The rapid progress of modern industry not only brings convenience to people’s lives, but also brings negative effects. Industrial development produces a large amount of waste metal, which brings harm to the environment and human health. Carbon nitride (g-C3N4) was successfully prepared using the thermal-polymerization method and petal-like g-C3N4 (CA-g-C3N4) was impregnated with citric acid (CA). Compared with g-C3N4, CA-g-C3N4 showed extremely high photocatalytic activity because the petal-like g-C3N4 (CA-g-C3N4) had a larger specific surface area, which increased the active sites on the surface of the photocatalyst and improved the photocatalytic activity. After citric acid treatment, the removal of hexavalent chromium (Cr(VI)) by g-C3N4 increased from 48% to 93%. The photocatalytic materials were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) and UV-vis diffuse reflectance spectra (UV-vis). In summary, this study confirmed that citric acid can improve the photocatalytic activity of g-C3N4 by increasing its specific surface area and the active site of the photocatalytic material so as to achieve the purpose of removing hexavalent chromium from water.

Fe5Ce5Ti catalytic material is reported for the removal of Hg0 and AsH3 from yellow phosphorus flue gas by catalytic oxidation. The mechanism of the reaction is inferred from characterization analysis.

Background Medicago ruthenica, a superior leguminous forage, is strongly drought-resistant and has wide adaptability. It is closely related to Medicago sativa (a commonly cultivated forage). Characterized by its high tolerance to environmental stress, M. ruthenica is a valuable genetic resource. However, its low yield limits its large-scale promotion and utilization. Leaf morphology, an important agronomic trait, is closely related to forage yield and photosynthetic efficiency. Results In this study, leaf width and leaf area were found significantly positively correlated with forage yield in M. ruthenica. Specifically, the cultivar M. ruthenica ‘Mengnong No.1’ (MN No.1) with a larger leaf area had higher photosynthetic efficiency. Furthermore, the key miRNA-target gene networks associated with high photosynthetic efficiency of M. ruthenica were identified using small RNAs and transcriptome sequencing. Totally, 63 differentially expressed miRNAs (DEMs) were identified, including some known miRNAs (miR408, miR171, and miR398, etc.). These known miRNAs corresponded to 55 target genes; 6 miRNA-target gene pairs had negatively correlated expression patterns. Degradome sequencing analysis further confirmed the authenticity of miR408-targeted cleavage of LAC5; namely, the miR408-LAC5 module may mediate the mechanism of high photosynthetic efficiency formation in M. ruthenica. Conclusions This study for the first time proposed that leaf morphology as a key trait affecting the high-yielding plant type of M. ruthenica. The key gene modules screened in this study may provide new insights into the elucidation of photosynthetic efficiency mechanism and the bio-design breeding of legume forages in the future.