Cellulose-based superabsorbent was synthesized by bacterial cellulose (BC) grafting acrylic acid (AA) in the presence of N,N′-methylenebisacrylamide (NMBA) as a crosslinker and ammonium persulfate (APS) as an initiator. The influence of different factors on composite synthesis, including the weight ratio of the monomer to BC, initiator content, crosslinker content, AA neutralization degree, reaction temperature, and reaction time on the water absorbency of the composite, were systematically learned. Under the optimized conditions, the maximum water absorbency of the composite was 322 ± 23 g/g distilled water. However, the water absorbency was much less for the different salt solutions and the absorption capacity of the composite decreased as the concentration of the salt solutions increased. The pH value had a significant influence on water absorption performance, and with the increase of temperature, the water retention rate of the composite decreased. Additionally, the structure of this composite was characterized with nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The results of NMR and FT-IR provided evidence that the composite was synthesized by BC and AA, and the microstructure showed that it had good performance for water absorption. In addition, the composite possessed suitable thermal stability, and that it could be used in a few high-temperature environments. Overall, this composite is promising for application in water absorption.

Bacterial cellulose (BC) has great potential to be used as a new filler to reinforce isotactic polypropylene (iPP) due to its high crystallinity, biodegradability, and efficient mechanical properties. In this study, esterification was used to modify BC, which improved the surface compatibility of the iPP and BC. The results indicated that the cellulose octoate (CO) changed the surface properties from hydrophilic to lipophilic. Compared to the pure iPP, the tensile strength, charpy notched impact strength, and tensile modulus of the iPP/BC composites increased by 9.9%, 7.77%, and 15.64%, respectively. However, the addition of CO reinforced the iPP/CO composites. The tensile strength, charpy notched impact strength, and tensile modulus of the iPP/CO composites increased by 14.23%, 14.08%, and 17.82% compared to the pure iPP. However, the elongation at break of both the composites is decreased. The SEM photographs and particle size distribution of the composites showed improvements when the change of polarity of the BC surface, interface compatibility, and dispersion of iPP improved.

To establish a recycling process for spent lithium-ion batteries (LIBs) suitable for industrialization, minimizing energy consumption and simplifying the recycling process are critical. Herein, we propose a roasting reduction method to recover valuable metals from spent LIBs by repurposing the pyrolysis gas of the LIBs. The pyrolysis gas serves as a reducing agent, while the carbon-based materials in the LIBs (graphite, electrolytes, separators, and binders) act as a carbon resource during the roasting process. The results show that the spent LiNi_0.65Co_0.15Mn_0.2O₂ (LNCM) cell can be completely reduced to Li, Ni, Co, Mn, or their respective compounds using pyrolysis gas at 550 °C. Through a combined environmentally friendly process of water leaching and citric acid leaching, 91.62% of Li, 98.71% of Ni, 99.46% of Co, and 98.51% of Mn are recovered from the roasted products. These recovery efficiencies are higher than that of carbothermal reduction using carbon-based materials in an inert atmosphere. The synergistic effect between the reductive gases in the pyrolysis gas and the carbon resource is a key factor enabling the reduction process of LNCM at lower temperatures compared to conventional carbothermic reduction under an oxygen-free atmosphere. Therefore, the recycling method based on the in situ reduction-leaching of LIBs is environmentally friendly, economical, and has promising applications in industrial scale-up.

Recycling valuable materials from retired Li-ion batteries (LIBs) can help alleviate the shortage of critical materials, thereby promoting both environmental and economic development. The oxygen-free roasting pre-treatment has emerged as a promising and reliable method for the selective recovery of valuable materials from retired LIBs. In this study, a retired LiNi_0.65Co_0.15Mn_0.2O₂ cell, without disassembling and crushing, is subjected to roasting under a carbon monoxide (CO) atmosphere. The composition of roasted products is analyzed, and results indicate that NCM is completely converted into Li₂CO₃, Ni, Co, and MnO at 500 °C, which is lower than the conventional carbothermal reaction temperature. The gaseous products generated during the process consist primarily of CO₂, CO, and H₂. Li, transition metals, and graphite are recovered through water and acid leaching processes. 97.48% of Li is recovered from the water-leaching solution after reduction roasting under a CO atmosphere. Subsequently, 99.99% Ni, 99.98% Co, and 99.94% Mn are obtained via acid leaching of the water-extraction residue. The reactions between decomposed products of NCM and Al (Cu) foil will be inhibited under a CO atmosphere. Based on the above results, the retired LIBs can be directly treated without dismantling and crushing by using pyrosis gases as reductants. Consequently, this method demonstrates significant potential for large-scale industrial applications.

Lumping kinetics models were built for the biological treatment of ABE (acetone-butanol-ethanol) fermentation wastewater by oleaginous yeast Trichosporon cutaneum with different fermentation temperatures. Compared with high temperature (33°C, 306 K) and low temperature (23°C, 296 K), medium temperature (28°C, 301 K) was beneficial for the cell growth and COD degradation during the early stage of fermentation but the final yeast biomass and COD removal were influenced little. By lumping method, the materials in the bioconversion network were divided into five lumps (COD, lipid, polysaccharide, other intracellular products, other extracellular products), and the nine rate constants (k1-k9) for the models can well explain the bioconversion laws. The Gibbs Free Energy (G) for this bioconversion was positive, showing that it cannot happen spontaneous, but the existence of yeast can after the chemical equilibrium and make the bioconversion to be possible. Overall, the possibility of using lumping kinetics for elucidating the laws of materials conversion in the biological treatment of ABE fermentation wastewater by T. cutaneum has been initially proved and this method has great potential for further application.