Water Matrix Research Articles

Rapid phenol mineralisation in a low-pressure dead-end light transmitting photocatalytic membrane reactor (LT-PMR)

Photocatalytic membrane reactors (PMRs) are widely studied for wastewater decontamination but reactions are too slow for scaled up application. This PMR study proposes a novel operation involving rapid decontamination in just one pass through the confined space within the membrane. This approach was demonstrated for the first time by light transmitting PMR (LT-PMR), conveniently receiving UV LED light (λpeak = 365 nm) via the permeate side to the photocatalyst P25 TiO2 microfiltration membrane coated on porous glass. A 93 % reduction in model contaminant phenol concentration from a 10 mg/L feed occurred at a flux of 4.7 L/m2/h. The phenol degradation occurred without any additional residence time from external vessels or recirculation. Phenol was almost entirely mineralised, confirmed by total organic carbon (TOC) measurements, with trace by-products identified by high pressure liquid chromatography (HPLC) analysis. Mass transfer and reaction rate constants from Langmuir-Hinshelwood modelling were comparable to literature. Highest reaction rates occurred at lowest permeate phenol concentrations, highlighting potential to destroy recalcitrant pollutants persisting through established treatments. LT-PMR is therefore an effective and practical process that very rapidly destroys phenol. Further work to explore improved flux by enhanced light transmission, tailored catalytic materials and demonstration on other pollutants and water matrices is warranted.

Investigation of direct Coagulation-Flocculation-Ultrafiltration (CFU) at lab-scale constant pressure and flux operation of copper removal

Limited heavy metal concentrations in drinking water are harmful. The size-exclusion separation process was found to be a technology for removing heavy metals and organic substances. Although promising, a single ultrafiltration process is insufficient for the separation of heavy metals. Therefore, an additional process is required. The combination of coagulation flocculation followed by ultrafiltration was investigated. In this study, water matrix was used to simulate the worst-case scenario by adding 2 mg of copper to the surface water. For the filtration process, a comparison of single ultrafiltration with and without pretreatment using aluminum sulfate was investigated. Filtration was performed in a lab-scale experiment employing a polyethersulfone (PES) membrane with an average pore size of 30 nm operated at constant flux 120 L/m²⋅h and constant pressure of 0.7 bar. Furthermore, TDS retention, copper concentration, and turbidity were observed. Higher Cu removal was found at filtration under constant flux compared to constant pressure (81% and 66%, respectively. In the case of treated water with coagulation (optimum coagulation of 30 mg/L), higher removal of Cu was observed at constant flux operation compared to constant pressure, with 73% and 89% removal, respectively. Additional coagulation resulted in less membrane fouling during the filtration experiment, which explained the better performance almost double that of single ultrafiltration.

Efficient water disinfection against antibiotic-resistant bacteria by visible-light heterogeneous photo-Fenton-like process with atomically dispersed Cu on graphitic carbon nitride as the catalyst

Waterborne microbial contamination poses significant environmental and health risks. Photocatalytic heterogeneous Fenton and Fenton-like processes can offer efficient pathogen removal, with benefits in recycling, solid–liquid separation, and byproduct avoidance. However, their low reaction efficiency and slow kinetics for low-valence metal regeneration are limitations. This study addresses these challenges by incorporating atomically dispersed Cu onto graphitic carbon nitride (g-CN) as a single-atom catalyst (SAC). The Cu atoms are stabilized by pyridinic N atoms through coordination, forming Cu-N4 catalytic sites that enhance photogenerated charge carrier transfer. This leads to a more efficient synergistic photocatalytic-Fenton-like reaction, generating more hydroxyl radicals and achieving effective water disinfection. Results show a 7-log bacterial inactivation of antibiotic-resistant Acinetobacter baumannii within 8 min, surpassing prior photocatalytic-Fenton-like disinfection systems. Density functional theory calculations confirm improved hydrogen peroxide adsorption, electron transport, and electron-hole separation in the Cu-N4 structure. The catalyst’s durability and stability were demonstrated through extensive cycling experiments, ion interference tests, and disinfection trials in various water matrices. Additionally, the Cu-SAC@CN catalyst, loaded onto a polytetrafluoroethylene membrane, achieved a 99% bacterial eradication rate within 20 min. This study provides valuable insights into the potential applications of heterogeneous photocatalytic-Fenton-like systems for efficient eradication of waterborne bacteria.

Photo-assisted oxygen-rich vacancy copper oxide catalyst to activate peroxymonosulfate (PMS) for efficient degradation of fulvic acid

In this study, novel copper oxide particles-activated peroxymonosulfate (CuO-S/PMS/UV) were employed to degrade fulvic acid(FA). Under the optimal treatment condition, the FA removal of the CuO-S/PMS/UV process was up to 97.74%. The removal rates of SUVA254, UVA365 UVA280 UVA463 and TOC within 40 min in the UV/CuO-S/PMS process were 23.4%, 95.6%, 63.2%, 100% and 40.8% respectively. The three-dimensional fluorescence spectrum analysis of FA during the degradation process revealed the disappearance of FA-associated functional structures. Furthermore, the impact of common anions in the water matrix on the degradation process was investigated, demonstrating that the system remains effective containing low concentrations of anions. Subsequently, mechanism studying showed that SO4•−, 1O2, h+, and •OH species were primarily involved in the degradation of FA, while O2•− has a limited effect in the degradation process. This study can provide valuable insights for the degradation of humic pollutants in the water environment.

Post-calcination as an effective approach to enhance adsorption of arsenic and antimony anions by Mg/Al layered double hydroxide-decorated spent coffee ground biochars: Role of charge properties and active sites

This study evaluated the effects of post-calcination on the charge properties and active sites of Mg/Al layered double hydroxide-decorated spent coffee ground biochars (LDHMgAl@SCGB) governing adsorption behaviors and mechanisms of arsenic (AsV) and antimony (SbV) anions from aqueous phases. Post-calcinated LDHMgAl@SCGB (PLDHMgAl@SCGB) exhibited higher adsorption capacities for AsV and SbV compared to spent coffee ground biochars (SCGB) and LDHMgAl@SCGB as post-calcination of LDHMgAl@SCGB enhanced the charge properties (surface zeta potential at pH 7.0: SCGB = −21.8 mV, LDHMgAl@SCGB = 28.5 mV, and PLDHMgAl@SCGB = 34.4 mV) and increased active sites by eliminating the anions (i.e., Cl− ions) and water molecules at its interlayers. The calculated kinetic, intra-particle diffusion, and isotherm parameters indicated that the chemisorption and intra-particle diffusion were mainly responsible for the adsorption of AsV and SbV by SCGB, LDHMgAl@SCGB, and PLDHMgAl@SCGB. Moreover, post-calcination of LDHMgAl@SCGB enhanced its selectivity toward AsV and SbV by reinforcing the electrostatic surface complexation via its improvement of charge properties. Since PLDHMgAl@SCGB exhibited the excellent reusability for the adsorption of AsV (reuse efficiency >63.6%) and SbV (reuse efficiency >52.1%), it can be concluded that post-calcination of LDHMgAl@SCGB is a promising method for improving the adsorption capacities for AsV and SbV in real water matrices.

Effect of water matrix on sulfate radical behavior during BTB degradation by activated persulfate

Effect of water matrix on sulfate radical behavior during BTB degradation by activated persulfate

Comparison of four concentration methods of adenovirus, norovirus and rotavirus in tap water

Human enteric viruses, as adenovirus (HAdV), norovirus (HuNoV) and rotavirus (RVA) are significant causes of gastroenteritis associated with consumption of contaminated water worldwide. Various methods have been described for their detection and monitoring in water. The aim of this study was to compare the performance of four conditions for concentrating HAdV, HuNoV and RVA from water matrices, in order to develop a single protocol that could simultaneously concentrate all target viruses from tap water. The tested conditions were based on the adsorption-elution using electronegative filters, in which we evaluated cation-coated filtration by MgCl2 with or without acid rinse by H2SO4 and two elution buffers, namely NaOH and tris-glycine-beef extract. Genomic material was extracted and amplified by real-time PCR and real-time RT-PCR using commercial kits. Based on the statistical analysis of amplification results (cycles of quantification), the condition involving cation-coated filtration by MgCl2 using electronegative filters with acid rinse by H2SO4 combined with NaOH elution allowed efficient recovery of both HAdV, HuNoV and RVA from tap water compared to the other conditions. These findings confirm the effectiveness of the approach used to monitor three major enteric viruses in tap water.

Integration of single-atom photothermal catalysts with surface-localized high temperature in peroxymonosulfate-based Fenton-like systems for enhanced antibiotics degradation

This study delves into integrating single-atom catalysts with photothermal effect in peroxymonosulfate (PMS)-based Fenton-like systems for enhanced pollutant degradation. A single-atom photothermal catalyst (Co/PMCNs) was designed using mesoporous carbon spheres as both a single-atom support and a photothermal material. Near-infrared (NIR) light was employed due to its superior thermal effect and penetration capacity in water. It was found that Co/PMCNs could generate surface-localized high temperatures for accelerating PMS activation and reducing energy gap of activation reactions, leading to improved degradation performance. Surface-localized high temperatures were demonstrated as key in distinguishing photothermal heating from external heat sources for PMS activation. Moreover, this system performed well across various operating conditions and water matrices, with Co/PMCNs showing promising recyclability. This study highlights the impact of surface-localized high temperatures on heterogeneous catalysis under NIR irradiation, and underscores the potential of integrating single-atom catalysts with photothermal effects into advanced oxidation processes for effective water pollution control.

Photo-reductive decomposition of perfluorooctane sulfonate (PFOS) and its common alternatives by UV/VUV/sulfite process: Mechanism, kinetic modeling, and water matrix effects

The present study investigated the photo-reduction of perfluorooctane sulfonate (PFOS) and its alternatives, focusing on decomposition mechanisms, active species involvement, the influence of background water constituents, and kinetic model development. The decomposition and defluorination rates followed the order of PFOS > PFHxS > 6:2 FTSA > PFBS, with shorter chains and CH2 linkers enhancing the resistance of PFOS alternatives against the attack of hydrated electrons (eaq−). Two primary pathways were identified during the photodegradation of PFAS: (i) H/F exchange at CF bonds with the lowest bond dissociation energies (BDEs) and (ii) functional group cleavage followed by short-chain PFCAs formation, with OH playing a crucial role in transforming intermediates. Adding iodide and elevated temperatures demonstrated a synergistic effect on PFBS decomposition and defluorination, with high temperatures promoting functional group cleavage as the preferred defluorination pathway. The study examined the impact of background water constituents in different aqueous environments, from surface waters to wastewater streams and ion-exchange brine concentrates. Chloride exhibited a concentration-based dual impact on the UV/VUV/sulfite process: promotive effects at low dosages (1–10 mM) by acting as a secondary eaq− mediator, and adverse effects at high dosages (20–500 mM) due to the scavenging effect of generated chlorine radicals (Cl). High ionic strength adversely affected eaq− quantum efficiency. Additionally, bicarbonate and natural organic matter (NOM) had opposing effects on PFOS photo-reduction, primarily through eaq− scavenging and pH alteration. Kinetic modeling revealed reaction rate constants of the studied PFAS with eaq− ranging from 1.8 × 106 to 1.3 × 109 M−1 s−1, corroborating the concentration profiles of active species and highlighting the reductive nature of sulfite-mediated processes.

Zinc indium sulfide coupling with graphitic carbon nitride containing non-intrinsic oxygen vacancies to form Z-scheme heterojunction for boosting photodegradation of tetracycline

A novel graphitic carbon nitride containing non-intrinsic oxygen vacancies (Vo-CN) is interfacial coupling with zinc indium sulfide (ZIS) to form Z-scheme heterojunction (VCZ) for efficient tetracycline (TC) degradation. The TC removal rate by VCZ-1 (mass ratio of Vo-CN: ZIS is 1:20, 0.2 g/L) achieves 99.86 %. VCZ-1 reveals outstanding reusability and stability with an unchanged TC degradation rate after undergoing five cycles. VCZ-1 achieves high-efficiency TC degradation in various water matrices. The experimental and DFT calculations indicate that the built-in electric field drives charges on Vo-CN transfer to ZIS, forming a Z-scheme VCZ-1 heterojunction. The strong electronic coupling effect between Vo-CN and ZIS facilitates charge exchange at the heterojunction interface. Non-intrinsic oxygen vacancies in VCZ, as binding sites for electrons and holes, effectively lower the energy barrier for singlet excitons converting to triplet excitons. The triplet excitons are induced to transfer energies to dissolved oxygen and expedite 1O2 production. 1O2 synergizes with •O2– and •OH to attack O-containing groups and hexatomic rings in TC, inducing demethylation, hydroxylation, dihydroxylation, and ring-opening reactions. Three possible degradation pathways are inferred by UPLC/MS/MS and Fukui index of TC. The ecotoxicity evaluation of intermediate products highlights the benefits of VCZ-1 photocatalytic oxidation in ensuring environmental safety. This work proposes a novel idea for constructing efficient Z-scheme photocatalysts for environmental remediation.

Adsorption of ionic contaminants from complex water matrices by versatile chitosan-based beads

Most adsorbents are currently restricted by their single function in pollutant removal from complex wastewater. Herein, we constructed a versatile chitosan-based adsorbent (MC-DA) by grafting amphoteric copolymers with high pH-responsiveness property, aiming at the removal of multiple ionic contaminants. Specifically, the surface charge and hydrophobicity/hydrophilicity of MC-DA can be finely tuned under different pH conditions. As a result, the effective adsorption of cationic methylene blue (MB) and anionic Acid Orange 7 (AO7) with capacities of 627.4 mg/g and 1146.8 mg/g were achieved respectively, superior to most reported materials. Regarding the characterization results, the adsorption mechanisms for MB adsorption were electrostatic and hydrophobic interactions, while the electrostatic attraction was the main driving force for AO7 adsorption. Apart from the versatile adsorption performance, high acid resistance (pH ≥ 2.0), good reusability and rapid separation property under an external magnetic field suggested MC-DA’s promising environmental benefits and practical application potential in water remediation.

Target-triggered oxygen vacancy increase of Co3O4 nanoparticles with promoted peroxidase-like activity for specific turn-on colorimetric sensing of uranyl ions

As the most stable form of uranium in water and soil, uranyl ions (UO22+) possess strong biological toxicity and radioactivity, causing a great threat to human health. Therefore, it is of significance to develop reliable methods for monitoring uranyl ions in the environment. Here we propose a “light-up” colorimetric strategy based on target-accelerated peroxidase-mimicking activity of Co3O4 for the specific detection of uranyl ions. Original Co3O4 nanoparticles exhibit a certain peroxidase-like activity in catalyzing colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxTMB with the participation of H2O2. When UO22+ is introduced, it interacts with the nanozyme rapidly and specifically and promotes the latter’s catalytic ability via increasing active oxygen vacancies on Co3O4 surface. According to such a phenomenon and mechanism, selective determination of UO22+ with favorable performance is achieved, with a linear measurement range of 0.2–10 μM and a detection limit of 0.08 μM. Reliability and practicability of the proposed method are demonstrated by analyzing the pollutant in several environmental water matrices. Our work not only offers a novel, efficient yet convenient approach for measuring UO22+, but may also inspire the exploration of new nanozyme-based sensing principles and strategies for other analytical applications.

Efficient photocatalytic water decontamination over a wide pH range by C and O co-doped carbon nitride with tunable band structure

The metal-free, non-toxic, and highly tunable structure of carbon nitride confers unique advantages in photocatalytic advanced oxidation processes. Regulating the generation of radical and non-radical species during photocatalysis to maintain high degradation efficiency across different water matrices is of great practical significance for the application of carbon nitride. In this study, a C and O co-doped modified carbon nitride (UCN) with a high specific surface area was developed for efficient photodegradation of p-chlorophenol (p-Cl) without exogenous oxidants. Characterizations demonstrated that UCN in higher specific surface area exposed more active sites. Additionally, with rising doping levels, UCN exhibited enhanced light absorption capability and a narrower bandgap, which favored the separation of photogenerated electron-hole pairs. The primary active species were identified as holes, accompanied by the generation of superoxide radicals (·O2–) and singlet oxygen (1O2) depending on the pH value. Under acidic conditions, 1O2 was predominantly generated, whereas ·O2– dominated under alkaline conditions. As a result, the removal efficiency of p-Cl was enhanced under both strongly acidic and alkaline conditions. The pseudo-first-order rate constants for p-Cl removal at pH 3, 7, and 11 were 0.0558, 0.0354, and 0.0443 min−1, respectively. Moreover, combining DFT calculations and LC-MS data, analysis on the intermediate products of p-Cl degradation revealed unique characteristics at different pH values, further proving the flexible tunability and providing insights into the practical application of modified carbon nitride.

Current Challenges in Monitoring Low Contaminant Levels of Per- and Polyfluoroalkyl Substances in Water Matrices in the Field.

The Environmental Protection Agency (EPA) of the United States recently released the first-ever federal regulation on per- and polyfluoroalkyl substances (PFASs) for drinking water. While this represents an important landmark, it also brings about compliance challenges to the stakeholders in the drinking water industry as well as concerns to the general public. In this work, we address some of the most important challenges associated with measuring low concentrations of PFASs in drinking water in the field in real drinking water matrices. First, we review the "continuous monitoring for compliance" process laid out by the EPA and some of the associated hurdles. The process requires measuring, with some frequency, low concentrations (e.g., below 2 ppt or 2 ng/L) of targeted PFASs, in the presence of many other co-contaminants and in various conditions. Currently, this task can only (and it is expected to) be accomplished using specific protocols that rely on expensive, specialized, and laboratory-scale instrumentation, which adds time and increases cost. To potentially reduce the burden, portable, high-fidelity, low-cost, real-time PFAS sensors are desirable; however, the path to commercialization of some of the most promising technologies is confronted with many challenges, as well, and they are still at infant stages. Here, we provide insights related to those challenges based on results from ab initio and machine learning studies. These challenges are mainly due to the large amount and diversity of PFAS molecules and their multifunctional behaviors that depend strongly on the conditions of the media. The impetus of this work is to present relevant and timely insights to researchers and developers to accelerate the development of suitable PFAS monitoring systems. In addition, this work attempts to provide water system stakeholders, technicians, and even regulators guidelines to improve their strategies, which could ultimately translate in better services to the public.

Fast diffusion kinetics improves electron transfer regime selectivity to boost peroxymonosulfate activation

Electron transfer process (ETP) is barely influenced by half-life and migration distance in peroxymonosulfate (PMS) activation because it directly extracts electrons from pollutants for oxidation. However, the enhanced ETP selectivity is still challenging due to the poor mass transfer of PMS and pollutant. In this work, 2D porous N-doped carbon (PNC) with high reactant diffusion kinetics and multiple diffusion modes was designed to induce the interlayer confinement for efficient PMS activation with elevated ETP selectivity. Taking tetrabromobisphenol A as target pollutant, the confined PNC/PMS system achieved significantly enhanced PMS activation performance with the selectivity of ETP up to 97.8%. The vertical mass transfer of reactants into the inner interlayer space of the catalysts was proved to be promoted by the construction of molecule tunnels according to a diffusion model. Density functional theory calculations indicated that the subsequently triggered interlayer confinement facilitated the co-adsorption of PMS/pollutant on the interlayer surface and narrowed the energy gap of charge migration, resulting in enhanced PMS activation performance and ETP selectivity. Benefiting from the almost 100 % ETP selectivity, the confined PNC/PMS system exhibited substantially increased PMS utilization efficiency, admirable anti-interference ability towards various water matrices as well as long-term stability in a continuous-flow reactor. This work provides a new protocol for efficient and selective PMS activation by interlayer confinement in water remediation.

A synergistic adsorption-catalysis with co-doped Fe/Mn porous PET waste for simultaneous and ambient remediation of hazardous pharmaceutical drugs and dye in multi-component systems by enhancing singlet oxygen

Valorizing single-use plastic waste as an effective activator in environmental protection has gained great interest from policymakers, legislators, and scientific research communities. Herein, low-cost and highly porous alkali Fe/Mn-doped carbon nanomaterials derived from polyethylene terephthalate (PET) waste (MF/cPET-x) were fabricated via facile pyrolysis and alkali-metal impregnation methods. Detailed characterizations of MF-cPET-x demonstrated that the ratio of alkaline impregnation and pyrolysis temperature affects the porous characteristics, content, and size of active sites, specific surface area, and yield of carbon residue/nanocomposite. The main aim of this study was to evaluate and optimize the MF/cPET-x applied for the detoxification of various kinds of pharmaceutical drugs (tetracycline, naproxen, paracetamol, and levofloxacin) and various dyestuff in their single, binary, ternary, and quaternary solutions. The magnetic porous MF/cPET-1 was found to show a most effective PMS activation for single/multiple toxic pollutants removal attaining levels >91.0 % in a wide range of temperatures (5–35 °C) and pH (3.0–9.0), without significant detectable metal leaching (>0.16 mg L−1). The outstanding catalytic performance in complex water environments was mainly attributed to the deposition of Mn/Fe nanoparticles with small grain size on a polymeric scaffold, bimetal synergistic effect, high specific surface area, high stability, and excellent anti-interference capability against coexisting substances. Physicochemical properties of the recycled composite, masking, and EPR analyses confirmed that the dominant reactive species in the following order: 1O2 > OH > SO4− > O2−. This work offers a new and straightforward approach for preparing porous alloy composite from plastic waste for pollutant degradation in various water matrices.

Functional characterization of a novel Chlamydomonas reinhardtii hydrolase involved in biotransformation of chloramphenicol

Microalgae-based biotechnology is one of the most promising alternatives to conventional methods for the removal of antibiotic contaminants from diverse water matrices. However, current knowledge regarding the biochemical mechanisms and catabolic enzymes involved in microalgal biodegradation of antibiotics is scant, which limits the development of enhancement strategies to increase their engineering feasibility. In this study, we investigated the removal dynamics of amphenicols (chloramphenicol, thiamphenicol, and florfenicol), which are widely used in aquaculture, by Chlamydomonas reinhardtii under different growth modes (autotrophy, heterotrophy, and mixotrophy). We found C. reinhardtii removed >92 % chloramphenicol (CLP) in mixotrophic conditions. Intriguingly, gamma-glutamyl hydrolase (GGH) in C. reinhardtii was most significantly upregulated according to the comparative proteomics, and we demonstrated that GGH can directly bind to CLP at the Pro77 site to induce acetylation of the hydroxyl group at C3 position, which generated CLP 3-acetate. This identified role of microalgal GGH is mechanistically distinct from that of animal counterparts. Our results provide a valuable enzyme toolbox for biocatalysis and reveal a new enzymatic function of microalgal GGH. As proof of concept, we also analyzed the occurrence of these three amphenicols and their degradation intermediate worldwide, which showed a frequent distribution of the investigated chemicals at a global scale. This study describes a novel catalytic enzyme to improve the engineering feasibility of microalgae-based biotechnologies. It also raises issues regarding the different microalgal enzymatic transformations of emerging contaminants because these enzymes might function differently from their counterparts in animals.

Vanadium doped Fe-Mn bimetallic oxides as cathodic materials for boosted heterogeneous electro-Fenton degradation of organic contaminants

The design of cathode materials with both sustainable H2O2 selectivity and accelerated recyclable regeneration remains a challenge for contaminants removal in heterogeneous electro-Fenton (HEF) process. Herein, a series of ternary Fe0.50Mn0.5−δVδOx (δ = 0.005, 0.01, 0.05) metal oxides have been synthesized and employed as cathodic materials for the degradation of various organic contaminants in water matrix. 99.7 % removal rate was achieved for carbamazepine (CBZ) in 60 min with 98.8 % mineralization rate. Simultaneously, the catalyst exhibited outstanding degradation efficiency (96.0–99.7 %) with other pollutants including sulfonamides (SMX), bisphenol A (BPA), 2,4-dichlorophenol (2,4-DPC) and ofloxacin (OFX), demonstrating its potential application. Factors affecting the EF process, including current density, pH, oxygen flow rate and compatibility of inorganic anions were thoroughly evaluated and the degradation mechanism was studied in detail. Density functional theory (DFT) calculations revealed that the improved catalytic efficiency was originated from vanadium doping to access optimized electronic structure, which endows enhanced 2e− ORR selectivity as well as excellent overall performance for the EF process. This work may enrich the study on EF system and offers a promising strategy for contaminants removal with FeMnVO materials in water treatment applications.

Removal of antibiotic resistant bacteria and antibiotic resistance genes by an electrochemically driven UV/chlorine process for decentralized water treatment

The UV/chlorine (UV/Cl2) process is a developing advanced oxidation process and can efficiently remove antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs). However, the transportation and storage of chlorine solutions limit the application of the UV/Cl2 process, especially for decentralized water treatment. To overcome the limitation, an electrochemically driven UV/Cl2 process (E-UV/Cl2) where Cl2 can be electrochemically produced in situ from anodic oxidation of chloride (Cl−) ubiquitously present in various water matrices was evaluated in this study. >5-log inactivation of the ARB (E. coli) was achieved within 5 s of the E-UV/Cl2 process, and no photoreactivation of the ARB was observed after the treatment. In addition to the ARB, intracellular and extracellular ARGs (tetA, sul1, sul2, and ermB) could be effectively degraded (e.g., log(C0/C) > 4 for i-ARGs) within 5 min of the E-UV/Cl2 process. Atomic force microscopy showed that the most of the i-ARGs were interrupted into short fragments (< 30 nm) during the E-UV/Cl2 process, which can thus effectively prevent the self-repair of i-ARGs and the horizontal gene transfer. Modelling results showed that the abatement efficiencies of i-ARG correlated positively with the exposures of •OH, Cl2−•, and ClO• during the E-UV/Cl2 process. Due to the short treatment time (5 min) required for ARB and ARG removal, insignificant concentrations of trihalomethanes (THMs) were generated during of the E-UV/Cl2 process, and the energy consumption (EEO) of ARG removal was ∼0.20‒0.27 kWh/m3-log, which is generally comparable to that of the UV/Cl2 process (0.18–0.23 kWh/m3-log). These results demonstrate that the E-UV/Cl2 process can provide a feasible and attractive alternative to the UV/Cl2 process for ARB and ARG removal in decentralized water treatment system.

Validation of the Chemical and Biological Steps Required Implementing an Advanced Multi-Omics Approach for Assessing the Fate and Impact of Contaminants in Lagoon Sediments.

The increasing use of chemicals requires a better understanding of their presence and dynamics in the environment, as well as their impact on ecosystems. The aim of this study was to validate the first steps of an innovative multi-omics approach based on metabolomics and 16S metabarcoding data for analyses of the fate and impact of contaminants in Mediterranean lagoons. Semi-targeted analytical procedures for water and sediment matrices were implemented to assess chemical contamination of the lagoon: forty-six compounds were detected, 28 of which could be quantified in water (between 0.09 and 47.4 ng/L) and sediment (between 0.008 and 26.3 ng/g) samples using the UHPLC-MS/MS instrument. In addition, a non-targeted approach (UHPLC-HRMS) using four different sample preparation protocols based on solid/liquid extractions or an automated pressurized fluid extraction system (EDGE®) was carried out to determine the protocol with the best metabolome coverage, efficiency and reproducibility. Solid/liquid extraction using the solvent mixture acetonitrile/methanol (50/50) was evaluated as the best protocol. Microbial diversity in lagoon sediment was also measured after DNA extraction using five commercial extraction kits. Our study showed that the DNeasy PowerSoil Pro Qiagen kit (Promega, USA) was the most suitable for assessing microbial diversity in fresh sediment.