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1.
J Environ Manage ; 301: 113793, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34601347

RESUMO

Municipal wastewater treatment plants (WWTPs) have been regarded as the main receptors of microplastics in industrial and domestic wastewater. The excess sludge they generate is an important carrier for the microplastics to enter the environment. In China, relevant regional studies are still in an initial phase. In this work, microplastics in the sewage sludges at different sampling points of five WWTPs in Nanjing City (an important city in the Yangtze River basin) were investigated, including their abundance, morphology and chemical composition. Furthermore, the influence factors such as population density, economic development level, wastewater source and treatment process were also discussed. The analysis results through optical microscope and FT-IR showed that the detected microplastics were divided into fragments, films, fibers and granules. Their chemical component reached up to 19 species, including small amounts of petroleum resins which was scarcely detected in other studies. Wastewater source was the primary factor influencing the microplastic abundance and size in sludge. And the microplastic shape and chemical components were closely related to the industrial type. Furthermore, because the removal effect on the microplastics with different morphologies were varied with the treatment process, the preliminary suggestions on the technology for particular wastewater were proposed. This study provides partial regional data and analysis for the microplastics contained in the sludge of WWTPs, expecting to provide a certain theoretical support for the operations management of WWTPs and standardized sludge treatment.


Assuntos
Poluentes Químicos da Água , Purificação da Água , China , Monitoramento Ambiental , Microplásticos , Plásticos , Esgotos , Espectroscopia de Infravermelho com Transformada de Fourier , Eliminação de Resíduos Líquidos , Águas Residuárias/análise , Poluentes Químicos da Água/análise
2.
J Hazard Mater ; 423(Pt A): 127039, 2022 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-34481385

RESUMO

In this study, a copper-based catalyst (CuCN) with CuNx active sites highly dispersed in a porous carbon nitride matrix was synthesized and applied to a heterogeneous photo-assisted Photo-Fenton (PF) system to degrade tetracycline (TET). The results showed that the CuCN/PF system degraded up to 93.6% of TET within 60 min for ultrapure water matrix under the best experimental conditions, and more than 70% of TET for both river and lake water matrix. Toxicological tests suggested that the environmental risk caused by TET can be effectively inhibited by the CuCN/PF system. The good visible-light response and charge transport abilities of CuCN catalyst were identified in photoelectrochemical experiments. Free radical scavenging experiments and electron paramagnetic resonance (EPR) spectroscopy indicated that the active species in the degradation process were·OH, h+,·O2- and 1O2. Density functional theory (DFT) calculations revealed the positive effect of CuNx sites in CuCN on the formation of hydroxyl radicals by activating H2O2. This work will provide a new insight for the development of high-efficiency heterogeneous catalysts in wastewater environmental remediation.

3.
J Neurosci Res ; 2021 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-34676594

RESUMO

Much evidence has proved that excitotoxicity induced by excessive release of glutamate contributes largely to damage caused by ischemia. In view of the key role played by NMDA receptors in mediating excitotoxicity, compounds against NMDA receptors signaling pathways have become the most promising type of anti-stroke candidate compounds. However, the limited therapeutic time window for neuroprotection is a key factor preventing NMDA receptor-related compounds from showing efficacy in all clinical trials for ischemic stroke. In this perspective, the determination of therapeutic time windows of these kinds of compounds is useful in ensuring a therapeutic effect and accelerating clinical application. This mini-review discussed the therapeutic time windows of compounds against NMDA receptors signaling pathways, described related influence factors and the status of clinical studies. The purpose of this review is to look for compounds with wide therapeutic time windows and better clinical application prospect.

4.
J Environ Sci (China) ; 108: 22-32, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34465434

RESUMO

In this study, three magnetic flocculants with different chelating groups, namely, carboxymethyl chitosan-modified Fe3O4 flocculant (MC), acrylamide-grafted magnetic carboxymethyl chitosan flocculant (MCM), and 2-acrylamide-2-methylpropanesulfonic acid copolyacrylamide-grafted magnetic carboxymethyl chitosan flocculant (MCAA) were prepared, synthesized, and characterized by photopolymerization technology. They were applied to the flocculation removal of Cr(III), Co(II), and Pb(II). The effect of flocculation condition on the removal performance of Cr(III), Co(II), and Pb(II) was studied. Characterization results show that the three magnetic carboxymethyl chitosan-based flocculants have been successfully prepared with good magnetic induction properties. Flocculation results show that the removal rates of MC, MCM, and MCAA on Cr(III) are 51.79%, 82.33%, and 91.42%, respectively, under the conditions of 80 mg/L flocculant, pH value of 6, reaction time of 1.5 hr, G value of 200 s-1, and precipitation magnetic field strength of 120 mT. The removal rates of Co(II) by MC, MCM, and MCAA are 54.33%, 84.99%, and 90.49%, respectively. The removal rates of Pb(II) by MC, MCM, and MCAA are 61.54%, 91.32%, and 95.74%, respectively. MCAA shows good flocculation performance in composite heavy metal-simulated wastewater. The magnetic carboxymethyl chitosan-based flocculant shows excellent flocculation performance in removing soluble heavy metals. This research provides guidance and ideas for the development of efficient and low-cost flocculation technology to remove heavy metals in wastewater.


Assuntos
Quitosana , Metais Pesados , Floculação , Fenômenos Magnéticos , Águas Residuárias
5.
J Environ Manage ; 299: 113589, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34467861

RESUMO

In this study, two multifunctional nano-chitosan flocculants (CPAM-NCS1 and CPAM-NCS2) were made through the graft modification of cationic monomer and carboxymethylchitosan (CMCTS) to remove combined contaminants. The effects of various factors (pH, flocculant dosage and hydraulic mixing conditions) on the flocculation performance under single and composite pollution conditions were systematically investigated, the optimal chemical oxygen demand (COD) and the chromaticity removal rates in the dye wastewater were 79.9% and 83.9% at wastewater pH 7, the fast stirring rate 300 rpm, the fast stirring time 8 min, and the dosage of CPAM-NCS1 80 mg/L, respectively. The optimal removal rates of Cu (II) obtained by CPAM-NCS1 and CPAM-NCS2 at were 80.3% and 75.2% at 60 mg/L and the wastewater pH 7, respectively. The optimal removal rates of Cu (II) and disperse orange were 85.3% and 89.4%, respectively, in a composite pollutant system in which Cu (II) and disperse orange coexisted when the pH of the composite system was 9 and the dosage of CPAM -NCS1 was 60 mg/L. This study proved that nanoflocculants made by modifying CMCTS with different structures can demonstrate ideal flocculation removal performance for dye and heavy metal wastewaters.


Assuntos
Metais Pesados , Águas Residuárias , Cátions , Corantes , Floculação
6.
J Environ Manage ; 299: 113590, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34474256

RESUMO

In this work, the removal of ammonia nitrogen and phenol by pulsed discharge plasma (PDP) and modified zeolite was investigated. The Fe-zeolite and Mn-zeolite catalysts were prepared by the impregnation method. Catalysts' morphology, specific surface area, and chemical bond structure were characterized. Based on the pollutants removal experiments, Fe-zeolite (0.01) in the PDP system had better catalytic oxidation of phenol and adsorption effect of ammonia nitrogen. The removal efficiency of the pollutants increased with the increase of discharge voltage and solution conductivity, but decreased with the increase of discharge distance. During the plasma discharge process, the pH value in the solution decreased, and the solution conductivity gradually increased. After PDP/Fe-zeolite system treatment, the toxicity of the wastewater was significantly reduced. This study provided a new treatment method for inorganic and organic pollutants treated by PDP.


Assuntos
Poluentes Químicos da Água , Zeolitas , Amônia , Nitrogênio , Fenol , Fenóis , Poluentes Químicos da Água/análise
7.
J Oncol ; 2021: 6242798, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34335760

RESUMO

Objective: Colorectal cancer (CRC) is the most common cancer. But, the molecular mechanisms of CRC progression are not fully understood. This study was conducted to explore how the long noncoding RNA actin filament-associated protein 1-antisense RNA1 (lncRNA AFAP1-AS1) participates in CRC progression through the regulation of microRNA-195-5p (miR-195-5p) and wingless-type inducible signaling pathway protein-1 (WISP1). Methods: The expressions of AFAP1-AS1, miR-195-5p, and WISP1 were detected by RT-qPCR or western blot. A dual-luciferase assay confirmed the target relationship of AFAP1-AS1, miR-195-5p, and WISP1. Colony formation, wound-healing, and Transwell assays were used to detect the growth, migration, and invasion abilities of cells, respectively. Results: AFAP1-AS1 and WISP1 expressions were notably increased, and miR-195-5p expression was markedly reduced in CRC. The dual-luciferase assay verified that AFAP1-AS1 could bind to miR-195-5p. AFAP1-AS1 knockdown could inhibit the malignant behavior of CRC cells. miR-195-5p could target and regulate WISP1 expression. Overexpression of WISP1 or miR-195-5p inhibition reversed the inhibition effect of AFAP1-AS1 knockdown on the biological activity of CRC cells. Conclusions: AFAP1-AS1 knockdown may inhibit the proliferation, migration, and invasion of CRC cells through the miR-195-5p/WISP1 axis.

8.
Water Sci Technol ; 84(2): 484-498, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34312353

RESUMO

To cope with the increasingly severe challenges of zinc oxide nanoparticles (ZnO-NPs) in the field of the aquatic environment, this paper uses poly-aluminum ferric chloride (PAFC) and cationic polyacrylamide (CPAM) as coagulants to enhance the removal of ZnO-NPs from water. In two environments (pure-water environment and kaolin environment) that simulate suspended solids, we studied the dosage, pH, precipitation time, and hydraulic power of ZnO-NPs at three different initial concentrations (1, 2, and 30 mg/L). The effects of various conditions on the performance of PAFC, CPAM, and PAFC/CPAM to remove ZnO-NPs were examined. Results showed that the overall removal rate of ZnO-NPs in the kaolin environment was slightly higher than that in the pure-water environment. In contrast the removal rate of ZnO-NPs in the PAFC/CPAM was significantly higher than that of PAFC or CPAM alone. The coagulation removal conditions of ZnO-NPs were optimized using a response-surface model. Under the best conditions, the removal rate of ZnO-NPs with an initial mass concentration of 30 mg/L in the PAFC/CPAM combination in pure-water and kaolin environments was 98.54% and 99.17%, respectively. Finally, by studying the changes in floc size during coagulation, enhanced coagulation was an efficient method of removing ZnO-NPs from water.


Assuntos
Nanopartículas , Poluentes Químicos da Água , Óxido de Zinco , Resinas Acrílicas , Cloretos , Compostos Férricos , Poluentes Químicos da Água/análise
9.
Macromol Rapid Commun ; 42(14): e2100154, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34142406

RESUMO

The hierarchically bicontinuous polystyrene monoliths (HBPMs) with homogeneous skeletons and glycopolymer surfaces are fabricated for the first time based on the medium internal phase emulsion (MIPE) templating method via activator generated by electron transfer for atom transfer radical polymerization (AGET ATRP). The synergistic self-assembly of amphiphilic diblock glycopolymer (ADG) and Pluronic F127 (PF127) at the oil/water interface via hydrogen bonding interaction contributes to the formation of bicontinuous MIPE with deformed neighboring water droplets, resulting in the highly interconnected HBPM after polymerization. There is a bimodal pore size distribution in the HBPM, that is, through pores (150-5000 nm) and mesopores (10-150 nm). The HBPMs as prepared show excellent biocompatibility, homogeneous skeletons, strong mechanical strength, and high bed permeability, overcoming the practical limitations of the second generation of polystyrene (PS) monoliths. Glycoprotein concanavalin A (Con A) can be easily and quickly separated by the HBPM in hydrophilic interaction chromatography (HILIC) mode. These results suggest the HBPMs have great potentials in catalysis, separations, and biomedical applications.


Assuntos
Poliestirenos , Esqueleto , Concanavalina A , Interações Hidrofóbicas e Hidrofílicas , Polimerização
10.
Anticancer Drugs ; 32(9): 950-961, 2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34016832

RESUMO

This study aims to explore the biological actions of circular RNA (circRNA) ArfGAP with SH3 domain, ankyrin repeat and PH domain 2 (circ_ASAP2, circ_0006089) in cisplatin (DDP) resistance of gastric cancer. Circ_ASAP2, ecto-5'-nucleotidase (NT5E) and miR-330-3p were quantified by quantitative real-time PCR or western blot. The measurements of the IC50 value and cell proliferation were done using 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay. Cell colony formation, cell cycle distribution, apoptosis, migration and invasion were evaluated by the colony formation, flow cytometry and transwell assays. Dual-luciferase reporter assay was performed to confirm the targeted relationship between different molecules. The role of circ_ASAP2 in tumor growth was gauged by in vivo animal studies. Circ_ASAP2 and NT5E were overexpressed in DDP-resistant gastric cancer tissues and cells. Knockdown of circ_ASAP2 promoted DDP sensitivity, apoptosis and repressed proliferation, migration and invasion of DDP-resistant gastric cancer cells in vitro and diminished tumor growth in vivo. Moreover, NT5E was a downstream effector of circ_ASAP2 in regulating cell DDP sensitivity and functional behaviors. Mechanistically, circ_ASAP2 directly bound to miR-330-3p to promote NT5E expression. Furthermore, circ_ASAP2 modulated cell DDP sensitivity and functional behaviors by targeting miR-330-3p. Knockdown of circ_ASAP2 promoted DDP sensitivity and suppressed malignant behaviors of DDP-resistant gastric cancer cells through targeting the miR-330-3p/NT5E axis.

11.
Carbohydr Polym ; 261: 117891, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33766376

RESUMO

In this study, three magnetic flocculants, namely, MC, MC-g-PAM, and MC-g-PAA, were prepared. The structure characteristics, flocculation performance, and floc characteristics of the three magnetic flocculants were systematically studied and compared. SEM, FT-IR, XPS, XRD, TG-DSC, and VSM characterization results show that MC, MC-g-PAM, and MC-g-PAA are successfully prepared and exhibit good magnetic induction. The removal rates of copper ions by MC, MC-g-PAM, and MC-g-PAA under the optimal coagulation conditions are 93.39 %, 88.64 %, and 61.41 %, respectively. Kinetic fitting shows that the flocculation reaction process of MC and MC-g-PAM conforms to pseudo first-order kinetics, while the flocculation reaction process of MC-g-PAA conforms to pseudo second-order kinetics. The flocs produced by MC-g-PAA have larger particle size and fractal dimension than those by MC and MC-g-PAM. At 80 mg/L dosage and pH 6, the floc size and floc fractal dimension obtained by MC-g-PAA reach the maximum values of 48.28 um and 1.468, respectively. Zeta potential studies show that the flocculation functions of the three flocculants are mainly adsorption bridging, adsorption electric neutralization, and chelating precipitation. Recycling experiments show that MC-g-PAA has good recyclability, and the recovery rate after the fifth use is 77.24 % with the Cu(II) removal rate of 67.53 %.

12.
Crit Rev Biotechnol ; 41(2): 273-299, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33525937

RESUMO

With the rapid development of industry and agriculture, large amounts of organic pollutants have been released into the environment. Consequently, the degradation of refractory organic pollutants has become one of the toughest challenges in remediation. To solve this problem, intimate coupling of photocatalysis and biodegradation (ICPB) technology, which allows the simultaneous action of photocatalysis and biodegradation and thus integrates the advantages of photocatalytic reactions and biological treatments, was developed recently. ICPB consists mainly of porous carriers, photocatalysts, biofilms, and an illuminated reactor. Under illumination, photocatalysts on the surface of the carriers convert refractory pollutants into biodegradable products through photocatalytic reactions, after which these products are completely degraded by the biofilms cultivated in the carriers. Additionally, the biofilms are protected by the carriers from the harmful light and free radicals generated by the photocatalyst. Compared with traditional technologies, ICPB remarkably improves the degradation efficiency and reduces the cost of bioremediation. In this review, we introduce the origin and mechanisms of ICPB, discuss the development of reactors, carriers, photocatalysts, and biofilms used in ICPB, and summarize the applications of ICPB to treat organic pollutants. Finally, gaps in this research as well as future perspectives are discussed.


Assuntos
Poluentes Ambientais , Biodegradação Ambiental , Biofilmes , Catálise , Titânio
13.
Environ Sci Pollut Res Int ; 28(8): 9327-9337, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33141384

RESUMO

Municipal wastewater treatment plants (WWTPs) are considered to be major contributors of microplastics to the aquatic environment. Detailed research in China, which is relevant to the local situation, remains in the initial stage. Herein, the microplastic abundance, morphology, and removal efficiency of two WWTPs (C and P) equipped with tertiary treatment processes in different districts of Nanjing, an important city in the Yangtze River Basin, were investigated. The influence of technology, operational parameters, daily capacity, and sewage source and its proportion were discussed. Observations by optical microscope and FT-IR analysis and systematic calculation revealed that the microplastics have four shapes, including fragments, granules, film, and fibers, with various sizes and proportions, which were dependent on wastewater source. The total removal rates of 97.67% and 98.46% for WWTP C and WWTP P, respectively, indicated their highly efficient reduction of microplastics. Treatment technology had a considerable influence on the removal rate, especially the secondary and tertiary processes. However, a large number of microplastics from WWTPs were still released into the environmental waters due to the huge daily capacity. Sewage source determined the concentration, morphology feature, and chemical composition of microplastics to a certain extent. Compared with industrial wastewater, domestic wastewater possibly contained smaller microplastics of polyethylene and polypropylene with lower abundance. Furthermore, additional attention was provided on the flocculation process, drainage system, and treatment efficiency of microplastics with different shapes. This work is expected to provide some technical supports to guide the operation and management of WWTPs.


Assuntos
Poluentes Químicos da Água , Purificação da Água , China , Cidades , Monitoramento Ambiental , Microplásticos , Plásticos , Espectroscopia de Infravermelho com Transformada de Fourier , Eliminação de Resíduos Líquidos , Águas Residuárias/análise , Poluentes Químicos da Água/análise
14.
Environ Sci Pollut Res Int ; 28(3): 2522-2548, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33105014

RESUMO

Discharge plasma technology is a new advanced oxidation technology for water treatment, which includes the effects of free radical oxidation, high energy electron radiation, ultraviolet light hydrolysis, and pyrolysis. In order to improve the energy efficiency in the plasma discharge processes, many efforts have been made to combine catalysts with discharge plasma technology. Some heterogeneous catalysts (e.g., activated carbon, zeolite, TiO2) and homogeneous catalysts (e.g., Fe2+/Fe3+, etc.) have been used to enhance the removal of pollutants by discharge plasma. In addition, some reagents of in situ chemical oxidation (ISCO) such as persulfate and percarbonate are also discussed. This article introduces the research progress of the combined systems of discharge plasma and catalysts/oxidants, and explains the different reaction mechanisms. In addition, physical and chemical changes in the plasma catalytic oxidation system, such as the effect of the discharge process on the catalyst, and the changes in the discharge state and solution conditions caused by the catalysts/oxidants, were also investigated. At the same time, the potential advantages of this system in the treatment of different organic wastewater were briefly reviewed, covering the degradation of phenolic pollutants, dyes, and pharmaceuticals and personal care products. Finally, some suggestions for future water treatment technology of discharge plasma are put forward. This review aims to provide researchers with a deeper understanding of plasma catalytic oxidation system and looks forward to further development of its application in water treatment.


Assuntos
Preparações Farmacêuticas , Poluentes Químicos da Água , Catálise , Oxidantes , Oxirredução , Plasma/química , Águas Residuárias , Poluentes Químicos da Água/análise
15.
Eur J Med Chem ; 212: 113028, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33248848

RESUMO

Inhibition of the soluble epoxide hydrolase (sEH) is a promising new therapeutic approach in the treatment of inflammation. Driven by the in-house database product lead 1, a hybridization strategy was utilized for the design of a series of novel benzo [d]thiazol derivatives. To our delight, D016, a byproduct of compound 9, was obtained with an extraordinarily low IC50 value of 0.1 nM but poor physical and chemical properties. After removal of a non-essential urea moiety or replacement of the urea group by an amide group, compounds 15a, 17p, and 18d were identified as promising sEH inhibitors, and their molecular binding modes to sEH were constructed. Furthermore, compounds 15a and 18d exhibited more effective in vivo anti-inflammatory effect than t-AUCB in carrageenan-induced mouse paw edema. Compound 15a also showed moderate metabolic stability with a half-time of 34.7 min. Although 18d was unstable in rat liver microsomes, it might be a "prodrug". In conclusion, this study could provide valuable insights into discovery of new sEH inhibitors, and compounds 15a and 18d were worthy of further development as potential drug candidates to treat inflammation.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Benzotiazóis/farmacologia , Edema/tratamento farmacológico , Inibidores Enzimáticos/farmacologia , Epóxido Hidrolases/antagonistas & inibidores , Inflamação/tratamento farmacológico , Animais , Anti-Inflamatórios não Esteroides/síntese química , Anti-Inflamatórios não Esteroides/química , Benzotiazóis/síntese química , Benzotiazóis/química , Carragenina , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Edema/induzido quimicamente , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Epóxido Hidrolases/metabolismo , Células Hep G2 , Humanos , Inflamação/induzido quimicamente , Ligantes , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Microssomos Hepáticos/química , Microssomos Hepáticos/metabolismo , Simulação de Acoplamento Molecular , Estrutura Molecular , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade
16.
J Hazard Mater ; 403: 123623, 2021 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-32846266

RESUMO

As(III) oxidation to As(V) is deemed necessary for better arsenic removal, and separation is still the optimal approach for water remediation from As(III). Herein, sulfite (SIV) was adopted to activate MnFe2O4 for simultaneous oxidation and adsorption of As(III) in neutral water. The As(III) removal was more efficient than a peroxidation of As(III) followed by adsorption. The adsorption capacity of MnFe2O4/S(IV) for As(III) (26.257 mg g-1) was much higher than those of MnFe2O4 alone for As(III) (9.491 mg g-1) and As(V) (9.142 mg g-1). The mechanistic study corroborated that intermediate Mn(III) was the dominant oxidant responsible for rapid oxidation of As(III), and the dual roles of S(IV) as a complexing ligand and a precursor of oxysulfur radicals accelerated the redox cycle of Mn(II)/Mn(III). Moreover, S(IV) enhanced arsenic adsorption by driving more production of monodentate complexes. As(III) can be effectively removed over a wide range of temperatures (283.15-313.15 K) and pH (3-10) with the optimal pH of 7. The effect of coexisting ions and reusability of MnFe2O4 were also investigated. Especially, the superior performance of MnFe2O4/S(IV) for As(III) removal in various water matrixes may help develop new removal technologies based on active Mn(III) for the water decontamination from As(III).

17.
Sci Total Environ ; 760: 144307, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33341637

RESUMO

Developing robust and effective adsorbent for removing ubiquitous pharmaceutical diclofenac (DCF) from the aquatic environment is vitally important for environmental safety. Hence, a novel chitosan-based multilayer adsorbent (FCS-PD) with magnetic separation ability and surface functionality was successfully assembled, which had countless potential for removing contaminants from water. A series of instrumental technologies were performed to demonstrate the physicochemical properties of FCS-PD. Its adsorption performance toward DCF removal was comprehensively evaluated in synthetic water and surface water. The effects of microplastics, inorganic ions and humic acid on the adsorption were investigated. The maximum adsorption capacity of FCS-PD was calculated as 434.78 mg/g under neutral conditions, exhibiting superior adsorption performance than most reported adsorbents. The DCF in surface water was practically removed at low concentration (50 µg/L). FCS-PD presented a multistage kinetics controlled by chemisorption and intraparticle diffusion, which was emphasized by the pseudo-second-order kinetic and intra-particle diffusion analysis. After five cycles of adsorption and regeneration, the adsorption capacity only decreased by 9.9%, indicating the satisfactory regeneration of FCS-PD. The analysis of high-resolution X-ray photoelectron spectroscopic (XPS) and Fourier transform infrared spectroscopy (FTIR) revealed that the quaternary ammonium groups on the outer layer and the amino and hydroxyl groups on the chitosan layer are involved in the capture of DCF under electrostatic force and hydrogen bonding.

18.
J Environ Sci (China) ; 99: 239-248, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33183701

RESUMO

In this study, a high-efficiency cationic flocculant, P(DAC-MAPTAC-AM), was successfully prepared using UV-induced polymerization technology. The monomer Acrylamide (AM): Acryloxyethyl Trimethyl ammonium chloride (DAC): methacrylamido propyl trimethyl ammonium chloride (MAPTAC) ratio, monomer concentration, photoinitiator concentration, urea content, and cationic monomer DAC:MAPTAC ratio, light time, and power of high-pressure mercury lamp were studied. The characteristic groups, characteristic diffraction peaks, and characteristic proton peaks of P(DAC-MAPTAC-AM) were confirmed by fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), 1H nuclear magnetic resonance spectrometer (1H NMR), and scanning electron microscopy (SEM). The effects of dosage, pH value, and velocity gradient (G) value on the removal efficiencies of turbidity, COD, ammonia nitrogen, and total phenol by poly aluminum ferric chloride (PAFC), P(DAC-MAPTAC-AM), and PAFC/P(DAC-MAPTAC-AM) in the flocculation treatment of coal chemical wastewater were investigated. Results showed that the optimal conditions for the flocculation of coal chemical wastewater using P(DAC-MAPTAC-AM) alone are as follows: dosage of 8-12 mg/L, G value of 100-250 s - 1, and pH value of 4-8. The optimal dosage of PAFC is 90-150 mg/L with a pH of 2-12. The optimal dosage for PAFC/P(DAC-MAPTAC-AM) is as follows: PAFC dosage of 90-150 mg/L, P(DAC-MAPTAC-AM) dosage of 8-12 mg/L, and pH range of 2-6. When P(DAC-MAPTAC-AM) was used alone, the optimal removal efficiencies of turbidity, COD, ammonia nitrogen, and total phenol were 81.0%, 35.0%, 75.0%, and 80.3%, respectively. PAFC has good tolerance to wastewater pH and good pH buffering. Thus, the flocculation treatment of coal chemical wastewater using the PAFC/P(DAC-MAPTAC-AM) compound also exhibits excellent resistance and buffering capacity.


Assuntos
Carvão Mineral , Águas Residuárias , Acrilamida , Cátions , Floculação
19.
Sci Total Environ ; 742: 140508, 2020 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-32629256

RESUMO

In this study, resin-based hydrated iron oxide (HFOR) composites were prepared and used as a functional adsorbent for the simultaneous removal of p-Arsanilic acid (p-ASA) and arsenate (As (V)). The effects of solution pH and coexisting substances on the adsorption of different arsenic species were also investigated. Results showed that the coexisting substances slightly affected the adsorption process of two arsenic species. Analysis of the adsorption behavior, isotherm equilibrium, and adsorption kinetics, as well as that results of the X-ray photoelectron spectroscopy, zeta potential, and other analytical methods revealed that the satisfactory adsorption performance of HFOR can be attributed to the electrostatic interactions induced by the positively charged groups and the coordination of the hydrated iron oxide nanoparticles, which exhibited excellent specific adsorption for both arsenic species. Moreover, HFOR showed high acid and alkali resistance and reusability, as well as a constant co-removal performance for different arsenic species in five consecutive operating cycles (55 mg As/g of As(V) and 18 mg/g of p-ASA). Results of continuous running fixed-bed column experiments confirmed that HFOR enabled excellent simultaneous adsorption for p-ASA and As(V).

20.
Drug Dev Ind Pharm ; 46(7): 1177-1184, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32538184

RESUMO

Most of the mesoporous chiral mesoporous silica (CMS) was synthesized by the chiral surfactant-directing method. In this study, a facile method was designed to synthesize CMS. In this method, achiral amphiphile was used as templating agents, and dilute ammonia solution was applied to induce the chirality of the CMS. Meanwhile, its morphology can be controlled by changing the concentration of the aqueous ammonia solution. The obtained CMS was characterized by dynamic light scattering (DLS), X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The results showed that all of the CMS possessed highly ordered mesostructures, and as the concentration of ammonia decreases, the chirality of the CMS becomes more obvious. Water-insoluble drug curcumin (Cur) was used as a model drug. The characteristics of CMS before and after drug loading were further detected by Fourier transform infrared spectrometer (FT-IR), N2 adsorption-desorption and differential scanning calorimetry (DSC). The result showed that Cur was successfully loaded inside the pores of the CMS and remained an amorphous state due to steric inhibition. Additionally, CMS could significantly increase the release rate of Cur under different pH conditions.


Assuntos
Dióxido de Silício , Água , Portadores de Fármacos , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X
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