Xuzhou University of Technology

Regarding the unclear influence of Fe-N modification sequences on biochar performance, this study systematically investigated the effects of Fe and N introduction sequences on biochar characteristics using lotus stalk as a precursor, urea as the nitrogen source, and FeCl₃·6H₂O as the iron source. The novelty of this work lies in revealing the synergistic mechanism of Fe-catalyzed carbon gasification coupled with N etching/cross-linking under simultaneous doping conditions, and establishing a clear structure-activity relationship correlating doping sequence with microstructure and adsorption performance. The optimal modified biochar was screened for AMOX adsorption from aqueous solution, and the adsorption mechanisms were elucidated through multi-scale characterization and batch adsorption experiments. The results show that simultaneous Fe-N doping combined with pyrolysis at 700 °C for 4 h (FeN-BC-4h) induced a synergistic effect of Fe-catalyzed carbon gasification and N etching, constructing a hierarchical pore structure with a specific surface area of 752.06 m² g^-1 and a total pore volume of 0.73 cm³ g^-1. The equilibrium adsorption capacity for AMOX reached 130.92 mg g^-1, surpassing samples with single or sequential doping and representing a 2.55-fold enhancement compared to raw biochar. The surface of FeN-BC-4h was highly heterogeneous, with chemisorption dominating the adsorption process. Intraparticle diffusion served as the rate-controlling step, and the adsorption was an endothermic spontaneous reaction that increased system disorder. The adsorption mechanisms included pore filling, π-π electron donor-acceptor interactions, hydrogen bonding, Fe-O/Fe-N coordination complexation, and electrostatic interactions. FeN-BC-4h maintained stable and efficient adsorption within the pH range of 4-9, exhibited magnetic responsiveness, and retained approximately 67.03% of its adsorption capacity after three regeneration cycles via HCl washing. This research provides theoretical insights and technical references for the high-value utilization of lotus stalk-based biochar and the efficient removal of antibiotic pollutants.

In recent years, a significant number of waste photovoltaic panels have reached the end-of-life stage, making the recovery of aluminum from waste crystalline silicon solar cells (WCSSC) highly important. This study proposes an environmentally friendly method for removing aluminum from WCSSC in waste photovoltaic panels using phosphoric acid. The effects of various influencing factors on the aluminum removal efficiency (E_Al) from WCSSC via phosphoric acid treatment were systematically investigated through single-factor experiments and orthogonal tests. Furthermore, hydrogen aluminum phosphate hydrate (APH) was prepared by adjusting the P/Al molar ratio of the reaction filtrate with aluminum hydroxide. Single-factor experiment results indicate that as the reaction temperature increases, the time required for E_Al to reach its maximum value decreases; specifically, E_Al peaks at 98.11% at 90 °C within 6 min. Orthogonal test results show that the order of factors influencing E_Al is as follows: temperature > the concentration of H₃PO₄ > particle size > stirring speed > liquid-solid ratio. Thermodynamic analysis reveals that E_Al increases sharply in multiples when the temperature exceeds 45 °C. Kinetics studies demonstrate that at reaction temperatures of 60 °C, 75 °C, and 90 °C, the dissolution process is dominated by different control mechanisms: chemical reaction control at 60 °C, diffusion control or diffusion control through the product film at 75°C-90 °C, respectively. APH was successfully prepared under the conditions with a P/Al molar ratio of 2.94:1, a roasting temperature of 300 °C, and a roasting duration of 2h. This study offers a feasible approach for recycling crystalline silicon solar cells from waste photovoltaic panels.

The polymerization methodologies hold critical importance in fabricating high-quality gel polymer electrolytes (GPEs) for solid-state batteries. This work introduces a plasma-activated instantaneous polymerization strategy for the synthesis of initiator-free poly(ethylene glycol) diacrylate (PEGDA)-based GPEs within seconds. The N radicals produced by N₂ plasma can efficiently initiate the polymerization of PEGDA monomers without requiring chemical initiators. Notably, the plasma-derived GPEs (N-GPEs) exhibit superior ionic conductivity (0.69 × 10^-3 S cm^-1) compared to thermally polymerized counterparts (0.42 × 10^-3 S cm^-1), due to the formation of optimized ion-conduction pathways. Remarkably, this initiator-free synthetic protocol demonstrates dual interfacial advantages, not only on suppression of initiator-induced side reactions at lithium metal anodes but also formation of a Li₃N-enriched solid electrolyte interphase (SEI) through reactive nitrogen species, collectively enhancing the interfacial stability and ion transport kinetics. Electrochemical evaluations demonstrate that symmetric Li||Li cells with N-GPEs show stable cycling over 1600 h with minimal polarization (21 mV at 0.1 mA cm^-2). When integrated into Li||LiFePO₄ full cells, the system achieves 96.3% capacity retention after 200 cycles at 0.5 C, which is much better than the counterpart. This plasma-enabled polymerization technology establishes a paradigm shift in fabrication of polymer electrolyte, offering a rapid and energy-efficient route to high-performance GPEs for energy storage.