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1.
Water Res ; 257: 121688, 2024 Jun 15.
Article in English | MEDLINE | ID: mdl-38723349

ABSTRACT

A membrane-aerated biofilm-coupled Fe/C supported sludge system (MABR-Fe/C) was constructed to achieve in situ electron production for NO3--N reduction enhancement in different Fe/C loadings (10 g and 200 g). The anoxic environment formed in the MABR-Fe/C promoted a continual Fe2+release of Fe/C in 120 d operation (average Fe2+concentrations is 1.18 and 2.95 mg/L in MABR-Fe/C10 and MABR-Fe/C200, respectively). Metagenomics results suggested that the electrons generated from ongoing Fe2+ oxidation were transferred via the Quinone pool to EC 1.7.5.1 rather than EC 1.9.6.1 to complete the process of NO3--N reduction to NO2--N in Acidovorax, Ottowia, and Polaromonas. In the absence of organic matter, the NO3--N removal in MABR-Fe/C10 and MABR-Fe/C200 increased by 11.99 and 12.52 mg/L, respectively, compared to that in MABR. In the further NO2--N reduction, even if the minimum binding free energy (MBFE) was low, NO2--N in Acidovorax and Dechloromonas preferentially bind the Gln-residues for dissimilatory nitrate reduction (DNR) in the presence of Fe/C. Increasing Fe/C loading (MABR-Fe/C200) caused the formation of different residue binding sites, further enhancing the already dominant DNR. When DNR in MABR-Fe/C200 intensified, the TN in the effluent increased by 3.75 mg/L although the effluent NO3--N concentration was lower than that in MABR-Fe/C10. This study demonstrated a new MABR-Fe/C system for in situ electron generation to enhance biological nitrogen removal and analyzed the NO3--N reduction pathway and metabolic mechanism, thus providing new ideas for nitrogen removal in electron-deficient wastewater.


Subject(s)
Biofilms , Electrons , Iron , Sewage , Waste Disposal, Fluid , Wastewater , Sewage/microbiology , Waste Disposal, Fluid/methods , Iron/metabolism , Wastewater/chemistry , Nitrate Reductase/metabolism , Oxidation-Reduction , Bioreactors , Carbon
2.
MedComm (2020) ; 5(5): e555, 2024 May.
Article in English | MEDLINE | ID: mdl-38706741

ABSTRACT

Indoleamine 2,3-dioxygenase 1 (IDO1), the key enzyme in the catabolism of the essential amino acid tryptophan (Trp) through kynurenine pathway, induces immune tolerance and is considered as a critical immune checkpoint, but its impacts as a metabolism enzyme on glucose and lipid metabolism are overlooked. We aim to clarify the potential role of IDO1 in aerobic glycolysis in pancreatic cancer (PC). Analysis of database revealed the positive correlation in PC between the expressions of IDO1 and genes encoding important glycolytic enzyme hexokinase 2 (HK2), pyruvate kinase (PK), lactate dehydrogenase A (LDHA) and glucose transporter 1 (GLUT1). It was found that IDO1 could modulate glycolysis and glucose uptake in PC cells, Trp deficiency caused by IDO1 overexpression enhanced glucose uptake by stimulating GLUT1 translocation to the plasma membrane of PC cells. Besides, Trp deficiency caused by IDO1 overexpression suppressed the apoptosis of PC cells via promoting glycolysis, which reveals the presence of IDO1-glycolysis-apoptosis axis in PC. IDO1 inhibitors could inhibit glycolysis, promote apoptosis, and exhibit robust therapeutic efficacy when combined with GLUT1 inhibitor in PC mice. Our study reveals the function of IDO1 in the glucose metabolism of PC and provides new insights into the therapeutic strategy for PC.

3.
Analyst ; 149(11): 3245-3262, 2024 May 28.
Article in English | MEDLINE | ID: mdl-38687206

ABSTRACT

Artificial superhydrophobic surfaces that do not absorb water, like the lotus leaf, show tremendous promise in numerous applications. However, superhydrophobic surfaces are rarely used because of their low stability and endurance. A stable organic superhydrophobic surface (SHS) composed of novel morphology Ag-nanoparticles (NPs) has been fabricated on a copper alloy via etching, immersion, spraying, and annealing treatment, along with a static water contact angle (WCA) of 158 ± 1° and sliding angle (SA) less than 2°. The surface texture, composition, and morphology of the substrate surfaces were explored by using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, and DFT-based Ag atom distribution. The anti-corrosion study of non-coated and Ag-NP-coated copper alloy was undertaken using electrochemical impedance spectroscopy. Ag-NPs +SA@SHS enhanced the corrosion resistance as compared with bare Cu alloy. The water droplet rolled down the coated Cu alloy, removed the chalk powder from the surface, and indicated an excellent self-cleaning function. Photodegradation of Congo red (CR) and methylene blue (MB) dye samples was assessed by measuring the absorbance through UV-Visible spectrophotometry, where the Ag-NPs coated on the copper alloy were used as a catalyst. The performance of the SHS@Ag-NPs in the aqueous solution was 99.31% and 98.12% for industrial pollutants (CR and MB), with degradation rates of 5.81 × 10-2 s-1 and 5.89 × 10-2 s-1, respectively. These findings demonstrated a simple, rapid, and low-energy fabrication technique for SHS@Ag-NPs. This research reveals a valuable approach for the fabrication of SHS@Ag-NPs on various substrates to extend the superhydrophobic surfaces with ultra-fast self-healing properties, for outdoor applications such as anti-corrosion, for an innovative approach for the remediation of polluted water treatment, and for industrial applications.

4.
Sci Total Environ ; 930: 172601, 2024 Jun 20.
Article in English | MEDLINE | ID: mdl-38657817

ABSTRACT

Antibiotic residues in mariculture wastewater seriously affect the aquatic environment. Antibiotic Resistance Genes (ARGs) produced under antibiotic stress flow through the environment and eventually enter the human body, seriously affecting human health. Microalgal-bacterial symbiotic system (MBSS) can remove antibiotics from mariculture and reduce the flow of ARGs into the environment. This review encapsulates the present scenario of mariculture wastewater, the removal mechanism of MBSS for antibiotics, and the biomolecular information under metagenomic assay. When confronted with antibiotics, there was a notable augmentation in the extracellular polymeric substances (EPS) content within MBSS, along with a concurrent elevation in the proportion of protein (PN) constituents within the EPS, which limits the entry of antibiotics into the cellular interior. Quorum sensing stimulates the microorganisms to produce biological responses (DNA synthesis - for adhesion) through signaling. Oxidative stress promotes gene expression (coupling, conjugation) to enhance horizontal gene transfer (HGT) in MBSS. The microbial community under metagenomic detection is dominated by aerobic bacteria in the bacterial-microalgal system. Compared to aerobic bacteria, anaerobic bacteria had the significant advantage of decreasing the distribution of ARGs. Overall, MBSS exhibits remarkable efficacy in mitigating the challenges posed by antibiotics and resistant genes from mariculture wastewater.


Subject(s)
Anti-Bacterial Agents , Drug Resistance, Microbial , Microalgae , Wastewater , Wastewater/microbiology , Anti-Bacterial Agents/pharmacology , Drug Resistance, Microbial/genetics , Microalgae/genetics , Microalgae/physiology , Waste Disposal, Fluid/methods , Bacteria , Metagenomics , Aquaculture , Water Pollutants, Chemical/analysis , Symbiosis , Genes, Bacterial
5.
J Hazard Mater ; 470: 134138, 2024 May 15.
Article in English | MEDLINE | ID: mdl-38574657

ABSTRACT

Electro-Fenton membranes (EFMs) can synchronously realize organic micropollutants destruction and fouling mitigation in a single filtration process with the assistance of hydroxyl radicals (•OH). Herein, a nanoarray-structured EFM (NS-EFM) was designed by assembling Fenton reactive CoFe-LDH nanowires using a low-temperature hydrothermal method. Combined with a defect-engineering strategy, the oxygen vacancies (OVac) in the CoFe-LDH nanoarrays were tailored by manipulating the stoichiometry of cations to optimize the Fenton reactivity of NS-EFMs. The optimized NS-EFM demonstrated exceptional sulfamethoxazole (SMX) removal (99.4%) and fast degradation kinetics (0.0846 min-1), but lower energy consumption (0.22 kWh m-3 per log removal of SMX). In-depth mechanism analysis revealed that the intrinsic electronic properties of OVac endowed NS-EFM with enhanced reactivity and charge transferability at metallic active sites of CoFe-LDH, thereby intensifying •OH generation. Besides, the nanoarray-structured NS-EFM built a confined microreactor space, leading to expedited •OH microflow to SMX. Meanwhile, the hydrophilic nature of CoFe-LDH nanoarrays synergistically contributed to the high flux recovery (95.0%) and minimal irreversible membrane fouling (5.0%), effectively alleviating membrane fouling within pores and on surfaces. This study offers insights into the potential of defect engineering as a foundational strategy in the design of EFMs, significantly advancing the treatment of organic pollutants and control of membrane fouling.

6.
Environ Sci Ecotechnol ; 21: 100416, 2024 Sep.
Article in English | MEDLINE | ID: mdl-38584706

ABSTRACT

Water reuse is an effective way to solve the issues of current wastewater increments and water resource scarcity. Ultrafiltration, a promising method for water reuse, has the characteristics of low energy consumption, easy operation, and high adaptability to coupling with other water treatment processes. However, emerging organic contaminants (EOCs) in municipal wastewater cannot be effectively intercepted by ultrafiltration, which poses significant challenges to the effluent quality and sustainability of ultrafiltration process. Here, we develop a cobalt single-atom catalyst-tailored ceramic membrane (Co1-NCNT-CM) in conjunction with an activated peroxymonosulfate (PMS) system, achieving excellent EOCs degradation and anti-fouling performance. An interfacial reaction mechanism effectively mitigates membrane fouling through a repulsive interaction with natural organic matter. The generation of singlet oxygen at the Co-N3-C active sites through a catalytic pathway (PMS→PMS∗→OH∗→O∗→OO∗→1O2) exhibits selective oxidation of phenols and sulfonamides, achieving >90% removal rates. Our findings elucidate a multi-layered functional architecture within the Co1-NCNT-CM/PMS system, responsible for its superior performance in organic decontamination and membrane maintenance during secondary effluent treatment. It highlights the power of integrating Co1-NCNT-CM/PMS systems in advanced wastewater treatment frameworks, specifically for targeted EOCs removal, heralding a new direction for sustainable water management.

7.
Bioresour Technol ; 399: 130550, 2024 May.
Article in English | MEDLINE | ID: mdl-38460562

ABSTRACT

Sunlight illumination has the potential to control the stability and sustainability of dynamic membrane (DM) systems. In this study, an up-flow anaerobic sludge blanket (UASB) reactor was combined with DM under different illumination positions (direct, indirect and no illumination) to treat wastewater. Results indicated that the UASB achieved a COD removal up to 87.05 % with an average methane production of 0.28 L/d. Following treatment by the UASB, it was found that under illumination, the removal of organic substances by DM exhibited poor performance due to algal proliferation. However, the DM systems demonstrated efficient removal of ammonia nitrogen, ranging from 96.21 % to 97.67 % after stabilization. Total phosphorus removal was 45.72 %, and membrane flux remained stable when directly illuminated. Conversely, the DM system subjected to indirect illumination showed unstable membrane flux and severe fouling resistance. These findings offer valuable insights into optimizing illumination positions in DM systems under anaerobic conditions.


Subject(s)
Waste Disposal, Fluid , Water Purification , Waste Disposal, Fluid/methods , Anaerobiosis , Lighting , Methane , Bioreactors , Sewage
8.
Water Res ; 254: 121340, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38428235

ABSTRACT

Membrane electrochemical reactor (MER) shows superiority to electrochemical oxidation (EO) in high salinity organic wastewater (HSOW) treatment, but requirement of proton exchange membranes (PEM) increases investment and maintenance cost. In this work, the feasibility of using low-cost pressure-driven membranes as the separation membrane in MER system was systematically investigated. Commonly used pressure-driven membranes, including loose membranes such as microfiltration (MF) and ultrafiltration (UF), as well as dense membranes like nanofiltration (NF) and reverse osmosis (RO), were employed in the study. When tested in a contamination-free solution, MF and UF exhibited superior electrochemical performance compared to PEM, with comparable pH regulation capabilities in the short term. When foulant (humic acid, Ca2+ and Mg2+) presented in the feed, UF saved the most energy (43 %) compared to PEM with similar removal rate of UV254 (∼85 %). In practical applications of MER for treating nanofiltration concentrate (NC) of landfill leachate, UF saved 27 % energy compared to PEM per cycle with the least Ca2+ and Mg2+ retention in membrane and none obvious organics permeation. For fouled RO and PEM with ion transport impediment, water splitting was exacerbated, which decreased the percentage of oxidation for organics. Overall, replacing of PEM with UF significantly reduce the costs associated with both the investment and operation of MER, which is expected to broaden the practical application for treating HSOW.


Subject(s)
Protons , Water Purification , Salinity , Feasibility Studies , Osmosis
9.
Water Res ; 254: 121383, 2024 May 01.
Article in English | MEDLINE | ID: mdl-38432002

ABSTRACT

The gravity-driven membrane (GDM) system is desirable for energy-efficient water treatment. However, little is known about the influence of cations on biofilm properties and GDM performance. In this study, typical cations (Ca2+ and Na+) were used to reveal the combined fouling behavior and mechanisms. Results showed that Ca2+ improved the stable flux and pollutant removal efficiency, while Na+ adversely affected the flux. Compared with GDM control, the concentration of pollutants was lower in Ca-GDM, as indicated by the low biomass, proteins, and polysaccharides. A heterogeneous and loose biofilm was observed in the Ca-GDM system, with roughness and porosity increasing by 43.06 % and 32.60 %, respectively. However, Na+ induced a homogeneous and dense biofilm, with porosity and roughness respectively reduced by 17.48 % and 22.04 %. The richness of bacterial communities increased in Ca-GDM systems, while it decreased in Na-GDM systems. High adenosine triphosphate (ATP) concentration in Ca-GDM system was consistent with the abundant bacteria and their high biological activity, which was helpful for the efficient removal of pollutants. The abundance of Apicomplexa, Platyhelminthes, Annelida and Nematoda increased after adding Ca2+, which was related to the formation of loose biofilms. Computational simulations indicated that the free volumes of the biofilms in Ca-GDM and Na-GDM were 13.7 and 13.2 nm3, respectively. The addition of cations changed intermolecular forces, Ca2+ induced bridging effects led to large and loose floc particles, while the significant dehydration of hydrated molecules in the Na-GDM caused obvious aggregation. Overall, microbiological characteristics and contaminant molecular interactions were the main reasons for differences in GDM systems.


Subject(s)
Environmental Pollutants , Water Purification , Membranes, Artificial , Filtration/methods , Biofilms , Water Purification/methods , Cations
10.
J Hazard Mater ; 469: 133890, 2024 May 05.
Article in English | MEDLINE | ID: mdl-38422736

ABSTRACT

Graphene oxide (GO)-based laminar membranes are promising candidates for next-generation nanofiltration membranes because of their theoretically frictionless nanochannels. However, nonuniform stacking during the filtration process and the inherent swelling of GO nanosheets generate horizontal and vertical defects, leading to a low selectivity and susceptibility to pore blockage. Herein, both types of defects are simultaneously patching by utilizing tannic acid and FeⅢ. Tannic acid first partially reduced the upper GO framework, and then coordinated with FeⅢ to form a metal-polyphenol network covering horizontal defects. Due to the enhanced steric hindrance, the resulting membrane exhibited a two-fold increase in sulfonamide contaminants exclusion compared to the pristine GO membrane. A non-significant reduction in permeance was observed. In terms of fouling control, shielding defects significantly alleviated the irreversible pore blockage of the membrane. Additionally, the hydrophilic metal-polyphenol network weakened the adhesion force between the membrane and foulants, thereby improving the reversibility of fouling in the cleaning stage. This work opens up a new way to develop GO-based membranes with enhanced separation performance and antifouling ability.

11.
ACS Appl Mater Interfaces ; 16(8): 11026-11034, 2024 Feb 28.
Article in English | MEDLINE | ID: mdl-38361494

ABSTRACT

A Mo(S,Se)2 interfacial layer is formed inevitably and uncontrollably between the Mo electrode and Cu2ZnSn(S,Se)4 (CZTSSe) absorber during the selenization process, which significantly influences the performance of CZTSSe solar cells. In this work, an ultrathin MoS2 layer is intentionally inserted into Mo/CZTSSe to reduce the recombination and thus optimize the interface quality. It is revealed that the absorber exhibits a continuous and compact morphology with bigger grains and remarkably without pinholes across the surface or cross-sectional regions after MoS2 modification. Benefitting from this, the shunt resistance (RSh) of the device increased evidently from ∼395 to ∼634 Ω·cm2, and simultaneously, the reverse saturation current density (J0) realized an effective depression. As a result, the power conversion efficiency (PCE) of the MoS2-modified device reaches 9.64% via the optimization of the thickness of the MoS2 layer, indicating performance improvements with respect to the MoS2-free case. Furthermore, the main contribution to the performance improvement is derived and analyzed in detail from the increased RSh, decreased J0, and diode ideality factor. Our results suggest that the Mo/CZTSSe interface quality and performance of CZTSSe solar cells can be modulated and improved by appropriately designing and optimizing the thickness of the inserted MoS2 layer.

12.
Clin Cancer Res ; 30(7): 1382-1396, 2024 Apr 01.
Article in English | MEDLINE | ID: mdl-38261467

ABSTRACT

PURPOSE: Although somatic mutations were explored in depth, limited biomarkers were found to predict the resistance of EGFR tyrosine kinase inhibitors (EGFR-TKI). Previous studies reported N6-methyladenosine (m6A) levels regulated response of EGFR-TKIs; whether the germline variants located in m6A sites affected resistance of EGFR-TKIs is still unknown. EXPERIMENTAL DESIGN: Patients with non-small cell lung cancer (NSCLC) with EGFR-activating mutation were enrolled to investigate predictors for response of EGFR-TKIs using a genome-wide-variant-m6A analysis. Bioinformatics analysis and series of molecular biology assays were used to uncover the underlying mechanism. RESULTS: We identified the germline mutation USP36 rs3744797 (C > A, K814N) was associated with survival of patients with NSCLC treated with gefitinib [median progression-free survival (PFS): CC vs. CA, 16.30 vs. 10.50 months, P < 0.0001, HR = 2.45] and erlotinib (median PFS: CC vs. CA, 14.13 vs. 9.47 months, P = 0.041, HR = 2.63). Functionally, the C > A change significantly upregulated USP36 expression by reducing its m6A level. Meanwhile, rs3744797_A (USP36 MUT) was found to facilitate proliferation, migration, and resistance to EGFR-TKIs via upregulating MLLT3 expression in vitro and in vivo. More importantly, MLLT3 and USP36 levels are tightly correlated in patients with NSCLC, which were associated with prognosis of patients. Mechanistically, USP36 MUT stabilized MLLT3 by deubiquitinating MLLT3 in nucleoli and consequently activating its downstream signaling (HIF1α and Snai). Furthermore, inhibition of MLLT3 alleviated USP36 variant-induced EGFR-TKIs resistance in EGFR-mutant NSCLC. CONCLUSIONS: These findings characterized rs3744797 as an oncogenic variant in mediating EGFR-TKI resistance and tumor aggressiveness through deubiquitinating MLLT3, highlighting the variant as a predictive biomarker for EGFR-TKI response in NSCLC.


Subject(s)
Carcinoma, Non-Small-Cell Lung , Drug Resistance, Neoplasm , Lung Neoplasms , Ubiquitin Thiolesterase , Humans , Carcinoma, Non-Small-Cell Lung/drug therapy , Carcinoma, Non-Small-Cell Lung/genetics , ErbB Receptors , Germ Cells/metabolism , Germ-Line Mutation , Lung Neoplasms/drug therapy , Lung Neoplasms/genetics , Mutation , Nuclear Proteins/genetics , Protein Kinase Inhibitors/adverse effects , Ubiquitin Thiolesterase/genetics
13.
Electrophoresis ; 45(7-8): 639-650, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38227365

ABSTRACT

In this work, we proposed a double moving redox boundary (MROB) model to realize the colorless analyte electrophoresis titration (ET) by the two steps of the redox reaction. Single MROB has been proposed for the development of ET sensing (Analyst, 2013, 138, 1137. ACS Sensor, 2019, 4, 126.), and faces great challenges in detecting the analyte without color change during redox reaction. Herein, a novel model of double-MROB electrophoresis, including its mechanisms, equations, and procedures, was developed for titration by using ascorbic acid as a model analyte. The first MROB was created with ferric iron (Fe3+) and iodide ion (I-) in which Fe3+ was reduced as Fe2+ and I- was oxidized as molecular iodine (I2) used as an indicator of visible MROB due to blue starch-iodine complex. The second boundary was then formed between the molecular iodine and model analyte of ascorbic acid. Under given conditions, there was a quantitative relationship between velocity of MROB (VMROB(ii)) and ascorbic acid concentration (CVit C) in the double-MROB system (1/VMROB(ii) = 0.6502CVit C + 4.5165, and R = 0.9939). The relevant relative standard deviation values of intraday and inter-day were less than ∼5.55% and ∼6.64%, respectively. Finally, the titration of ascorbic acid in chewable vitamin C tablets was performed by the developed method, the titration results agreed with those via the classic iodometric titration. All the results briefly demonstrated the validity of the double MROB model, in which Vit C was used as a model analyte. The developed method had potential use in quantitative analysis of redox-active species in biomedical samples.


Subject(s)
Ascorbic Acid , Oxidation-Reduction , Ascorbic Acid/analysis , Ascorbic Acid/chemistry , Limit of Detection , Reproducibility of Results , Models, Chemical , Iodine/chemistry , Iodine/analysis , Linear Models , Electrophoresis/methods
14.
Gastroenterology ; 166(3): 466-482, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38065340

ABSTRACT

BACKGROUND & AIMS: Although immunotherapy shows substantial advancement in colorectal cancer (CRC) with microsatellite instability high, it has limited efficacy for CRC with microsatellite stability (MSS). Identifying combinations that reverse immune suppression and prime MSS tumors for current immunotherapy approaches remains an urgent need. METHODS: An in vitro CRISPR screen was performed using coculture models of primary tumor cells and autologous immune cells from MSS CRC patients to identify epigenetic targets that could enhance immunotherapy efficacy in MSS tumors. RESULTS: We revealed EHMT2, a histone methyltransferase, as a potential target for MSS CRC. EHMT2 inhibition transformed the immunosuppressive microenvironment of MSS tumors into an immunomodulatory one by altering cytokine expression, leading to T-cell-mediated cytotoxicity activation and improved responsiveness to anti-PD1 treatment. We observed galectin-7 up-regulation upon EHMT2 inhibition, which converted a "cold" MSS tumor environment into a T-cell-inflamed one. Mechanistically, CHD4 repressed galectin-7 expression by recruiting EHMT2 to form a cotranscriptional silencing complex. Galectin-7 administration enhanced anti-PD1 efficacy in MSS CRC, serving as a potent adjunct cytokine therapy. CONCLUSIONS: Our findings suggest that targeting the EHMT2/galectin-7 axis could provide a novel combination strategy for immunotherapy in MSS CRC.


Subject(s)
Colorectal Neoplasms , Humans , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/genetics , Immunotherapy , Cytokines , Galectins/genetics , Microsatellite Repeats , Microsatellite Instability , Tumor Microenvironment , Histocompatibility Antigens , Histone-Lysine N-Methyltransferase
15.
Water Res ; 249: 120948, 2024 Feb 01.
Article in English | MEDLINE | ID: mdl-38064787

ABSTRACT

Scientists have been focusing on applying more natural processes instead of industrial chemicals in drinking water treatment to achieve the purpose of carbon emissions reduction. In this study, we shortened the infiltration range of riverbank filtration, a natural water purification process, to form the short-distance riverbank filtration (sRBF) which retained its ability in water quality improvement and barely influenced the groundwater environment, and integrated it with ultrafiltration (UF) to form a one-step sRBF-UF system. This naturalness-artificiality combination could realize stable contaminants removal and trans-membrane pressure (TMP) increase relief for over 30 days without dosing chemicals. Generally, both sRBF and UF played the important role in river water purification, and the interaction between them made the one-step sRBF-UF superior in long-term operation. The sRBF could efficiently remove contaminants (90 % turbidity, 60 % total nitrogen, 30 % ammonia nitrogen, and 25 % total organic carbon) and reduce the membrane fouling potential of river water under its optimum operation conditions, i.e., a hydraulic retention time of 48 h, an operation temperature of 20 °C, and a synergistic filter material of aquifer and riverbank soil. Synergistic adsorption, interception, and microbial biodegradation were proved to be the mechanisms of contaminants and foulants removal for sRBF. The sequential UF also participated in the reduction of impurities and especially played a role in intercepting microbial metabolism products and possibly leaked microorganisms from sRBF, assuring the safety of product water. To date, the one-step sRBF-UF was a new attempt to combine a natural process with an artificial one, and realized a good and stable product quality in long-term operation without doing industrial chemicals, which made it a promised alternative for water purification for cities alongside the river.


Subject(s)
Ultrafiltration , Water Purification , Membranes, Artificial , Filtration , Carbon , Nitrogen
16.
Water Res ; 249: 121003, 2024 Feb 01.
Article in English | MEDLINE | ID: mdl-38086205

ABSTRACT

The application of ultrafiltration (UF) in wastewater reclamation alleviates the demand for limited water supplies. However, the membrane fouling caused by the effluent organic matter (EfOM) becomes a major obstacle for UF application. In this study, a pre-oxidation strategy for UF using a Sb-SnO2 (ATO) anode in flow-through mode was proposed with the hopes to improve the performance of UF during wastewater reclamation. The results indicated that this flow-through ATO (FA) anode significantly outperformed a boron-doped diamond (BDD) anode in terms of EfOM degradation and membrane fouling control. It is noteworthy that apart from oxidation, the self-aggregation behavior of foulants was also involved in the mechanisms of membrane fouling mitigation. On the one hand, FA pre-oxidation relieved the burden of membrane fouling by decomposing the macromolecular EfOM into small molecular organic matter, and even mineralizing it. The effective destruction of unsaturated EfOM by FA pre-oxidation made a remarkable contribution to fouling mitigation due to the strong correlation between the total fouling index and UV254. On the other hand, the surface morphology of membrane and interface properties of foulants revealed the self-aggregation behavior of foulants. FA pre-oxidation made the foulants aggregate spontaneously and reduced the potential of forming a dense cake layer on the membrane surface, which was conductive for water permeation. Overall, FA pre-oxidation proved to be a feasible and chemical-free option for UF pretreatment to simultaneously produce high-quality reused water and alleviate membrane fouling during wastewater reclamation.


Subject(s)
Wastewater , Water Purification , Ultrafiltration , Water Purification/methods , Membranes, Artificial , Water Supply
17.
Water Res ; 250: 121037, 2024 Feb 15.
Article in English | MEDLINE | ID: mdl-38142506

ABSTRACT

The complex organic and inorganic solutes present in nanofiltration's purification by-product (NF concentrate, NFC) pose challenges to the water processing procedure. To address this, a three-compartment membrane electrolyzer was proposed that facilitates electro-driven ion migration for crystallization alongside synchronous anodic oxidation for organic degradation. With a hydraulic retention time (HRT) of 5 min and a current exceeding 50 mA, the system effectively separated over 25 % of inorganic salts and accomplished reclamation through crystallization in the concentration compartment. Simultaneously, it achieved oxidation of pollutants by more than 35 % based on the total nitrogen index and removed upwards of 15 % of organic carbon. Notably, the efficiency of pollutant removal correlated strongly with the intensity of the current. Furthermore, this study uncovered two issues encountered during the electrochemical process: membrane fouling and electrode fouling. During concentration, metal cations readily formed organic pollution by complexing with organic pollutants, while the crystallization of inorganics on the surface of anion exchange membranes emerged as a pivotal factor hindering current enhancement, similar to the formation of deposited salt in a solution. Long HRT can lead to electrode contamination and corrosion which subsequently affect current efficiency. Energy consumption verified the feasibility of the electrolyzer for NFC processing. Based on our findings, a current intensity of 100 mA (equivalent to a density of 8 mA/cm2) was deemed optimal, striking a balance between pollutant removal and various limiting factors associated with each pollutant. Consequently, this innovative advancement in membrane electrolyzers helps in overcoming limitations in synergistic desalination, ion recovery, and organic removal, establishing a fundamental component of the abbreviated flow process for future NFC treatment.


Subject(s)
Environmental Pollutants , Water Purification , Carbon , Oxidation-Reduction , Environmental Pollution , Oxidative Stress , Water Purification/methods , Membranes, Artificial
18.
Water Res ; 250: 121038, 2024 Feb 15.
Article in English | MEDLINE | ID: mdl-38157600

ABSTRACT

The application of magnetic fields (MFs) and magnetic particles (MPs) in water treatment has attracted widespread attention due to their stability, strong biological compatibility, and less chemical consumption. This study introduced MPs and MFs to GDM and probed their effects on filtration performance. Predeposited large MPs (P-large) and batch-added little MPs (B-little) intervened biocake layer development, forming more open and porous structures, they also reduced biomass secretion, resulting in flux increases of 13 % in P-large and 40 % in B-little than P-little, respectively. Besides, MFs controlled MPs distribution on the biocake layer, resulting in forming of more rough and open structures. A relatively lower magnetic field of 20 mT facilitated biomass secretion, while a higher magnetic field of 50 mT decreased biomass. Furthermore, applying magnetic fields decreased the ratios of α-helix and ß-sheet, and increased random coil percentage. Thus, applying magnetic field mediation would contribute to the flux improvements in I-20 and I-50 by 29 % and 32 % relative to I-0. Economic analysis suggested introducing MPs and MFs to GDM was economically feasible, synergy of MPs and MFs had more economic advantages on the community scale and MPs-assisted GDM had significant economic advantages on both community and household scales. Future works should focus on developing new technologies for the recycling of MPs and membranes. This study provided new insight into the protein secondary structures associated with GDM performance and would encourage new sustainable MFs and MPs-assisted GDM technological developments.


Subject(s)
Membranes, Artificial , Water Purification , Water Purification/methods , Filtration/methods , Recycling
19.
Mol Biol Evol ; 40(12)2023 Dec 01.
Article in English | MEDLINE | ID: mdl-38064674

ABSTRACT

The de novo synthesis of deoxythymidine triphosphate uses several pathways: gram-negative bacteria use deoxycytidine triphosphate deaminase to convert deoxycytidine triphosphate into deoxyuridine triphosphate, whereas eukaryotes and gram-positive bacteria instead use deoxycytidine monophosphate deaminase to transform deoxycytidine monophosphate to deoxyuridine monophosphate. It is then unusual that in addition to deoxycytidine monophosphate deaminases, the eukaryote Dictyostelium discoideum has 2 deoxycytidine triphosphate deaminases (Dcd1Dicty and Dcd2Dicty). Expression of either DcdDicty can fully rescue the slow growth of an Escherichia coli dcd knockout. Both DcdDicty mitigate the hydroxyurea sensitivity of a Schizosaccharomyces pombe deoxycytidine monophosphate deaminase knockout. Phylogenies show that Dcd1Dicty homologs may have entered the common ancestor of the eukaryotic groups of Amoebozoa, Obazoa, Metamonada, and Discoba through an ancient horizontal gene transfer from a prokaryote or an ancient endosymbiotic gene transfer from a mitochondrion, followed by horizontal gene transfer from Amoebozoa to several other unrelated groups of eukaryotes. In contrast, the Dcd2Dicty homologs were a separate horizontal gene transfer from a prokaryote or a virus into either Amoebozoa or Rhizaria, followed by a horizontal gene transfer between them. ThyXDicty, the D. discoideum thymidylate synthase, another enzyme of the deoxythymidine triphosphate biosynthesis pathway, was suggested previously to be acquired from the ancestral mitochondria or by horizontal gene transfer from alpha-proteobacteria. ThyXDicty can fully rescue the E. coli thymidylate synthase knockout, and we establish that it was obtained by the common ancestor of social amoebae not from mitochondria but from a bacterium. We propose horizontal gene transfer and endosymbiotic gene transfer contributed to the enzyme diversity of the deoxythymidine triphosphate synthesis pathway in most social amoebae, many Amoebozoa, and other eukaryotes.


Subject(s)
Amoeba , Dictyostelium , DCMP Deaminase/genetics , DCMP Deaminase/metabolism , Gene Transfer, Horizontal , Escherichia coli/genetics , Escherichia coli/metabolism , Amoeba/metabolism , Thymidylate Synthase/genetics , Deoxycytidine Monophosphate
20.
Environ Sci Technol ; 57(45): 17649-17658, 2023 11 14.
Article in English | MEDLINE | ID: mdl-37910031

ABSTRACT

Cyanobacteria fouling in ultrafiltration (UF) drinking water treatment poses a significant threat to the stability and sustainability of the process. Both phycocyanin found in cyanobacteria and the polymer membrane exhibit strong fluorescence, which could be readily detected using front-face excitation-emission matrix (FF-EEM) spectroscopy. In this study, FF-EEM was employed for the nondestructive and in situ characterization of algae fouling evolution in UF, while also analyzing fouling mechanisms and reversibility. The results indicated that phycocyanin fluorescence on the membrane surface showed a linear correlation with the specific algal cell count on the membrane surface before reaching saturation. As fouling progressed, membrane fluorescence decreased, which was associated with the extent of the surface coverage on the membrane. The plateau in membrane fluorescence indicated full coverage, coinciding with the cake filtration mechanism, cake compression, and deterioration of fouling reversibility. These findings highlight the promise of FF-EEM as a valuable tool for monitoring and evaluating fouling of cyanobacteria in UF systems.


Subject(s)
Cyanobacteria , Water Purification , Ultrafiltration/methods , Phycocyanin , Membranes, Artificial , Filtration , Water Purification/methods
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