Extracting the winter wheat using the decision tree based on time series dual-polarization SAR feature and NDVI.

Winter wheat is one of the most important crops in the world. It is great significance to obtain the planting area of winter wheat timely and accurately for formulating agricultural policies. Due to the limited resolution of single SAR data and the susceptibility of single optical data to weather conditions, it is difficult to accurately obtain the planting area of winter wheat using only SAR or optical data. To solve the problem of low accuracy of winter wheat extraction only using optical or SAR images, a decision tree classification method combining time series SAR backscattering feature and NDVI (Normalized Difference Vegetation Index) was constructed in this paper. By synergy using of SAR and optical data can compensate for their respective shortcomings. First, winter wheat was distinguished from other vegetation by NDVI at the maturity stage, and then it was extracted by SAR backscattering feature. This approach facilitates the semi-automated extraction of winter wheat. Taking Yucheng City of Shandong Province as study area, 9 Sentinel-1 images and one Sentinel-2 image were taken as the data sources, and the spatial distribution of winter wheat in 2022 was obtained. The results indicate that the overall accuracy (OA) and kappa coefficient (Kappa) of the proposed method are 96.10% and 0.94, respectively. Compared with the supervised classification of multi-temporal composite pseudocolor image and single Sentinel-2 image using Support Vector Machine (SVM) classifier, the OA are improved by 10.69% and 5.66%, respectively. Compared with using only SAR feature for decision tree classification, the producer accuracy (PA) and user accuracy (UA) for extracting the winter wheat are improved by 3.08% and 8.25%, respectively. The method proposed in this paper is rapid and accurate, and provide a new technical method for extracting winter wheat.

Medical waste incineration fly ash-based magnesium potassium phosphate cement: Calcium-reinforced chlorine solidification/stabilization mechanism and optimized carbon reduction process strategy.

The traditional solidification/stabilization (S/S) technology, Ordinary Portland Cement (OPC), has been widely criticized due to its poor resistance to chloride and significant carbon emissions. Herein, a S/S strategy based on magnesium potassium phosphate cement (MKPC) was developed for the medical waste incineration fly ash (MFA) disposal, which harmonized the chlorine stabilization rate and potential carbon emissions. The in-situ XRD results indicated that the Cl- was efficiently immobilized in the MKPC system with coexisting Ca2+ by the formation of stable Ca5(PO4)3Cl through direct precipitation or intermediate transformation (the Cl- immobilization rate was up to 77.29%). Additionally, the MFA-based MKPC also demonstrated a compressive strength of up to 39.6 MPa, along with an immobilization rate exceeding 90% for heavy metals. Notably, despite the deterioration of the aforementioned S/S performances with increasing MFA incorporation, the potential carbon emissions associated with the entire S/S process were significantly reduced. According to the Life Cycle Assessment, the potential carbon emissions decreased to 8.35 × 102 kg CO2-eq when the MFA reached the blending equilibrium point (17.68 wt.%), while the Cl- immobilization rate still remained above 65%, achieving an acceptable equilibrium. This work proposes a low-carbon preparation strategy for MKPC that realizes chlorine stabilization, which is instructive for the design of S/S materials.

Rapid immobilization of arsenic in contaminated soils by microwave irradiation combined with magnetic biochar: Microwave-induced electron transfer for oxidation and immobilization of arsenic (III).

Biochar with adjustable redox activity is an effective strategy for immobilization of excess arsenic (As(III)) contaminated soil. However, biochar exhibits limitations in terms of electron transfer efficiency and immobilization efficiency due to insufficient activation energy. In this study, As(III) in the soil was rapidly immobilized by adding magnetic biochar (Fe-BC) and introducing microwave irradiation energy to enhance electron transport efficiency. The results showed that the pore structure and iron species (ZVI, Fe3O4) loaded onto the biochar could be modulated by controlling the temperature and time of microwave pyrolysis, which enhanced the microwave absorption capacity and the immobilization performance of As. After adding Fe-BC (10 wt%) and treating with microwave irradiation for 3 h, the content of As(III) in the soil was reduced to 54.56 %. Compared with the conventional heating treatment, the percentage of stabilized As (residual form) increased by 11.21 %. The localized hot spots formed through the absorption of microwave energy by biochar promote the formation of arsenic-containing mineral crystals (FeAsO4 and Fe3AsO7), thus enhancing the immobilization efficiency. In addition, microwave-induced electron transfer facilitated the oxidation of As(III) to As(V) by surface quinone and carbonyl groups on the Fe-BC. Density functional theory calculation further proved that the surface groups of the Fe-BC had a stronger electron-withdrawing ability under microwave irradiation, thereby promoting the adsorption and immobilization of As(III). This work provided a new perspective on the technology of rapid remediation of heavy metals contaminated soil using biochar.

Comparative efficacy of early TIPS, Non-early TIPS, and Standard treatment in patients with cirrhosis and acute variceal bleeding: a network meta-analysis.

BACKGROUND: Cirrhosis is a chronic disease characterized by chronic liver inflammation and diffuse fibrosis. A combination of vasoactive drugs, preventive antibiotics, and endoscopy is the recommended standard treatment for patients with acute variceal bleeding; however, this has been challenged. We compared the effects of early transjugular intrahepatic portosystemic shunt (TIPS), non-early TIPS, and standard treatment in patients with cirrhosis and acute variceal bleeding. MATERIALS AND METHODS: The present network meta-analysis was conducted in accordance with the criteria outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Assessing the methodological quality of systematic reviews guidelines. The review has been registered with the International Prospective Register of Systematic Reviews. The PubMed, Embase, Cochrane Library, ClinicalTrials.gov, and World Health Organization-approved trial registry databases were searched for randomized controlled trials (RCTs) evaluating early TIPS, non-early TIPS, and standard treatment in patients with cirrhosis and acute variceal bleeding. RESULTS: Twenty-four RCTs (1894 patients) were included in the review. Compared with standard treatment, early TIPS [odds ratio (OR), 0.53; 95% credible interval (Cr), 0.30-0.94; surface under the cumulative ranking curve (SUCRA), 98.3] had a lower risk of all-cause mortality (moderate-to-high-quality evidence), and early TIPS (OR, 0.19; 95% CrI, 0.11-0.28; SUCRA, 98.2) and non-early TIPS (OR, 0.30; 95% CrI, 0.23-0.42; SUCRA, 1.8) were associated with a lower risk of rebleeding (moderate-to-high-quality evidence). Early TIPS was not associated with a reduced risk of hepatic encephalopathy, and non-early TIPS (OR, 2.78; 95% CrI, 1.89-4.23, SUCRA, 0) was associated with an increased incidence of hepatic encephalopathy (moderate-to-high-quality evidence). There was no difference in the incidence of new or worsening ascites (moderate-to-high-quality evidence) among the three interventions. CONCLUSION: Based on the moderate-to-high quality evidence presented in this study, early TIPS placement was associated with reduced all-cause mortality [with a median follow-up of 1.9 years (25th-75th percentile range 1.9-2.3 years)] and rebleeding compared to standard treatment and non-early TIPS. Although early TIPS and standard treatment had a comparable incidence of hepatic encephalopathy, early TIPS showed superiority over non-early TIPS in this aspect. Recent studies have also shown promising results in controlling TIPS-related hepatic encephalopathy. However, it is important to consider individual patient characteristics and weigh the potential benefits against the risks associated with early TIPS. Therefore, we recommend that clinicians carefully evaluate the patient's condition, considering factors such as severity of variceal bleeding, underlying liver disease, and overall clinical status, before making a treatment decision. Further well-designed RCTs comparing early TIPS with non-early TIPS are needed to validate these findings and provide more definitive guidance.

Biomedical document relation extraction with prompt learning and KNN.

Document-level relation extraction is designed to recognize connections between entities a cross sentences or between sentences. The current mainstream document relation extraction model is mainly based on the graph method or combined with the pre-trained language model, which leads to the relatively complex process of the whole workflow. In this work, we propose biomedical relation extraction based on prompt learning to avoid complex relation extraction processes and obtain decent performance. Particularity, we present a model that combines prompt learning with T5 for document relation extraction, by integrating a mask template mechanism into the model. In addition, this work also proposes a few-shot relation extraction method based on the K-nearest neighbor (KNN) algorithm with prompt learning. We select similar semantic labels through KNN, and subsequently conduct the relation extraction. The results acquired from two biomedical document benchmarks indicate that our model can improve the learning of document semantic information, achieving improvements in the relation F1 score of 3.1% on CDR.

Promotion of bio-oil production from the microwave pyrolysis of cow dung using pretreated red mud as a bifunctional additive: Parameter optimization, energy efficiency evaluation, and mechanism analysis.

To address the issues of high oxygen content and energy consumption in the microwave-assisted pyrolysis of biomass for biofuel production, this study used high-temperature pretreated red mud (RM) as an additive. The pretreated RM exhibited dual functionalities, namely microwave absorption and catalytic properties, during the microwave-assisted pyrolysis of cow dung (CD). This study also evaluated the optimization potential of energy recovery efficiency. The results showed that the addition of pretreated RM significantly increased the oil yield during the microwave-assisted pyrolysis of CD. The highest oil yield (59.63%) was obtained via the microwave-assisted pyrolysis of CD over catalysis with RM pretreated at 750 °C (RM750). Through the optimization of the RM750-to-CD mixing ratio, optimal oil quality and energy recovery efficiency were achieved. At a mixing ratio of 1:1, the pyrolysis oil featured the highest aromatic hydrocarbon content and lowest acid content. The high-temperature pretreatment of RM increased the Fe2O3 content, which enhanced the dielectric properties and magnetic loss ability of the reactants. This resulted in localized high temperatures and the formation of "hot spots," which can promote the deoxygenation and hydrogenation reactions of oil. Consequently, the lower heating rate of oil increased from 35.12 to 40.11 MJ kg-1. The released oxygen escaped in the form of CO. In addition, pyrolytic char was used as an in situ microwave absorbing material owing to its increased Fe2O3 content and graphitization degree, leading to an increase in energy recovery efficiency from 4.71% to 9.98%. This study provides valuable guidance for the efficient utilization of diversified solid wastes and demonstrates the potential application of microwave-assisted pyrolysis technology in the resource utilization of solid wastes.

Synergistic optimization of bio-oil quality and heavy metal solidification during microwave co-pyrolysis of cow dung and red mud.

To decrease the environmental risks caused by heavy metals (HMs) in red mud (RM) and improve the quality of pyrolysis oil from biomass, high-temperature pretreated RM and cow dung (CD) were microwave co-pyrolyzed. Then, the optimization potential of energy consumption was evaluated and the interaction mechanism between RM and CD was explored. The results showed that the increase in transition metal oxides and specific surface area improved the microwave-absorption and catalytic capacity of the pretreated RM. By optimizing the parameters, a pretreatment temperature of 650 °C resulted in a 21.65% reduction in acid content of bio-oil, higher HMs immobilization rates (>91%) and a 7.44% reduction in energy consumption. The synergistic optimization of bio-oil quality, HMs immobilization and energy consumption was achieved. After microwave co-pyrolysis with cow dung, the larger specific surface area (92.90 m2 g-1) and higher carbon crystallinity (ID/IG = 1.02) of pyrolysis residues enhanced the physical adsorption to HMs. The complexation of HMs with -OH could further enhance the solidification of HMs. This work will provide support to efficient resource utilization of solid waste, and demonstrate the great potential of microwave co-pyrolysis in HMs immobilization.

Preparation of high performance porous carbon by microwave synergistic nitrogen/phosphorus doping for efficient removal of Cu2+ via capacitive deionization.

Sargassum biochar has potential advantages as an electrode material due to its natural microscopic pore channels. However, conventional pyrolysis method is prone to thermal damage to the biochar, and incapable to form a complete pore structure resulting in poor biochar electrode performance. In this study, a strategy of microwave pyrolysis coupled with KOH activation was used to prepare nitrogen/phosphorus double-doped graded porous biochar (STC) using ammonium dihydrogen phosphate as dopant. The carbon material STC-1.24-800 prepared by the optimal parameters had a high specific surface area (SSA) of 1367.6 m2 g -1 and a total pore volume of 1.499 cm3 g-1. The precise inside-out heating characteristics of microwave facilitated the generation of suitable meso-micropore distribution ratios in carbon, and the graded porous structure provided abundant active sites for charge accumulation and ion diffusion. The doped nitrogen/phosphorus atoms responding to the microwave field, generated spin to promote microwave absorption, introducing surface structural defects to produce electron density differences. The change in the nature of the electron donor and its electron density enhanced the electrical conductivity and chemical stability of STC. Nitrogen/phosphorus polar surface functional groups improved hydrophilicity and wettability. STC-1.24-800 had a higher specific capacitance of 531 F g-1 and exhibits great cycle performance in capacitive deionization (CDI) applications (1.0 V, 50 mg L-1 Cu2+) as well as adsorption performance (56.16 mg g -1). The present work can provide a novel feasible idea for preparing diatomically doped graded porous biochar for CDI electrode application by microwave irradiation.

Synergistic optimization of syngas quality and heavy metal immobilization during continuous microwave pyrolysis of sludge: Competitive relationships, reaction mechanisms, and energy efficiency assessment.

To realize the efficient resource utilization of sewage sludge, this work explored the competitive relationship and reaction mechanisms between syngas quality optimization and heavy metals (HMs) immobilization. The results showed that continuous microwave pyrolysis (CMP) technology with an instantaneous temperature increase could shorten the pyrolysis time, and the biogas yield and syngas concentration reached 51.68 wt% and 83.6 vol%, respectively. Although a higher pyrolysis (750 °C) temperature could optimize the syngas quality, the HMs immobilization efficiency was reduced due to the deep pyrolysis of the biochar. The moderate pyrolysis temperature (650 °C) facilitated the rapid formation of biochar with abundant surface functional groups and pore structure, thus enhancing HMs immobilization. Furthermore, the HMs could also form more stable crystalline compounds with inorganic components (SiO2, Al2O3, inorganic sulfur). By optimizing the process parameters, the risk factor of HMs in the sludge decreased from 117.36 to 62.5 while obtaining high-quality syngas. The energy utilization efficiency of microwave pyrolysis also increased significantly from 11.20% to 82.01%. This work provided new insight into the efficient resource utilization and environmentally friendly treatment of sludge, and demonstrated that CMP technology has significant potential for future industrial applications as an alternative to traditional pyrolysis.

Is a single dose of commonly used antibiotics effective in preventing maternal infection after cesarean section? A network meta-analysis.

OBJECTIVE: This study aimed to compare the efficacy of different antibiotic classes and dosages in preventing maternal infection after cesarean delivery. METHODS: Databases were searched for randomized controlled trials (RCTs) published between January 1980 and January 2021 on antibiotic use for the prevention of maternal infection after cesarean delivery. The outcomes were endometritis, febrile morbidity, and wound infection, reported as odds ratios (OR) and surface under the cumulative ranking curve analysis scores. RESULTS: A total of 31 RCTs met the inclusion criteria. In the network meta-analysis (NMA) for endometritis, pooled network OR values indicated that the following interventions were superior to placebo: cephalosporins (OR: 0.18, 95% credibility interval [CrI]: 0.07-0.45), penicillins (OR: 0.19, 95% CrI: 0.07-0.50), penicillins (multiple doses) (OR: 0.20, 95% CrI: 0.05-0.65), combination therapies (OR: 0.22, 95% CrI: 0.09-0.54), and cephalosporins (multiple doses) (OR: 0.25, 95% CrI: 0.08-0.74). In the NMA for febrile morbidity, placebo was more effective than the other interventions. In the NMA for wound infection, pooled network OR values indicated that the following interventions were superior to placebo: penicillin (OR: 0.14, 95% CrI: 0.05-0.37), cephalosporins (OR: 0.19, 95% CrI: 0.08-0.41), cephalosporins (multiple doses) (OR: 0.20, 95% CrI: 0.06-0.58), combination therapies (OR: 0.29, 95% CrI: 0.13-0.57), macrolides (OR: 0.33, 95% CrI: 0.15-0.74), and penicillins (multiple doses) (OR: 0.40, 95% CrI: 0.17-0.91). CONCLUSIONS: Compared with placebo, a single dose of commonly used antibiotics may prevent maternal infection after cesarean delivery. However, the incidence of febrile morbidity was not reduced.

Prognostic Value of Combined Lactate Dehydrogenase, C-Reactive Protein, Cancer Antigen 153 and Cancer Antigen 125 in Metastatic Breast Cancer.

BACKGROUND: Breast cancer (BC), especially metastatic BC, is one of the most lethal diseases in women. CA 125 and CA 15-3 are commonly used indicators for diagnosis and prognosis of BC. Some serological indicators, such as lactate dehydrogenase (LDH) and C-reactive protein (CRP), can also be used to assess the prognosis and progression in BC. METHODS: Univariate Cox regression analysis and LASSO regression analysis were performed to identify prognostic factors and build prognostic models. We distributed the patients into 2 groups based on the median risk score, analyzed prognosis by Kaplan-Meier curve, and screened independent prognostic factors by multivariate Cox regression analysis. RESULT: We identified 4 indicators-LDH, CRP, CA 15-3, and CA 125-related to the prognosis in BC and established a prognostic model. The high LDH group showed worse overall survival (OS) than low LDH group (P = .017; hazard ratio (HR), 1.528; 95% confidence interval (CI), 1.055-2.215). The high CRP group showed worse OS than low CRP group (P = .004; HR, 1.666; 95% CI, 1.143-2.429). The high CA153 group showed worse OS than low CA 15-3 group (P=.011; HR, 1.563; 95% CI, 1.075-2.274). The high CA 125 group showed worse OS than low CA 125 group (P = .021; HR, 1.499; 95% CI, 1.031-2.181). The area under the curve for risk score was .824, Ki-67 was .628, age was .511, and grade was .545. Risk score was found to be an independent prognostic factor using multivariate Cox regression analysis. CONCLUSION: We successfully established an optimization model by combining 4 prognosis-related indicators to assess the prognosis in patients with metastatic BC.

Lead zinc slag-based geopolymer: Demonstration of heavy metal solidification mechanism from the new perspectives of electronegativity and ion potential.

Lead-zinc slag (LZS) is a solid waste product that is rich in silicon and aluminum and has enormous resource potential for functional environmental functional geopolymer materials. Unfortunately, the solidification mechanism of heavy metals in geopolymers is still unclear, which is detrimental to the heavy metal solidification of LZS. In this study, we comprehensively studied and demonstrated the solidification mechanisms of Pb and Zn in geopolymers, based on the preparation of high-performance LZS-based geopolymers (compressive strength up to 89.3 MPa, and Pb and Zn solidification efficiency up to 93.1% and 90.0%, respectively). Thereafter, the solidification mechanism differences between Pb and Zn were explained by electronegativity and ion potential. Due to the ionic potential order of Zn2+> Pb2+> Na+, both Zn2+ and Pb2+ could exchange with Na+ in the geopolymer. In addition, due to the electronegativity order of Pb > Si > Zn, Pb could attack the [SiO4] structure and form covalent bonds in the Pb-O structure, while Zn did not (shown by Raman spectroscopy). As a result, Pb simultaneously solidified in the geopolymer through covalent bonding and ion exchange, while Zn was solidified mainly by ion exchange. Thus, this work provides new perspectives and ideas for the solidification mechanisms of heavy metals in geopolymers.

Optimized strategies for (BiO)2CO3 and its application in the environment.

Photocatalysis is a new type of technology, which has been developed rapidly for solving environmental problems such as wastewater or air pollutants in recent years. Also, the effective performance and non-secondary pollution of photocatalytic technology attract much attention from researchers. As a "sillén" phase oxide, the (BiO)2CO3 (BOC) is a great potential photocatalyst attributing to composed of alternate Bi2O22+ and CO32- layers, which is a benefit for transportation of electrons. Besides, BOC has attracted much attention from researchers because of its excellent characters of non-toxic, environmentally friendly, and low-cost. However, BOC has a defect on wide band gap, which is limited for the usage of visible light, so a great number of published papers focus on the modifications of BOC to improve its photocatalytic efficiency. This article mainly summarizes the modifications of BOC and its application in the environment, guiding for designing BOC-based materials with high photocatalytic activity driven by light. Moreover, the research trend and prospect of BOC photocatalyst were briefly summarized, which could lay the foundation for forming a green and efficient BOC-based photocatalytic reaction system. Importantly, this review might provide a theoretical basis and guidance for further research in this field.

In-depth exploration of mechanism and energy balance characteristics of an advanced continuous microwave pyrolysis coupled with carbon dioxide reforming technology to generate high-quality syngas.

This study firstly coupled advanced continuous microwave pyrolysis with CO2 reforming technology to recover syngas from cow manure and CO2. The contribution of CO2 to syngas, pyrolysis mechanism, and energy balance characteristics were analyzed thoroughly. The results showed that continuous microwave pyrolysis coupled with CO2 reforming technology has superiorities over other pyrolysis methods in bio-gas generation. The bio-gas yield, syngas content, and heating value of syngas reached the maximum value of 71.02 wt%, 85.70 vol%, and 10.87 MJ/Nm3, respectively. CO2 strengthened pyrolysis and reacted with pyrolysis products to produce high-quality syngas and reduce H2S. Due to the limited substances that can react with CO2 and excessive energy consumption with increasing CO2 concentration, the utilization efficiencies of CO2 and energy decreased from 36.31% and 27.27% to 31.16% and 24.24%, respectively. This work provides basic theory and technical support for advanced technology to recover high-quality syngas from biomass with low energy consumption.

Depression Detection on Reddit With an Emotion-Based Attention Network: Algorithm Development and Validation.

BACKGROUND: As a common mental disease, depression seriously affects people's physical and mental health. According to the statistics of the World Health Organization, depression is one of the main reasons for suicide and self-harm events in the world. Therefore, strengthening depression detection can effectively reduce the occurrence of suicide or self-harm events so as to save more people and families. With the development of computer technology, some researchers are trying to apply natural language processing techniques to detect people who are depressed automatically. Many existing feature engineering methods for depression detection are based on emotional characteristics, but these methods do not consider high-level emotional semantic information. The current deep learning methods for depression detection cannot accurately extract effective emotional semantic information. OBJECTIVE: In this paper, we propose an emotion-based attention network, including a semantic understanding network and an emotion understanding network, which can capture the high-level emotional semantic information effectively to improve the depression detection task. METHODS: The semantic understanding network module is used to capture the contextual semantic information. The emotion understanding network module is used to capture the emotional semantic information. There are two units in the emotion understanding network module, including a positive emotion understanding unit and a negative emotion understanding unit, which are used to capture the positive emotional information and the negative emotional information, respectively. We further proposed a dynamic fusion strategy in the emotion understanding network module to fuse the positive emotional information and the negative emotional information. RESULTS: We evaluated our method on the Reddit data set. The experimental results showed that the proposed emotion-based attention network model achieved an accuracy, precision, recall, and F-measure of 91.30%, 91.91%, 96.15%, and 93.98%, respectively, which are comparable results compared with state-of-the-art methods. CONCLUSIONS: The experimental results showed that our model is competitive with the state-of-the-art models. The semantic understanding network module, the emotion understanding network module, and the dynamic fusion strategy are effective modules for depression detection. In addition, the experimental results verified that the emotional semantic information was effective in depression detection.

Co-microwave pyrolysis of electroplating sludge and municipal sewage sludge to synergistically improve the immobilization of high-concentration heavy metals and an analysis of the mechanism.

To improve the harmless treatment of high-concentration heavy metals (HMs) in electroplating sludge (ES), this study tried to combine the microwave pyrolysis technology and the addition of municipal sewage sludge (MS) to synergistically improve the immobilization of high-concentration HMs in ES. The results showed that the immobilization rate of HMs was less than 75% in ES pyrolysis biochar. Notably, the immobilization rate of HMs up to 98.00% in co-pyrolysis biochar. Finally, it was found by various characterizations that the organic carbon and inorganic minerals in MS played an important role in the immobilization of HMs through physical and chemical effects. HMs reacted with inorganic minerals to form HMs crystalline minerals (e.g., CuCl, Cu2NiSnS4, and NiSi2, ZnS) to realize the immobilization of HMs. The addition of organic carbon was conducive to the formation of biochar with higher carbon crystallinity (ID/IG = 0.96) and larger specific surface area (52.50 m2 g-1), thereby enhancing the physical adsorption to HMs. Meanwhile, the complexation reaction between HMs and functional groups such as -OH, Si-O-Si could also further improve the immobilization of HMs. Therefore, this study provided a technical and theoretical basis for the harmless disposal of waste containing multiple HMs with high-concentrations.

Effects of oxygen vacancy defect on microwave pyrolysis of biomass to produce high-quality syngas and bio-oil: Microwave absorption and in-situ catalytic.

This paper proposed to use ferric oxide (Fe2O3) and ferroferric oxide (Fe3O4) as catalysts with both microwave absorption and catalytic properties. Carbon dioxide (CO2) was introduced as the reaction atmosphere to further improve the quality of biofuel produced by microwave pyrolysis of food waste (FW). The results showed the bio-gas yield and the syngas concentration (H2 + CO) increased to 70.34 wt% and 61.50 mol%, respectively, using Fe3O4 as the catalyst. The content of aliphatic hydrocarbons in bio-oil produced with the catalyst Fe2O3 increased to 67.48% and the heating value reached 30.45 MJ/kg. Compared with Fe2O3 catalyst, Fe3O4 exhibited better microwave absorption properties and catalytic properties. Transmission electron microscopy (TEM) and Electron paramagnetic resonance (EPR) characterizations confirmed that the crystal surface of Fe3O4 formed more oxygen vacancy defects and unpaired electrons. Additionally, according to the X-ray photoelectron spectroscopy (XPS) analysis, the content of lattice oxygen in Fe3O4 was 14.11%, a value that was much lower than Fe2O3 (38.54%). The oxygen vacancy defects not only improved the efficient utilization of microwave energy but also provided the reactive sites for the reaction between the volatile organic compounds (VOCs) and CO2 to generate CO. This paper provides a new perspective for selecting catalysts that have both microwave absorption and catalytic properties during the microwave pyrolysis of biomass.

Bio-carrier-enhanced aerobic granulation: Effects on the extracellular polymeric substances production and microorganism community.

In this study, the strengthening effect of bio-carrier inoculation in the process of aerobic granulation and its influence on the microbial secretion of extracellular polymeric substances (EPS) has been systematically explored, to further understand and perfect the rapid granulation mechanism. Complete granulation was achieved within 15 days, and the granule morphology realized in a reactor inoculated with the bio-carrier (R1) was better than that in the control group (R2), in which complete granulation was not achieved during the entire operation period. However, AGS gradually disintegrated after the 20th day because of the strong shearing force, the crushed AGS enhanced granulation, however did not ensure stability. The average EPS content in R1 20 mg﹒gVSS-1 higher than that in R2, and the protein (PN) content changes around 41.23-82.56 mg﹒gVSS-1 during the granulation process. This indicates that the bio-carrier stimulates microorganisms to secrete more EPS, and PN may have a greater effect on the aggregation of microorganisms. The results showed that the addition of the bio-carrier shortened the AGS granulation time, and increased the EPS content, and the broken AGS played an auxiliary role as the nucleus for floc attachment.

Effects of Process Parameters on Sulfur Migration and H2S Generation during Supercritical Water Gasification of Sludge.

The generation of sulfur-containing pollution products affects the quality of biofuels obtained from the supercritical water gasification (SCWG) of sludge. This study investigates the effects of the gasification temperature, moisture content, and reaction atmosphere on the evolution of sulfur-containing compounds. The results showed that temperature was the key parameter causing the migration of sulfur from sludge to biogas and liquid products. The sludge decomposition reaction was dominated by ionic reactions at 360 °C, while the decomposition of organic matter was converted to free radical reactions as the temperature increased from 380 °C to 440 °C. The mercaptan and thioether contents of the bio-oil decreased to 0.3% at 440 °C. Correspondingly, the concentration of H2S increased from 6.7 ppm to 38.0 ppm. The decomposition of organic sulfur with an unstable structure (S-H bond and S-C bond) was the main cause of the increase in the content of H2S. Additionally, the solubility and oxidation properties of supercritical water were extremely strong. Some sulfur-containing organic compounds were converted into SO42- via hydrolysis and oxidation reactions, forming sulfate crystals with heavy metals in the bio-char, which aided in achieving the synergistic immobilization of sulfur and heavy metals.