-phase separation technologies, such as ion exchange and precipitation, struggle with the unique physicochemical properties of organic media. In this study, we introduce a highly effective dithiocarbamate-functionalized cellulose sorbent (DPE6) as a solvent-tolerant platform designed to overcome these limitations in the capture of CMs (Ni^II and Pb^II) from polar organic solvents. DPE6 demonstrated exceptionally rapid sorption kinetics, achieving equilibrium within 10 min, and exhibited superior maximum sorption capacities for Ni^II (968 and 976 μmol g^-1) and Pb^II (1217 and 1128 μmol g^-1) in pure methanol (MeOH) and N,N-dimethylformamide (DMF), respectively. Advanced spectroscopic characterization, utilizing Fourier-transform infrared (FT-IR), X-ray photoelectron (XPS), and X-ray absorption spectroscopy (XAS), provided conclusive evidence that metal uptake is driven by robust surface complexation with sulfur-active sites. To validate practical utility, DPE6 was applied to the recovery of Pb from organic effluents derived from the recycling of spent perovskite solar cells. The sorbent achieved quantitative extraction efficiencies of 91-99%, markedly outperforming commercial resins which failed in strongly solvating media. These findings position functionalized cellulose as a transformative solution for nonaqueous separations, offering a sustainable pathway for critical material recovery in advanced manufacturing sectors.