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At present, the research on Fe/Mn autotrophic denitrification is very limited, and the underlying mechanism in electrochemical system is not clear. In this study, an electrochemical system based on Fe-Mn autotrophic denitrification was constructed for the treatment of low C/N wastewater. The underlying mechanism and electrochemical process of Fe/Mn-mediated autotrophic denitrification were elucidated. The results showed that pyrite and manganese mineral matrix had no significant effect on COD removal, but had significant effect on nitrogen removal. R1 (activated carbon matrix) had the lowest nitrogen removal rate, with an average of 66.06 %. The mean removal rate of R2 (iron matrix) and R3 (manganese matrix) were 93.94 % and 95.89 %, respectively. The coupling of iron/manganese ammoxidation and autotrophic denitrification was the main mechanism to achieve efficient nitrogen removal. ICP and FIRT results showed that strong REDOX reactions of Fe, Mn and sulfur occurred at the anode of MFC. Direct precipitation of iron and manganese and electrochemical flocculation (FeOOH) effectively improved phosphorus removal. The phosphorus removal rates of R2 and R3 reached 93.89 % and 95.85 %, respectively. R3 has high electron transfer efficiency with a maximum voltage of 680 mV. Metagenomic analysis showed that 19 important transcripts associated with nitrogen metabolism pathways and 4 nitrogen metabolism pathways were detected. Enzymes encoded by nap A and nar Ggenes were abundant in R3 system. Reductase encoded by nrfAand nrfHgenes was abundant in R2 system. Iron REDOX genes iroE, iroN, oorA, and manganese REDOX genes moxR, moxAwere detected. The results of metabolic pathways and related enzymes further revealed the coupling cycle relationship between metal elements and nitrogen, phosphorus and sulfur in electrochemical systems. This study can not only provide a new method for efficient nitrogen and phosphorus removal of sewage, but also provide scientific basis for improving the geochemical cycle of metal elements and nitrogen elements.

High online operating costs and low consumer utility still need to be addressed in the sales of community fresh e-commerce. Herein, we develop a new community fresh marketing model composed of retailers for online operating costs and consumers for low consumer utility by dividing community consumers into essential type and expectant type in this study. Then, the profit functions of community fresh retailers are developed in this study according to utility theory. Finally, a revised model of the fresh quality transparency (FQT) factor is conducted and discussed in this study. The results suggest that the profits obtained from essential consumers and expectant consumers by the community fresh e-commerce retailers are higher within a certain range of freshness costs compared to the basic model’s projection; meanwhile, the profits from expectant consumers contribute more than those from essential consumers. However, if the freshness cost exceeds a certain critical value, the abovementioned profits predicted from the new model will be lower. This study enriches the supply chain theory of community fresh food and provides retailers with theoretical guidance on differentiated services and pricing to better match the needs of community consumers.

The impact of extracellular organic matter (EOM) on the coagulation behavior and harvest of algae remains unclear. In this study, bounded EOM (bEOM) and dissolved EOM (dEOM) extracted from laboratory-grown Microcystis aeruginosa were characterized in terms of specific ultraviolet absorbance, molecular weight (MW) distribution, Three dimensional excitation emission spectrum (3D-EEM), and component content. Three coagulants, namely, polyferric sulfate (PFS), polydimethyl diallyl ammonium chloride (PD), and PFS-PD, were used to determine the suitable coagulant and conditions for EOM removal. The coagulation behavior for EOM removal and the roles of EOM on algae water treatment were investigated. Results indicated that PFS-PD exhibited the highest efficiency in removing dissolved organic carbon. MW distribution and 3D-EEM analysis showed that the removal of high-MW protein-like substances in bEOM was acceptable and few low-MW microbial product-like and fulvic/humic-like substances in dEOM were coagulated. In addition to charge neutralization, the complex interaction mechanisms between N–H/C–N groups of bEOM and hydroxyl iron facilitated the formation of primary microflocs. High-MW fraction in bEOM promoted floc growth and sedimentation. EOM contributed to the removal of algae cells with its adherence to the surface of cell wall, and no positive impact was observed for the dissociative EOM.

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Metal doping, an alternative strategy to enhance the adsorption performance of metal–organic frameworks (MOFs), is a hot research direction of MOF modification. However, the commonly used doping metals are mostly rare metals, which increase the cost and may lead to secondary pollution. Thus, the practical application of metal doping in MOF modification is limited. Herein, Aluminum (Al), an abundant, cheap, and environmentally friendly metal, was doped in UiO-66-NH2to prepare Al-UiO-66-NH2to adsorb tetracycline (TC) effectively. The optimal Al doping ratio for preparing Al-UiO-66-NH2was determined, and the physicochemical characteristics of the prepared Al-UiO-66-NH2were obtained. Adsorption performance and reusability were investigated. Furthermore, the possible adsorption mechanisms were explored, and the anti-interference adsorption ability and application potential were evaluated. The optimal Al doping ratio was 1:1 (Zr/Al molar ratio), and the adsorption capacity of Al-UiO-66-NH2was 6.86 times higher than that of UiO-66-NH2. Compared with UiO-66-NH2, Al-UiO-66-NH2had smaller particle size, larger specific surface area and pore size, and more coordinated NH2-BDC. For TC adsorption, the process was spontaneous and endothermic and fitted well with the pseudo-second-order kinetic and Langmuir isotherm models. The maximum adsorption capacity obtained by the Langmuir model was 520 mg/g. Pore filling, electronic interaction, H-bonding interaction, complexation, π-π interaction, and Lewis acid–base interaction took part in the adsorption. Al-UiO-66-NH2could be reused, while exhibiting high water stability and a certain anti-interference performance for TC adsorption. Overall, Al-UiO-66-NH2was an alternative MOF adsorbent for the treatment of wastewater containing TC with desirable application potential.

We compared the discriminative validity, agreement and sensitivity of EQ-5D-5L and SF-6D utility scores in people living with HIV/AIDS (PLWHIV). We conducted a cross-sectional survey among PLWHIV aged more than 18 years old in 9 municipalities in Yunnan Province, China. A convenience sample was enrolled. We administered the SF-12 and EQ-5D-5L to measure health-related quality of life. The utility index of the SF-6D was derived from the SF-12. We calculate correlation coefficients to evaluate the relationship and agreement of 2 instruments. To evaluate the homogeneity of the EQ-5D-5L and SF-6D, intraclass correlation coefficients, scatter plots, and Bland–Altman plots were computed and drawn. We also used receiver operating characteristic curves to compare the discriminative properties and sensitivity of the econometric index. A total of 1797 respondents, with a mean age of 45.6 ± 11.7 years, was interviewed. The distribution of EQ-5D-5L scores skewed towards full health with a skewness of −3.316. The overall correlation between EQ-5D-5L and SF-6D index scores was 0.46 (P < .001). The association of the 2 scales appeared stronger at the upper end. An intraclass correlation coefficient of 0.59 between the EQ-5D-5L and SF-6D meant a moderate correlation and indicated general agreement. The Bland–Altman plot displayed the same results as the scatter plot. The receiver operating characteristic curve showed that the AUC for the SF-6D was 0.776 (95% CI: 0.757, 0.796) and that for the EQ-5D-5L was 0.732 (95% CI: 0.712, 0.752) by the PCS-12, and it was 0.782 (95% CI: 0.763, 0.802) for the SF-6D and 0.690 (95% CI: 0.669, 0.711) for the EQ-5D-5L by the MCS-12. Our study demonstrated evidence of the performance of EQ-5D-5L and SF-6D index scores to measure health utility in people living with HIV/AIDS. There were significant differences in their performance. We preferred to apply the SF-6D to measure the health utility of PLWHIV during the combined antiretroviral therapy period. Our study has demonstrated evidence for instrument choice and preference measurements in PLWHIV under combined antiretroviral therapy.

To investigate the electrochemical process and metabolic mechanism of sulfonamide wastewater treatment under chromium and copper stress in bioelectrochemical system, electron transfer and antibiotic resistance genes (ARGs) transfer were investigated. Metagenomics was used to reveal metabolic pathways, antibiotic resistance mechanisms, carbohydrate active enzymes, etc. The results indicated that copper stress not only did not affect the electricity production performance of the electrochemical system, but also promoted the electron transfer efficiency. Copper stress can also effectively control ARGs and mobile genetic elements (MGEs). The metagenomics analysis showed that Cu increased the abundance of coxA and cox1 genes in the electrochemical system and increased the C-type cytochrome, thereby improving the ability of electron transfer. In contrast, chromium stress affected electrochemical system performance and accelerated ARGs transfer, and increasing the risk of resistance gene horizontal transfer. The mechanism of antibiotic resistance was mainly through the efflux function of antibiotics (61.5%), which was mainly related to Proteobacteria (51.5%) and Firmicutes (25.4%). The results also indicated that the glycolysis process was promoted by Cu, while the process was negatively affected by Cr. This study revealed the effect of chromium and copper stress on the metabolic mechanisms of microorganisms in bioelectrochemical system at the genetic level and provided a theoretical basis for risk control of livestock and poultry wastewater.

Connecting external circuits can effectively inhibit the CH4emissions from constructed wetlands (CW). In this study, the effect of external circuits, plant roots position and external resistance value on the electrical, CH4emission and pollutant removing performance of sequencing batch constructed wetland-microbial fuel cell (CW-MFC) was investigated for the first time. After connecting external circuit, the CH4emission from rhizosphere-anode-closed (RAC) constructed wetland-microbial fuel cell (CW-MFC) and rhizosphere-cathode-closed (RCC) CW-MFC was significantly reduced by 49.39% and 74.19%, respectively. When the external resistance was 1000, the highest power density was observed in RAC CW-MFC with a number of 73.32 mW m−3. In comparison, CW-MFC with rhizosphere at cathode emitted less CH4, while CW-MFC with rhizosphere at anode had a better electrical performance. Based on the high-throughput sequencing analysis, dynamic community structure of bacteria and archaea and the related microbial processes in the anode and cathode of CW-MFC were studied. Proteobacteria, Bacteroidetesand Methanosaetawere observed to be dominant in CW-MFCs, and the circuit conditions, external resistance and rhizosphere location all played important roles in the microbial community structure of CW-MFCs.