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Ultrafine particles (UFPs; PM0.1) possess intensified health risk due to their smaller size and unique spatial variability. One of major emission sources for UFPs is vehicle exhaust, which varies based on the traffic composition in each type of roadside sector. The current challenge of epidemiological UFPs study is limited characterization ability due to expensive instruments. This study assessed the UFPs particle number concentrations (UFPs PNC) exposure dose for typical healthy adults and children at three different roadside sectors, including industrial roadside (IN), residential roadside (RS), and urban background (UB). Furthermore, this study also developed and utilized machine learning (ML) algorithms that could accurately characterize the UFPs exposure dose and explain the covariates effects on the model outputs, representing the intra-urban variability of UFPs between sectors. It was found that the average inhaled UFPs dose for healthy adults and children during off-peak season (warm period) were 1.71 ± 0.19 × 1010; 1.28 ± 0.22 × 1010; 1.09 ± 0.18 × 1010 #/hour and 1.33 ± 0.15 × 1010; 0.99 ± 0.17 × 1010; 0.86 ± 0.14 × 1010 #/hour at IN, RS, UB. Inhaled UFPs were mainly deposited in tracheobronchial (TB) respiratory fraction for adults (67.7%) and in alveoli (ALV) fraction for children (67.5%). Among three ML algorithms implemented in this study, XGBoost possessed the highest UFPs PNC exposure dose estimation performances with R2 = 0.965; 0.959; 0.929 & RMSE = 0.79 × 108; 0.54 × 108; 0.15 × 105 #/hour at IN, RS, and UB which then followed by multiple linear regression (MLR), and random forest (RF). Furthermore, SHAP analysis from the XGBoost model has successfully pointed out the spatial variability of each roadside sector by quantifying the approximated contributions of covariates to the model's output. Findings in this study highlighted the potential use of ML models as an alternative for preliminary particle exposure source apportionment.
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Anaerobic membrane bioreactor (AnMBR) offer promise in municipal wastewater treatment, with potential benefits including high-quality effluent, energy recovery, sludge reduction, and mitigating greenhouse gas emissions. However, AnMBR face hurdles like membrane fouling, low energy recovery, etc. In light of net-zero carbon target and circular economy strategy, this work sought to evaluate novel AnMBR configurations, focusing on performance, fouling mitigation, net-energy generation, and nutrients-enhancing integrated configurations, such as forward osmosis (FO), membrane distillation (MD), bioelectrochemical systems (BES), membrane photobioreactor (MPBR), and partial nitrification-anammox (PN/A). In addition, we highlight the essential role of AnMBR in advancing the circular economy and propose ideas for the water-energy-climate nexus. While AnMBR has made significant progress, challenges, such as fouling and cost-effectiveness persist. Overall, the use of novel configurations and energy recovery strategies can further improve the sustainability and efficiency of AnMBR systems, making them a promising technology for future sustainable municipal wastewater treatment.
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Reatores Biológicos , Eliminação de Resíduos Líquidos , Águas Residuárias , Eliminação de Resíduos Líquidos/métodos , Anaerobiose , Membranas ArtificiaisRESUMO
Recently, many efforts have been made to address the rapid spread of newly identified COVID-19 virus variants. Wastewater-based epidemiology (WBE) is considered a potential early warning tool for identifying the rapid spread of this virus. This study investigated the occurrence of SARS-CoV-2 in eight wastewater treatment plants (WWTPs) and their sewerage systems which serve most of the population in Taoyuan City, Taiwan. Across the entire study period, the wastewater viral concentrations were correlated with the number of COVID-19 cases in each WWTP (Spearman's r = 0.23-0.76). In addition, it is confirmed that several treatment technologies could effectively eliminate the virus RNA from WWTP influent (> 90%). On the other hand, further results revealed that an inverse distance weighted (IDW) interpolation and hotspot model combined with the geographic information system (GIS) method could be applied to analyze the spatiotemporal variations of SARS-CoV-2 in wastewater from the sewer system. In addition, socio-economic factors, namely, population density, land use, and income tax were successfully identified as the potential drivers which substantially affected the onset of the COVID-19 outbreak in Taiwan. Finally, the data obtained from this study can provide a powerful tool in public health decision-making not only in response to the current epidemic situation but also to other epidemic issues in the future.
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COVID-19 , RNA Viral , Humanos , Águas Residuárias , SARS-CoV-2 , Vigilância Epidemiológica Baseada em Águas Residuárias , COVID-19/epidemiologiaRESUMO
Since the outbreak of COVID-19 few years ago, the increasing of the number of medical waste has become a huge issue because of their harmful impact to environment. A major concern associated to the limitation of technologies for dealing with medical waste, especially conventional technologies, are overcapacities since pandemic occurs. Moreover, the outbreak of new viruses from post COVID-19 should become a serious attention to be prevented not only environmental issues but also the spreading of viruses to new pandemic near the future. The high possibility of an outbreak of new viruses and mutation near the future should be prevented based on the experience associated with the SARS-CoV-2 virus in the last 3 yr. This review presented information and strategies for handling medical waste during the outbreak of COVID-19 and post-COVID-19, and also information on the current issues related to technologies, such as incineration, pyrolysis/gasification, autoclaves and microwave treatment for the dealing with high numbers of medical waste in COVID-19 to prevent the transmission of SARS-CoV-2 virus, their advantages and disadvantages. Plasma technology can be considered to be implemented as an alternative technology to deal with medical waste since incinerator is usually over capacities during the pandemic situation. Proper treatment of specific medical waste in pandemics, namely face masks, vaccine vials, syringes, and dead bodies, are necessary because those medical wastes are mediums for transmission of the SARS-CoV-2 virus. Furthermore, emission controls from incinerator and plasma are necessary to be implemented to reduce the high concentration of CO2, NOx, and VOCs during the treatment. Finally, future strategies of medical waste treatment in the perspective of potential outbreak pandemic from new mutation viruses are discussed in this review paper.Implications: Journal of the air and waste management association may consider our review paper to be published. In this review, we give important information related to the technologies, managements and strategies for handling the medical waste and control the transmission of SARS-CoV-2 virus, starting from proper technology to control the high number of medical waste, their pollutants and many strategies for controlling the spreading of SARS-CoV-2 virus. Moreover, this review also describes some strategies associated with control the transmission not only the SARS-CoV-2 virus but also the outbreak of new viruses near the future.
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COVID-19 , Resíduos de Serviços de Saúde , Humanos , COVID-19/epidemiologia , COVID-19/prevenção & controle , SARS-CoV-2 , Pandemias/prevenção & controle , TecnologiaRESUMO
Because of the small size effect leading to the high bandgap of TiO2 P25, the photocatalytic membrane using this photocatalyst has low antifouling efficiency. This study prepared CuO@TiO2 composite photocatalyst with a lower bandgap than TiO2 P25 and used it as antifouling coatings on the PES membrane with PAA intermediate adhesive layer. PAA was grafted onto the surface of the PES membranes through free radicals generated by the cold plasma treatment of the PES membrane. The composite photocatalysts were characterized by FTIR, SEM-EDS, TEM-EDS, XRD, BET, UV-Vis DRS, XPS, and ESR methods demonstrating high surface area (51.0 m2/g), decreased bandgap, and the formation of active free radicals under UV light irradiation. Under photocatalysis and hydrogen peroxide activation, the degradation of AB260 (acid blue 260) catalyzed by 10%CuO@TiO2 reached about 92% after 60 min. Besides, the photocatalytic and antifouling activities of CuO@TiO2/PAA/PES membranes are high and stable over five continuous cycles. The water flux of the modified membrane was not significantly influenced and only decreased about 10% compared to the pristine membrane. In addition, the flux recovery ratios (FRR) of fouled membranes treated by photocatalysis were almost 100%.
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Incrustação Biológica , Peróxido de Hidrogênio , Incrustação Biológica/prevenção & controle , Raios UltravioletaRESUMO
Besides photocatalysts, novel catalytic wet-air oxidation (CWAO) catalysts capable of operating under mild conditions are a potential candidate to fabricate antifouling filtration membranes. This study optimized the CWAO catalyst consisting of three metal oxide components (ZnO, CuO, and Fe3O4) and used it to fabricate composite membranes with PES (polyethersulfone). The catalyst was characterized by methods such as FTIR, BET, XRD, UV-Vis DRS, XPS, ESR. The activity of the catalyst and the composite membranes was tested by the Acid Yellow 42 (AY42) degradation experiments in both cases with and without hydrogen peroxide at room conditions with air aeration. The pure water fluxes of composite membranes were also investigated based on a vacuum filtration system. The major degradation pathways of AY42 by the catalyst were proposed from the DFT (Density Functional Theory) and NBO (Natural Bond Orbital) calculations. The results showed that the optimal catalyst has molar ratios of Zn, Cu, and Fe metal ions of 0.05, 0.588, and 0.362, respectively, with AY42 decomposition efficiency of 88% in 3 h. The main factors affecting the catalytic efficiency of the CWAO catalyst determined from the trapping experiment were e- and O2. The results from different materials characterization methods have demonstrated the successful synthesis of the catalyst with a high surface area (103.5 m2/g) and small pore diameters (â¼10 nm). The AY42 degradation of composite membranes was stable over five repeated cycles with over 70% efficiency. The pure water fluxes of composite membranes have also been significantly improved and are proportional to catalyst contents.
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Incrustação Biológica , Incrustação Biológica/prevenção & controle , Oxirredução , Água , Zinco , CatáliseRESUMO
Nitric oxide (NO) is an air pollutant impacting the environment, human health, and other biotas. Among the technologies to treat NO pollution, photocatalytic oxidation under visible light is considered an effective means. This study describes photocatalytic oxidation to degrade NO under visible light with the support of a photocatalyst. MgO@g-C3N4 heterojunction photocatalysts were synthesized by one-step pyrolysis of MgO and urea at 550 °C for two hours. The photocatalytic NO removal efficiency of the MgO@g-C3N4 heterojunctions was significantly improved and reached a maximum value of 75.4% under visible light irradiation. Differential reflectance spectroscopy (DRS) was used to determine the optical properties and bandgap energies of the material. The bandgap of the material decreases with increasing amounts of MgO. The photoluminescence spectra indicate that the recombination of electron-hole pairs is hindered by doping MgO onto g-C3N4. Also, NO conversion, DeNOx index, apparent quantum efficiency, trapping tests, and electron spin resonance measurements were carried out to understand the photocatalytic mechanism of the materials. The high reusability of the MgO@g-C3N4 heterojunction was shown by a five-cycle recycling test. This study provides a simple way to synthesize photocatalytic heterojunction materials with high reusability and the potential of heterojunction photocatalysts in the field of environmental remediation.
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Vitrification technology provides a solution for the issue of safe disposal of hazardous waste containing harmful chemical composition and organic pollutants. This review discusses application of vitrification technologies to treat hazardous waste including, asbestos, fly ash, electronic sludge, nuclear waste, medical waste and radioactive waste. Vitrification processes via Joule heating, microwave heating, plasma technology, electric arc furnaces and incinerators are compared herein. Stabilization of hazardous waste can be achieved by vitrification with the addition of flux agents/additives. Furthermore, crystalline structures, containing the silicate-glass network, are formed as a result of vitrification, depending on the type of flux agents/additives used. In addition, the concentration of heavy metals can be degraded in the final residue and leaching resistance can be achieved. Moreover, energy consumption, pollution prevention and the foreground of the practical application of vitrification are discussed. Vitrification with the advantage of encapsulating pollutants from the hazardous waste is proven to be a promising approach for hazardous waste treatment.
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Poluentes Ambientais , Metais Pesados , Eliminação de Resíduos , Cinza de Carvão/química , Resíduos Perigosos , Incineração , Metais Pesados/química , Resíduos Sólidos , Tecnologia , VitrificaçãoRESUMO
Novel phycosphere associated bacteria processes are being regarded as a potential and cost-effective strategy for controlling anthropogenic contaminants in wastewater treatment. However, the underlying concern with the process is its vulnerability to improper organic or nutrient intake. This study established a synergistic interaction between microalgae and activated sludge in a three-photobioreactor system (without external aeration) to understand how pollutants could be mitigated whilst simultaneously yielding biomass under different C/N ratios of 1:1, 5:1 and 10:1. The result showed that the superior biomass productivity was facilitated at a C/N ratio of 5:1 (106 mg L-1 d-1), and the high degradation rate constants (kCOD = 0.25 d-1, kTN = 0.29 d-1, kTP = 0.35 d-1) was approximated using a first-order kinetic model. The removal of pollutants was remarkably high, exceeding 90% (COD), 93% (TN), and 96% (TP). Nevertheless, the C/N ratio of 1:1 resulted in a threefold drop in biomass-specific growth rate (µ = 0.07 d-1). Microalgal assimilation, followed by bacterial denitrification, is the major pathway of removing total nitrogen when the C/N ratio exceeds 5:1. Activated sludge plays an important role in improving microalgae tolerance to high concentration of ammonia nitrogen and boosting nitrification (light phase) and denitrification (dark phase). The use of phycosphere associated bacteria could be a promising strategy for controlling nutrients pollution and other environmental considerations in wastewater.
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Poluentes Ambientais , Microalgas , Bactérias/metabolismo , Biomassa , Técnicas de Cocultura , Poluentes Ambientais/metabolismo , Microalgas/metabolismo , Nitrogênio/análise , Esgotos/microbiologia , Águas ResiduáriasRESUMO
Conventional biological treatment has been reported to be ineffective for pollutant removal in tannery wastewater due to high salinity. To overcome it, this work used salt-tolerant bacteria (STB) isolated from a membrane bioreactor to evaluate the organic and nutrient removal through a series of batch experiments. Compared with the control, the STB reactor enhanced the reduction of persistent organics by 11% based on the double exponential decay model. Besides, the removal of NH4+-N is 26% higher, satisfying the first-order decay model. The nitrification was inhibited entirely in control during 48 h, whilst the assimilation process involved 55% of total nitrogen removal. In the STB reactor, nitrification occurred after 12 h, resulting in significantly increased NO2--N and NO3--N concentrations according to the logistic function. Although nitrification was successfully activated, C/N ratios and free ammonia were identified as limiting factors for STB activity, requiring mitigation strategies in further studies.
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Nitrosomonas , Purificação da Água , Amônia , Reatores Biológicos , Cinética , Nitrificação , Nitritos , Nitrobacter , Nitrogênio , Dinâmica não Linear , Águas ResiduáriasRESUMO
Ocean life forms are fundamentally well adapted to natural environmental variations, and they can even tolerate extreme conditions for a short time. However, several anthropogenic stressors are causing such drastic changes in the ocean ecosystem. First, the review attempts to outline the impact of climatic and non-climatic stressors on ocean life, and it also outlines the synergistic impact of both stressors. Then the impact on human health caused by the damage of the marine ecosystem has been discussed. Furthermore, the type of prior studies and current mitigation adaptation programs have been presented. Finally, some perspectives about future research and mitigation adaptation are offered.
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Adaptação Fisiológica , Ecossistema , Aclimatação , Mudança Climática , Humanos , Oceanos e MaresRESUMO
The information of plasma technologies applications for environmental clean-up on treating and degrading metals, metalloids, dyes, biomass, antibiotics, pesticides, volatile organic compounds (VOCs), bacteria, virus and fungi is compiled and organized in the review article. Different reactor configurations of plasma technology have been applied for reactive species generation, responsible for the pollutants removal, hydrogen and methane production and microorganism inactivation. Therefore, in this review article, the reactive species from discharge plasma are presented here to provide the insight into the environmental applications. The combinations of plasma technology with flux agent and photocatalytic are also given in this review paper associated with the setup of the plasma system on the removal process of metals, VOCs, and microorganisms. Furthermore, the potential of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) inactivation via plasma technology is also described in this review paper. Detailed information of plasma parameter configuration is given to support the influence of the critical process in the plasma system to deal with contaminants.
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COVID-19 , Compostos Orgânicos Voláteis , Bactérias/genética , Humanos , Metais , SARS-CoV-2RESUMO
OBJECTIVE: The aim of the present study was to analyze the clinical features of Dubin-Johnson syndrome (DJS) related to ABCC2 gene mutations in children and to review the relevant literature to improve understanding of this type of genetic disease and reduce misdiagnosis. METHODS: Three children with clinically suspected DJS who were treated at Beijing Children's Hospital of Capital Medical University between 2017 and 2020 were enrolled in the study. The target genes were captured and sequenced using GenCap target gene capture technology and a new generation of high-throughput sequencing technology (Beijing Mykino Company). The clinical and genetic characteristics were analyzed and summarized. RESULTS: Two of the cases were female and one was male. All three cases were in early infancy and in good general health. Case 1 was complicated with unilateral hypertrophy, Case 2 was complicated with pneumonia, anemia, myocardial injury, and bilateral inguinal hernia, and Case 3 was complicated with patent foramen ovale and a ventricular septal defect. In all three cases, total bilirubin was elevated, with the main increase being in direct bilirubin (DBIL) and varying degrees of elevated alanine aminotransferase (ALT), γ-glutamyl transferase (GGT), and total bile (TBA). Genetic testing indicated that there were seven gene mutations in ABCC2, two mutation sites of which had not been reported previously. CONCLUSION: The clinical manifestations of DJS are non-specific and are mainly characterized by elevated DBIL. Some children might have different degrees of hepatic function abnormality and cholestasis. Due to the lack of serological markers, the diagnosis of DJS is difficult, but genetic testing, along with the formation of pedigree analysis and verification, could be used for accurate diagnosis. Novel mutations might enrich the spectrum of ABCC2 gene mutation.
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This review details the current information on e-waste treatment using plasma technology. The current status of e-waste treatment via plasma technology from the scientific literature is presented herein, namely, moist paste battery, galvanic sludge, resin, printed circuit board, and semiconductor industries. The concept of plasma technology, classification of e-waste, contaminants of e-waste (metals, metalloids, and VOCs), and vitrification of the final product are presented herein. This review paper focuses on fusing flux agents to vitrify e-waste. Furthermore, this paper covers laboratory-scale investigations, plasma technology benefits, and reuse of material from plasma post-treatment. The use of plasma technology combined with flux agents could be recommended to eliminate contaminants from e-waste. Materials from plasma post-treatment may also be applied in environmental reuse applications.
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Resíduo Eletrônico , Resíduo Eletrônico/análise , Metais , Plasma , Reciclagem , Esgotos , TecnologiaRESUMO
BACKGROUND: This study aims to investigate the impacts on the proliferation, inhibition, apoptosis, and cell cycle of hepatic stellate cells (HSC-T6) in rats by using traditional Chinese medicine (TCM) in serum. METHODS: Twenty-seven rats were randomly divided into nine groups on average: a blank control (BC) group (fed by distilled water), a positive control group (colchicine solution, 0.05 mg/mL), and seven TCM groups [with the aim of clearing the liver of choleresis with 0.24 g/mL (weight of TCM herbs per milliliter), 0.73 g/mL, 1.22 g/mL, 2.45 g/mL, 7.34 g/mL, 12.24 g/mL, 24.48 g/mL]. Each rat received gavage with a dose of 1 mL/100 g twice a day for 7 days to prepare the drug serum. The HSC-T6 were divided into a TCM serum group, a positive control group, and a BC group. The TCM group and the positive control group were given corresponding drug serum for incubation, while the BC group received the medium without drug serum. RESULTS: The cellular proliferation inhibition rate in the positive control and TCM groups was significantly higher (P<0.01) than that in the BC group. The number of cells in the positive, 0.24 g/mL TCM, 1.22 g/mL TCM, and 7.34 g/mL TCM groups increased significantly (P<0.05) in the G0/G1 phase compared with the BC group. The number of cells in the positive group and all the TCM groups clearly increased in phase S by 0.73 g/mL in the TCM group, 2.45 g/mL in the TCM group, 12.24 g/mL in the TCM group, and 24.48 g/mL in the TCM group compared with the BC group, and the difference was statistically significant (P<0.05). The number of cells in the G2/M phase of the positive control group and all the TCM groups decreased significantly. Compared with the BC group, the positive group, 0.24 g/mL TCM group, 0.73 g/mL TCM group, 1.22 g/mL TCM group, 2.45 g/mL TCM group have statistically difference (P<0.05). CONCLUSIONS: A Qinggan Lidan prescription may exert anti-hepatic fibrosis effects by blocking HSC-T6 in the G0/G1 and S phases and by suppressing the proliferation of HSC-T6.
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Apoptose , Células Estreladas do Fígado , Animais , Proliferação de Células , Cirrose Hepática , RatosRESUMO
OBJECTIVE: To investigate the clinical effect of acupuncture combined with western medicine in the treatment of children with abdominal Henoch-Schonlein purpura with spleen-stomach damp-heat syndrome. METHODS: A total of 60 children with abdominal Henoch-Schonlein purpura with spleen-stomach damp-heat syndrome were randomly divided into treatment group and control group, with 30 patients in each group. The patients in the control group were given Hydroprednisone 2 mgâ¢kg-1â¢d-1, and in addition to the treatment in the control group, those in the treatment group were given acupuncture at Tianshu (ST25), Neiguan (PC6), Zusanli (ST36), Zhongwan (CV12), Qihai (CV6), and Sanyinjiao (SP6) once a day, with a needle retaining time of 15 minutes. Both groups were treated for 7 days. The scores of abdominal pain, hematochezia, hematemesis, vomiting, poor appetite, abdominal distension, purpura, occult blood in stool, and abdominal ultrasound were determined before and after treatment, and the time to the disappearance of abdominal pain was observed. Clinical outcome was evaluated. RESULTS: The treatment group had a significantly higher effective rate than the control group ï¼»96.7% (29/30) vs 80.0% (24/30), P<0.05ï¼½. Both groups had significant reductions in the scores of abdominal pain, hematochezia, hematemesis, poor appetite, abdominal distension, purpura, occult blood and abdominal ultrasound and the total score after treatment (P<0.05), and compared with the control group after treatment, the treatment group had significantly lower scores of abdominal pain, poor appetite, abdominal distension, and abdominal ultrasound and total score (P<0.05). The treatment group had a significantly shorter time to disappea-rance of abdominal pain than the control group (P<0.05). CONCLUSION: Acupuncture combined with western medicine has a better clinical effect than western medicine alone in the treatment of abdominal Henoch-Schonlein purpura with spleen-stomach damp-heat syndrome and can significantly improve clinical symptoms and signs and shorten the time to disappearance of abdominal pain.
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Terapia por Acupuntura , Vasculite por IgA , Criança , Temperatura Alta , Humanos , Vasculite por IgA/terapia , Estômago , Resultado do TratamentoRESUMO
The pursuit of robust photocatalysts that can completely degrade organic contaminants with high performance as well as high energy efficiency, simplicity in preparation, and low cost is an appealing topic that potentially promotes photocatalysts for being used widely. Herein, we introduce a new and efficient SnO2/Bi2S3/BiOCl-Bi24O31Cl10 (SnO2/Bi2S3-Bi25) composite photocatalyst by taking advantage of the robust, simple, and potentially scalable one-pot synthesis, including the hydrothermal process followed by thermal decomposition. Interestingly, we observed the formation of BiOCl-Bi24O31Cl10 (abbreviated as Bi25) heterojunctions derived from reactions between Bi2S3 and SnCl4·5H2O precursor solutions under the hydrothermal condition and thermal decomposition of BiOCl. This Bi25 heterojunction acts as an interface to reduce the recombination of photogenerated electron-hole (e--h+) pairs as well as to massively enhance the visible light harvesting, thereby significantly enhancing the photocatalytic degradation performance of the as-prepared composite photocatalyst. In detail, the photocatalytic degradation of Rhodamine B (RhB) activated by visible light using 15% SnO2/Bi2S3-Bi25 shows the efficiency of 80.8%, which is superior compared to that of pure Bi2S3 (29.4%) and SnO2 (0.1%). The SnO2/Bi2S3-Bi25 composite photocatalyst also presents an excellent photostability and easy recovery from dye for recycling. The trapping test revealed that the photogenerated holes play a crucial factor during the photocatalytic process, whereas superoxide radicals are also formed but not involved in the photocatalytic process. Successful fabrication of SnO2/Bi2S3-Bi25 composite photocatalysts via a straightforward method with drastically enhanced photocatalytic performance under visible light activation would be useful for practical applications.
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Flux agents play an important role in the pyrolysis treatment of vitrifying hazardous wastes. Among these is plasma jets, a cost-less flux agent derived from shell powder which can be used to create vitrification. It is a promising option to be applied in the vitrification of elements and to remove the VOCs of hazardous waste, namely, resin from PCB scrap in an atmospheric-pressure microwave plasma reactor. In this study, a laboratory scale experiment was conducted. The experiment was performed in the pyrolysis of resin which was added with flux agents. The economic evaluation of the flux agents, and the circular economy concept of the final residue derived from the plasma pyrolysis was then analyzed post treatment. To test the strength and weakness of the experiment, the SWOT analysis was performed. The outcome helped in the understanding of the cost-less flux agent used in the pyrolysis treatment of hazardous waste. Results showed that fusing shell powder in resin was better for improving the removal efficiency of VOCs, such as benzene and toluene as well as toxic metals than compared to other flux agents such as limestone and quartz sand. Moreover, the final residue of resin was found to fulfil the concept of circular economy where it could be reused as an absorbent of methyl blue, thereby indicating good absorption performance, from 1 ppm-100 ppm. The twelve strategies that were derived from the SWOT analysis could be used as information outlining the current internal and external condition for the development and application of shell powder. Shell powder, as a cost-less flux agent, has the potential for enhancing waste management and circular economy when used in the pyrolysis treatment of future hazardous wastes.
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Vitrificação , Gerenciamento de Resíduos , Resíduos Perigosos , Pirólise , ToluenoRESUMO
Resin has been widely used for thermosetting printed circuit boards (PCBs) and is a key part of e-waste from scrap PCBs. It requires appropriate treatment because of its harmful elements (metals and metalloids) and organic compounds that are toxic to human health and the environment. The purpose of this study is to eliminate volatile organic compounds (VOCs) and elements (metals and metalloids) in resin via the use of powdered snail shell (Babylonia formosae) in an atmospheric-pressure microwave plasma reactor. Shell powder plays a significant role in the destruction of benzene and toluene with removal efficiency 98.8 % and 100 %, respectively, compared to quartz sand with removal efficiency 44.9 %. A high ratio of shell powder increases the inertization of metals and metalloids by more than 96 %. The crystalline structures of these materials are dominated by calcite formations (CaCO3), confirming the elimination of metals and metalloids. Raman spectroscopy shows that the shell powder vitrifies these elements. The use of shell powder is thus recommended to degrade hazardous substances and to vitrify elements from resin in plasma pyrolysis.
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Removal of nitrogen oxide pollution has attracted much attention, and photocatalysis is considered as an effective method to treat polluted gas. Currently, modified semiconductors with approximate band gap are used as visible-light-driven photocatalysts. Herein, this is the first investigation of photocatalytic removal of NO under visible light over Cr-doped ZnO nanoparticles (Cr-ZnO NPs). Furthermore, the trapping species experiment and electron spin resonance measurement were conducted to identify the primary reactive factor of the photocatalytic reaction. In this study, Cr-ZnO NPs were synthesized by the sol-gel method with a narrow band gap, enhanced NO photocatalytic degradation performance, low NO2 conversion yield, and high stability under visible light.