A review of distribution and functions of extracellular DNA in the environment and wastewater treatment systems.

Extracellular DNA refers to DNA fragments existing outside the cell, originating from various cell release mechanisms, including active secretion, cell lysis, and phage-mediated processes. Extracellular DNA serves as a vital environmental biomarker, playing crucial ecological and environmental roles in water bodies. This review is summarized the mechanisms of extracellular DNA release, including pathways involving cell lysis, extracellular vesicles, and type IV secretion systems. Then, the extraction and detection methods of extracellular DNA from water, soil, and biofilm are described and analyzed. Finally, we emphasize the role of extracellular DNA in microbial community systems, including its significant contributions to biofilm formation, biodiversity through horizontal gene transfer, and electron transfer processes. This review offers a comprehensive insight into the sources, distribution, functions, and impacts of extracellular DNA within aquatic environments, aiming to foster further exploration and understanding of extracellular DNA dynamics in aquatic environments as well as other environments.

Toxicity threshold and ecological risk of nitrate in rivers based on endocrine-disrupting effects: A case study in the Luan River basin, China.

Nitrate, as a crucial nutrient, is consistently targeted for controlling water eutrophication globally. However, there is considerable evidence suggesting that nitrate has endocrine-disrupting potential on aquatic organisms. In this study, the sensitivity of various adverse effects to nitrate nitrogen (nitrate-N) was compared, and a toxicity threshold based on endocrine-disrupting effects was derived. The spatiotemporal variations of nitrate-N concentrations in the Luan River basin were investigated, and the associated aquatic ecological risks were evaluated using a comprehensive approach. The results showed that reproduction and development were the most sensitive endpoints to nitrate, and their distribution exhibited significant differences compared to behavior. The derived threshold based on endocrine-disrupting effects was 0.65 mgL-1, providing adequate protection for the aquatic ecosystem. In the Luan River basin, the mean nitrate-N concentrations during winter (4.4 mgL-1) were significantly higher than those observed in spring (0.7 mgL-1) and summer (1.2 mgL-1). Tributary inputs had an important influence on the spatial characteristics of nitrate-N in the mainstream, primarily due to agricultural and population-related contamination. The risk quotients (RQ) during winter, summer, and spring were evaluated as 6.7, 1.8, and 1.1, respectively, and the frequency of exposure concentrations exceeding the threshold was 100 %, 64.3 %, and 42.5 %, respectively. At the ecosystem level, nitrate posed intermediate risks to aquatic organisms during winter and summer in the Luan River basin and at the national scale in China. We suggest that nitrate pollution control should not solely focus on water eutrophication but also consider the endocrine disruptive effect on aquatic animals.

Recovery strategies and mechanisms of anammox reaction following inhibition by environmental factors: A review.

Anaerobic ammonium oxidation (anammox) is a promising biological method for treating nitrogen-rich, low-carbon wastewater. However, the application of anammox technology in actual engineering is easily limited by environmental factors. Considerable progress has been investigated in recent years in anammox restoration strategies, significantly addressing the challenge of poor reaction performance following inhibition. This review systematically outlines the strategies employed to recover anammox performance following inhibition by conventional environmental factors and emerging pollutants. Additionally, comprehensive summaries of strategies aimed at promoting anammox activity and enhancing nitrogen removal performance provide valuable insights into the current research landscape in this field. The review contributes to a comprehensive understanding of restoration strategies of anammox-based technologies.

A High-Resolution 3D Ultrasound Imaging System Oriented towards a Specific Application in Breast Cancer Detection Based on a 1 × 256 Ring Array.

This paper presents the design and development of a high-resolution 3D ultrasound imaging system based on a 1 × 256 piezoelectric ring array, achieving an accuracy of 0.1 mm in both ascending and descending modes. The system achieves an imaging spatial resolution of approximately 0.78 mm. A 256 × 32 cylindrical sensor array and a digital phantom of breast tissue were constructed using the k-Wave toolbox. The signal is acquired layer by layer using 3D acoustic time-domain simulation, resulting in the collection of data from each of the 32 layers. The 1 × 256 ring array moves on a vertical trajectory from the chest wall to the nipple at a constant speed. A data set was collected at intervals of 1.5 mm, resulting in a total of 32 data sets. Surface rendering and volume rendering algorithms were used to reconstruct 3D ultrasound images from the volume data obtained via simulation so that the smallest simulated reconstructed lesion had a diameter of 0.3 mm. The reconstructed three-dimensional image derived from the experimental data exhibits the contour of the breast model along with its internal mass. Reconstructable dimensions can be achieved up to approximately 0.78 mm. The feasibility of applying the system to 3D breast ultrasound imaging has been demonstrated, demonstrating its attributes of resolution, precision, and exceptional efficiency.

Effect of biochar on the SPNA system at ambient temperatures.

Biochar has been extensively studied in wastewater treatment systems. However, the role of biochar in the single-stage partial nitritation anammox (SPNA) system remains not fully understood. This study explored the impact of biochar on the SPNA at ambient temperatures (20 °C and 15 °C). The nitrogen removal rate of the system raised from 0.43 to 0.50 g N/(L·d) as the biochar addition was raised from 2 to 4 g/L. Metagenomic analysis revealed that gene abundances of amino sugar metabolism and nucleotide sugar metabolism, amino acid metabolism, and quorum sensing were decreased after the addition of biochar. However, the gene abundance of enzymes synthesizing NADH and trehalose increased, indicating that biochar could stimulate electron transfer reactions in microbial metabolism and assist microorganisms in maintaining a steady state at lower temperatures. The findings of this study provide valuable insights into the mechanism behind the improved nitrogen removal facilitated by biochar in the single-stage partial nitritation anammox system.

Inhibiting PLA2G7 reverses the immunosuppressive function of intratumoral macrophages and augments immunotherapy response in hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is an exceptionally immunosuppressive malignancy characterized by limited treatment options and a dismal prognosis. Macrophages constitute the primary and heterogeneous immune cell population within the HCC microenvironment. Our objective is to identify distinct subsets of macrophages implicated in the progression of HCC and their resistance to immunotherapy. METHODS: Intratumoral macrophage-specific marker genes were identified via single-cell RNA sequencing analyses. The clinical relevance of phospholipase A2 Group VII (PLA2G7), a pivotal enzyme in phospholipid metabolism, was assessed in patients with HCC through immunohistochemistry and immunofluorescence. Flow cytometry and an in vitro co-culture system were used to elucidate the specific role of PLA2G7 in macrophages. Orthotopic and subcutaneous HCC mouse models were employed to evaluate the potential of the PLA2G7 inhibitor in complementing immune checkpoint blockade (ICB) therapy. RESULTS: Single-cell RNA sequencing analyses disclosed predominant PLA2G7 expression in intratumoral macrophages within the HCC microenvironment. The macrophage-specific PLA2G7 was significantly correlated with poorer prognosis and immunotherapy resistance in patients with HCC. PLA2G7high macrophages represent a highly immunosuppressive subset and impede CD8 T-cell activation. Pharmacological inhibition of PLA2G7 by darapladib improved the therapeutic efficacy of anti-programmed cell death protein 1 antibodies in the HCC mouse models. CONCLUSIONS: Macrophage-specific PLA2G7 serves as a novel biomarker capable of prognosticating immunotherapy responsiveness and inhibiting PLA2G7 has the potential to enhance the efficacy of ICB therapy for HCC.

Identification of SGMS2 as a molecule involved in natural killer cell recruitment and its in-deep analysis in the liver cancer microenvironment: Evidence from large populations cohort.

BACKGROUND: Liver cancer, a common malignancy within the digestive system, presents with a particularly grim prognosis. Within the immune microenvironment, the role of natural killer (NK) cells in liver cancer remains unclear. METHODS: We sourced data on clinical parameters and gene expressions for liver cancer patients from The Cancer Genome Atlas Program database and carried out all analyses using R software and its relevant codes. RESULTS: In our research, we delved into the genes intertwined with NK cells in hepatocellular carcinoma (HCC). Leveraging the QUANTISEQ and MCPCOUNTER algorithms to quantify NK cells, we spotlighted genes vital to the recruitment of NK cells. Among these genes, GDE1, WDFY3, DNAJB14, PKD2, DGAT2, SGMS2 and MKNK2 showed a strong correlation with patient outcomes. We also mapped out the single-cell expression trajectories of these genes within the HCC milieu. From our findings, SGMS2 emerged as a key gene warranting further scrutiny. Our in-depth analysis of SGMS2 shed light on its influence over specific biological pathways, its contribution to the immune landscape and its role in genomic instability within HCC. Drawing from this, we formulated a predictive model rooted in SGMS2-associated genes. This model showcased remarkable precision across both training and validation cohorts. CONCLUSIONS: Overall, our investigation underscored the profound implications of SGMS2, a gene pivotal to NK cell infiltration, in the landscape of HCC, thereby positioning it as a potential linchpin in oncological strategies.

Inactivated vaccines reduce the risk of liver function abnormality in NAFLD patients with COVID-19: a multi-center retrospective study.

BACKGROUND: Abnormal liver function was frequently observed in nonalcoholic fatty liver disease (NAFLD) patients infected with SARS-CoV-2. Our aim was to explore the effect of SARS-CoV-2 inactivated vaccines on liver function abnormality among NAFLD patients with COVID-19. METHODS: The multi-center retrospective cohort included 517 NAFLD patients with COVID-19 from 1 April to 30 June 2022. Participants who received 2 doses of the vaccine (n = 274) were propensity score matched (PSM) with 243 unvaccinated controls. The primary outcome was liver function abnormality and the secondary outcome was viral shedding duration. Logistic and Cox regression models were used to calculate the odds ratio (OR) and hazard ratio (HR) for the outcomes. Sensitivity analysis was conducted to assess robustness. FINDINGS: PSM identified 171 pairs of vaccinated and unvaccinated patients. Liver function abnormality was less frequent in the vaccinated group (adjusted OR, 0.556 [95% CI (confidence interval), 0.356-0.869], p = 0.010). Additionally, the vaccinated group demonstrated a lower incidence of abnormal bilirubin levels (total bilirubin: adjusted OR, 0.223 [95% CI, 0.072-0.690], p = 0.009; direct bilirubin: adjusted OR, 0.175 [95% CI, 0.080-0.384], p < 0.001) and shorter viral shedding duration (adjusted HR, 0.798 [95% CI, 0.641-0.994], p = 0.044) than the unvaccinated group. Further subgroup analysis revealed similar results, while the sensitivity analyses indicated consistent findings. INTERPRETATION: SARS-CoV-2 vaccination in patients with NAFLD may reduce the risk of liver dysfunction during COVID-19. Furthermore, vaccination demonstrated beneficial effects on viral shedding in the NAFLD population. FUNDING: 23XD1422700, Tszb2023-01, Zdzk2020-10, Zdxk2020-01, 2308085J27 and JLY20180124.

Effect of green value capture on the manufacturing firm performance considering green dynamic capabilities and profitability models.

Ensuring and improving the green value acquisition of manufacturing enterprises is one of the critical issues to be solved for manufacturing enterprises to achieve green value and high-quality development. Based on the theory of enterprise value acquisition and dynamic capability theory, we explain the "black box" of the relationship between green value creation and enterprise performance of manufacturing enterprises. The logical thread of "green value creation-profit model-enterprise performance" is constructed, and a green value acquisition mechanism model is proposed. Based on 263 questionnaires from Chinese manufacturing enterprises, the model is empirically tested using multiple regression analysis. The results show that green value creation has a positive impact on corporate performance, while the profit model plays a mediating role between green value creation and corporate performance. Green dynamic capability plays a positive moderating role between green value creation and corporate performance, while green active ability plays a positive moderating role between value creation and profit model.

CD36-BATF2\MYB Axis Predicts Anti-PD-1 Immunotherapy Response in Gastric Cancer.

Despite the utilization of anti-PD-1 therapy in gastric cancer (GC), the absence of a reliable predictive biomarker continues to pose a challenge. In this study, we utilized bioinformatic analysis and immunohistochemistry to develop a prediction model for activated CD4+ memory T cells, considering both mRNA and protein levels. An elevation of activated CD4+ memory T cells in GC was noted, which exhibited a strong association with the patients' overall survival. By utilizing WGCNA and DEG analysis, we discovered that BATF2, MYB, and CD36 are genes that exhibit differential expression and are linked to activated CD4+ memory T cells. Afterwards, a forecast model was built utilizing Stepwise regression and immunohistochemistry relying on the three genes. The model's high-risk score showed significant associations with a suppressive immune microenvironment. Moreover, our model exhibited encouraging prognostic value and superior performance in predicting response to immune checkpoint blockade therapy compared with the conventional CD8+PD-L1 model. In terms of mechanism, CD36 could function as a receptor upstream that identifies Helicobacter pylori and fatty acids. This recognition then results in the reduction of the BATF2-MYB protein complex and subsequent alterations in the transcription of genes associated with classical T cell activation. As a result, the activation state of CD4+ memory T cells is ultimately suppressed. The CD36-BATF2/MYB signature serves as a robust predictor of anti-PD-1 immunotherapy response in GC.

Extracellular polymeric substances and microbial community shift during the start-up of a single-stage partial nitritation/anammox process.

A sequencing batch reactor (SBR) was operated to investigate variations of extracellular polymeric substances (EPS) and microbial community during the start-up of the single-stage partial nitritation/anammox (SPN/A) process at intermittent aeration mode. The SPN/A system was successfully started on day 34, and the nitrogen removal efficiency and total nitrogen loading rate were 82.29% and 0.31 kg N/(m3 ·day), respectively. Furthermore, the relationship between the protein secondary structures and microbial aggregation was strongly related. The α-helix/ (ß-sheet + random coil) ratios increased obviously from 0.20 ± 0.03 to 0.23 ± 0.01, with the sludge aggregation mean size increased from 56 to 107 µm during the start-up of SPN/A. During the start-up of SPN/A, Candidatus Kuenenia was the primary anammox bacteria, whereas Nitrospira was the main functional bacteria of nitrite-oxidizing bacteria. Correlation between the microbial community and EPS components was performed. The EPS and microbial community played important roles in keeping stable nitrogen removal and the formation of sludge granules. PRACTITIONER POINTS: Intermittent aeration strategy promoted SPN/A system start-up. EPS composition and protein secondary structure were related with the sludge disintegration and aggregation. Microbial community shift existed and promoted the stability of sludge and reactor performance during SPN/A start-up.

Doping profile architecture towards lower loss and higher efficiency for laser diodes.

A doping optimization model towards lower loss and higher efficiency at the target operating current is investigated. This model considers the effect of doping concentration on the series resistance and the internal loss. 780 nm lasers doped with a normal doping profile (Dop_normal) and an optimized doping profile (Dop_optimize) are both designed and fabricated. After doping optimization, the power loss decreased by 17%, the output power of the lasers increased by 26% and the electro-optical conversion efficiency increased by 22%. The model provides significant theoretical guidance for the optimization of the laser doping.

From waste-activated sludge to algae: a self-reliant cultivation process in photoreactors using saline conditions.

In this study, microalgae-bacteria (MB) systems using saline conditions (3 and 5% salinity) were built in order to use waste-activated sludge (AS) as raw material for cultivating lipid-rich microalgae. Algae were observed to be flourishing in 60 days of operation, which totally used the N and P released from the sludge biomass. A prominent improvement of lipid content in MB consortia was obtained under algae growth and salinity stimulation, which occupied 119-136 mg/g-SS rather than a low content of 12.1 mg/g-SS in AS. Lipid enrichment also brought a 3.1-3.3 times total heat release (THR) in the MB biomass. The marine spherical algae Porphyridium, as well as filamentous Geitlerinema, Nodularia, Leptolyngbya were found to be the main lipid producers and self-flocculated to 23.0% (R1) and 33.5% (R2) volume under the effect of residue EPS. This study had a big meaning in not only waste sludge reduction but also in manufacturing useful bioenergy products.

Dahuang Zhechong pill attenuates hepatic sinusoidal capillarization in liver cirrhosis and hepatocellular carcinoma rat model via the MK/integrin signaling pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Dahuang Zhechong pill (DHZCP), a traditional Chinese medicine, was derived from the famous book Unk "Synopsis of Prescriptions of the Golden Chamber" during the Han dynasty. Owing to its ability to invigorate the circulation of blood in Chinese medicine, DHZCP is usually used for treating liver cirrhosis (LC) and hepatocellular carcinoma (HCC). Clinical application have shown that DHZCP exhibits satisfactory therapeutic effects in HCC adjuvant therapy; however, little is known about its underlying mechanisms. AIM OF THE STUDY: We aimed to clarify the mechanism of DHZCP against hepatic sinusoidal capillarization in rats with LC and HCC by inhibiting the MK/integrin signaling pathway of liver sinusoidal endothelial cells (LSECs). MATERIALS AND METHODS: The contents of 29 characteristic components in DHZCP were determined by ultraperformance liquid chromatography-tandem mass spectrometry. DEN (Diethylnitrosamine)-induced LC and HCC rat models were constructed, and DHZCP was administered when the disease entered the LC stage. After 4 or 12 weeks of administration, hematoxylin and eosin staining, Masson staining, Metavir score, and SSCP (Single strand conformation polymorphism) gene mutation detection were used to confirm tissue fibrosis and cancer. The levels of NO, ET-1 and TXA2, which can regulate vasomotor functions and activate the MK/Itgα6/Src signaling pathway were evaluated by using immunohistochemistry, chemiluminescence, immunofluorescence, Western blot analysis, and enzyme-linked immunosorbent assay (ELISA). Similar methods were also used to evaluate the levels of VEGF, VEGFR, Ang-2 and Tie, which can promote pathological angiogenesis and activate the MK/Itgα4/NF-κB signaling pathway. In vitro cell experiments were performed using potential pharmacodynamic molecules targeting integrins in DHZCP were selected by molecular docking, and the effects of these molecules on the function of LSECs were studied by Itgα4+ and Itgα6+ cell models. RESULTS: At the stage of LC, the animal experiments demonstrated that DHZCP mainly inhibited the MK/Itgα6 signaling pathway to increase the number and size of hepatic sinus fenestration, reversed the ET-1/NO and TXA2/NO ratios, regulated hepatic sinus relaxation and contraction balance, reduced the portal vein pressure, and inhibited cirrhotic carcinogenesis. At the HCC stage, DHZCP could also significantly inhibit the MK/Itgα4 signaling pathway, reduce pathological angiogenesis, and alleviate disease progression. The results of the cell experiments showed that Rhein, Naringenin, Liquiritin and Emodin-8-O-ß-D-glucoside (PMEG) were involved in vascular regulation by affecting the MK/integrin signaling pathway. Liquiritin and PMEG mainly blocked the MK/α6 signal, which is important in regulating the vasomotor function of the liver sinus. Naringenin and Rhein mainly acted by blocked the signaling of MK/α4 action signal, which are potent molecules that inhibit pathological angiogenesis. CONCLUSIONS: DHZCP could improve the hepatic sinusoidal capillarization of LC and HCC by inhibiting the MK/Itgα signaling pathway and inhibited disease progression. Rhein, Naringenin, Liquiritin and PMEG were the main active molecules that affected the MK/Itgα signaling pathway.

A review of anammox metabolic response to environmental factors: Characteristics and mechanisms.

Anaerobic ammonium oxidation (anammox) is a promising low carbon and economic biological nitrogen removal technology. Considering the anammox technology has been easily restricted by environmental factors in practical engineering applications, therefore, it is necessary to understand the metabolic response characteristics of anammox bacteria to different environmental factors, and then guide the application of the anammox process. This review presented the latest advances of the research progress of the effects of different environmental factors on the metabolic pathway of anammox bacteria. The effects as well as mechanisms of conventional environmental factors and emerging pollutants on the anammox metabolic processes were summarized. Also, the role of quorum sensing (QS) mediating the bacteria growth, gene expression and other metabolic process in the anammox system were also reviewed. Finally, interaction and cross-feeding mechanisms of microbial communities in the anammox system were discussed. This review systematically summarized the variations of metabolic mechanism response to the external environment and cross-feeding interactions in the anammox process, which would provide an in-depth understanding for the anammox metabolic process and a comprehensive guidance for future anammox-related metabolic studies and engineering applications.

A scheduling route planning algorithm based on the dynamic genetic algorithm with ant colony binary iterative optimization for unmanned aerial vehicle spraying in multiple tea fields.

The complex environments and weak infrastructure constructions of hilly mountainous areas complicate the effective path planning for plant protection operations. Therefore, with the aim of improving the current status of complicated tea plant protections in hills and slopes, an unmanned aerial vehicle (UAV) multi-tea field plant protection route planning algorithm is developed in this paper and integrated with a full-coverage spraying route method for a single region. By optimizing the crossover and mutation operators of the genetic algorithm (GA), the crossover and mutation probabilities are automatically adjusted with the individual fitness and a dynamic genetic algorithm (DGA) is proposed. The iteration period and reinforcement concepts are then introduced in the pheromone update rule of the ant colony optimization (ACO) to improve the convergence accuracy and global optimization capability, and an ant colony binary iteration optimization (ACBIO) is proposed. Serial fusion is subsequently employed on the two algorithms to optimize the route planning for multi-regional operations. Simulation tests reveal that the dynamic genetic algorithm with ant colony binary iterative optimization (DGA-ACBIO) proposed in this study shortens the optimal flight range by 715.8 m, 428.3 m, 589 m, and 287.6 m compared to the dynamic genetic algorithm, ant colony binary iterative algorithm, artificial fish swarm algorithm (AFSA) and particle swarm optimization (PSO), respectively, for multiple tea field scheduling route planning. Moreover, the search time is reduced by more than half compared to other bionic algorithms. The proposed algorithm maintains advantages in performance and stability when solving standard traveling salesman problems with more complex objectives, as well as the planning accuracy and search speed. In this paper, the research on the planning algorithm of plant protection route for multi-tea field scheduling helps to shorten the inter-regional scheduling range and thus reduces the cost of plant protection.

Digital finance and regional green innovation: evidence from Chinese cities.

Digital finance realizes the combination of finance and technology, makes up for many deficiencies of traditional finance, and brings opportunities for green and innovative development. However, systematic research on regional digital finance and green innovation is still lacking. Based on this, this study aims to analyze the impact of digital finance on the regional level of green innovation. For the analysis, the fixed-effect model, the mediating effect model, and the moderating effect model are used to perform regression on the panel data of Chinese cities. The results show that digital finance can significantly improve the level of regional green innovation. Improving the level of regional green financial services is its main mechanism, but the intermediary role of industrial structure optimization and upgrading fails to pass the test. In addition, the results of heterogeneity analysis show that digital finance plays a greater role in promoting green innovation in areas with high levels of traditional financial supply and Internet infrastructure construction. It is worth noting that digital finance does not really play the role of universal benefit, widening the regional green innovation gap. The main contributions of this study are to prove the positive effect of digital finance on green innovation at the regional level, clarify its transmission mechanism and urban heterogeneity analysis, and find that the current digital finance cannot bridge the gap of regional green innovation.

How does digital economy affect green total factor productivity at the industry level in China: from a perspective of global value chain.

The digital economy is an important way to relieve current pressure on resources and the environment. Based on ecological modernization theory and global value chain theory, this paper adopts panel data of 17 manufacturing industries from 2000 to 2014, uses the non-radial directional distance function and the meta-frontier method to measure China's green total factor productivity (GTFP) and its sub-indices, and takes the embedding degree and embedding position as moderating variables and threshold variables to construct an econometric model to explore the relationship among the digital economy, global value chain, and GTFP. The results show that (1) the digital economy has a positive effect on GTFP in both time and space. And in terms of time, the digital economy mainly enhances GTFP by improving technical efficiency and narrowing the technology gap. (2) Global value chain embedding position positively moderates the relationship between the digital economy and GTFP; In terms of sub-samples, labor-intensive and capital-intensive industries show the same impact characteristics as the total sample. (3) Further, it is found that the digital economy and GTFP have nonlinear characteristics. There is a single threshold effect on the embedding position. When the embedding position is low, the digital economy is positively correlated with GTFP but not significant; when the threshold value is crossed, the digital economy can significantly promote GTFP. The conclusions of this paper are helpful to realize the digital economy to promote the green development of the manufacturing industry, and provide an effective reference for the realization mechanism of China's green economy transformation and ecological civilization construction in the post-pandemic era.

Effect of filamentous algae in a microalgal-bacterial granular sludge system treating saline wastewater: Assessing stability, lipid production and nutrients removal.

In this study modified microalgal-bacterial granular sludge (MBGS) was constructed and employed to compare the performance for treating 1%-5% saline wastewater with aerobic granular sludge (AGS). Filamentous algae were found to flourish at 1% salinity when nutrients were temporarily restricted to low level (COD 0, N 10 mg/L, P 0.5 mg/L). A significant improvement of granule stability was detected as the integrity coefficients of MBGS was only 0.12-0.24 rather than 0.19-0.48 of AGS under 1%-5% salinities, which reduced the risk of particle disintegration. Filamentous algae including Leptolyngbya and Geitlerinema occupied 91.2% of identified algae, and were beneficial for enhancing the biomass content and lipid production to about 1.27-1.37, 3.1-5.0 times than AGS. The MBGS had best nitrogen and phosphorus removal efficiencies of 93.4% and 64.6% at 1% salinity, and showed higher resistance to 3%-5% salinities. This study could provide meaningful information for using this modified MBGS technology in practice.

Efficient Sequestration of Hexavalent Chromium by Graphene-Based Nanoscale Zero-Valent Iron Composite Coupled with Ultrasonic Pretreatment.

Nanoscale zero-valent iron (nZVI) has attracted considerable attention for its potential to sequestrate and immobilize heavy metals such as Cr(VI) from an aqueous solution. However, nZVI can be easily oxidized and agglomerate, which strongly affects the removal efficiency. In this study, graphene-based nZVI (nZVI/rGO) composites coupled with ultrasonic (US) pretreatment were studied to solve the above problems and conduct the experiments of Cr(VI) removal from an aqueous solution. SEM-EDS, BET, XRD, and XPS were performed to analyze the morphology and structures of the composites. The findings showed that the removal efficiency of Cr(VI) in 30 min was increased from 45.84% on nZVI to 78.01% on nZVI/rGO and the removal process performed coupled with ultrasonic pretreatment could greatly shorten the reaction time to 15 min. Influencing factors such as the initial pH, temperature, initial Cr(VI) concentration, and co-existing anions were studied. The results showed that the initial pH was a principal factor. The presence of HPO42-, NO3-, and Cl- had a strong inhibitory effect on this process, while the presence of SO42- promoted the reactivity of nZVI/rGO. Combined with the above results, the process of Cr(VI) removal in US-nZVI/rGO system consisted of two phases: (1) The initial stage is dominated by solution reaction. Cr(VI) was reduced in the solution by Fe2+ caused by ultrasonic cavitation. (2) In the following processes, adsorption, reduction, and coprecipitation coexisted. The addition of rGO enhanced electron transportability weakened the influence of passivation layers and improved the dispersion of nZVI particles. Ultrasonic cavitation caused pores and corrosion at the passivation layers and fresh Fe0 core was exposed, which improved the reactivity of the composites.