Effects of exogenous N-acyl homoserine lactones (AHLs) on methanogenic activities and microbial community differences during anaerobic digestion.

N-acyl homoserine lactones (AHLs) function as signaling molecules influencing microbial community dynamics. This study investigates the impact of exogenously applied AHLs on methane production during waste-activated sludge (WAS) anaerobic digestion (AD). Nine AHL types, ranging from 10-4 to 10 µg/g VSS, were applied, comparing microbial community composition under optimal AHL concentrations. Firmicutes, Bacteroidetes, Chloroflexi, and Proteobacteria were identified in anaerobic digesters with C4-HSL, C6-HSL, and C8-HSL. Compared to the control, Halobacterota increased by 19.25%, 20.87%, and 9.33% with C7-HSL, C10-HSL, and C12-HSL. Exogenous C7-HSL enhanced the relative abundance of Methanosarcina, Romboutsia, Sedimentibacter, Proteiniclasticum, Christensenellaceae_R-7_group. C10-HSL increased Methanosarcina abundance. C4-HSL, C6-HSL, C8-HSL, C10-HSL, and C12-HSL showed potential to increase unclassified_Firmicutes. Functional Annotation of Prokaryotic Taxa (FAPROTAX) predicted AHLs' impact on related functional genes, providing insights into their role in AD methanogenesis regulation. This study aimed to enhance the understanding of the influence of different types of exogenous AHLs on AD and provide technical support for regulating the methanogenesis efficiency of AD by exogenous AHLs.

Environmental Applications of 3D g-C3N4-Based Hydrogel with Synergistic Effect of Adsorption and Photodegradation.

In this paper, g-C3N4-based hydrogel with a 3D network structure was synthesized via a simple and cheap reaction, using hydroxyethyl cellulose (HEC) and graphitic carbon nitride (g-C3N4) as the main materials. Electron microscope images revealed that the microstructure of g-C3N4-HEC hydrogel was rough and porous. The luxuriant scaly textures of this hydrogel were due to the uniform distribution of g-C3N4 nanoparticles. It was found that this hydrogel showed great removal ability of bisphenol A (BPA) through a synergistic effect of adsorption and photodegradation. The adsorption capacity and degradation efficiency of g-C3N4-HEC hydrogel (3%) for BPA were 8.66 mg/g and 78% under the conditions of C0 = 9.94 mg/L and pH = 7.0, which were much higher than those for the original g-C3N4 and HEC hydrogel. In addition, g-C3N4-HEC hydrogel (3%) exhibited excellent removal efficiency (98%) of BPA (C0 = 9.94 mg/L) in a dynamic adsorption and photodegradation system. Meanwhile, the mechanism of removal was investigated in depth. The superior batch and continuous removal capability of this g-C3N4-based hydrogel make it promising for environmental applications.

Effectively enhanced photodegradation of Bisphenol A by in-situ g-C3N4-Zn/Bi2WO6 heterojunctions and mechanism study.

In our work, a series of in-situ g-C3N4-Zn/Bi2WO6 heterojunctions were synthesized by a two-step solvothermal method followed with calcination process, using dicyanamide as the precursor for g-C3N4. C3N4-Zn/BWO heterojunctions were of gossypine shape, and both C3N4 and Zn were finely distributed into BWO nanosheets, forming a hierarchical structure. C3N4-Zn/BWO with 2.0 g of precursor addition and calcined at 520 °C exhibited effectively enhanced photodegradation for typical organic contaminant BPA, degrading 93% within 120 min, and implied a maximum rate constant k of 0.0211 min-1, indicating synergistic effect of C3N4 and Zn components in C3N4-Zn/BWO heterojunction. The enhancement of photocatalysis was due to quick carriers' separations via Z-scheme system and enlarged specific surface area of as-synthesized C3N4-Zn/BWO heterojunction. Main reactive oxidation species were detected to be h+ and O2-, and nine intermediates were confirmed via anlysis of LC-MS/MS. This study provided an alternative strategy to design novel photocatalysts containing multicomponents for higher photocatalytic activity.

Determination of polybrominated diphenyl ethers in human semen.

Some persistent organic pollutants (POPs) have been found in human semen but until this point it was unclear whether polybrominated diphenyl ethers (PBDEs) could be detected in human semen. In this study, PBDEs were found for the first time in human semen samples (n=101) from Taizhou, China. The concentrations of total PBDEs (∑PBDEs) varied from 15.8 to 86.8 pg/g ww (median=31.3 pg/g ww) and 53.2 to 121 pg/g ww (median=72.3 pg/g ww) in semen and blood samples, respectively. The ∑PBDE level in semen was about two times lower than in human blood, which was different in the distribution in the two matrices from other POPs. A correlation of ∑PBDE concentration was found between paired semen and in blood. The results suggest that semen could be used to detect PBDE burden in human body as a non-invasive matrix. In addition, the levels of BDE-209 and BDE-153, especially the latter, were much higher in blood than in semen, while the levels of BDE-28, BDE-47 and BDE-99 were comparable in the two matrices, suggesting that low brominated congeners could be more easily transferred to semen than high brominated congeners. Considering different toxicities among the PBDE congeners, it might be more significant to measure PBDEs in semen than in blood for evaluating male reproduction risks of PBDEs.

Dual body burdens of polychlorinated biphenyls and polybrominated diphenyl ethers among local residents in an e-waste recycling region in Southeast China.

E-waste recycling resulted in serious pollution of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in Taizhou of Zhejiang Province, China. The aims of this study were to assess dual body burdens of the two pollutants and potential health risk for local residents. Blood samples were collected from two e-waste recycling sites, Luqiao (where PCBs-containing e-wastes were recycled) and Wenling (where PBDEs-containing e-wastes were recycled). The mean summation SigmaPCBs (CB-105, 118, 153, 183, and 180) and summation SigmaPBDEs (BDE-28, 47, 99, 100, 153, 154, 180, and 209) were 204.20 and 117.58 ng g(-1) lipid in the blood from Luqiao, respectively, while they were 83.80 and 357.44 ng g(-1) lipid from Wenling, respectively. The PCBs levels among Luqiao residents were comparable to the values reported for US populations, while the PBDEs levels among two study populations were higher than the values from US populations. This is the first report to present dual body burdens of PCBs and PBDEs at so high levels. Based on previous epidemiologic data, it is suggested that dual burdens of PCBs and PBDEs at so high levels might pose health risk for local residents. In addition, no correlation between PCBs or PBDEs concentrations and the ages of the volunteers was observed in the two populations, which was explained by similar exposure time. No correlation of PBDEs with PCBs concentrations suggested different pathways of human exposures to PCBs and PBDEs. Our findings have raised concern about human health risk of dual exposure to PCBs and PBDEs resulting from e-waste recycling.