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OBJECTIVE: To evaluate the efficacy and safety of hydroxychloroquine sulfate (HCQ) in the treatment of low risk phospholipase A2 receptor (PLA2R)-associated membranous nephropathy (MN). METHODS: A total of 110 patients with low risk PLA2R-associated MN were included in the study. Patients who met the inclusion and exclusion criteria were assigned randomly to two groups: the HCQ treatment group and the control group. The control group received standard supportive treatment according to the guidelines, while the HCQ treatment group received HCQ in addition to the supportive treatment. The clinical data of the patients were analyzed, with comparisons made at baseline and during the six-month follow-up period. Any adverse reactions were recorded. RESULTS: The baseline data were comparable between the HCQ treatment group and the control group. At the end of the six-month follow-up period, the reductions in urine protein excretion and serum PLA2R antibody titer were more notable in the HCQ treatment group than those in the control group, with these differences being statistically significant (p < 0.05). Compared to the control group, the HCQ treatment group had fewer patients who were converted from low risk to moderate-to-high risk (p = 0.084). There were also no severe adverse reactions in the HCQ treatment group. CONCLUSION: In patients with low risk PLA2R-associated MN, adequate supportive therapy combined with HCQ is superior to supportive therapy alone in controlling proteinuria and reducing serum PLA2R antibody titers. Additionally, our study demonstrated that the incidence of adverse reactions did not increase. TRIAL REGISTRATION: This study was registered in the Chinese Clinical Trial Registry (Registration No.: ChiCTR1900021757, Date of registration: 2019-03-08).
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Glomerulonefrite Membranosa , Hidroxicloroquina , Receptores da Fosfolipase A2 , Humanos , Hidroxicloroquina/uso terapêutico , Glomerulonefrite Membranosa/tratamento farmacológico , Receptores da Fosfolipase A2/imunologia , Feminino , Masculino , Pessoa de Meia-Idade , Adulto , Resultado do Tratamento , Autoanticorpos/sangue , ProteinúriaRESUMO
Ethylene (C2 H4 ) is a major chemical for the modern society, and new technologies for its production are of strategic importance globally. Recently, oxidative dehydrogenation of ethane (C2 H6 ) using CO2 as a milder oxidant (CO2 -ODH) is proposed as a potential way for C2 H4 production, and development of effective catalysts for the process is drawing wide attention. Here, we report on a facilely prepared ZSM-5 supported Zn system, i. e., ZnZSM-5, which showed great promise in CO2 -ODH. Samples with different Zn loadings were prepared and evaluated, and the highest performance was obtained over 0.05ZnZSM-5 at 700 °C and a CO2 :C2 H6 feeding ratio of 5 : 1. During 340â min TOS, the C2 H6 conversion decreased moderately from 36.2 % to 23.1 %, and the C2 H4 yield stabilized at 21.9 % to 27.9 %. Based on systematic characterization and investigation of reaction conditions, the structure-performance relationship and reaction network were discussed in detail.
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The indirect electro-epoxidation of ethylene (C2 H4 ), produced from CO2 electroreduction (CO2 R), holds immense promise for CO2 upcycling to valuable ethylene oxide (EO). However, this process currently has a mediocre Faradaic efficiency (FE) due to sluggish formation and rapid dissociation of active species, as well as reductive deactivation of Cu-based electrocatalysts during the conversion of C2 H4 to EO and CO2 to C2 H4 , respectively. Herein, we report a bromine-induced dual-enhancement strategy designed to concurrently promote both C2 H4 -to-EO and CO2 -to-C2 H4 conversions, thereby improving EO generation, using single-atom Pt on N-doped CNTs (Pt1 /NCNT) and Br- -bearing porous Cu2 O as anode and cathode electrocatalysts, respectively. Physicochemical characterizations including synchrotron X-ray absorption, operando infrared spectroscopy, and quasi in situ Raman spectroscopy/electron paramagnetic resonance with theoretical calculations reveal that the favorable Br2 /HBrO generation over Pt1 /NCNT with optimal intermediate binding facilitates C2 H4 -to-EO conversion with a high FE of 92.2 %, and concomitantly, the Br- with strong nucleophilicity protects active Cu+ species in Cu2 O effectively for improved CO2 -to-C2 H4 conversion with a FE of 66.9 % at 800â mA cm-2 , superior to those in the traditional chloride-mediated case. Consequently, a single-pass FE as high as 41.1 % for CO2 -to-EO conversion can be achieved in a tandem system.
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Gamma-ray (γ-ray) irradiation was introduced into zeolite synthesis. The crystallization process of zeolite NaA, NaY, Silicalite-1, and ZSM-5 were greatly accelerated. The crystallization time of NaA zeolite was significantly decreased to 18â h under γ-ray irradiation at 20 °C, while more than 102â h was needed for the conventional process. Unexpectedly, more mesopores were created during this process, and thus the adsorption capacity of CO2 increased by 6-fold compared to the NaA prepared without γ-ray irradiation. Solid experimental evidence and density function theory (DFT) calculations demonstrated that hydroxyl free radicals (OH*) generated by γ-rays accelerated the crystallization of zeolite NaA. Besides NaA, mesoporous ZSM-5 with MFI topology was also successfully synthesized under γ-ray irradiation, which possessed excellent catalytic performance for methanol conversion, suggesting the universality of this new synthetic strategy for various zeolites.
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CuO/MCM-41 catalyst was synthesized by a simple method with the modification of ethylene glycol (EG) and characterized by powder X-ray diffraction (XRD), nitrogen sorption, scanning electron microscopy (SEM) and transmission electron microscope (SEM). Its catalytic performance in the hydrogenation of CO2 to methanol was also investigated. The results indicated that the as-synthesized CuO/MCM-41-EG catalyst took the properties of high dispersion, small particle size and high surface area, and then showed catalytic performance for the CO2 hydrogenation to methanol. At the optimum reaction temperature of 240 °C, the CuO/MCM-41-EG catalyst gave 15% CO2 conversion and 35% methanol selectivity.
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In 2018, China began to gradually promote the pilot policy of centralized band purchasing of medicines. Implementing this policy has resulted in a significant decrease in drug prices. However, there needs to be a clear consensus on the impact and mechanism of action on the innovation of pharmaceutical companies. Therefore. Taking the data of Chinese Shanghai and Shenzhen A-share pharmaceutical listed companies from 2016 to 2022 as a sample, this paper empirically investigates the impact of the centralized banded purchasing policy of drugs on the innovation of pharmaceutical enterprises by using a double difference model and further analyzes the mechanism of its action. The results show that implementing the centralized banded purchasing policy can promote pharmaceutical enterprises' innovation input and output, which is robust under the parallel trend and placebo tests. Further exploring the impact mechanism of the centralized band purchasing policy on pharmaceutical enterprises' innovation, it can be found that it promotes innovation inputs through three channels: government subsidies, enterprise profits, and operating income. In addition, the impact of centralized band purchasing on enterprise innovation is heterogeneous in terms of region, enterprise nature, and scale. Therefore, the positive effects of the centralized band purchasing policy on promoting innovation in pharmaceutical enterprises should be fully recognized, and enterprise heterogeneity should be taken into account when implementing the policy. This study provides empirical evidence on the implementation effect of the centralized banded purchasing policy and provides lessons for continuously optimizing the policy to promote the high-quality development of pharmaceutical enterprises.
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Indústria Farmacêutica , China , Custos de Medicamentos , Indústria Farmacêutica/economia , Pesquisa Empírica , Preparações Farmacêuticas/economiaRESUMO
Heterogeneous Fenton reaction represents one of the most reliable technologies to ensure water safety, but is currently challenged by the sluggish Fe(III) reduction, excessive input of chemicals for organic mineralization, and undesirable carbon emission. Current endeavors to improve the catalytic performance of Fenton reaction are mostly focused on how to accelerate Fe(III) reduction, while the pollutant degradation step is habitually overlooked. Here, we report a nanoconfinement strategy by using graphene aerogel (GA) to support UiO-66-NH2-(Zr) binding atomic Fe(III), which alters the carbon transfer route during phenol removal from kinetically favored ring-opening route to thermodynamically favored oligomerization route. GA nanoconfinement favors the Fe(III) reduction by enriching the reductive intermediates and allows much faster phenol removal than the unconfined analog (by 208 times in terms of first-order rate constant) and highly efficient removal of total organic carbon, i.e., 92.2 ± 3.7% versus 3.6 ± 0.3% in 60 min. Moreover, this oligomerization route reduces the oxidant consumption for phenol removal by more than 95% and carbon emission by 77.9%, compared to the mineralization route in homogeneous Fe2++H2O2 system. Our findings may upgrade the regulatory toolkit for Fenton reactions and provide an alternative carbon transfer route for the removal of aqueous pollutants.
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AIM: Although sodium glucose cotransporter2 inhibitor (SGLT-2I) is widely used in clinical practice, sufficient renin-angiotensin system (RAS) inhibition remains the cornerstone of diabetic kidney disease (DKD) treatment. The aim of this single-center study was to evaluate the efficacy and safety of dual RAS blockade compared with angiotensin-converting enzyme inhibitor (ACEI)/angiotensin II receptor blocker (ARB) monotherapy in non-elderly DKD patients with preserved eGFR (WHO Standard, < 60y). METHODS: This single-center study was registered in Chinese Clinical Trial Registry (ChiCTR1900024752), and approved by the ethical committee (KY201994). In this study, we recruited non-elderly type 2 diabetes volunteers with initial diagnosis of DKD to receive dual RAS blockade or monotherapy. 150 non-elderly DKD patients with preserved eGFR were recruited. The patients were randomly divided into dual RAS blockade group and monotherapy group. The dual RAS blockade group treatment regimen was an 80 mg valsartan plus a 4 mg perindopril tert-butylamine per day. At the same time, monotherapy group patients who received the 8 mg perindopril tert-butylamine or 160 mg valsartan monotherapy. The clinical data of the three groups were compared at baseline and collected during the follow-up period of 12 months. RESULTS: The baseline of patients who received dual RAS blockade was similar to that of monotherapy group. After 12 months of treatment, the median level of proteinuria in the dual RAS blockade group was significantly lower than that in the monotherapy group. There was no significant difference in the estimated glomerular filtration rate (eGFR) level, potassium, blood pressure and no serious adverse reactions. CONCLUSIONS: In non-elderly DKD patients with preserved eGFR, dual RAS blockade is superior to control proteinuria, and does not increase the probability of adverse reactions such as hyperkalemia, hypotension and acute kidney injury in 12 months.
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Background: Neonatal sepsis is one of the major causes of morbidity and mortality in newborns. However, atypical clinical manifestations and symptoms make the early diagnosis of neonatal sepsis a challenge. Relatively high-serum soluble urokinase-type plasminogen activator receptor (suPAR) has been implicated as a diagnostic biomarker for adult sepsis. Therefore, the meta-analysis is intended to explore the diagnostic value of suPAR for neonatal sepsis. Methods: The PubMed, Cochrane Library, Embase, Web of Science, China National Knowledge Infrastructure, China Biological Medicine Disk, and Wanfang databases were retrieved from inception to 31 December 2022 to collect diagnostic accuracy studies about suPAR for neonatal sepsis. Two reviewers independently screened the literature, extracted data, and assessed the risk of bias in the included studies using the quality assessment of diagnostic accuracy studies-2 (QUADAS-2) tool. Then, a meta-analysis was performed using Stata 15.0 software. Results: A total of six articles involving eight studies were included. The results of the meta-analysis showed that the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 0.89 [95%CI (0.83-0.93)], 0.94 [95%CI (0.77-0.98)], 14 [95%CI (3.5-55.2)], 0.12 [95%CI (0.08-0.18)], and 117 [95%CI (24-567)], respectively. The area under the curve (AUC) of summary receiver operator characteristic (SROC) curves was 0.92 [95%CI (0.90-0.94)]. Sensitivity analysis confirmed the stability of the results, and publication bias was not observed. Fagan's nomogram results demonstrated the clinical availability of the findings. Conclusion: Current evidence suggests that suPAR has potential diagnostic value for neonatal sepsis. Owing to the limited quality of the included studies, more high-quality studies are needed to verify the above conclusion.
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Objectives: To evaluate the relationship between mannose-binding lectin (MBL) polymorphism and neonatal sepsis to provide ideas for early diagnosis and control of neonatal sepsis using meta-analysis. Methods: The China National Knowledge Infrastructure, WanFang Data, China Biological Medicine Disc, PubMed, Embase, Cochrane Library, and Web of Science databases were electronically searched to collect studies on the association between the MBL gene variants and the risk of neonatal sepsis. Original articles from case-control and cohort studies on the relationship between MBL polymorphisms and neonatal sepsis were considered eligible. Meta-analysis was performed using Stata 15.0 software. The chi-square-based Q test and I2 statistics were used to assess heterogeneity. Forest plots were used to display the results graphically. Potential publication bias was assessed using the Egger and Begg tests and funnel plots. Results: Twenty-two studies, including 4565 cases and 12,746 controls, were included in this meta-analysis. Meta-analysis showed a significant relationship between MBL rs1800450 (codon 54, G > A) and neonatal sepsis in the variant vs. wild types. However, the analysis showed MBL exon 1 gene polymorphism (A/O), MBL rs5030737 (codon 52, C > T), and rs1800451 (codon 57, G > A), involved in existing research, were not associated with the risk of sepsis in neonates. Conclusions: Current evidence shows that MBL rs1800450 is associated with neonatal culture-proven sepsis. Owing to the limited quantity and quality of the included studies, more high-quality studies are required to verify the above conclusion.
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BACKGROUND: The relationship between circulating miRNAs and neonatal sepsis and the mechanism of action are still unclear at this time. Therefore, the potential diagnostic role of miRNAs in neonatal sepsis (NS) was studied through meta-analysis. METHOD: Web of Science, Cochrane Library, PubMed, and Embase are retrieved, supplemented by manual search, and the search was conducted to find related studies without time limit until May 2022.The quality of the literature was assessed via QUADAS criteria and meta-analyzed via Stata 11.0 software, including the assessment of specificity, sensitivity, likelihood ratio and diagnostic odds ratio. Then, sensitivity analysis and heterogeneity testing were conducted, and finally, the summary receiver operating characteristics (SROC) curve was drawn. RESULT: This study included 14 articles, including 20 miRNAs and 1597 newborns(control group: 727 and case group: 870). Among them, one article was of low quality, three articles were of high quality, and the rest were of medium quality. According to the results of random effects model analysis, the pooled specificity and sensitivity of miRNA for the diagnosis of NS were 0.83 (95%CI: 0.79-0.87) and 0.76 (95%CI: 0.72-0.80), respectively. And negative likelihood ratio, positive likelihood ratio, and diagnostic odds ratio were 0.29 (95%CI: 0.24-0.34), 4.51 (95%CI: 3.52-5.78), and 15.81 (95%CI: 10.71-23.35), respectively. The area under the SROC curve was 0.86, and there was no evidence publication bias detected in the funnel plot. CONCLUSION: Circulating miRNAs may be very useful in the development of early diagnostic strategies for neonatal sepsis.
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MicroRNAs , Sepse Neonatal , Recém-Nascido , Humanos , Sepse Neonatal/diagnóstico , Biomarcadores , Suplementos Nutricionais , Razão de ChancesRESUMO
OBJECTIVE: Early-onset neonatal sepsis (EONS) remains an important cause of neonatal mortality and has many risk factors, therefore, this study aimed to investigate the perinatal risk factors for EONS. METHODS: We searched CNKI, Wan Fang, VIP, CBM, PubMed, Embase, and Web of Science to compile studies regarding the incidence of neonatal early-onset sepsis, published up to 1 May 2022. To evaluate the quality of the included studies, we used the Newcastle-Ottawa Scale, and the RevMan5.3 software was used for meta-analysis. RESULTS: A total of 17 studies were included, with 1987 cases in the case group and 4814 cases in the control group. Meta-analysis showed that perinatal asphyxia or intrauterine distress (OR = 3.00, 95% CI: 2.18-4.13), amniotic fluid meconium contamination (OR = 4.51, 95% CI: 2.31-8.81), group B streptococcal (GBS) colonization in pregnant women (OR = 2.13, 95% CI: 1.48-3.05), chorioamnionitis (OR = 4.58, 95% CI: 2.61-8.05), premature rupture of membranes (OR = 2.63, 95% CI: 2.09-3.30), lower gestational age (OR = 1.31, 95% CI: 1.18-1.44), maternal urinary or reproductive tract infection (OR = 3.61, 95% CI: 2.14-6.11), perinatal fever (OR = 3.59, 95% CI: 2.25-5.71), very low birth weight (OR = 3.79, 95% CI: 2.14-6.73), and vaginal examination ≥3 times (OR = 7.95, 95% CI: 4.04-15.64) were the perinatal risk factors for EONS. CONCLUSION: Perinatal asphyxia or intrauterine distress, meconium contamination in amniotic fluid, GBS colonization in pregnant women, chorioamnionitis, premature rupture of membranes, lower gestational age, maternal urinary tract or reproductive tract infection, perinatal fever, very low birth weight, and vaginal examinations ≥3 times may increase the risk of EONS.
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Corioamnionite , Sepse Neonatal , Nascimento Prematuro , Infecções do Sistema Genital , Gravidez , Recém-Nascido , Humanos , Feminino , Sepse Neonatal/epidemiologia , Sepse Neonatal/etiologia , Asfixia , Corioamnionite/epidemiologia , Líquido Amniótico , FebreRESUMO
STUDY OBJECTIVES: Auditory stimulation devices (white and pink noise) are used to mask sounds and facilitate relaxation and sleep; however, the effectiveness of this intervention is not well established. This systematic review examined the scientific literature for the effect of specific types of auditory stimulation on sleep outcomes in adults. METHODS: The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement guided this review. Searches were conducted in 9 databases for intervention studies that could easily be employed in clinical practice. We excluded other types of auditory stimulation (music alone, binaural tones, and synchronization). Two reviewers screened abstracts and full-text articles for eligibility, with conflicts resolved by a third reviewer, and extracted data. Risk of bias was assessed with the Effective Public Health Practice Project Quality Assessment Tool for Quantitative Studies. RESULTS: Thirty-four studies reported results of 1,103 persons participating in 3 categories of interventions: white noise (18), pink noise (11), and 6 multiaudio (some combination of white, pink, music, or silence). Nineteen studies had positive findings in terms of improving sleep outcomes: 6 white noise (33%), 9 pink noise (81.9%), and 4 multiaudio (66.7%). Multiaudio had the lowest (better) risk of bias (mean/standard deviation: 1.67/0.82) compared to white (2.38/0.69) and pink noise (2.36/0.81). CONCLUSIONS: Although there was no strong evidence to support use of auditory stimulation, none of the studies reported any adverse effects with short-term application of auditory stimulation during sleep. Future research needs to include confounding factors that can affect outcomes, including one's noise sensitivity, personality, and other conditions or medications that may affect sleep. CITATION: Capezuti E, Pain K, Alamag E, Chen XQ, Philibert V, Krieger AC. Systematic review: auditory stimulation and sleep. J Clin Sleep Med. 2022;18(6):1697-1709.
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Transtornos do Sono-Vigília , Sono , Estimulação Acústica , Adulto , Humanos , Ruído/efeitos adversos , SomRESUMO
Pathogenic bacteria and antibiotic resistance genes (ARGs) in bioaerosols are major threats to human health. In this study, the microbial community structure and ARG distribution characteristics of airborne bacteria in total suspended particulates (TSP) and PM2.5 were investigated under different air quality levels in Xinxiang, Central China. The results revealed that with the deterioration of air quality, the concentrations of airborne bacteria in both TSP and PM2.5 decreased; however, the relative amounts of pathogenic bacteria increased. The predominant genera in pathogenic bacteria of Bacillus, Sphingomonas, Corynebacterium, Rhodococcus, and Staphylococcus were identified in both TSP and PM2.5. Although the airborne bacteria concentrations and absolute abundances of ARGs in TSP were higher than those in PM2.5 under identical air quality conditions, the bacterial community structure and relative amounts of pathogenic bacteria were similar. In addition, the relationship between environmental factors of ions, metal elements, and meteorological parameters and the community structures of airborne bacteria and pathogenic bacteria were also analyzed. The effects of soluble ions and metal elements on several dominant genera of total bacteria and pathogenic bacteria differed, probably due to the strong tolerance of pathogenic bacteria to harsh atmospheric environments Different subtypes of ARGs showed various distribution characteristics with variations in air quality. The deterioration of air quality can inhibit the dissemination of ARGs, as the minimum values of all ARGs and class 1 integrase intI1 were observed under Severely Polluted conditions. This study provides a comprehensive understanding of the effect of air pollution levels on the airborne bacteria community composition and ARG distribution.
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Poluição do Ar , Antibacterianos , Microbiologia do Ar , Poluição do Ar/análise , Antibacterianos/farmacologia , Bactérias , Resistência Microbiana a Medicamentos/genética , Monitoramento Ambiental , Genes Bacterianos , HumanosRESUMO
Objective: The objective is to identify the risk factors for necrotizing enterocolitis (NEC) in neonates by a meta-analysis, and to provide a reference for the prevention of NEC. Methods: The databases, including Chinese Biomedical Literature Datebase, China National Knowledge Infrastructure, Wanfang database, and Weipu Periodical database, PubMed, Web of Science, Embase, Cochrane Library, were searched for studies on the risk factors for NEC in neonates. The meta-analysis was carried out with the aid of Stata software. Results: A total of 52 studies were included, with 48 case-control studies and 4 cohort studies. There were 166,580 neonates in total, with 33,522 neonates in the case group and 133,058 neonates in the control group. The meta-analysis showed that gestational diabetes (OR = 3.62, 95% CI:1.77-7.41), premature rupture of membranes (OR = 3.81, 95% CI:1.16-12.52), low birth weight (OR = 3.00, 95% CI:2.26-3.97), small for gestational age (OR = 1.85, 95% CI:1.15-2.97), septicemia (OR = 4.34, 95% CI:3.06-6.15), blood transfusion (OR = 3.08, 95% CI:2.16-4.38), congenital heart disease (OR = 2.73, 95% CI:1.10-6.78), respiratory distress syndrome (OR = 2.12, 95% CI:1.24-3.63), premature birth (OR = 5.63, 95% CI:2.91-10.92), pneumonia (OR = 4.07, 95% CI:2.84-5.82) were risk factors for NEC in neonates. Breastfeeding (OR = 0.37, 95% CI:0.23-0.59), take probiotics (OR = 0.30, 95% CI:0.22-0.40), prenatal use of glucocorticoids (OR = 0.39, 95% CI:0.30-0.50), Hyperbilirubinemia (OR = 0.28, 95% CI:0.09-0.86) were protective factors for NEC in neonates. Conclusions: Gestational diabetes, premature rupture of membranes, low birth weight, small for gestational age, septicemia, blood transfusion, congenital heart disease, respiratory distress syndrome, premature birth, and pneumonia may increase the risk of NEC in neonates. Breastfeeding, taking probiotics, prenatal use of glucocorticoids, and Hyperbilirubinemia may reduce the risk of NEC in neonates.
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Because lower olefins (C2 = -C4 = ) are important bulk petrochemicals, their direct production from CO2 hydrogenation is highly attractive. However, the selectivity towards C2 = -C4 = by the modified Fischer-Tropsch synthesis is restricted to 56.7 % with high undesired methane selectivity. Here, a series of bifunctional catalysts containing In2 O3 -ZnZrOx oxides and various SAPO-34 zeolites with different crystal sizes (0.4-1.5â µm) and pore structures was developed for the production of lower olefins by CO2 hydrogenation. The C2 = -C4 = selectivity reached as high as 85 % among all hydrocarbons with very low CH4 selectivity of only 1 % at a CO2 conversion of 17 %. This demonstrated that the small crystal size, hierarchical pore structure, and appropriate amount of Brønsted acid sites of SAPO-34 endowed the bifunctional catalysts with high C2 = -C4 = selectivity. This work shows an efficient way for developing bifunctional catalysts for direct CO2 hydrogenation to lower olefins.
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H-type aluminosilicate zeolites are extensively used as solid-acid catalysts and support materials in industrial catalysis. However, the conventional synthesis methods involving hydrothermal syntheses and ion-exchange processes suffer from severe water pollution and toxic gas emissions. Herein, H-type MFI zeolite catalysts with a unique stacked structure were directly synthesized in the presence of NH4 F and with the help of zeolite confinement through a solvent-free route without further ion-exchange procedures. A range of exâ situ and inâ situ characterization procedures were used to provide evidence of the simultaneous use of pre-made ZSM-5 and NH4 F as a confined Al source and mineralizer, respectively. The confined zeolite framework of ZSM-5 prevented the formation of AlFx species between NH4 F and Al atoms, ensuring that the prepared samples had desirable acidic properties. Moreover, the resulting morphology could be controlled by using different silica substrates. The obtained H-type MFI zeolites showed excellent catalytic performance in methanol-to-gasoline reactions owing to their unique structure and directly exposed acidic sites. The developed one-pot strategy provides an alternative method for the facile synthesis of H-type zeolites with defined morphology.
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Three different approaches, including (1) manipulating the site chemistry, (2) controlling the spacing between neighbouring sites and (3) altering the adsorbates by the use of chelates, were successfully used to prepare MCM-41 adsorbents with excellent selectivity for silver adsorption from solutions containing copper.
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Cobre/isolamento & purificação , Prata/isolamento & purificação , Adsorção , Cátions/química , Fenômenos Químicos , Físico-Química , Cobre/química , Porosidade , Dióxido de Silício/química , Prata/químicaRESUMO
Toxic heavy metal containing Cr(VI) species is a serious threat for ecological environment and human beings. In this work, a new mussel-inspired polydopamine microsphere (PDA-sphere) is prepared through in situ oxidative polymerization at air condition with controllable sizes. The adsorption of Cr(VI) ions onto PDA-sphere is highly pH dependent with the optimal pH ranging from 2.5 to 3.8. A rapid Cr(VI) removal can approach in 8min for equilibrium. More importantly, the prepared materials exhibit a remarkable sorption selectivity, coexisting SO42-, NO3- and Cl- ions at high levels; The applicability model further proves its effective performances with treated capacity of 42,000kg/kg sorbent, and the effluent can be reduced from 2000ppb to below 50ppb, which meets the drinking water criterions recommended by WHO. 1kg sorbent can also purify approximately 100t Cr(VI) contaminated wastewaters basing on the wastewater discharges of China. Such capacity for application ranks the top level for Cr(VI) removal. Additionally, the exhausted materials can be well regenerated by binary alkaline and salts mixtures. Such efficient adsorption can be ascribed to the well-dispersed morphology as well as the strong affinity between Cr(VI) and catechol or amine groups by XPS investigation. All the results suggest that polydopamine microspheres may be ideal materials for Cr(VI) treatment in waters.
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In the present study, polymer-supported zirconium phosphate (ZrP-CP) was prepared for selective removal of lead from the contaminated water. ZrP-CP was characterized using nitrogen adsorption technique, scanning electron microscope (SEM), and X-ray diffraction (XRD). Lead sorption on ZrP-CP was found to be pH dependent due to the ion- exchange mechanism. Also, ZrP-CP was proved to be more selective than the polystyrene strong-acid cation exchanger D-001 to remove lead ion from water, where other competing cations such as Na(+), Ca(2+), and Mg(2+) ions coexist at high concentrations. Generally, lead sorption isotherms on ZrP-CP can be divided into two distinct regions at different load levels, and isotherms at both regions can be well elucidated by Langmuir model. The distribution coefficients (K(d)) and binding constants (B(L)) obtained experimentally indicated that stronger sorption affinity of ZrP-CP towards the lead ion occurs at a relatively lower load level. Also, lead sorption onto ZrP-CP was found to be an endothermic and entropy-driven process. High selectivity of ZrP-CP towards the lead ion was possibly attributed to the crystal state of zirconium phosphate and a specific interaction between orthophosphate and lead ion. Fixed-bed column runs showed that lead sorption on ZrP-CP could result in a conspicuous decrease of this toxic metal from 0.5 mg/L to below 0.01 mg/L, which is recommended as the standard of drinking water by WHO (the treatment technique standard set by US EPA is 0.015 mg/L). Also, the spent sorbent can be readily regenerated for reuse by dilute HNO(3) or HCl solution.