Simulated Sewage Research Articles

Synthesis of high-value porous carbon from waste plastics and structure regulation promote solar interface water evaporation

Water scarcity and waste plastics elimination are long-term problems facing sustainable development, and solar interface evaporation to produce clean water is regarded as a promising water treatment technology. Herein, we report on low-cost waste plastic bottles synthetic carbon-based photothermal materials. By KOH activation and perforation, the surface crack structure of porous carbon is formed to facilitate multi-stage reflection of solar light, and significantly improve the solar light absorbance and photothermal conversion ability. Three-dimensional solar evaporators with low thermal conductivity and super hydrophilic wood sponge are fabricated, and the rectangular hole is designed to regulate water movement and prevent heat dissipation. When exposed to 1 sun illumination (1 kW/m2), an evaporation rate of 1.59 kg·m-2·h-1 is achieved, along with an energy conversion efficiency of 88.49 %. In addition, different micro-surface rough structures are constructed to boost the solar light absorption, thereby enhancing the photothermal conversion ability, among which the micro-cone structure increased the evaporation rate to 1.93 kg·m−2·h−1, demonstrating excellent stability over 15 cycles. In the simulated sewage purification process, the removal rate of pollutants is 99.9 %, and the evaporator without obvious salt accumulation in the seawater for 24 h, showing good salt resistance and self-cleaning ability. This research has important reference value for high-value preparation of carbon-based photothermal materials from waste plastics, extraction of clean water and environmental sustainable protection.

Responses of colonization and development of periphytic biofilms to three typical tire wear particles with or without incubation-aging in migrating aqueous phases

Understanding the behavior of tire wear particles (TWPs) and their impact on aquatic environments after aging is essential. This study explored the characteristics of TWPs generated using different methods (rolling friction, sliding friction, and cryogenic milling) and their transformation after exposure to environmental conditions mimicking runoff and sewage, focusing on their effects on river water and periphytic biofilms. Laboratory experiments indicate that at low exposure levels (0.1 mg/L), TWPs promoted biofilm growth, likely due to zinc release acting as a nutrient and the aggregation of particles serving as biofilm scaffolds. However, at higher concentrations (100 mg/L), TWPs inhibited biofilm development. This inhibition is linked to toxic byproducts like N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine-quinone and environmentally persistent free radicals, which reduce biofilm biomass, alter algal diversity, and decrease the production of essential biofilm components such as proteins and polysaccharides, consistent with the inhibitory behavior of TWPs on bis-(3′-5′)-cyclic diguanosine monophosphate and quorum sensing signals, including acyl-homoserine lactone and autoinducer-2. Aging processes, particularly after simulated sewage treatment, further affect ecological impacts of TWPs, reducing the benefits observed at low concentrations and intensifying the negative effects at high concentrations. Contribution of here lies in systematically revealing the impact of TWPs on the development of aquatic biofilms, emphasizing the logical relationship between their aging characteristics, environmental behavior, and ecological risks. It assesses not only the release effects of typical additives and conventional size effects but also highlights the emerging photochemical toxicity (persistent free radicals), thus providing valuable insights into the aquatic ecological risk assessment of TWPs.

Enhanced removal of ciprofloxacin and associated antibiotic-resistant genes from wastewater using a biological aeration filters in combination with Fe3O4-modified zeolite.

Antibiotics release into the water environment through sewage discharge is a significant environmental concern. In the present study, we investigated the removal of ciprofloxacin (CIP) in simulated sewage by biological aeration filter (BAF) equipped with Fe3O4-modified zeolite (Fe3O4@ZF). Fe3O4@ZF were prepared with impregnation method, and the Fe3O4 particles were successfully deposited on the surface of ZF in an amorphous form according to the results of XPS and XRD analysis. The modification also increased the specific surface area (from 16.22 m²/g to 22 m²/g) and pore volume (from 0.0047 cm³/g to 0.0063 cm³/g), improving the adsorption efficiency of antibiotics. Fe3O4 modified ZF improved the treatment performance significantly, and the removal efficiency of CIP in BAF-Fe3O4@ZF was 79%±2.4%. At 10ml/L CIP, the BAF-Fe3O4@ZF reduced the relative abundances of antibiotics resistance genes (ARGs) int, mexA, qnrB and qnrS in the effluent by 57.16%, 39.59%, 60.22%, and 20.25%, respectively, which effectively mitigate the dissemination risk of ARGs. The modification of ZF increased CIP-degrading bacteria abundance, such as Rhizobium and Deinococcus-Thermus, and doubled bacterial ATP activity, promoting CIP degradation. This study offers a viable, efficient method to enhance antibiotic treatment and prevent leakage via sewage discharge.

Preparation of DyVO4 by Sol-Gel Method and Research of Its Photocatalytic Activity

Using dysprosium oxide (Dy2O3), ammonium metavanadate (NH4VO3), nitric acid (HNO3) and citric acid (C6H8O7·H2O) as main raw materials, DyVO4 was successfully prepared by sol-gel method. DyVO4 samples were characterized by thermogravimetry differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD), scanning electron microscope (SEM), diffuse reflectance spectrum (DRS) and Fourier transform infrared spectroscopy (FT-IR). Under condition of ultraviolet light, taking 10 mg/L methyl orange solution as simulated sewage, the effects of synthesis temperature and illumination time on the photocatalytic activity of DyVO4 were studied. The results show that pure tetragonal zircon DyVO4 samples can be obtained under calcination conditions of 600 °C to 900 °C. The average grain size is about 2 μm and the breadth of band gap is about 3.52 eV. The sample prepared at 800 °C has the best photocatalytic activity. Under ultraviolet light illumination for 150 min, the degradation rate of 10 mg/L methyl orange can reach nearly 100% in presence DyVO4. DyVO4 prepared by sol-gel method is a photocatalyst which has broad application prospect.

ULTRASONIC-ASSISTED ELECTRODEPOSITION OF CoMo/Al2O3 COMPOSITE COATING ON THE SURFACE OF STEEL AND ITS CORROSION RESISTANCE IN SIMULATED SEWAGE WATER

The ultrasonic is applied during the electrodeposition process of CoMo/Al2O3 composite coating on 10# steel to enhance its corrosion resistance in simulated sewage water. The influence of ultrasonic power on the thickness, roughness, chemical composition, surface morphology, and corrosion resistance of the composite coating is investigated. In an aqueous solution, a co-deposition of cobalt and molybdenum can be induced to form CoMo alloy coating. The Al2O3 nanoparticles are incorporated into CoMo alloy to form CoMo/Al2O3 composite coating. When the ultrasonic power increases from 0[Formula: see text]W to 100 W, the electrodeposition rate of the composite coating increases from 63.25[Formula: see text]mg/h to 153.73[Formula: see text]mg/h, and the thickness of the composite coating also increases from 15.6[Formula: see text][Formula: see text]m to 28.1[Formula: see text][Formula: see text]m. The surface roughness of composite coating electrodeposited without ultrasonic is about 0.436[Formula: see text][Formula: see text]m. The CoMo/Al2O3 composite coating electrodeposited at 100[Formula: see text]W ultrasonic power exhibits the smallest surface roughness of 0.193[Formula: see text][Formula: see text]m and presents a denser surface morphology composed of 74.4% Co, 10.3% Mo, and 15.3% Al, resulting in better corrosion resistance with the smallest corrosion current density of only 9.7[Formula: see text][Formula: see text]A/cm2. However, when the ultrasonic power is 150[Formula: see text]W, the intense hydrogen evolution on the surface of the cathode reduces the density of the coating surface, which leads to the deterioration of corrosion resistance.

Effects and driving factors of domestic sewage from different sources on nitrous oxide emissions in a bog

Abstract Direct sewage discharge may enhance soil nitrous oxide (N2O) emissions, worsening the greenhouse effect. However, the effects of sewage discharge into bogs on N2O flux, drivers and influencing mechanisms remain unclear. Additionally, investigating the impact of reclaimed water on N2O flux is important for bog replenishment and water shortage alleviation. This study simulated sewage from different sources into a bog and analyzed N2O fluxes, soil (organic carbon, total nitrogen, ammonium nitrogen, nitrate nitrogen, total phosphorus, available phosphorus, pH and electrical conductivity), plant (species richness and biomass) and microorganisms (ammonia-oxidizing archaea, napA, nirS, nirK and nosZ genes). Results showed that the reclaimed water did not significantly change N2O flux, while 50% tap water mixed with 50% domestic sewage and domestic sewage significantly increased the N2O flux. Among soil factors, available nitrogen and pH were key in influencing N2O flux. Among plant parameters, species richness was the primary factor affecting N2O flux. Nitrogen transformation functional genes contributed the most to the increase in the N2O fluxes, with an increase in domestic sewage input leading to a higher abundance of these genes and subsequent N2O emissions. Therefore, domestic sewage should be considered, as it significantly increases N2O emissions by affecting the soil, plants and microorganisms, thereby increasing the global warming potential. This study’s findings suggest that using treated reclaimed water for bog replenishment could be an environmentally friendly approach to wetland management.

Absorption of Ammonium by Three Substrates Materials in Constructed Wetland System

The adsorption characteristics of ammonia nitrogen for constructed wetland were studied with ceramsite, quartz sand, and gravel. The material was characterized using scanning electron microscopy and a BET-specific surface area analyzer. It was found that the surface of ceramide was coarser than that of quartz sand and gravel, and the internal pores were more developed. The specific surface area of ceramide (18.97 m2·g-1) was higher than that of quartz sand and gravel. In the pure ammonia nitrogen solution and Grade I B standard for the wastewater treatment plant effluent ammonia nitrogen solution of the effluent from the simulated sewage plant, the adsorption capacity of the three substrates was as follows:ceramsite > gravel > quartz sand. The saturated adsorption capacity (63.55 m2·g-1) of ceramides was the highest in the mixed solution. The adsorption process of ammonia nitrogen by ceramides accorded with the pseudo-second-order kinetic model (R2 of 0.99 in the pure ammonia nitrogen solution and 0.98 in the mixed solution). The Freundlich and Langmuir models were used to fit the isothermal adsorption results in a pure ammonia nitrogen solution. It was found that the Freundlich model described the adsorption characteristics of the ceramics more accurately than the Langmuir model (R2=0.93), indicating that the adsorption of ammonia nitrogen by the ceramics was multilayer adsorption. In conclusion, the adsorption capacity of ceramide was strong, and the adsorption capacity of ceramide in the mixed solution was 31% higher than that in the pure ammonia nitrogen solution, which was suitable to be used as the matrix filler of constructed wetland.

Self-powered Pb(II) removal driven by Zn-air batteries using N, P-doped active straw carbon as cathode

Electrochemical systems have been widely applied in heavy-metal ions (HMIs) pollution control, while their applications are greatly restricted by excessive energy consumption. Self-powered environmental remediation systems (SERSs) can shed the energy reliance to achieve HMIs decontamination and simultaneous electricity output through electrokinetic migration. In this work, SERSs based on Zn-air batteries (ZABs) were achieved to remove bivalent lead (Pb(II)) by circulating effluent as electrolyte. Straw biomass derived N, P functional active nanocarbon (NP-ASC) with hierarchical porosity and electron modulation effect was designed for achieving high oxygen reduction reaction (ORR) activity and efficient Pb(II) uptake. SERSs with electrode active area of 1 cm2 realize outstanding Pb(II) removal efficiency (98.1 %) and electricity generation (67.5 mWh∙cm−2) in simulated sewage. ZABs assembled with NP-ASC delivered specific capacity of 795 mAh∙g−1 and cycling stability for 340 h. This study provides a guide for designing a novel SERS using functionalized biomass nanocarbon.

A Sandwich Structure Ag/MgFe2O4-Deposited Surface Carbonized Wood for Integrated Solar Steam Generation and Photoreduction of Cr(VI).

The severe deterioration of the marine ecosystem significantly negatively impacts the performance of solar-driven steam generation (SSG) and the quality of the obtained freshwater. Herein, a bifunctional Ag/MgFe2O4@SCW reactor with a sandwich structure is designed for efficient SSG and Cr(VI) reduction, which is constructed via in situ deposit Ag nanoparticles (NPs) and MgFe2O4 onto surface carbonized wood (SCW). Owing to the advanced sandwich structure and strong interfacial interactions between each component, an ultra-high evaporation rate of 1.55kg m-2 h-1 and the efficiency of 88.6% are achieved using Ag/MgFe2O4@SCW under 1 sun. The system exhibits the long-term evaporation performance in the simulated sewage and strong acid/base solutions along with water-harvesting capacity in outdoor solar desalination. The quality of distilled water after desalination of actual seawater and NaCl solutions with different concentrations meets the WHO-recommended drinkable water standards. Furthermore, Ag/MgFe2O4@SCW shows outstanding antibacterial property, self-desalting capacity, as well as reusability and structure stability. Most importantly, the fast carrier separation endows Ag/MgFe2O4@SCW with superior photocatalytic activity and Cr(VI) photoreduction of up to 96.1% after 180min of illumination. The bifunctional Ag/MgFe2O4@SCW reactor provides an advanced synergistic mechanism for improving SSG and photocatalytic performance, while being promising for solar-powered production of clean water.

Effects of flow rate and wastewater concentration on the transformation of nitrogen in sediment-water system of sewage pipelines.

In this work, the transformation law of nitrogen in sediment-water system under different flow rates and wastewater concentrations were investigated in a simulated sewage pipeline system. Results showed that the different flow rates and wastewater concentrations in the pipeline caused differences in microbial community in sediments and nitrogen transformation. When the flow rate increased from 0.05 to 0.2 m/s, the scouring effect was enhanced, resulting in higher concentrations of NH4 + -N and NO3 - -N in the overlying water. At 0.2 m/s, the relative abundance of Clostridium_sensu_stricto_1 in sediments was higher, resulting in a greater conversion of amino acid nitrogen (AAN) to NH4 + -N. Meanwhile, many denitrifying bacteria (Trichococcus, Dechloromonas, norank_f__norank_o__Gaiellales, Thiobacillus) had high relative abundance in the sediments, and the denitrification process was common. When the wastewater concentration was high, the nitrification reaction was great in overlying and interstitial water. Moreover, the ammoniation process was great in the sediments, and the variation flux of AAN was large (remarkably reduced). PRACTITIONER POINTS: AAN transformed to NH4 + -N in sediment under different flow rate and concentration. Scouring was enhanced at 0.2 m/s, increasing nitrogen contents in overlying water. Difference in microbial community led to more AAN conversion to NH4 + -N at 0.2 m/s. The ammoniation process was greater in sediment at a high concentration of sewage. NH4 + -N migrated from overlying water to sediment at a high concentration of sewage.

In-situ oxygen generation using Titanium foam/IrO2 electrode for efficient sulfide control in sewers

Hydrogen sulfide (H2S) causes corrosion of pipeline network and endangers sewer’s normal operation, while the rehabilitation or replacement of sewer network incurs expensive manpower and material costs. Conventional chemical dosing strategies such as oxygen injection and caustic soda addition, confront issues with transport and storage of chemical reagents as well as dose control. In contrast, electrochemical treatment techniques have evoked growing attention in sewer management due to its capacity of in-situ effective agent production, real-time dose control and amenability to automation. In this study, the performances of anodic oxygen production using Ti/IrO2 and Titanium foam/IrO2 as electrodes were investigated. Titanium foam/IrO2 electrode exhibited the superior oxygen evolution capacity, with the dissolved oxygen (DO) level attained in the range 8–9 mg L-1 (i.e., higher than that of 5–6 mg L-1 by Ti/IrO2 electrode). It was also indicated that a decrease in flow rate or an increase in current density would accelerate its in-situ oxygen production. DO production with the presence of COD, NH4+, HCO3−, H2PO4−/HPO42− was approximately 6.78–8.37 mg L-1. Moreover, this electrochemical method was illustrated to successfully achieve sulfide removal efficiency of 90 % in the simulated sewage experiment. The cathode compartment simultaneously produced caustic soda (∼0.4 wt% in 210 min), thereby contributing to further sulfide removal. Additionally, the effect of real sewage with different conductivities on sulfide removal proved the wide applicability of electrochemical technology in sewer management. Overall, this study demonstrated the practical potential of concurrent in-situ anodic oxygen production and cathodic caustic soda generation for sulfide control in sewers.

Efficacy of Nitrogen and Phosphorus Removal and Microbial Characterization of Combined A2O-MBBR Constructed Wetlands

A combined anaerobic–anoxic–oxic moving bed biofilm reactor (A2O-MBBR) constructed wetlands process was used to treat low carbon-to-nitrogen (C/N) simulated sewage. The results showed that the removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), total nitrogen (TN), and total phosphorus (TP) by this process were 94.06%, 94.40%, 67.11%, and 84.57%, respectively, and the concentrations of COD, NH4+-N, TN, and TP in the effluent were lower than the Class I-A standard of GB18918-2002. In the anoxic zone, NH4+-N had an inhibitory effect on phosphorus uptake via phosphorus-accumulating organisms (PAOs). The highest community diversity was observed in the anoxic zone sludge at 24 d. During the water-quality-shock loads stage, microbial community diversity decreased in a combined A2O-MBBR constructed wetlands reactor. At the phylum level, bacteria within the mature activated sludge were dominated by Proteobacteria, while Planctomycetes bacteria were the dominant species in the constructed wetlands. At the genus level, Tolumonas spp. were the dominant species in the 12 d and 24 d constructed wetlands and the anaerobic zone, with relative abundance percentages ranging from 20.24 to 33.91%. In the water-quality-shock loads stage, they were replaced by denitrifying bacteria such as Herbaspirillum spp. Unclassified_Burkholderiales was the dominant species in the constructed wetlands, with a relative abundance of 33.09%.

Selective Fluorescent Sensing for Iron in Aqueous Solution by A Novel Functionalized Pillar[5]arene.

Iron ion is one of the most physiologically important elements in metabolic processes, indispensable for all living systems. Since its excess can lead to severe diseases, new approaches for its monitoring in water samples are urgently needed to meet requirements. Here, we firstly report a novel and universal route for the synthesis of a series of pillar[n]arene derivates containing one benzoquinone unit by photocatalysis. With this in hand, an anthracene - appended water - soluble pillar[5]arene (H) with excellent fluorescence sensing potency was prepared. H enabled the ultrasensitive detection of iron ions in aqueous solution with limits of detection of 10-8 M. Over a wide range of metal ions, H exhibited specific selectivity toward Fe3+ . More importantly, H could still properly operate in a simulated sewage sample, coexisting with multiple interference ions.

Upgraded β-cyclodextrin-based broad-spectrum adsorbents with enhanced antibacterial property for high-efficient dyeing wastewater remediation

The dyeing wastewater contains amounts of refractory organic compounds, and severely endangers the ecosystem and human health. To alleviate this problem, in this study, the low-cost broad-spectrum nano-adsorbent (denoted as CD/CA-g-CS) with strong antibacterial activity has been synthesized by chemical binding of β-cyclodextrin (β-CD) with chitosan (CS) and citric acid (CA) for high-efficient dyes scavenger. Taking advantage of the extraordinary water insolubility, porous nature and abundant surface groups, the synthesized CD/CA-g-CS outperforms the previously reported adsorbents in terms of adsorption performance. The CD/CA-g-CS exhibits ultrahigh adsorption capacities of 801.66, 770.50 and 946.66 mg/g, respectively mg/g for the cationic dyes of malachite green (MG), basic red (BR) and methylene blue (MB), respectively, while 389.64, 619.60 and 429.22 mg/g for the anionic dyes of acid blue (AB), acid red (AR) and acid yellow (AY), respectively. The chemical monolayer absorption is further demonstrated by the analysis based on the pseudo-second-order adsorption kinetics and Langmuir isotherm models. The regenerable CD/CA-g-CS not only performs well in one-step removal of the mixed dyes in the simulated sewage, but also exhibits superior performance in purifying real industrial wastewater. Moreover, CD/CA-g-CS endowed with antibacterial activity leads to an inhibition rate of over 99.99 % for E. coli. The newly developed CD/CA-g-CS adsorbents are highly promising for high-efficient dyeing wastewater remediation.

The removal of ammonia-nitrogen from aquaculture water based on cavitation effect of ultrasonic vibration

This paper mainly studies the mechanism and efficiency of ammonia-nitrogen removal from circulating sewage in closed fish tank system. According to some factors affecting the removal efficiency (ultrasonic power, ultrasonic time and water oxygen concentration). Simulated circulating sewage mixed with oxygen through a venturi tube and then entered a closed experiment box for ultrasonic experiments. Finally, the removal efficiency was determined by Knott's reagent photometry. In the experiment, the PH value of the simulated sewage was 7.5, the indoor water temperature was 20 °C, and the free ammonia was selected as 0.02 mg/L (total ammonia-nitrogen was 1.6 mg/L) according to the standard. The experiment found that when the ultrasonic power is 400 W, the action time is 2 h, and the oxygen concentration of water is 23.8 mg/L, the efficiency of removing ammonia-nitrogen in water is about 65 %. When applied on fishing vessels, increasing the power can increase the removal efficiency.

Electrodeposition of Zn-Ni/PTFE composite coating on 20 steel and its corrosion behavior in simulated sewage

Zn-Ni alloy coating was electrodeposited on 20 steel, which was commonly used in the manufacture of pipes and connectors. Polytetrafluoroethylene (PTFE) is a kind of polymer chemical material. Although many researchers have prepared metal composite coatings with decent corrosion resistance by adding PTFE particles to the plating solution, a large number of PTFE particles are easy to agglomerate in aqueous solutions, which affects the compactness and properties of composite coatings. In this paper, by adding PTFE emulsion to Zn-Ni plating solution, the agglomeration phenomenon of PTFE particles can be effectively reduced to improve the content of PTFE particles in Zn-Ni/PTFE composite coating and enhance corrosion resistance, which has certain innovation and significance. The surface morphology, chemical composition and phase structure of Zn-Ni alloy coating and Zn-Ni/PTFE composite coatings were characterized and analyzed by scanning electron microscopy, energy dispersive spectrometer and X-ray diffraction. Moreover, the bonding strength and thickness of Zn-Ni alloy coating and Zn-Ni/PTFE composite coatings were tested by grid testing and step profiler. The results show that PTFE particles incorporate into the coating and play a role in increasing the corrosion resistance of the composite coating in simulated sewage. However, the incorporated PTFE particles have no obvious effect on the phase structure of the composite coating. When the addition amount of PTFE emulsion is 30 mL/L, the electrodeposited Zn-Ni/PTFE composite coating has the highest content of PTFE particles (4.24 %), and the corrosion current density is only 0.90 μA/cm2, which is nearly two orders of magnitude lower than that of 20 steel. The Zn-Ni/PTFE composite coating electrodeposited from the plating solution containing 30 mL/L PTFE emulsion has the lightest corrosion degree in simulated sewage and shows excellent corrosion resistance, which can effectively delay the corrosion of 20 steel.

The Spatial-Temporal Effects of Bacterial Growth Substrates on Antibiotic Resistance Gene Spread in the Biofilm.

Biofilm is considered as the hotspot of antibiotic resistance gene (ARG) dissemination. Bacterial growth substrates are important factors for biofilm formation, but its spatial-temporal effects on ARG spread in biofilm is still unclear. In this study, microfluidics combined with microscopic observation were used to reveal spatial-temporal effects of bacterial growth substrates on ARG transfer at real time. The initial horizontal gene transfer events were found to be independent of substrate levels. However, subsequent transfer processes varied greatly depending on the availability of growth substrates. The proportion of transconjugants was much higher (~12%) when observed in substrate-rich regions (under the channel) at 24 h, followed by an exponential decline, with the distance far from the channel. Furthermore, three-dimensional observation revealed that vertical gene transfer influenced by the concentrations of bacterial growth substrates was important for ARG spread in biofilm. The transfer frequency was 8.2 times higher in the high substrate concentration (50×) compared to low concentration (0.5×) in simulated sewage, underscoring the substantial impact of bacterial growth substrate variability on ARG dissemination. This study is helpful for in-depth understanding of ARG dissemination through biofilms and indicates that reducing pollutant emission is important for ARG control in the environment.

Inclusion of hydrodynamic properties of bathing waters is critical in selecting faecal indicators to assess public health impacts of faecal contamination

The EU Bathing Water Directive (BWD) requires member states to assess bathing water quality according to the levels of faecal indicator bacteria (FIB) in designated bathing areas. However, this criterion has two significant limitations given that the BWD does not; (i) account for differences in hydrodynamic properties of bathing waters and, (ii) assumes that all faecal pathogens decay equally in aquatic environments. This study simulated sewage discharge events in three hypothetical aquatic environments characterised by different advection and dispersion parameters in the solute transport equation. Temporal changes in the downstream concentration of six faecal indicators were determined in simulations that utilised measured decay rates of each faecal indicator from a programme of controlled microcosm experiments in fresh and seawater environments. The results showed that the decay rates of faecal indicators are not a critical parameter in advection dominant water bodies, such as in fast-flowing rivers. Therefore, faecal indicator selection is less important in such systems and for these, FIB remains the most cost-effective faecal indicator to monitor the public health impacts of faecal contamination. In contrast, consideration of faecal indicator decay is important when assessing dispersion and advection/dispersion dominant systems, which would pertain to transitional (estuarine) and coastal waterbodies. Results suggest that the inclusion of viral indicators, such as crAssphage and PMMoV, could improve the reliability of water quality modelling and minimise the risk of waterborne illnesses from faecal contamination.

Preparation of La2Ti2O7 by Sol-Gel Method and Its Photocatalytic Activity

Using lanthanum nitrate, butyl titanate and citric acid as the main raw materials, lanthanum titanate (La2Ti2O7) was successfully prepared by sol-gel method. The samples were characterized by thermogravimetric differential thermal analysis (TG-DTA), X-ray diffractometry (XRD), scanning electron microscopy (SEM) and Fourier infrared spectroscopy (FT-IR). Using 10 mg/L azo dye methyl orange solution as simulated sewage, the photocatalytic activity of La2Ti2O7 was studied by changing the synthesis temperature and light time under ultraviolet light. The results show that pure La2Ti2O7 samples can be obtained at 600 °C∼900 °C. SEM showed that La2Ti2O7 was dominated by irregular particles, and the average grain size was 4 ∼ 6μm. The La2Ti2O7 samples are consistent with approximation zero order kinetic for the degradation of methyl orange. The photocatalytic results showed that the photocatalytic activity of La2Ti2O7 prepared by calcination at 800 °C and 900 °C for methyl orange solution was significantly better than that of other temperature sections. The photocatalytic activity of La2Ti2O7 calcined at 900 °C was the best, and the degradation rate of methyl orange reached about 95% for degradation 60 min. This indicates that La2Ti2O7 is a novel photocatalyst with wide application prospects in the field of UV photocatalysis.

Robust, Scalable, and Cost-Effective Surface Carbonized Pulp Foam for Highly Efficient Solar Steam Generation.

Recently, a solar-driven evaporator has been applied in seawater desalination, but the low stability, high cost, and complex fabrication limit its further application. Herein, we report a novel, low-cost, scalable, and easily fabricated pulp-natural rubber (PNR) foam with a unique porous structure, which was directly used as a solar-driven evaporator after facile surface carbonization. This surface carbonized PNR (CPNR) foam without interface adhesion or modification was composed of a top photothermal layer with light absorption ability and a bottom hydrophilic foam layer with a porous and interconnected network structure. Due to the strong light absorption ability (93.2%) of the carbonized top layer, together with the low thermal conductivity (0.1 W m K-1) and good water adsorption performance (9.9 g g-1) of the bottom layer, the evaporation rate and evaporation efficiency of the pulp foam evaporator under 1 sun of illumination attained 1.62 kg m-2 h-1 and 98.09%, respectively, which were much higher than those of most cellulose-based solar-driven evaporators. Furthermore, the CPNR foam evaporator with high cost-effectiveness presented high light-thermal conversion, heat localization, and good salt rejection properties due to the unique porous structure. Additionally, the CPNR foam evaporator exhibited potential applications in the treatments of simulated sewage, metal ion concentration, and seawater desalination. Its cost-effectiveness was clearly higher than that of most reported evaporators as well. Therefore, this novel, low-cost, and stable pulp foam evaporator demonstrated here can be a very promising solution for water desalination and purification.