A high-throughput, turbulent-mixing, condensation aerosol concentrator for direct aerosol collection as a liquid suspension.

Trace measurement of aerosol chemical composition in workplace atmospheres requires the development of high-throughput aerosol collectors that are compact, hand-portable, and can be operated using personal pumps. We describe the design and characterization of a compact, high flow, Turbulent-mixing Condensation Aerosol-in-Liquid Concentrator (TCALC) that allows direct collection of aerosols as liquid suspensions, for off-line chemical, biological, or microscopy analysis. The TCALC unit, measuring approximately 12 × 16 × 18 cm, operates at an aerosol sample flowrate of up to 10 L min, using rapid mixing of a hot flow saturated with water vapor and a cold aerosol sample flow, thereby promoting condensational growth of aerosol particles.

Acyl-Homoserine Lactone Enhances the Resistance of Anammox Consortia under Heavy Metal Stress: Quorum Sensing Regulatory Mechanism.

Anaerobic ammonium oxidation (anammox) represents an energy-efficient process for the removal of biological nitrogen from ammonium-rich wastewater. However, the susceptibility of anammox bacteria to coexisting heavy metals considerably restricts their use in engineering practices. Here, we report that acyl-homoserine lactone (AHL), a signaling molecule that mediates quorum sensing (QS), significantly enhances the nitrogen removal rate by 24% under Cu stress.

Compact, high-flow, water-based, turbulent-mixing, condensation aerosol concentrator for collection of spot samples.

A new high-flow, compact aerosol concentrator, using rapid, turbulent mixing to grow aerosol particles into droplets for dry spot sample collection, has been designed and tested. The "TCAC (Turbulent-mixing, Condensation Aerosol Concentrator)" is composed of a saturator for generating hot vapor, a mixing section where the hot vapor mixes with the cold aerosol flow, a growth tube where condensational droplet growth primarily occurs, and a converging nozzle that focuses the droplets into a beam. The prototype concentrator utilizes an aerosol sample flow rate of 4 L min.

Development of tungsten-modified iron oxides to decompose an over-the-counter painkiller, Acetaminophen by activating peroxymonosulfate.

Acetaminophen (APAP) is a well-known type of over-the-counter painkillers and is frequently found in surface waterbodies, causing hepatotoxicity and skin irritation. Due to its persistence and chronic effects on the environment, innovative solutions must be provided to decompose APAP, effectively. Innovative catalysts of tungsten-modified iron oxides (TF) were successfully developed via a combustion method and thoroughly characterized using SEM, TEM, XRD, XPS, a porosimetry analysis, Mössbauer spectroscopy, VSM magnetometry, and EPR.

Environmental implications of superoxide radicals: From natural processes to engineering applications.

The roles of superoxide radical (O) in the domains of physiological, physical, and material chemistry are becoming increasingly recognized. Although extensive efforts have been directed to understand O functions in diverse aquatic systems, there is a lack of systematic and in-depth review for its kinetics and mechanisms in various environmental scenarios. This review aims to bridge this gap through discussion of O generation pathways under both natural and controlled conditions.

Fragmentation of polypropylene into microplastics promoted by photo-aging; release of metals, toxicity and inhibition of biodegradability.

The widespread presence of microplastics (MP) in water represents an environmental problem, not only because of the harmful effects of their size and potential to vector other pollutants, but also because of the release of additives, degradation products and residues contained in the polymer matrix. The latter includes metallic catalysts, which are often overlooked. This study focuses on the photo-aging of polypropylene (PP) and the resulting structural changes that promote its fragmentation microplastics (PP-MPs) and release of metals, as well as the resulting toxicity of leachates and their potential to inhibit biodegradation of organics in water.

Enhancing photocatalytic CO reduction with TiO-based materials: Strategies, mechanisms, challenges, and perspectives.

The concentration of atmospheric CO has exceeded 400 ppm, surpassing its natural variability and raising concerns about uncontrollable shifts in the carbon cycle, leading to significant climate and environmental impacts. A promising method to balance carbon levels and mitigate atmospheric CO rise is through photocatalytic CO reduction. Titanium dioxide (TiO), renowned for its affordability, stability, availability, and eco-friendliness, stands out as an exemplary catalyst in photocatalytic CO reduction.

Bimolecular versus Trimolecular Reaction Pathways for HO with Hypochlorous Species and Implications for Wastewater Reclamation.

The benchmark advanced oxidation technology (AOT) that uses UV/HO integrated with hypochlorous species exhibits great potential in removing micropollutants and enhancing wastewater treatability for reclamation purposes. Although efforts have been made to study the reactions of HO with hypochlorous species, there exist great discrepancies in the order of reaction kinetics, the rate constants, and the molecule-level mechanisms. This results in an excessive use of hypochlorous reagents and system underperformance during treatment processes.

Molecular insights into the bonding mechanisms between selenium and dissolved organic matter.

Natural organic matter (NOM) plays a critical role in the mobilization and bioavailability of metals and metalloids in the aquatic environment. Selenium (Se), an environmental contaminant of aquatic systems, has drawn increasing attention over the years. While Se is a vital micronutrient to human beings, animals and plants, excess Se intake may pose serious long-term risks.

Chlorination of Emerging Contaminants for Application in Potable Wastewater Reuse: Disinfection Byproduct Formation, Estrogen Activity, and Cytotoxicity.

With increasing water scarcity, many utilities are considering the potable reuse of wastewater as a source of drinking water. However, not all chemicals are removed in conventional wastewater treatment, and disinfection byproducts (DBPs) can form from these contaminants when disinfectants are applied during or after reuse treatment, especially if applied upstream of advanced treatment processes to control biofouling. We investigated the chlorination of seven priority emerging contaminants (17β-estradiol, estrone, 17α-ethinylestradiol, bisphenol A (BPA), diclofenac, -nonylphenol, and triclosan) in ultrapure water, and we also investigated the impact of chlorination on real samples from different treatment stages of an advanced reuse plant to evaluate the role of chlorination on the associated cytotoxicity and estrogenicity.

Characterization of a multi-stage focusing nozzle for collection of spot samples for aerosol chemical analysis.

Concentrated collection of aerosol particles on a substrate is essential for their chemical analysis using various microscopy and laser spectroscopic techniques. An impaction-based aerosol concentration system was developed for focused collection of particles using a multi-stage nozzle that consists of a succession of multiple smooth converging stages. Converging sections of the nozzle were designed to focus and concentrate a particle diameter range of 900-2500 nm into a relatively narrower particle beam to obtain particulate deposits with spot diameters of 0.

Enhancement of bio-S recovery and revealing the inhibitory effect on microorganisms under high sulfide loading.

Biodesulfurization is a mature technology, but obtaining biosulfur (S) that can be easily settled naturally is still a challenge. Increasing the sulfide load is one of the known methods to obtain better settling of S. However, the inhibitory effect of high levels of sulfide on microbes has also not been well studied.

Implementation of laser flash photolysis for radical-induced reactions and environmental implications.

Confronted with the imperative crisis of water quality deterioration, the pursuit of state-of-the-art decontamination technologies for a sustainable future never stops. Fitting into the framework of suitability, advanced oxidation processes have been demonstrated as powerful technologies to produce highly reactive radicals for the degradation of toxic and refractory contaminants. Therefore, investigations on their radical-induced degradation have been the subject of scientistic and engineering interests for decades.

The role of reactive phosphate species in the abatement of micropollutants by activated peroxymonosulfate in the treatment of phosphate-rich wastewater.

This study investigated the mechanisms of forming reactive species to degrade micropollutants through the activation of peroxymonosulfate (PMS) by phosphate, a prevalent ion in wastewater. Considering the density functional theory results, the formation of hydrogen bonds between phosphate and PMS molecules might be the crucial step in the overall reactions, which prefers producing OH and reactive phosphate species (RPS, namely HPO, HPO, and PO) to yielding SO. Besides, in the phosphate (5 mM)/PMS system at pH = 8, HPO was modeled to be the dominant radical with a steady-state concentration of 3.

Merits and Limitations of Radical vs. Nonradical Pathways in Persulfate-Based Advanced Oxidation Processes.

Urbanization and industrialization have exerted significant adverse effects on water quality, resulting in a growing need for reliable and eco-friendly treatment technologies. Persulfate (PS)-based advanced oxidation processes (AOPs) are emerging as viable technologies to treat challenging industrial wastewaters or remediate groundwater impacted by hazardous wastes. While the generated reactive species can degrade a variety of priority organic contaminants through radical and nonradical pathways, there is a lack of systematic and in-depth comparison of these pathways for practical implementation in different treatment scenarios.

Effects of wavelength on the treatment of contaminants of emerging concern by UV-assisted homogeneous advanced oxidation/reduction processes.

Pollutants of emerging concern in aqueous environments present a significant threat to both the aquatic ecosystem and human health due to their rapid transfer. Among the various treatment approaches to remove those pollutants, UV-assisted advanced oxidation/reduction processes are considered competent and cost-effective. The treatment effectiveness is highly dependent on the wavelength of the UV irradiation used.

Dissolved organic matter promotes photocatalytic degradation of refractory organic pollutants in water by forming hydrogen bonding with photocatalyst.

Removing refractory organic pollutants in real water using photocatalysis is a great challenge because coexisting dissolved organic matter (DOM) can quench photogenerated holes and thus prevent generation of reactive oxygen species (ROS). Herein, for the first time, we develop a hydrogen bonding strategy to avoid the scavenging of photoexcited holes, by which DOM even promotes photocatalytic degradation of refractory organic pollutants. Theoretical calculations combined with experimental studies reveal the formation of hydrogen bonding between DOM and a hydroxylated S-scheme heterojunction photocatalyst (Mo-Se/OHNT) consisting of hydroxylated nitrogen doped TiO (OHNT) and molybdenum doped selenium (Mo-Se).

Overlooked Transformation of Nitrated Polycyclic Aromatic Hydrocarbons in Natural Waters: Role of Self-Photosensitization.

Photochemical transformation is an important process that involves trace organic contaminants (TrOCs) in sunlit surface waters. However, the environmental implications of their self-photosensitization pathway have been largely overlooked. Here, we selected 1-nitronaphthalene (1NN), a representative nitrated polycyclic aromatic hydrocarbon, to study the self-photosensitization process.

NanoSpot collector for aerosol sample collection for direct microscopy and spectroscopy analysis.

We describe design and characterization of an aerosol NanoSpot collector, designed for collection of airborne particles on a microscopy substrate for direct electron and optical microscopy, and laser spectroscopy analysis. The collector implements a water-based, laminar-flow, condensation growth technique, followed by impaction onto an optical/electron microscopy substrate or a transmission electron microscopy grid for direct analysis. The compact design employs three parallel growth tubes allowing a sampling flow rate of 1.

Phosphorus doping significantly enhanced the catalytic performance of cobalt-single-atom catalyst for peroxymonosulfate activation and contaminants degradation.

Increasing studies have been conducted to explore strategies for enhancing the catalytic performance of metal-doped C-N-based materials (e.g., cobalt (Co)-doped CN) via heteroatomic doping.

Recent advances and challenges of photoelectrochemical cells for hydrogen production.

Photoelectrocatalytic water splitting and organic reforming have recently received significant attention among researchers due to the potential opportunity to convert sunlight into hydrogen energy using efficient and low-cost photoelectrode materials under practical operating conditions. This paper discusses an overview of various aspects related to the implementation of photoelectrochemical (PEC) cells for hydrogen generation. Information on () reaction energies of photosplitting and photoreforming, () state-of-the-art semiconductor-based materials for PEC hydrogen evolution reaction (HER) active both under UV and visible-light irradiation, () PEC photo-efficiency indicators, and () criteria for the standardization of photoelectrochemical reactor performances are summarized.

Mechanistic and quantitative profiling of electro-Fenton process for wastewater treatment.

Electro-Fenton (EF) process represents an energy-efficient and scalable advanced oxidation technology (AOT) for micropollutants removal in wastewaters. However, mechanistic profiling and quantitation of contribution of each subprocess (i.e.

Ferrate(VI) mediated degradation of the potent cyanotoxin, cylindrospermopsin: Kinetics, products, and toxicity.

The presence of cylindrospermopsin (CYN), a potent cyanotoxin, in drinking water sources poses a tremendous risk to humans and the environment. Detailed kinetic studies herein demonstrate ferrate(VI) (FeO, Fe(VI)) mediated oxidation of CYN and the model compound 6-hydroxymethyl uracil (6-HOMU) lead to their effective degradation under neutral and alkaline solution pH. A transformation product analysis indicated oxidation of the uracil ring, which has functionality critical to the toxicity of CYN.

Insights into performance and mechanism of ZnO/CuCoO composite as heterogeneous photoactivator of peroxymonosulfate for enrofloxacin degradation.

In this study, we designed a plain strategy for fabrication of the novel composite ZnO/CuCoO and applied it as catalyst for peroxymonosulfate (PMS) activation to decompose enrofloxacin (ENR) under simulated sunlight. Compared to ZnO and CuCoO alone, the ZnO/CuCoO composite could significantly activate PMS under simulated sunlight, resulting in the generation of more active radicals for ENR degradation. Thus, 89.