This paper proposes an integrated coupling process of alkali leaching, HBTA-TOPO synergistic extraction, and carbonation for the resource utilization of spent carbon anode (SCA), a typical lithium-bearing industrial solid waste from electrolytic aluminum production, whose lithium content exceeds the ore grade. Compared with conventional acid leaching methods, the adopted alkaline leaching approach features mild reaction conditions, low equipment corrosion risk, and eliminates the volatilization of toxic hydrogen fluoride (HF) gas, thus showing prominent environmental safety advantages. Under the optimal alkaline leaching conditions (NaOH concentration of 10 mol/L, reaction temperature of 90 °C, liquid-to-solid ratio of 10:1, and reaction time of 120 min), the maximum Li+ leaching rate reaches 89.46%. As the leaching process proceeds, lithium in the carbon slag rapidly migrates to the alkaline leaching solution. The Na–Al–F bonds of cryolite (Na3AlF6) and lithium cryolite (Na2LiAlF6) present in the SCA gradually break, and soluble ions such as Na+, Li+, Al3+, and F− enter the solution. High-concentration Na+ reacts with free F− to form sodium fluoride (NaF), which adheres to the SCA, leading to an increase in the sodium-aluminum ratio (Na/Al) of the SCA. The HBTA-TOPO synergistic extraction system is proposed for the extraction and enrichment of lithium in the lithium alkaline leaching solution, and the extraction residue is used to repair and regenerate cryolite. The extraction efficiency of Li+ reaches and the yield of cryolite reaches 81.54% and 76.54%. The molecular ratio of sodium fluoride to aluminum fluoride in synthetic cryolite products is relatively high. This integrated process realizes the efficient recovery of lithium and the high-value regeneration of cryolite from SCA, providing a sustainable technical route for the clean utilization of electrolytic aluminum solid waste. This integrated closed-loop process realizes the simultaneous recovery of lithium and high-value regeneration of cryolite from SCA, which not only mitigates the environmental pollution caused by SCA stacking and the scarcity of lithium resources, but also provides a sustainable technical route for the clean and high-value utilization of electrolytic aluminum solid waste.
Payload drones are often limited more by frame weight than by motor power. This work aims to design, optimize, and validate a flat octocopter frame with eight independently driven rotors arranged symmetrically on separate arms. The drone frame design in SOLIDWORKS uses Finite Element Analysis (FEA) and topology optimization to remove material from low-stress regions while keeping the main load paths intact. The final design cuts the frame mass by 37.3% compared to the baseline model and reduces the 3D printing time by about five hours using a Creality K1C printer with Polylactic Acid (PLA) filament. These changes increase the available thrust-to-weight margin for payload without exceeding the allowable stress or deformation limits of the material. The electronic components also identified compatible flight controllers, ESCs, motors, and radio systems to show that the proposed frame can be integrated into a complete multirotor platform. Overall, this work demonstrates a practical approach to designing lighter octocopter frames that are easier to 3D print and can be used more effectively for delivery and inspection missions.
This study presents a comprehensive projection of China’s forest product yield dynamics (encompassing commodity timber and logs) through 2100, employing an innovative integration of machine learning and economic modeling. We developed a hybrid analytical framework combining random forest algorithms with Cobb-Douglas production functions to assess multi-dimensional drivers, including climatic variables, socio-economic indicators, and demographic trends. Our multi-model validation demonstrated strong predictive performance (R2 are 0.86 and 0.92), particularly in quantifying climate-production interactions, with sensitivity analysis identifying surface downward shortwave radiation (RSDS), population density (POP), and mean annual temperature (MAT) as dominant predictors explaining 68% of yield variance. Future yields exhibited significant spatial and temporal variations under different SSP scenarios, especially under SSP126, where yields were more stable, and under SSP245 and SSP370, where yields showed a moderate increasing trend. The SSP585 shows higher fluctuations and a decreasing trend in yields due to climate change. Geospatial modeling uncovered critical regional disparities, suggesting potential production migration from traditional southern bases to north-eastern/northwestern frontiers under climate stress. The southern subtropical belt emerged as particularly vulnerable to thermal extremes and precipitation variability, while northern regions demonstrated greater climate resilience but require substantial silvicultural adaptation. These results provide a scientific basis for developing more precise forest management policies and sustainable development strategies to help meet the challenges posed by future demand for forest products and climate change.
Investigations into the photoinduced reactions of deoxyribonucleic acid (DNA) bases are important for human health. Herein, we have synthesized colloidal CdS nanoparticles by a method reported in the literature. The mean particle diameter of the semiconductor was about 55 nm. The colloidal CdS particles were used as a photocatalyst to investigate the organic transformation of guanine (2-amino-6-oxopurine). The products of the semiconductor-induced reaction were analyzed by liquid chromatography-mass chromatography (LC-MS) measurements. The solitary product of the photocatalytic reaction of guanine was revealed as 2,5-diamino-4H-imidazol-4-one. The likely reaction pathway for the formation of the product has been presented. To our understanding, the present work is the first account on the mechanistic aspects of the semiconductor-induced photocatalytic reaction of guanine.
A2B2O7 complex oxides have a great potential to be used in high-temperature catalytic processes. Herein, a series of A2B2O7 (A = La, Nd, Sm, Gd, Er, Yb; B = Ti, Sn, Zr, Ce) compounds with all four kinds of typical sub-crystalline phases were synthesized to study their bulk and surface properties. FTIR spectroscopy was adopted as a novel method in this study to identify distinctively these phases. Whereas, it cannot be used to distinguish the subtle structure difference between disordered and ordered pyrochlores, nor that between the disordered defect fluorite and the rare earth. To discriminate these exquisite phase differences, XPS spectra must be supplementarily used. Specifically, it was discovered that the coordination numbers of the A- and B-site cations are the key factor affecting their binding energies. Furthermore, the electronegativity of the A- and B-site elements significantly influences the binding energy of surface lattice oxygen, reflecting their electrophilic and nucleophilic properties, which can thus be used to effectively identify the sub-crystalline phase. The oxygen vacancy concentration of different sub-crystalline phases is the primary factor controlling the amount of surface chemisorbed oxygen species on A2B2O7 compounds, with superoxide anions (O2−) identified as the major species.
