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1.
J Environ Manage ; 348: 119171, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37832287

RESUMO

Membrane fouling caused by inorganic ions and natural organic matters (NOMs) has been a severe issue in membrane distillation. Microbubble aeration (MB) is a promising technology to control membrane fouling. In this study, MB aeration was introduced to alleviate humic acid (HA) composited fouling during the treatment of simulative reverse osmosis concentrate (ROC) by vacuum membrane distillation (VMD). The objective of this work was to explore the HA fouling inhibiting effect by MB aeration and discuss its mechanism from the interfacial point of view. The results showed that VMD was effective for treating ROC, followed by a severe membrane fouling aggravated with the addition of 100 mg/L HA in feed solution, resulting in 45.7% decline of membrane flux. Analysis using the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory and zeta potential distribution of charged particles proved the coexistence of HA and inorganic cations (especially Ca2+), resulting in more serious membrane fouling. The introduction of MB aeration exhibited excellent alleviating effect on HA-inorganic salt fouling, with the normalized flux increased from 19.7% to 37.0%. The interfacial properties of MBs played an important role, which altered the zeta potential distributions of charged particles in HA solution, indicating that MBs adhere the HA complexations. Furthermore, this mitigating effect was limited at high inorganic cations concentration. Overall, MBs could change the potential characteristics of HA complexes, which also be used for other similar membrane fouling alleviation.


Assuntos
Substâncias Húmicas , Purificação da Água , Substâncias Húmicas/análise , Destilação/métodos , Microbolhas , Membranas Artificiais , Purificação da Água/métodos , Cátions
2.
Environ Sci Technol ; 57(44): 17144-17153, 2023 11 07.
Artigo em Inglês | MEDLINE | ID: mdl-37877900

RESUMO

Recent research has primarily focused on the utilization of reductants as activators for Fe(VI) to generate high-valent iron species (Fe(IV)/Fe(V)) for the degradation of emerging organic contaminants (EOCs). However, a significant drawback of this approach arises from the reaction between reductants and ferrates, leading to a decrease in oxidation capacity. This study introduces a novel discovery that highlights the potential of the iron(III)-(1,10-phenanthroline) (Fe(III)-Phen) complex as an activator, effectively enhancing the degradation of EOCs by Fe(VI) and augmenting the overall oxidation capacity of Fe(VI). The degradation of EOCs in the Fe(VI)/Fe(III)-Phen system is facilitated through two mechanisms: a direct electron transfer (DET) process and electron shuttle action. The DET process involves the formation of a Phen-Fe(III)-Fe(VI)* complex, which exhibits a stronger oxidation ability than Fe(VI) alone and can accept electrons directly from EOCs. On the other hand, the electron shuttle process utilizes Fe(III)-Phen as a redox mediator to transfer electrons from EOCs to Fe(VI) through the Fe(IV)/Fe(III) or Fe(IV)/Fe(II)/Fe(III) cycle. Moreover, the Fe(III)-Phen complex can improve the utilization efficiency of Fe(V) by preventing its self-decay. This study's findings may present a viable option for utilizing an effective catalyst to enhance the oxidation of EOCs by Fe(VI) and Fe(V).


Assuntos
Poluentes Químicos da Água , Purificação da Água , Compostos Férricos , Elétrons , Substâncias Redutoras , Oxirredução , Ferro
3.
J Food Biochem ; 45(9): e13898, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34378802

RESUMO

Hypericum patulum has been used as a folk medicine for its varied therapeutic effects including antifungal, wound-healing, spasmolytic, stimulant, hypotensive activities. The water decoction is drank as tea could treat cold, infantile malnutrition. The present study aims to isolate the constituents of the plant and investigate their effects on the glucose consumption in insulin-resistant HepG2 cells, furthermore, lipid metabolism in oleic acid (OA)-treated HepG2 cells was also studied. The phytochemical investigation of the plant led to the isolation of eleven compounds, and their structures were identified by spectroscopic analysis as n-dotriacontanol (1), shikimic acid (2), 1-O-caffeoylquinic acid methyl ester (3), 5-O-caffeoylquinic acid methyl ester (4), 5-O-coumaroylquinic acid methyl ester (5), 5-O-caffeoylquinic acid butyl ester (6), quercetin-3-O-α-L-rhamnoside (7), quercetin (8), quercetin-3-O-(4×´-methoxy)-α-L-rahmnopyranosyl (9), hyperoside (10), and rutin (11). The results revealed that compounds 7, 9, and 10 could enhance glucose consumption significantly in hyperglycemia induced HepG2 cells and insulin-resistant HepG2 cells. In addition, the western blotting analysis result exhibited that compounds 7, 9, and 10 in high concentration (5 µM, H) group could dramatically upregulate the expression of PPARγ protein, and even the effect of them had no significant difference compared with that of rosiglitazone. Furthermore, compounds 9 and 10 in middle concentration (2.5 µM, M) group and H group could dramatically promote triglyceride metabolism and decrease TG content in OA-treated HepG2 cells, and even in H group, reactive oxygen species (ROS) level were significantly decreased compared with model group. PRACTICAL APPLICATIONS: Hypericum patulum is a well-known plant of the genera Hypericum for its varied preventive and therapeutic potential activities. To study the chemical constituents and their effects on glucose and lipid metabolism in vitro, we detected glucose consumption in insulin-resistant HepG2 cells, triglyceride content and reactive oxygen species level in OA-treated HepG2 cells. In addition, PPARγ protein was also detected by western blotting analysis in the study. Compounds 1, 2, 3, 5, 6, 9, 10, and 11 were isolated from the plant for the first time. Quercetin-3-O-(4"-methoxy)-α-L-rahmnopyranosyl (9) and hyperoside (10) had potential therapeutic benefit against glucose and lipid metabolic disease. Therefore, this study might have certain guiding significance for further research and development of H. patulum.


Assuntos
Hypericum , Flavonoides , Glucose , Células Hep G2 , Humanos , Ácido Oleico
4.
Fish Shellfish Immunol ; 96: 114-121, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31786342

RESUMO

Our study investigated the effects of spinetoram on the developmental toxicity and immunotoxicity of zebrafish. 10 h post-fertilization (hpf) zebrafish embryos were exposed to several concentrations of spinetoram (0, 5.0 mg/L, 7.5 mg/L, 10 mg/L) for up to 96 hpf, and their mortality, heart rate, number of innate and adaptive immune cells, oxidative stress, apoptosis and gene expression were detected. Studies indicated that the spinetoram exposed zebrafish embryos showed yolk sac edema, slow growth, decreased heart rate, decreased number of immune cells, delayed thymic development and cell apoptosis. In addition, there were also significant changes in oxidative stress related indicators in zebrafish, the content of ROS and MDA and the activity of CAT and SOD increased with the increase of spinetoram concentration. Moreover, we detected the expression of TLR4 related genes including TLR4, MYD88 and NF-κB p65 which were significantly up-regulated in the treated groups. Meanwhile, we also found that pro-inflammatory factors IL-6, IL-8, IFN-γ and CXCL-c1c were up-regulated, but anti-inflammatory factor IL-10 was down-regulated in the treated groups. Briefly, our results show that spinetoram induces the developmental toxicity and immunotoxicity of zebrafish to a certain extent, providing basis for the further research on the molecular mechanism of spinetoram exposure to aquatic ecosystems.


Assuntos
Inseticidas/toxicidade , Macrolídeos/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/crescimento & desenvolvimento , Peixe-Zebra/imunologia , Animais , Embrião não Mamífero/anatomia & histologia , Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/imunologia , Desenvolvimento Embrionário/efeitos dos fármacos
5.
Environ Technol ; 39(17): 2203-2214, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28683691

RESUMO

In this study, a biological denitrifying process using a sequencing batch reactor (SBR) was employed to treat reverse osmosis (RO) concentrate with high conductivity produced from a coking wastewater plant. From the results, the average removal efficiencies for chemical oxygen demand, total nitrogen, and nitrate were 79.5%, 90.5%, and 93.1%, respectively. Different microbial communities were identified after sequencing the V1-V3 region of the 16S rRNA gene using the MiSeq platform, and the major bacterial phyla in the SBR system were Proteobacteria and Bacteroidetes. The main microorganisms responsible for denitrification were from the genera Hyphomicrobium, Thauera, Methyloversatilis, and Rhodobacter. Quantitative real-time PCR was used to quantify the absolute levels of denitrifying genes, including narG, nirS, nirK, and nosZ, during the start-up and stable operation of the SBR. The abundances of narG, nirK, and nosZ were lower during stable operation than those in the start-up period. The abundance of nirS at a concentration of 104-105 copies/ng in DNA was much higher than that of nirK, making it the dominant functional gene responsible for nitrite reduction. The higher nitrate removal efficiency suggests that biological denitrification using SBR is an effective technique for treating RO concentrate produced from coking wastewater plants.


Assuntos
Reatores Biológicos , Coque , Águas Residuárias , Desnitrificação , Osmose , RNA Ribossômico 16S , Microbiologia da Água
6.
Water Sci Technol ; 76(11-12): 3289-3298, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29236008

RESUMO

A biological denitrifying process was employed for the treatment of nanofiltration (NF) concentrate with high conductivity, which was generated from coking wastewater in a sequencing batch reactor (SBR). The results showed that the average removal efficiencies of chemical oxygen demand (COD), total nitrogen (TN) and nitrate were 47.6%, 61.1% and 94.6%, respectively. Different microbial communities were identified by sequencing the V1-V3 region of the 16S rRNA gene using the MiSeq platform, showing that the most abundant bacterial phylum in the SBR system was Proteobacteria, with the subclasses ß-Proteobacteria and α-Proteobacteria being dominant. The key microorganisms responsible for denitrification belonged to the genera Thauera, Hyphomicrobium, Methyloversatilis, Hydrogenophaga, Ignavibacterium, Rubrivivax and Parvibaculum. Quantitative real-time polymerase chain reaction was used to assess the absolute abundance of microbial genera, using 16S rRNAs and denitrifying genes such as narG, nirS, nirK, nosZ, in both SBR start-up and stable operation. The abundances of narG, nirK and nosZ were lower during stable operation than those during the start-up period. The abundance of nirS at a level of 104-105copies/ng in DNA was much higher than that of nirK, thus being the dominant functional gene in nitrite reduction.


Assuntos
Reatores Biológicos/microbiologia , Coque/análise , Águas Residuárias/química , Bactérias/classificação , Bactérias/genética , Betaproteobacteria/genética , Análise da Demanda Biológica de Oxigênio , Desnitrificação , Resíduos Industriais/análise , Nitratos , Nitritos , Nitrogênio/química , Proteobactérias/genética , RNA Ribossômico 16S/genética , Reação em Cadeia da Polimerase em Tempo Real , Eliminação de Resíduos Líquidos
7.
J Environ Sci (China) ; 25(8): 1565-74, 2013 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-24520694

RESUMO

A full-scale plant using anaerobic, anoxic and oxic processes (A1/A2/O), along with a pilot-scale membrane bioreactor (MBR), nanofiltration (NF) and reverse osmosis (RO) integrated system developed by Shanghai Baosteel Chemical Co. Ltd., was investigated to treat coking wastewater for industrial reuse over a period of one year. The removals reached 82.5% (COD), 89.6% (BOD), 99.8% (ammonium nitrogen), 99.9% (phenol), 44.6% (total cyanide (T-CN)), 99.7% (thiocyanide (SCN-)) and 8.9% (fluoride), during the A1/A2/O biological treatment stage, and all parameters were further reduced by over 96.0%, except for fluoride (86.4%), in the final discharge effluent from the currently operating plant. The pilot-scale MBR process reduced the turbidity to less than 0.65 NTU, and most of the toxic organic compounds were degraded or intercepted by the A1/A2/O followed MBR processes. In addition, parameters including COD, T-CN, total nitrogen, fluoride, chloride ion, hardness and conductivity were significantly reduced by the NF-RO system to a level suitable for industrial reuse, with a total water production ratio of 70.7%. However, the concentrates from the NF and RO units were highly polluted and should be disposed of properly or further treated before being discharged.


Assuntos
Coque , Resíduos Industriais , Ultrafiltração/métodos , Águas Residuárias , Reatores Biológicos , China , Membranas Artificiais , Osmose , Projetos Piloto
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