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Combined use of light-emitting diodes (LED) ultraviolet (UV) and chlorination provides alternative disinfection in drinking water, which could affect the biofilm formed subsequently. Two sequential integrations (UV-Cl and Cl-UV) and one simultaneous combination (UV/Cl) were adopted to investigate their impacts on biofilm formation. Natural organic matter after combined processes was more accessible for microbes. This might explain the promoted growth of culturable biofilm bacteria—biofilm bacteria stabilized at 104 CFU/mL without disinfection while increasing continuously to 105 CFU/mL in 106 days after combined processes. Contrarily, the viable biofilm bacteria were efficiently suppressed by combined processes, with the least bacteria observed in UV/Cl. The culturable ciprofloxacin-resistant bacteria in biofilm was suppressed by combined processes, with the survival reduced from 49.9% in the control to 27.7%, 16.0% and 10.8% in UV-Cl, Cl-UV and UV/Cl, respectively. The survival of sulfamethoxazole/trimethoprim-resistant bacteria was lower in UV/Cl (16.8%) than others (43.6–55.0%), consistent with the little sul1 and sul2 detected in UV/Cl. Although combined processes reduced most detected antibiotic resistance genes (i.e., blaTEM-1, tetA, sul1 and sul2), UV-Cl showed the potential to enrich tetA and sul2 in biofilm. Overall, UV/Cl outperformed the sequential combinations in the control of viable bacteria and the antibiotic resistance in the subsequently formed biofilm.

Combined processes of light-emitting diodes ultraviolet (LED UV) and chlorination (Cl

Industrial reverse osmosis concentrate (ROC) treatment with the fluidized bed reactor Fenton (FBR-Fenton) process was modeled with artificial neural network (ANN) and multilinear regression (MLR) t...

In Singapore, active, beautiful, clean waters design features (ABCWDFs), such as rain gardens and vegetated swales, are used as a sustainable approach for stormwater management. Field monitoring studies characterising the performance of these design features in the tropical region are currently limited, hampering the widespread implementation of these systems. This study characterised the performance of individual ABCWDFs in the tropical climate context by monitoring a rain garden (FB7) and a vegetated swale (VS1) that were implemented in a 4-ha urban residential precinct for a period of 15 months. Results showed that total suspended solids (TSS), total phosphorus (TP) and total nitrogen (TN) concentrations were low in the new residential precinct runoff, leading to poor removal efficiency despite the effluent concentrations of individual ABCWDFs that were within the local stormwater treatment objectives. Average TSS, TP and TN EMCs of four sub-catchment outlets were lower (23.2 mg/L, 0.11 mg/L and 1.00 mg/L, respectively) when compared to the runoff quality of the major catchments in Singapore, potentially demonstrating that the ABCWDFs are effective in improving the catchment runoff quality. Findings from this study can help to better understand the performance of ABCWDFs receiving low influent concentrations and implications for further investigations to improve stormwater runoff management in the tropics.

Microplastics (MPs) are ubiquitous in the environment, of which 94 % undergo the aging process. Accelerated aging induced by advanced oxidation processes (AOPs) is significant in explaining the formation pathway of secondary MPs and enables possible mineralization. In this study, ozonation coupled with hydrogen peroxide (O

Growing concerns about urban runoff pollution and water scarcity caused by urbanization have prompted the application of bioretention facilities to manage urban stormwater. The purpose of this study was to evaluate the performance of proposed bioretention facilities regarding road runoff pollutant removal and the variation characteristics of the media physicochemical properties and microbial diversity in dry-cold regions. Two types of bioretention facilities were designed and then constructed in Tianjin Eco-city, China, on the basis of combined soil filter media screened by a laboratory-scale test with a modified bioretention facility (MBF) containing soil moisture conservation ropes. Redundancy analysis was performed to evaluate the relationships between the variation in media physicochemical properties and microbial communities. An increase in media moisture could promote an increase in the relative abundance of several dominant microbial communities. In the MBF, the relatively low nitrate-nitrogen (NO3-N) (0.75 mg/L) and total nitrogen (TN) (4.71 mg/L) effluent concentrations, as well as better removal efficiencies for TN and NO3-N in challenge tests, were mainly attributed to the greater relative abundance of Proteobacteria (25.2%) that are involved in the microbial nitrogen transformation process. The MBF also had greater media microbial richness (5253 operational taxonomic units) compared to the conventional bioretention facility and in situ saline soils. The results indicate that stormwater runoff treated by both bioretention facilities has potential use for daily greening and road spraying. The proposed design approach for bioretention facilities is applicable to LID practices and sustainable stormwater management in other urban regions.

Significant aspects of advanced quantum technology today rely on rapid control of atomic matterwaves with hyperfine Raman transitions. Unfortunately, efficient Raman excitations are usually accompanied by uncompensated dynamic phases and coherent spin-leakages, preventing accurate and repetitive transfer of recoil momentum to large samples. We provide systematic study to demonstrate that the limitations can be substantially overcame by dynamically programming an adiabatic pulse sequence. Experimentally, counter-propagating frequency-chirped pulses are programmed on an optical delay line to parallelly drive five $\Delta m=0$ hyperfine Raman transitions of $^{85}$Rb atoms for spin-dependent kick (SDK) within $\tau=40$~nanoseconds, with an $f_{\rm SDK}\approx 97.6\%$ inferred fidelity. Aided by numerical modeling, we demonstrate that by alternating the chirps of successive pulses in a balanced fashion, accumulation of non-adiabatic errors including the spin-leakages can be managed, while the dynamic phases can be robustly cancelled. Operating on a phase-stable delay line, the method supports precise, fast, and flexible control of spinor matterwave with efficient Raman excitations., Comment: 18 pages, 13 figures, improved clarity with substantial revisions

We report on the frequency stabilization of a 739 nm Ti:sapphire laser to a hyperfine component of the 127 I 2 B(1)-X(11) P(70) transition using acousto-optic modulation transfer spectroscopy. A frequency stability of 3.83 × 10 − 11 around 13 s averaging time is achieved when the laser frequency is stabilized. The observed hyperfine transition of the molecular iodine is an ideal frequency reference for locking the lasers used in experiments with trapped ytterbium ions, since its second-harmonic frequency is the 2 S 1 2 − 2 P 1 2 transition of the ytterbium ion at 369.5 nm. By investigating the line broadening effects due to the iodine vapor pressure and laser power, the locking is optimized to the theoretical signal to noise ratio of this iodine transition.

The UV/Cl2 process (also known as chlorine photolysis, which is the combination of chlorine and simultaneous irradiation of UV light) is conventionally applied at acidic mediums for drinking water treatment and further treatment of wastewater effluents for secondary reuse. This is because the quantum yield of HO• from HOCl (ϕHO•, 254 = 1.4) is greater than the one from OCl- (ϕHO•, 254 = 0.278) by approximately 5 times. Moreover, chlorine photolysis in acidic mediums also tends to have lower radical quenching rates than that of their alkaline counterparts by up to 1000 times. The aim of this research is to investigate the applicability of the UV/Cl2 process by assessing its efficacy on the removal of trimethoprim (TMP) at not only acidic to neutral conditions (pH 6-7), but also alkaline mediums (pH 8-9). At alkaline pH, free chlorine exists as OCl- and since OCl- has a higher molar absorption coefficient as compared to HOCl at higher wavelengths, there would be higher reactive chlorine species (RCS) formation and contribution. TMP removal followed pseudo-first order kinetics and depicted that a maximum fluence based constant (kf′ = 0.275 cm2/mJ) was obtained using 42.25 μM (3 mg/L) of chlorine at pH 9, with an irradiation of 275 nm. At alkaline conditions, chlorine photolysis performance followed the trend of UV (275)/Cl2 > UV (265)/Cl2 > UV (310)/Cl2 > UV (254)/Cl2. RCS like Cl•, Cl2−• and ClO• contributed to the degradation of TMP. When the pH was increased from 6 to 8, contribution from hydroxyl radicals (HO• ) was decreased whilst that of RCS was increased. Application of UV (310)/Cl2 had the highest HO• generation, contributing to TMP removals up to 13% to 48% as compared to 5% to 27% in UV (254, 265, 275)/Cl2 systems at pH 6-9. Artificial neural networks modelling was found to be able to verify and predict the contribution of HO• and RCS conventionally calculated via the general kinetic equations in the UV/Cl2 system at 254, 265, 275 and 310 nm.

For specular reflection surface detection, high reflectivity is a large challenge to effectively extract the depth information of surface. Phase Measuring Deflectometry (PMD) based three-dimensional shape measurement is proposed for solving this problem. In this study, PMD method based on the characteristic of high specular reflectivity is used to perform structured light imaging on the glass surface to obtain depth information on the surface of the glass panel. In this paper, we propose a new image reconstruction method suitable for imaging specular reflection surface defects. According to the characteristic of the glass panel, the proposed method has a phase pre-unwrapping process and improves the least square method of unfolding and folding the phase algorithm. The experimental results show that the proposed method is more robust for imaging and detection of high-reflective plane than the traditional least squares method.

The management of contaminants of emerging concern (CECs) in water bodies is particularly challenging due to the difficulty in detection and their recalcitrant degradation by conventional means. In this review, CECs are characterized to give insights into the potential degradation performance of similar compounds. A two-pronged approach was then proposed for the overall management of CECs. Light-driven oxidation processes, namely photo/Fenton, photocatalysis, photolysis, UV/Ozone were discussed. Advances to overcome current limitations in these light-driven processes were proposed, focusing on recent trends and innovations. Light-based detection methodology was also discussed for the management of CECs. Lastly, a cost–benefit analysis on various light-based processes was conducted to access the suitability for CECs degradation. It was found that the UV/Ozone process might not be suitable due to the complication with pH adjustments and limited light wavelength. It was found that EEO values were in this sequence: UV only > UV/combination > photocatalyst > UV/O3 > UV/Fenton > solar/Fenton. The solar/Fenton process has the least computed EEO < 5 kWh m−3 and great potential for further development. Newer innovations such as solar/catalyst can also be explored with potentially lower EEO values.

The role of dissolved organic matters (DOM) in the matrix of water on the degradation of refractory pharmaceutical has aroused broad concerns. However, The effect of alpha-hydroxy acids as vulnerable aliphatic acids in the water on the degradation of Carbamazepine (CBZ) has been lack of research. The decomposition kinetics and transformation products (TPs) of CBZ by UV/H2O2 process were studied in the existence of glycolic acid (GA) and lactic acid (LA) and the degradation pathways were proposed. Both GA and LA had significantly negative effects on the decomposition kinetics and mineralization of CBZ by UV/H 2 O 2 process. The declination of steady-state OH concentration in the presence of GA and LA justified the negative effects. GA was demonstrated to be stronger at scavenging and competing OH with CBZ, compared with LA, with the rate constant of slightly less than the common OH scavenger methanol. One-step dosing mode of H 2 O 2 was better than multi-step dosing mode for CBZ decomposition, especially in the presence of GA and LA. The identification of TP253a, TP253b, TP271a, TP271b, TP226, and TP180 in the absence and presence of GA and LA were performed by HPLC-MS/MS and two main degradation pathways were presented. Except for TP271a and TP271b, GA and LA retarded the abundance peaks of other four TPs, of which the formation kinetics rates and decay kinetics rates were negatively affected. Tailing peaks of all TPs caused by GA and LA inevitably resulted in the toxicity of the treated effluent of UV/H 2 O 2 process even when CBZ was decomposed completely. Therefore, alpha-hydroxy acids play important roles in determining the fate and transformation of refractory pharmaceuticals in AOPs treatment.

Water is a limited and valuable resource. Singapore has four national sources of water supply, one of which is natural precipitation. Pollutants collected in stormwater runoff are deposited into drainage systems and reservoirs. Major nutrient pollutants found in local stormwater runoff include nitrate and phosphate, which may cause eutrophication. Bioretention systems are efficient in removing these pollutants in the presence of plants. This paper discusses plant traits that can enhance the phytoremediation of nutrient pollutants in stormwater runoff for application in bioretention systems. The plant species studied showed variations in chlorophyll florescence, leaf greenness, biomass production, and nitrate and phosphate removal. In general, dry biomass was moderately correlated to nitrate and phosphate removal (r = 0.339–0.501). Root, leaf, and total dry biomass of the native tree species showed a moderate to strong correlation with nitrate removal (r = 0.811, 0.657, and 0.727, respectively). Leaf dry biomass of fast-growing plants also showed a moderate to strong relationship with the removal of both pollutants (r = 0.707 and 0.609, respectively). Root dry biomass of slow-growing plants showed a strong relationship with phosphate removal (r = 0.707), but the correlation was weaker for nitrate removal (r = 0.557). These results are valuable for choosing plants for application in bioretention systems. Keywords: Nitrogen, Phosphorus, Plant traits, Bioretention system, Stormwater, Tropical plant, Nutrient pollutant, Native plants

Extensive studies have been conducted on bioretention filter media applied in best management practices for stormwater runoff treatment. To date, more reported studies are focused on pollutants elimination such as suspended solids and nutrients. There has been limited research on pathogen removal from stormwater runoff. More focused studies on pathogen removal are therefore required if the intended stormwater is harvested for indirect potable use. In this study, water treatment residuals (WTR), a recycled biofilter media was surface-modified with metals to assess its potential for E. coli removal from stormwater runoff. To achieve this goal, four types of modified WTRs, prepared using iron, copper, platinum, and silver as antibacterial agents, were tested in parallel batch tests. After the cost-effectiveness evaluation among the four modified WTRs for bacterial removal, Fe2O3- and CuO-WTRs were shortlisted for further mechanism and stability studies. Stable antibacterial performances (E. coli log removal of 0.58 ± 0.04 and 0.90 ± 0.04, respectively) were achieved using the Fe2O3- and CuO-WTRs under intermittent synthetic and natural stormwater runoff conditions. No significant metal leaching was observed over prolonged continuous treatment. The experimental results showed the bio-adsorption onto the surface modified Fe2O3- and CuO-WTR was a key mechanism for E. coli removal followed by E. coli inactivation at solid-liquid interface caused by the antibacterial effect of metal coatings (where CuO was reported to have higher biotoxicity than Fe2O3). These findings clearly suggested the potential of CuO-modified WTR for pathogen removal in stormwater treatment practices.

As water matrix, inorganic anions and natural organic matter (NOM) may impact the removal of pharmaceuticals not only on the kinetics but also on the transformation products formation. In this study, the effects of initial pH, inorganic anions and NOM on the transformation pathways of sulfamethoxazole (SMX) during photocatalytic decomposition were investigated. Three pathways including hydroxylation, hydrolysis and isoxazole ring oxidation were found during SMX photocatalysis. SMX in deionized water was degraded by hydroxylation principally in alkaline situation, while hydrolysis was the main pathway in acidic condition. Almost all the pathways for SMX decomposition were suppressed when anions were added, with the inhibitory effect followed the order of HPO42− > HCO3− > SO42− > Cl− > H2PO4−. The formation of products with larger energy barrier was affected more significantly when anions were added. The products formation was also impacted by the presence of NOM isolates including “Suwannee River Humic Acid” (SRHA), “Suwannee River Fulvic Acid” (SRFA) and “Suwannee River NOM” (SRNOM). The mechanisms of hydroxylation and isoxazole ring oxidation were inhibited by NOM, with the order of SRFA > SRHA > SRNOM, due to their hydroxyl radical scavenging abilities which were related to their aromaticity degree. Most of the hydrolysis products were favored in the presence NOM, and the enhancement effect was in accordance with the sequence of SRNOM > SRFA > SRHA due to the different photoinductive abilities of the NOM isolates.

Nature-based solutions or Green infrastructure (GI) used for managing stormwater pollution are growing in popularity across the globe. Stormwater GI models are important tools to inform the planning of these systems (type, design, size), in the most efficient and cost-effective manner. MUSIC, an example of such a tool, uses regression and first order decay models. Studies validating MUSIC model performance are, however, scarce, hindering future model development and transferability of the model for systems operating under different design and climatic conditions. To close this gap, this paper evaluates MUSIC for a field scale bioretention system, stormwater wetland and vegetated swale operating under Singapore tropical climate. The treatment modules were able to simulate outflows and effluent pollutant concentrations reasonably well for cumulative event volumes (mostly within ±25%) and cumulative TP and TN loads (within ±30%). Outflow TSS loads were significantly under-estimated as a result of greater variability in measured TSS concentrations across events. The findings indicate that simple empirical models such as MUSIC can be transferred to different regions provided that management decisions are based on long-term modelling efforts. The modules generally simulated the outflow hydrographs and pollutographs of the different inflow and drying/wetting conditions relatively poorly.

A novel bimetallic doped PAC (Fe-Mn/PAC) pellet was prepared with a facile sol-gel method and used as an ozone catalyst for phenolic wastewater (PWW) treatment. Adoption of Fe-Mn/PAC pellet in microbubble ozonation enhanced the 1-h chemical oxygen demand (COD) and phenol removal in PWW to 79% and 95%, respectively. With ozone dosage of 10 mg/L, 1 g/L Fe-Mn/PAC pellet exhibited ozone conversion of 92%. In comparison to microbubble ozonation process, Fe-Mn/PAC induced microbubble-catalytic ozonation process promoted ozone decomposition rate by 1.9 times. In terms of •OH production, Fe-Mn/PAC pellet enhanced •OH exposure by 10 times, with a Rct value of 2.92 × 10 -8. Rct kinetic model also suggested that Fe-Mn/PAC pellet obtained higher kinetic rate constants for initiating and promoting •OH generation. Usage of Fe-Mn/PAC pellet in microbubble ozonation for phenolic wastewater treatment also reduced the total ozone consumption by 70%. In Fe-Mn/PAC induced microbubble-catalytic ozonation process, the ratio between ozone consumption and COD removal (ΔO3/ΔCOD) was 0.91. Fe-Mn/PAC pellet characterization with X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared (FT-IR) and X-ray powder diffraction (XRD) analysis revealed successful doping of Fe-Mn on PAC substrate and larger numbers of carbon-oxygen/hydroxyl surface groups, which played key roles in ozone decomposition and •OH production.

Reverse osmosis (RO) is being used in many water reclamation facilities to produce high quality water that can be reused for different purposes. As a part of the RO process, a reject stream is produced as the reverse osmosis concentrate (ROC), which contains elevated levels of contaminants compared to the source water. Effective treatment and safe disposal of ROC via cost-effective means is very challenging. This study aims to develop a robust microbubble ozonation–biological process for industrial ROC treatment with a target effluent chemical oxygen demand (COD) lower than 60 mg/L. As compared to macrobubble ozonation, microbubble ozonation exhibited better ozone dissolution and 29% higher COD removal efficiency with the same ozone dosage. Under the optimum operating conditions with ozone dosage of 30 mg/L, ROC natural pH of 8.67 and ozonation duration of 1 h, microbubble ozonation achieved 42% COD removal efficiency while increasing the BOD5/COD ratio (ratio of biological oxygen demand over 5 days to the corresponding chemical oxygen demand) in ROC from 0.042 to 0.216. A biological activated carbon (BAC) column with an empty bed contact time (EBCT) of 120 min was combined with microbubble ozonation for continuous ROC treatment. Over the 100-day operation, the combined system performed consistent organics removal with an average effluent COD of 45 mg/L. Both LC-OCD data and fluorescence EEM spectra confirmed humic substances were the dominant organic species in ROC. Ozone pre-treatment could achieve significant removal of humic substances in raw ROC. ATP analysis found that ozone pre-treatment enhanced BAC biofilm activity by around 5 folds. 5 min acute toxicity assessment with Aliivibrio fischeri showed 4 times reduction of bioluminescence inhibition in ozone treated ROC. From the environmental point of view, Life cycle assessment (LCA) results demonstrated that Ozone-BAC system had significant environmental burdens on climate change and human toxicity due to the electricity production process. These environmental impacts can be mitigated by optimizing the ozonation process with reduced ozone dosage or utilizing renewable energy sources for electricity generation.

The rapid recombination of electron/hole pairs is a major setback in the application of WO

Rapid population growth, urbanization and high-intensity human activities cause a multitude of extremely serious environmental problems all over the world [...]

Fenton and ozone-based advanced oxidation processes (AOPs) are widely applied in industrial effluent treatment. In this chapter, the fundamentals of Fenton- and ozone-based AOPs are first introduced, including the technology background, reaction mechanisms, process operating conditions, and methods for improving. Subsequently, recent research on various industrial effluent treatments with Fenton and ozone-based AOPs are reviewed. Pilot- and full-scale applications of some AOP technologies for industrial effluent treatment are also discussed in this chapter.

This work addresses the problem of the animal shape and pose estimation from an occluded image. Most of exisiting 3D animal reconstruction methods focus on an automatic and accurate framework in normal conditions, but ignore some exceptional occasions, such as occlusion, which limits the practical applications of estimating the animal shape and pose to a large extent. In this paper, we introduce a random elimination strategy from fully annotated joints and propose a deep neural network for SMAL parameters regression from the partial joints. Our proposed method can effectively deal with the reconstruction of animals under the scenario of an occluded image. We have conducted extensive experiments and results demonstrate that our 3D animal shape and pose estimation method can yield good performance on occluded images.

Phenolic compounds are common ccontaminants in industrial effluents. In this study, a combined catalytic microbubble ozonation and biological process was developed and applied for efficient industrial phenolic wastewater (PWW) treatment. Catalytic activity of an iron-oxides (FeO

In recent years, fluidized-bed Fenton (FBR-Fenton) process has gained more attention in treating recalcitrant industrial wastewater. FBR-Fenton combines the effectiveness of homogeneous Fenton and sludge reduction of heterogeneous Fenton. Comparing to other modified Fenton processes, FBR-Fenton has greater economical and scaling up potential. However, large consumption of Fenton reagents and strict pH control are still the bottlenecks hampering the full-scale application of FBR-Fenton. While prior reviews mainly focused on the operation and performance of FBR-Fenton process, the present study critically discussed the challenges and bottlenecks for its full-scale industrial application. This study also comprehensively reviewed the development strategies for tackling these drawbacks, mainly over the recent five years. Homogeneous FBR-Fenton, heterogeneous FBR-Fenton and heterogeneous FBR-photo-Fenton processes were classified for the first time according to their reaction mechanisms and system designs. Important operational and design parameters affecting the cost-effectiveness of all FBR-Fenton technologies were reviewed, including the fundamentals, common practices and even innovative steps for enhancing the process performance. Up-to-date applications of FBR-Fenton technologies in recalcitrant wastewater/compounds treatment were also summarized, and it was found that upscaling of heterogeneous FBR-Fenton and heterogeneous FBR-photo-Fenton processes was still very challenging. Strategies to overcome the key technical limitations and enhance process cost-effectiveness were discussed in the future perspective part. Furthermore, modelling techniques such as computational fluid dynamics model and artificial neural network were suggested to be promising modelling techniques for speeding up the full-scale applications of FBR-Fenton technologies.

Un-biodegradable pharmaceuticals are one of the major growing threats in the wastewaters. In the current study, TiO2 thin film photocatalysts were designed by nanocrystal engineering and fabricated for degradation of the acetaminophen (ACE) in a photocatalytic reaction under UV light irradiation in batch and continuous systems. The photocatalyst was prepared by sputtering and then engineered by thermal treatment (annealing at 300°C (T300) and 650°C (T650)). The annealing effects on the crystallinity and photocatalytic activity of the TiO2 film were completely studied; it was found that annealing at higher temperatures increases the surface roughness and grain size which are favorable for photocatalytic activity due to the reduction in the recombination rate of photo-generated electron-hole pairs. For the continuous system, a flat plate reactor (FPR) was designed and manufactured. The photocatalytic performance was decreased with the increase of flow rate because the higher flow rate caused to form the thicker film of the liquid in the reactor and reduced the UV light received by photocatalyst. The reusability and durability of the samples after 6 h of photocatalytic reaction showed promising performance for the T650 sample (annealed samples in higher temperatures).

Peroxydisulfate-based advanced oxidation process has drawn increasing interest recently. Quenching the residual peroxydisulfate is essential for the accurate measurement of the concentration of target pollutants. However, it was rarely discussed which reductant is best for peroxydisulfate quenching. In this study, how the quenching of peroxydisulfate by four commonly used quenchers (methanol, ascorbic acid, sodium thiosulfate and sodium sulfite) affected the concentration of carbamazepine was investigated. Sodium sulfite reacted with carbamazepine directly, with the highest removal rate up to 39%. Higher carbamazepine removal rate was achieved by peroxydisulfate/sodium sulfite than by sodium sulfite alone. SO3•- and SO5•- rather than SO4•- played the major role in carbamazepine removal by sodium sulfite or peroxydisulfate/sodium sulfite. Methanol was found unable to reduce peroxydisulfate. Ascorbic acid, when used with a concentration more than three times higher than that of peroxydisulfate, was the best quencher with the lowest carbamazepine removal rate observed at a pH range of 3.5-10.0. Sodium thiosulfate was unfit for peroxydisulfate quenching at pH 3.5 as it was decomposed and formed bisulfite under strong acidic condition. The results of this study provided valuable guidance to the selection of proper quenchers for peroxydisulfate-related advanced oxidation processes.

In this study, peroxydisulfate (PDS) was used as electron acceptor to improve the photocatalytic activity of WO

The high recombination rate of photogenerated electron–hole pairs, poor photocorrosion stability, and the discrepancy between the optical absorption length and charge collection efficiency of cupric oxide (CuO) are the main limiting factors of visible-light-driven CuO photocatalysts for hydrogen evolution and photocatalytic degradation of organic pollutants. In this paper, we demonstrate a novel thin CuO film photocatalyst on a fluorine doped tin oxide (FTO) coated glass substrate with low back contact resistivity, high charge collection efficiency, high optical absorption, and high photocorrosion stability for hydrogen production and photocatalytic degradation of organic pollutants. This photocatalyst was fabricated by incorporating palladium (Pd) nanostructures into CuO to form a CuO:Pd light trapping thin film. The CuO:Pd light trapping thin film was then sandwiched between a nitrogen doped cupric oxide [CuO(N)] hole transporting layer and a CuO capping layer [CuO(N)–CuO:Pd–CuO]. The performance of the CuO(N)–CuO:Pd–CuO photocatalyst is further improved by incorporating a ZnO buffer layer and TiO2 protective layer, and decorating with a AuPd co-catalyst. Moreover, we demonstrate a significant improvement of photocorrosion stability and photocatalytic degradation efficiency of the CuO(N)–CuO:Pd–CuO–ZnO–TiO2 photocatalyst through plasma assisted in situ nano-crystal engineering of the ZnO buffer layer and TiO2 protective layer. The fabricated novel photocatalyst could retain 95% of the initial photocurrent density after 6 hours of standard illumination with solar light and could give a record high photocurrent density of ∼8 mA cm−2 for the CuO photocatalyst.

Predicting the second-order rate constants between aromatic contaminants and a sulfate radical (kSO4•−) is vital for the screening of pollutants resistant to sulfate radical-based advanced oxidation processes. In this study, a quantitative structure-activity relationship (QSAR) model was developed to predict the values for aromatic contaminants. The relationship between logkSO4•− and three molecular descriptors (electron density, steric energy, and ratio between oxygen atoms and carbon atoms) was built through multiple linear regression. The goodness-of-fit, robustness, and predictive ability of the model were characterized statistically with indicators showing that the model was reliable and applicable. Electron density was found to be the most influential descriptor that contributed the most to logkSO4•−. All data points fell within the applicability domain, and no outliers existed in the training set. The comparison with other models indicates that the QSAR model performs well in elucidating the mechanism of the reaction between aromatic compounds and sulfate radicals.

Micro-scale ZVI@GAC-based iron-carbon galvanic-cells (ZVI@GACs) were prepared with the Ca-Si-H/Ca-H formation process and first applied to initiate radical generation and coagulation processes in MBR for treating bio-refractory industrial wastewater (IWW). Batch tests revealed the H

Black TiO2 as a solar-driven photocatalyst has attracted enormous attention from scientists and engineers in water and wastewater treatment field. Most of the methods used for the preparation of black TiO2 are thermal treatment under a hydrogen atmosphere. Nevertheless, it is well known that working with hydrogen is not safe and needs special maintenance. Here, for the first time, we prepared black TiO2 by sintering P25 pellets at different temperatures (500–800 °C) under a vacuum atmosphere that showed the same performance with the prepared black TiO2 under a hydrogen atmosphere. The samples were characterized by X-ray diffraction, Raman spectra field emission scanning electron microscopy, transmission electron microscopy, electron paramagnetic resonance, X-ray photoelectron spectroscopy, and ultraviolet–visible deep resistivity sounding techniques. The differences between the formation of oxygen vacancy density and color turning in sintered powder and pellet were also studied. The results showed that th...

As the essential target of disinfection, bacterial materials should also be considered as one type of disinfection by-products precursors (DBPs). This study investigated the disinfection by-products formation potential (DBPFP) of bacterial materials during chlorination and chloramination. The bacterial materials were harvested from mature biofilm developed in remineralized desalinated seawater with different carbon sources. It was observed that calcium and magnesium which were added to desalinated seawater for remineralization could enhance DBPFP of bacterial materials, with magnesium being more effective. The enhancement effect was related to the ability of calcium and magnesium to shift low molecular weight fractions of bacterial materials to more hydrophobic and larger molecular weight fractions. Bacterial materials developed with humic acid as carbon source contained more hydrophobic and larger molecular weight fractions, hence had higher DBPFP than bacterial materials developed with acetate. DBPs yields of bacterial materials were lower than that of NOMs precursor during chlorination, but during chloramination DBPs yields of bacterial materials were higher. The extracellular polymeric substances (EPS) matrix had higher DBPs yield than biofilm cells. Polysaccharide was more likely to be the main DBPs precursor in the EPS matrix.