Transition metal oxides have been actively exploited for application in lithium ion batteries due to their facile synthesis, high specific capacity, and environmental-friendly. In this paper, Fe₃O₄@TiO₂@C yolk–shell (Y–S) spheres, used as anode material for lithium ion batteries, were successfully fabricated by Stӧber method. XRD patterns reveal that Fe₃O₄@TiO₂@C Y–S spheres possess a good crystallinity. But the diffraction peaks’ intensity of Fe₃O₄ crystals in the composites is much weaker than that of bare Fe₃O₄ spheres, indicating that the outer anatase TiO₂@C layer can cover up the diffraction peaks of inner Fe₃O₄ spheres. The yolk–shell structure of Fe₃O₄@TiO₂@C spheres is further characterized by TEM, HAADF-STEM, and EDS mapping. The yolk–shell structure is good for improving the cycling stability of the inner Fe₃O₄ spheres during lithium ions insertion–extraction processes. When tested at 200 mA/g, the Fe₃O₄@TiO₂@C Y–S spheres can provide a stable discharge capacity of 450 mAh/g over 100 cycles, which is much better than that of bare Fe₃O₄ spheres and TiO₂@C spheres. Furthermore, cyclic voltammetry curves show that the composites have a good cycling stability compared to bare Fe₃O₄ spheres.

The practical application of silica-based composites as an alternative to commercial graphite anode materials is hampered by their large volumetric expansion, poor conductivity, and low Coulombic efficiency. In this work, a novel silica/oxidized mesocarbon microbead/amorphous carbon (SiO₂/O’MCMB/C) hierarchical structure in which SiO₂ is sandwiched between spherical graphite and amorphous carbon shell was successfully fabricated through hydrogen bonding-assisted self-assembly and post-carbon coating method. The obtained three-layer hierarchical structure effectively accommodates the volumetric expansion of SiO₂ and significantly enhances the electronic conductivity of composite materials. Moreover, the outer layer of amorphous carbon effectively increases the diffusion rate of lithium ions and promotes the formation of stable SEI film. As a result, the SiO₂/O’MCMB/C composite exhibits superior electrochemical performance with a reversible capacity of 459.5 mA h/g in the first cycle, and the corresponding Coulombic efficiency is 62.8%. After 300 cycles, the capacity climbs to around 600 mA h/g. This synthetic route provides an efficient method for preparing SiO₂ supported on graphite with excellent electrochemical performance, which is likely to promote its commercial applications.

Diversity in bacterial communities was investigated along a petroleum hydrocarbon content gradient (0–0.4043 g/g) in surface (5–10 cm) and subsurface (35–40 cm) petroleum-contaminated soil samples from the Dagang Oilfield, China. Using 16S rRNA Illumina high-throughput sequencing technology and several statistical methods, the bacterial diversity of the soil was studied. Subsequently, the environmental parameters were measured to analyze its relationship with the community variation. Nonmetric multidimensional scaling and analysis of similarities indicated a significant difference in the structure of the bacterial community between the nonpetroleum-contaminated surface and subsurface soils, but no differences were observed in different depths of petroleum-contaminated soil. Meanwhile, many significant correlations were obtained between diversity in soil bacterial community and physicochemical properties. Total petroleum hydrocarbon, total organic carbon, and total nitrogen were the three important factors that had the greatest impacts on the bacterial community distribution in the long-term petroleum-contaminated soils. Our research has provided references for the bacterial community distribution along a petroleum gradient in both surface and subsurface petroleum-contaminated soils of oilfield areas.

In this work, air plasma surface treatment followed by oxidation in an atmospheric environment was used to generate activated low-density polyethylene (LDPE) with oxygen-containing functional groups and peroxide radicals. The resulting samples were then studied by using attenuated total internal reflectance–Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and the 2,2-diphenyl-1-picrylhydrazyl method. Peroxide radicals are generally considered active substances which can initiate the crosslinking reaction. Melt mixing of the surface-treated LDPE allowed activated polymer chains with peroxide radicals to initiate the crosslinking reaction, and the maximum gel fraction obtained was 4.1%. The rheological behaviors, including viscosity, storage and loss moduli, loss tangent, and Cole–Cole plots, of the slightly crosslinked LDPE were studied, and the results of tensile experiments revealed that the formation of slightly crosslinked structures can improve yield and fracture stresses without sacrificing the breakage strain.

A new, facile, and efficient way to prepare alkalinized g-C₃N₄ is presented. We calcined a mixture of KCl and melamine to obtain g-C₃N₄, whose in-plane structure was K⁺ doped so that alkalinized samples could be obtained by treatment with different concentrations of KOH. The different samples were used to oxidize As(III) in both visible light and natural light. The sample treated with 10 mol/L KOH showed the highest efficiency, converting all As(III) into As(V) within 120 min in both visible light and natural light, as the oxidative capacity of the As(III) in the alkalinized samples was significantly higher than that of the original samples. K⁺ doping improved the electron transport capacity of the samples, while the alkalinized samples could destroy their edge structures, so as to improve the separation efficiency of the photogenerated carrier. The experiment confirmed that alkalinized g-C₃N₄ significantly improves the oxidation ability of As(III) and plays an important role in the photocatalytic treatment of refractory nonmetallic ions.

A new oxadiazole-functionalized polyacrylonitrile fiber (PAN_AOF) was successfully fabricated by immobilizing the organic molecule 2-chloromethyl-5-phenyl-1,3,4-oxadiazole on aminated fiber (PAN_AF). The fibers were characterized completely by Fourier-transform infrared spectroscopy, elemental analysis, X-ray diffraction, and X-ray photoelectron spectroscopy techniques. Compared with PAN_AF, PAN_AOF showed a higher adsorption capability for Hg²⁺ ions in aqueous solutions. The functionalized fiber PAN_AOF exhibited a highly selective adsorption for Hg²⁺ when coexisting with other metal ions viz. Pb²⁺, Cd²⁺, Cu²⁺, Zn²⁺, Ni²⁺, Co²⁺, Cr³⁺, Ca²⁺, and Mg²⁺. The PAN_AOF presented the best adsorption capacity for Hg²⁺ at pH 5. Moreover, the adsorption experimental data fit well with the pseudo-second-order kinetic model and Langmuir isotherm. Notably, the PAN_AOF almost retained its original adsorption capacity (112 mg/g) after five cycles, indicating its excellent reusability in practical applications.

Well-shaped spherical agglomerates of FePO₄ particles were prepared by a novel method: chemical co-precipitation combined with spray-drying. Tap density analysis, Brunauer–Emmett–Teller analysis, characterizations of X-ray diffraction, scanning electron microscopy, and transmission electron microscopy confirmed that the micron-sized spherical agglomerates with high specific surface area and high tap density were composed of the uniform nano-sized particles. The effects of pH and reaction time on the morphology of the FePO₄ particles were investigated by experimental and theoretical analyses. The analyses revealed that amorphous FePO₄ was responsible for forming a well-shaped spherical agglomerate, and the ideal spherical particles were obtained at pH 3. The reaction time also played a significant role in controlling the size and surface morphology of the FePO₄ particles, and smooth spherical FePO₄ particles were obtained at a reaction time of 6 h. By this novel method, poly-porous spherical iron phosphate particles were prepared, which can be used with high efficiency in some special fields, especially as a precursor for synthesizing LiFePO₄ and catalysts.