The spent carbon cathode (SCC) is a hazardous solid waste from aluminum production. It has an abundant carbon source and a unique graphitic carbon layer structure, making it a valuable waste for recycling. This paper uses alkaline and acid leaching methods to report a straightforward way of extracting recovered carbon (RC) from SCC as anode material for lithium-ion batteries (LIBs). The results show that alkaline and acid leaching conditions at 70 °C with 1 M NaOH and HCl solution individually in 6 h and a liquid-solid ratio of 20:1 can result in RC with up to 94.63% carbon content than 49.38% in SCC, exhibiting a typical graphite structure. SCC and RC materials are obtained after calcination at 400 °C in an inert atmosphere and used as anode materials (SCC-400 and RC-400). In this paper, The initial charging specific capacities are 490.0 mA h g −1 , 195.4 mA h g −1 , and 423.2 mA h g −1 and initial coulombic efficiencies (ICE) are 67.8%, 78.9%, and 72.0% of RC-400, SCC, and SCC-400. RC-400 also shows excellent capacity retention and impedance values. This exciting finding provides a viable, non-hazardous, and resourceful method for treating and disposing of SCC from aluminum electrolysis.
Bating animal hides with trypsin is an essential step for making leathers. But the mechanism why the calcium in the hide influences the bating performance remains unclear. Here, the enzyme activity of trypsin was determined using N-alpha-benzoyl-L-arginine ethyl ester, bovine albumin (BSA) and collagen fibres as substrates in the presence and absence of calcium salts. The interactions of calcium with trypsin, BSA and collagen were analysed by fluorescence spectroscopy and molecular docking. Data reveal that calcium which binds to BSA and collagen improves the structural stability and enzyme resistance of hide proteins. As a result, a high calcium content of delimed hide is useful to obtain an intact surface of bated hide. However, a low calcium content of hide for pickling is necessary for producing leathers with high physical properties and uniform colour. According to these results, a novel bating system involving deliming, bating and redeliming operations was developed. This system provides a high calcium content of hide for bating and a low calcium content of hide for subsequent pickling and tanning, which effectively reduces the risk of hide damage and improves the physical properties and colour uniformity of leather.
危险品化学品经营许可证（带存储）