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1.
Clin Exp Immunol ; 214(1): 50-60, 2023 12 11.
Artigo em Inglês | MEDLINE | ID: mdl-37455659

RESUMO

As the largest proportion of myeloid immune cells in tumors, macrophages play an important role in tumor growth and regression according to their different phenotypes, thus reprogramming macrophages has become a new research direction for cancer immunotherapy. Yeast-derived whole ß-glucan particles (WGPs) can induce M0 macrophages to differentiate into M1 macrophages and convert M2 macrophages and tumor-associated macrophages (TAMs) into M1 macrophages. In vitro, studies have confirmed that WGP-treated macrophages increase the activating receptors in natural killer cells (NK cells) and enhance the cytotoxicity of NK cells. The extracellular regulated protein kinases (ERK) signaling pathway is involved in WGP-mediated regulation of the macrophage phenotype. Further in vivo studies show that oral WGP can significantly delay tumor growth, which is related to the increased proportion of macrophages and NK cells, the macrophage phenotype reversal, and the enhancement of NK cell immune function. NK-cell depletion reduces the therapeutic efficacy of WGP in tumor-bearing mice. These findings revealed that in addition to T cells, NK cells also participate in the antitumor process of WGP. It was confirmed that WGP regulates the macrophage phenotype to regulate NK-cell function.


Assuntos
Neoplasias , beta-Glucanas , Animais , Camundongos , Saccharomyces cerevisiae , beta-Glucanas/farmacologia , beta-Glucanas/metabolismo , Macrófagos , Células Matadoras Naturais , Imunidade
2.
J Environ Manage ; 347: 119119, 2023 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-37804630

RESUMO

Advanced oxidation processes (AOPs) based on peracetic acid (PAA) has been extensively concerned for the degradation of organic pollutants. In this study, metallic iron-modified sludge biochar (Fe-SBC) was employed to activate PAA for the removal of sulfamethoxazole (SMX). The characterization results indicated that FeO and Fe2O3 were successfully loaded on the surface of the sludge biochar (SBC). Fe-SBC/PAA system achieved 92% SMX removal after 30 min. The pseudo-first-order kinetic reaction constant of the Fe-SBC/PAA system was 7.34 × 10-2 min-1, which was 2.4 times higher than the SBC/PAA system. The degradation of SMX was enhanced with increasing the Fe-SBC dosage and PAA concentration. Apart from Cl-, NO3- and SO42- had a negligible influence on the degradation of SMX. Quenching experiments and electron paramagnetic resonance (EPR) techniques identified the existence of reactive species, of which CH3C(O)OO•, 1O2, and O2•- were dominant reactive species in Fe-SBC/PAA system. The effect of different water matrices on the removal of SMX was investigated. The removal of SMX in tap water and lake water were 79% and 69%, respectively. Four possible pathways for the decay of SMX were presented according to the identification of oxidation products. In addition, following the ecological structure-activity relationship model (ECOSAR) procedure and the germination experiments with lettuce seeds to predict the toxicity of the intermediates. The acute and chronic ecotoxicity of SMX solution was dramatically diminished by processing with Fe-SBC/PAA system. In general, this study offered a prospective strategy for the degradation of organic pollutants.


Assuntos
Ácido Peracético , Poluentes Químicos da Água , Sulfametoxazol , Ferro , Esgotos , Poluentes Químicos da Água/análise , Oxirredução , Água , Peróxido de Hidrogênio
3.
Cancer Immunol Immunother ; 71(8): 2007-2028, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34982184

RESUMO

Although therapeutic cancer vaccines have been gaining substantial ground, the development of cancer vaccines is impeded because of the undegradability of delivery systems, ineffective delivery of tumor antigens and weak immunogenicity of adjuvants. Here, we made use of a whole glucan particle (WGP) to encapsulate ovalbumin (OVA), thereby formulating a novel cancer vaccine. Results from in vitro experiments showed that WGP-OVA not only induced the activation of bone marrow-derived macrophages (BMDMs) including driving M0 BMDM polarization to the M1 phenotype, upregulating the costimulatory molecules and inducing the generation of cytokines, but also facilitated antigen presentation. After oral administration of the WGP-OVA formulation to mice with OVA-expressing tumors, these particles can increase tumor-infiltrating OVA-specific CD8+ CTLs and repolarize tumor-associated macrophages (TAMs) toward M1-like phenotype, which led to delayed tumor progression. These findings revealed that WGP could serve as both an antigen delivery system and an adjuvant system for promising cancer vaccines.


Assuntos
Vacinas Anticâncer , Neoplasias , Adjuvantes Imunológicos , Administração Oral , Animais , Glucanos/farmacologia , Macrófagos , Camundongos , Camundongos Endogâmicos C57BL , Neoplasias/terapia , Ovalbumina
4.
Ecotoxicol Environ Saf ; 208: 111522, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33120272

RESUMO

Nanofiltration concentration leachate is a high concentration organic wastewater with low biodegradability and high toxicity. To explore the feasibility of a combined Heat/UV activated persulfate process on nanofiltration concentrated leachate, the effects of persulfate concentration, initial solution pH before reaction, UV-lamp power and reaction temperature on the removal of organic pollutant were systematically investigated. Results indicated that the maximum rate of chemical oxygen demand (COD), ammonia-nitrogen (NH3-N) and absorbance of organic matter under UV light at 254 nm (UV254) removal from the leachate were 65.4%, 51.4% and 98.1%, respectively, at a persulfate concentration of 18 g L-1, initial solution pH before reaction of 9.0, UV-lamp power of 60 W and temperature of 80 °C. The results of three-dimensional fluorescence and UV254 showed that the removal rates of humic substances contained in the nanofiltration concentrated leachate were over 98%. In addition, the results of free radical scavenging showed that hydroxyl radicals were dominant under alkaline conditions. The results of this study demonstrated that coupling heat and ultraviolet activated persulfate oxidation is a promising technique for the treatment of nanofiltration concentrated leachate.


Assuntos
Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Amônia , Biodegradação Ambiental , Análise da Demanda Biológica de Oxigênio , Filtração , Temperatura Alta , Substâncias Húmicas/análise , Nitrogênio , Oxirredução , Temperatura , Raios Ultravioleta , Águas Residuárias
5.
Ecotoxicol Environ Saf ; 196: 110550, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32247244

RESUMO

Iron/zinc (Fe/Zn), phosphoric acid (H3PO4) or in combination (Fe/Zn + H3PO4) modified sludge biochar (SBC) were prepared and tested in this study to adsorb fluoroquinolones antibiotics including ciprofloxacin (CIP), norfloxacin (NOR) and ofloxacin (OFL) from water. Fe/Zn + H3PO4-SBC had an increased surface area (SBET), total pore volume (Vtot), mesoporous volume (Vmes), pore diameter (Dp) and oxygen-containing functional groups. It exhibited superior adsorption performance for CIP, NOR and OFL with the maximum adsorption amount of 83.7, 39.3, 25.4 mg g-1, respectively. Pseudo-second kinetic and Freundlich isotherm model presented the better fitting. The results of models and characterization analysis in combination indicated that physisorption and chemisorption, including pore filling, hydrogen bonding, π-π interaction, electrostatic interaction and functional groups complexation on a heterogeneous surface were the dominant process and mechanism. Liquid film diffusion was the main rate-limiting step. The adsorption process of CIP, NOR and OFL onto Fe/Zn + H3PO4-SBC were a spontaneous endothermic process. This study demonstrated that Fe/Zn + H3PO4 modified SBC exhibited high adsorption capacity, which was a promising adsorbent for fluoroquinolones as well as for other antibiotics effective removal from waters.


Assuntos
Antibacterianos/análise , Carvão Vegetal/química , Fluoroquinolonas/análise , Esgotos/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Ferro/química , Cinética , Modelos Teóricos , Ácidos Fosfóricos/química , Propriedades de Superfície , Zinco/química
6.
Carbohydr Polym ; 339: 122252, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-38823919

RESUMO

Drug delivery technologies that could convert promising therapeutics into successful therapies have been under broad research for many years. Recently, ß-glucans, natural-occurring polysaccharides extracted from many organism species such as yeast, fungi and bacteria, have attracted increasing attention to serve as drug delivery carriers. With their unique structure and innate immunocompetence, ß-glucans are considered as promising carriers for targeting delivery especially when applied in the vaccine construction and oral administration of therapeutic agents. In this review, we focus on three types of ß-glucans applied in the drug delivery system including yeast ß-glucan, Schizophyllan and curdlan, highlighting the benefits of ß-glucan based delivery system. We summarize how ß-glucans as delivery vehicles have aided various therapeutics ranging from macromolecules including proteins, peptides and nucleic acids to small molecular drugs to reach desired cells or organs in terms of loading strategies. We also outline the challenges and future directions for developing the next generation of ß-glucan based delivery systems.


Assuntos
Portadores de Fármacos , Sistemas de Liberação de Medicamentos , beta-Glucanas , Humanos , beta-Glucanas/química , Animais , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos/métodos , Sizofirano/química
7.
Chemosphere ; 313: 137531, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36509188

RESUMO

Perfluorobutane sulfonate (PFBS) is considered to be a promising alternative of perfluorooctane sulfonates (PFOS), while it is also hazardous. The UV/S (Ⅳ) system has been confirmed to be effective for PFOS removal from water, while it is inefficient for PFBS decomposition. A hybrid vacuum-ultraviolet (VUV)/S (Ⅳ)/KI process was investigated for the degradation of PFBS in aqueous solution. With KI involvement, the degradation rate of PFBS was boosted from 1.8802 µg h-1 up to 3.5818 µg h-1 in the VUV/S (Ⅳ) process. Alkaline conditions significantly increased the degradation efficiency of PFBS, which can be explained that S (Ⅳ) was dominated by SO32- rather than HSO3- and H2SO3 in alkaline conditions. Cl-, HCO3-, NO3-, NO2-, and HA would inhibit the performance of the VUV/S (Ⅳ)/KI process via various reactions. In addition, the toxicity of PFBS was significantly reduced by the VUV/S (Ⅳ)/KI process. Even in actual waters, the VUV/S (Ⅳ)/KI process also presented a satisfying performance in the degradation of PFBS.


Assuntos
Iodetos , Poluentes Químicos da Água , Vácuo , Água , Alcanossulfonatos , Raios Ultravioleta , Poluentes Químicos da Água/análise , Oxirredução
8.
Nanoscale ; 15(25): 10755-10762, 2023 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-37325817

RESUMO

There is an increasing trend in semi-artificial photosynthesis systems that combine living cells with inorganic semiconductors to activate a bacterial catalytic network. However, these systems face various challenges, including electron-hole recombination, photocorrosion, and the generation of photoexcited radicals by semiconductors, all of which impair the efficiency, stability, and sustainability of biohybrids. We first focus on a reverse strategy to improve highly efficient CO2 photoreduction on biosynthesized inorganic semiconductors using an electron conduit in the electroactive bacterium S. oneidensis MR-1. Due to the suppressed charge recombination and photocorrosion on CdS, the maximum photocatalytic production rate of formate in water was 2650 µmol g-1 h-1 (with a selectivity of ca.100%), which ranks high among all photocatalysts and is the highest for inorganic-biological hybrid systems in an all-inorganic aqueous environment. The reverse enhancement effect of electrogenic bacteria on photocatalysis on semiconductors inspires new insight to develop a new generation of bio-semiconductor catalysts for solar chemical production.


Assuntos
Dióxido de Carbono , Elétrons , Bactérias , Catálise , Fotossíntese , Água
9.
Sci Total Environ ; 864: 161082, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36565875

RESUMO

In this study, a novel magnetic poly (tetrafluoroethylene, PTFE) (Fe@PTFE) piezoelectric catalytic material was successfully prepared by a simple ball milling treatment. The prepared piezoelectric catalytic material Fe@PTFE exhibited excellent catalytic performance under the activation of ultrasonic (US) and realized the efficient degradation of imidacloprid (IMI) at low concentrations in an aqueous environment. It was demonstrated by various characterization methods that Fe0 was successfully loaded onto PTFE particles (1-15 µm) by ball milling. The US/Fe@PTFE system exhibited superior IMI degradation efficiency (99 %) and degradation rate (7.81× 10-2 min-1) under ultrasonic polarization with high efficiences of IMI degradation after five cycles. In addition, the system maintained excellent removal efficiencies in the real water matrixes. The mechanism study demonstrated that Fe@PTFE generated a variety of reactive oxygen species (•OH, 1O2 and O2•-) and H2O2 under the irradiation of US, and the production of H2O2 provided the conditions for the continuation of the Fenton-like reaction. Furthermore, the presence of O2•- in the system enhanced the recycling efficiency of Fe(III) and Fe(II), which further enhanced the degradation efficiency of the Fenton-like process. This study provides a novel perspective on a PTFE-based ultrasonic piezoelectric catalytic system for the efficient removal of organic pollutants in the environmental field.

10.
Sci Total Environ ; 859(Pt 1): 160001, 2023 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-36368385

RESUMO

Highly efficient and stable heterogeneous catalysts were desired to activate periodate (PI) for sustainable pollution control. Herein, iron-nitrogen-carbon catalyst was synthesized using a facile molten-salts mediated pyrolysis strategy (denoted as FeNC-MS) and employed to activate PI for the degradation of acetaminophen (ACE). Compared with iron-nitrogen-carbon catalyst prepared by direct pyrolysis method (marked as FeNC), FeNC-MS exhibited superior catalytic activity due to its large specific surface area (1600 m2 g-1) and the abundance of FeNx sites. The batch experiments revealed that FeNC/PI process achieved 37 % ACE removal within 20 min, while ACE removal in FeNC-MS/PI process was 98 % under the identical conditions. Integrated with electron paramagnetic resonance tests, quenching experiments, chemical probe identification, and electrochemical experiments, we demonstrated that FeNC-MS-PI complexes-mediated electron transfer was the predominant mechanism for the oxidation of ACE. Further analysis disclosed that FeNx sites in FeNC-MS were the main active sites for the activation of PI. Additionally, FeNC-MS/PI process exhibited significant resistance to humic acid and background electrolyte, and avoided the secondary pollution imposed by Fe leaching. The possible degradation pathways of ACE were proposed. The germination experiments of lettuce seeds showed that the ecotoxicity of ACE solution was significantly reduced after treatment with FeNC-MS/PI process. Overall, this study provided a facile strategy for the synthesis of efficient iron-nitrogen-carbon catalysts and gained fundamental insight into the mechanism of PI activation by iron-nitrogen-carbon catalysts for pollutants degradation.


Assuntos
Carbono , Nitrogênio , Nitrogênio/química , Carbono/química , Ferro/química , Acetaminofen/química , Peróxidos/química , Sais
11.
Environ Pollut ; 316(Pt 2): 120620, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36372368

RESUMO

The non-radical pathway of periodate (PI) activation for the removal of persistent organic contaminants has received increasing attention due to its higher stability and oxidative advantages. In this study, the degradation of sulfamethoxazole (SMX) by ball mill treated magnetic sludge biochar (BM-MSBC) through activation of PI by electron transfer mechanism was reported. Experimental and characterization results showed that the ball milling treatment resulted in a better pore and defect structure, which also significantly enhanced the electron transfer capacity of the sludge biochar. The BM-MSBC/PI system exhibited notable dependence of activator concentration and initial pH, while the effect of PI concentration was not significant. The coexisting substances (common anions and natural organic matters) hardly affect the degradation of SMX in the BM-MSBC/PI system. The phytotoxicity experiments suggested that the treatment of BM-MSBC/PI system could significantly reduce the biological toxicity of SMX solution. This study provides a novel, economical, and facile modification method for the application of sludge biochar in advanced oxidation processes.


Assuntos
Sulfametoxazol , Poluentes Químicos da Água , Esgotos , Elétrons , Carvão Vegetal/química , Poluentes Químicos da Água/análise , Adsorção
12.
PhytoKeys ; 236: 135-143, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38312774

RESUMO

A new species, Primulalizipingensis W.B.Ju, L.Y.He & X.F.Gao, found in Shimian County, Sichuan, China, is described and illustrated. It is morphologically similar to P.rhodochroa and P.socialis, but can be distinguished from them in having shorter plants covering with white farinose, leaf margin sharply dentate above the middle, the leaf blade becomes papery after drying, scapes obsolete, the bract linear-lanceolate to subulate, solitary at the base of the pedicel, and the white hairs present inside the corolla tube.

13.
J Hazard Mater ; 439: 129613, 2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-35863233

RESUMO

Manganese oxide-activated persulfate plays a critical role in water purification and in situ chemical oxidation processes, but the underlying mechanism needs to be further revealed. Herein, the detailed mechanism of MnO2 with various crystallographic structures (α-, ß-, γ-, and δ-MnO2) towards peroxymonosulfate (PMS) activation was investigated. PMS activated by tunnel structured α-, ß-, and γ-MnO2 showed higher acetaminophen (ACE) removal than layer structured δ-MnO2 with the removal efficiency following an order of α-MnO2 (85%) ≈ Î³-MnO2 (84%) > ß-MnO2 (65%) > Î´-MnO2 (31%). Integrated with chemical quenching experiments, electron paramagnetic resonance, Raman spectra, X-ray photoelectron spectroscopy, and Langmuir-Hinshelwood model on kinetic data, both surface-bound PMS complexes and direct oxidation by surface manganese species (Mn(Ⅳ, Ⅲ)(s)) were disclosed as the dominant oxidation mechanism for ACE degradation in α-, ß-, and γ-MnO2/PMS, which were rarely observed in previous reports. Moreover, the catalytic activity of α-, ß-, and γ-MnO2 was positively correlated to the MnIII(s) content on the catalyst surface. Higher content of MnIII(s) would stimulate the generation of more oxygen vacancies, which was conducive to the adsorption of PMS and the formation of reactive complexes. Overall, this study might provide deeper insight into the nonradical activation mechanism of PMS over different crystallographic MnO2.

14.
J Hazard Mater ; 434: 128860, 2022 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-35427969

RESUMO

In this study, a novel heterogeneous ultrasonic (US)-enhanced sludge biochar (SBC) activated periodate (PI) system was established and explored for the rapid removal of levofloxacin in the aqueous environment. This study focused on the mechanisms of US-enhanced SBC co-activation of PI for levofloxacin degradation. The results indicated that US and SBC exhibited a remarkable synergistic reinforcing activation effect on PI compared to single PI activation systems. The SBC/US/PI system achieved approximately 95% of levofloxacin removal, 51.5% of TOC removal, and 22% of dechlorination rate within 60 min with virtually no heavy metals released into the water matrix. In addition, the acute ecotoxicity of the solutions treated with the SBC/US/PI system was substantially reduced. The presence of IO3•, •OH, 1O2 and O2•- were identified in the SBC/US/PI system using quenching experiments and EPR technology while •OH and 1O2 were the predominant reactive species. Mechanistic studies have suggested that the cavitation effect of ultrasonic improved the dispersion and mass transfer efficiency of SBC and accelerated the desorption process of SBC. Possible pathways of levofloxacin degradation were proposed. This study provides a novel and promising strategy for the efficient removal of emerging contaminants such as antibiotics from the water matrix.


Assuntos
Esgotos , Poluentes Químicos da Água , Carvão Vegetal , Levofloxacino , Ácido Periódico , Ultrassom , Água , Poluentes Químicos da Água/análise
15.
Chemosphere ; 291(Pt 1): 132707, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34710451

RESUMO

The extensive use of imidacloprid (IMI) has led to its being frequently detected in natural water, also caused the potential damage to the ecosystem. Development of efficient, green and sustainable technique is demanded to eliminate this problem. A novel biochar (KMCBC) derived from agriculture waste of corn cob was first time co-modified by potassium hydroxide (KOH), ferric chloride (FeCl3) and zinc chloride (ZnCl2), which showed the greater adsorption amount (410 mg g-1 at 298 K) for imidacloprid (IMI). Pseudo-second-order kinetic and Langmuir isotherm models fitted well with the experimental data, together with the physicochemical characterization analysis, demonstrating that the adsorption process of IMI by KMCBC might be mainly controlled by micropore filling, π-π electron donor-acceptor and functional groups interactions (H-bonding and complexation). Additionally, the thermodynamics parameters suggested that IMI adsorption in this study was a spontaneous, endothermic and randomly increasing process. Besides, KMCBC owned the easy separation performance and promising environmental safety, also exhibited a high selective adsorption capacity regardless of solution pH (its optimum adsorption performance for IMI was obtained at pH = 5), inorganic ions strength and humic acid (HA) concentrations. The regenerated KMCBC (synergistic ultrasound/ethanol) could sustainably and efficiently adsorb IMI in the reuse cycles. Therefore, this study provided an efficient, green and sustainable adsorbent of KMCBC for IMI removal.


Assuntos
Poluentes Químicos da Água , Zea mays , Adsorção , Carvão Vegetal , Ecossistema , Concentração de Íons de Hidrogênio , Hidróxidos , Cinética , Fenômenos Magnéticos , Neonicotinoides , Nitrocompostos , Compostos de Potássio , Poluentes Químicos da Água/análise
16.
Environ Sci Pollut Res Int ; 28(24): 30459-30470, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33893912

RESUMO

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have gained increasing concern due to their persistent characteristics, wide distribution, biotoxicity, and bioaccumulative properties. The current remediation technologies for PFOA and PFOS are primarily focused on physical and chemical techniques. Phytoremediation has provided promising alternatives to traditional cleanup technologies due to their low operational costs, low maintenance requirements, end-use value, and aesthetic nature. In this review, uptake, translocation, and toxic effects of PFOS and PFOA are summarized and discussed. Several potential hyperaccumulators of PFOS and PFOA are provided according to the existing data. Biomass, chlorophyll, soluble protein, enzyme activities, oxidative stress, and other variables are assessed for potential indicator of PFOS/PFOA biotoxicity. The various studies on multiple scales are compared for identifying the threshold values. Several important implications and recommendations for future research are proposed at the end. This review provides an overview of current studies on plant uptake of PFOS and PFOA from the perspective of phytoremediation.


Assuntos
Ácidos Alcanossulfônicos , Fluorocarbonos , Biodegradação Ambiental , Caprilatos
17.
J Hazard Mater ; 407: 124777, 2021 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-33338812

RESUMO

Environmental concentration imidacloprid (IMI) has become a potential risk to ecological safety and human health, therefore an efficient, sustainable and environment friendly approach was urgently needed for its removal. In this study, a novel graphene oxide supported magnetic sludge biochar composite (GO/CoFe2O4-SBC) was first time synthesized and assessed for IMI removal at environmental concentration level. The maximum adsorption capacity of GO/CoFe2O4-SBC for IMI was 8.64 × 103 µg g-1. Physicochemical characteristics, kinetics (pseudo-second-order), isotherms (Freundlich and Temkin), thermodynamics and environmental factors analysis suggested that its outstanding adsorption performance was mainly attributed to pore filling, π-π conjugation and functional groups interaction. The mechanisms analysis indicated that intraparticle diffusion was the main rate-limiting step and its adsorption was a spontaneous, endothermic and randomness increased process. The magnetic sensitivity enabled it to be easily separated from water. The sustainable adsorption capacity (>90% of the initial adsorption capacity) of GO/CoFe2O4-SBC was well maintained by ethanol extraction even after five reuse cycles. GO/CoFe2O4-SBC also exhibited environmental security with its leaching concentrations of Fe and Co were below 0.5 mg L-1 in a wide pH range. The performance of GO/CoFe2O4-SBC suggested that it could be served as a promising adsorbent for environmental concentration IMI removal.


Assuntos
Grafite , Poluentes Químicos da Água , Adsorção , Carvão Vegetal , Humanos , Concentração de Íons de Hidrogênio , Cinética , Fenômenos Magnéticos , Neonicotinoides , Nitrocompostos , Esgotos , Poluentes Químicos da Água/análise
18.
Sci Total Environ ; 783: 146974, 2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-33866173

RESUMO

Iron/copper bimetallic nanoparticles based sludge biochar (Fe/Cu-SBC) was prepared by using a modified co-precipitation route. The Fe/Cu-SBC system prepared was subsequently applied to activate periodate (IO4-) to degrade diclofenac sodium (DCF) by using UV light at room temperature (25 °C). The physicochemical properties of both SBC and Fe/Cu-SBC such as morphology, physical properties, crystal structures and functional groups were examined. The type and number of surface functional groups were found to be increased and the catalytic performance was improved by the modification of Fe/Cu bimetallic nanoparticles. The influence of various parameters to evaluate the catalytic efficiency such as periodate (PI) concentration, dosage of catalysts, UV power, initial pH and coexisting anions were investigated. Under the optimized conditions (pH 6.9, UV-power 60 W, PI concentration of 5 mM and 0.1 g Fe/Cu-SBC), it was observed that 99.7% of DCF was degraded with a pseudo-first-order kinetics reaction constant 9.39 × 10-2 min-1. The radical scavenging experiments showed that IO3 radicals were the predominantly reactive oxidants in the Fe/Cu-SBC/UV system. Therefore, this investigation provides a feasible alternative for the degradation of PPCPs in wastewater.


Assuntos
Esgotos , Poluentes Químicos da Água , Carvão Vegetal , Diclofenaco , Ácido Periódico , Raios Ultravioleta
19.
J Hazard Mater ; 393: 122405, 2020 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-32120220

RESUMO

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) have attracted global attention due to their chemical durability, wide distribution, biotoxicity and bioaccumulative properties. Persulfate is a promising alternative to H2O2 for advanced oxidation processes and effective for organic removal. In this review, persulfate activation methods and operational factors in persulfate-based PFOA / PFOS degradation are analyzed and summarized. Moreover, the decomposing mechanisms of PFOA and PFOS are outlined in terms of molecular structures based a series of proposed pathways. PFOS could be converted to PFOA with the attack of SO4- and OH. And then PFOA defluorination occurs with one CF2 unit missing in each round and the similar procedure would occur continuously with sufficient SO4- and OH until entire decomposition. In addition, several knowledge gaps and research needs for further in-depth studies are identified. This review provides an overview for better understanding of the mechanisms and prospects in persulfate-based degradation of PFOA and PFOS.

20.
Sci Total Environ ; 718: 137299, 2020 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-32088478

RESUMO

A novel adsorbent of sludge biochar (SBC) and multi-walled carbon nanotube (CNT) composite was synthesized (CNT-SBC) to remove low concentrations of sulfamethoxazole (SMX) from water. The key factors of dose, contact time, pH and temperature were investigated. Higher dose of adsorbents provided more active sites for SMX adsorption. The effect of pH was due to the electrostatic interaction. Increasing the temperature was beneficial to SMX adsorption, which was a spontaneous endothermic process and the strength of the spontaneous increased with CNT supporting. As pseudo-second-order, Elovich, Langmuir and Freundlich models fitted the experimental data better, this suggested that both physisorption and chemisorption played vital roles during the adsorption process. In addition, liquid film diffusion was the main rate-limiting step of adsorption. Compared with SBC (5.43 × 103 µg g-1), CNT-SBC-1 (CNT:SBC = 1:2), CNT-SBC-2 (CNT:SBC = 1:4) and CNT-SBC-3 (CNT:SBC = 1:6) exhibited better adsorption performance with up to 2.35 × 104, 1.49 × 104 and 1.22 × 104 µg g-1 at 25 °C, respectively. The characterization analysis demonstrated that the stronger adsorption capacity of CNT-SBC was mainly attributed to the pore filling, functional groups complexation and π-π interaction. In summary, as an efficient and environment-friendly adsorbent, CNT-SBC has promising potential for low concentrations of SMX and other emerging contaminants removal from water.


Assuntos
Nanotubos de Carbono , Poluentes Químicos da Água , Adsorção , Carvão Vegetal , Cinética , Esgotos , Sulfametoxazol
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