Organic Matter Pollution Research Articles

Development of a photoelectrocatalytic method to improve the efficiency of E. coli removal

The photoelectrocatalytic technology has attracted significant attention for effectively eliminating organic matter and microbiological pollutants in the environment, owing to its remarkable efficiency and low power consumption. The major goal of this research is to develop and determine the optimal conditions that will facilitate the photoelectrocatalytic technique's enhancement of E. coli eradication. The WO3/BiVO4 photoanode was fabricated on a conductive glass substrate using the automatic dip coating process, employing a layer-by-layer deposition method. Subsequently, the WO3/BiVO4 photoanode was calcinated at 550 °C for 60 minutes. The produced WO3/BiVO4 electrodes were employed as working electrodes to investigate and determine the optimal parameters for enhancing the eradication of E. coli process. The primary factors investigated in this study were the concentration of KCl electrolyte solution and the applied potential. These parameters were examined to identify the best circumstances that would result in the highest efficiency for the degradation of E. coli in a photoelectrochemical system. The study also aimed to comprehend the catalytic mechanism implicated in eliminating E. coli by implementing three different processes: photocatalysis, electrocatalysis, and photoelectrocatalysis. We discovered that the key factors directly influencing E. coli eradication effectiveness under the photoelectrocatalytic process were applied potential and electrolyte solution concentration. The optimum conditions eliminated 99.99% of E. coli in 150 minutes with an initial concentration of 106 CFU/ml, an electrolyte concentration of 0.01 M KCl, and an applied potential of 2.0 V. The study confirmed photoelectrocatalytic cells' efficacy in removing microorganisms and recommended their application in a wider range of wastewater treatment systems.

The effect and spectral response mechanism of dissolved organic matter (DOM) in Pb(II) adsorption onto biochar

This study investigated the interaction of biochar-derived dissolved organic matter (DOM) and metal pollutant Pb(II) during adsorption. Research data showed that the adsorption capacity of biochar and residual biochar (after removal of DOM) was 277.62 and 204.47 mg g−1, respectively, indicating that DOM played a significant role in enhancing the adsorption efficiency of Pb(II). The results indicated that the adsorption process of Pb(II) on biochar and residual biochar followed the pseudo-second-order kinetic equation (R2 > 0.99), and the adsorption isotherm was much closer Freundlich model. A combination of three-dimensional excitation-emission matrix (3D-EEM), synchronous fluorescence, Fourier transform infrared spectroscopy (FT-IR), and two-dimensional correlation spectroscopy (2D-COS) was employed to investigate the interaction between DOM and Pb(II). 3D-EEM indicated the presence of four major components of DOM, namely two protein-like substances, one humic acid-like substance, and one fulvic acid-like substance. The synchronous fluorescence revealed a gradual quenching of the fluorescence of the DOM sample with an increase in Pb(II) concentration, indicating a static quenching mechanism between DOM and Pb(II). FTIR-2D-COS analysis showed a specific sequence of DOM binding with Pb(II) is as follows: 1500 > 1010 > 880 > 1390 > 1260 cm−1. This findings have significant implications for the role of DOM in environmental science and have potential applications in various fields.

Effect of microplastics on the adherence of coexisting background organic contaminants to natural organic matter in water

Microplastics (MPs) may interact with background organic substances (including natural organic matter and organic pollutants) after entering the aquatic environment and affect their original binding. Thus, the interaction of MPs with background organic substances (i.e., humic acid (HA), polychlorinated biphenyls (PCBs), and hydroxy PCBs) were elucidated. According to the results, PCB and hydroxy PCB displayed a strong propensity to adhere to HAs in the absence of MPs. However, the PCBs and hydroxy PCBs that were initially bound to HAs shifted from HAs to MPs in the presence of MPs. Further analysis demonstrated that this transfer was dominated by van der Waals interactions, with hydrogen bond interactions as an additional driving force. Upon the interaction, large MPs-HA-PCB/ hydroxy PCB aggregates with MPs as the core and HAs as the outermost layer were formed. Significant changes in the properties of background organic matter, including the distribution of PCB/hydroxy PCB around HA, diffusion coefficient, and hydrogen bond networks in the HA-PCB/ hydroxy PCB domains, occurred during the MP–HA–PCB/hydroxy PCB interaction. These results provide molecular-level evidence that the intrusion of MPs changes the binding preference of background organic pollutants and can lead to a redistribution of background organic pollutants.

Degradation mechanism of saliferous compounding heavy metals-organic wastewater by manganese and iron cycling in the microbial fuel cell

With the rapid development of industry and agriculture, the heavy metal ions and organic matter pollution coexistence systems become increasingly common, aggravating environmental damage and endangering water safety. Therefore, an urgent need to find a general method to achieve the typical removal of two pollutants or promote the removal of one to improve another degradation, solving the related pollution problems. Meanwhile, the related research microorganism’s salt and heavy metal tolerance is lower, limiting the related research. Therefore, the study makes the deep-sea sediment as the strain source, obtaining the low-valence manganese-oxidizing functional bacteria (OMF) with salt-tolerant and heavy metal-tolerant characteristics, constructing the closed-circuit microbial fuel cell (MFC), carried out the degradation mechanism of saliferous compounding heavy metals-organic wastewater by manganese and iron cycling processes. The results showed that under the salt content conditions of 3%, pH = 6, external resistance of 510 Ω, Mn2+ concentration of 11 g/L, Mn2+:Fe2+ = 1:0.3 and OMF (Rhodococcus erythropolis: Microbacterium kitamiense: Dietzia = 1:2:1) inoculation amount of 20%. The maximum removal rates of organic pollutants (400 mg/L), Cu2+ (250 mg/L), Co2+ (150 mg/L) and Ni2+ (200 mg/L) were 94.72%, 91.23%, 99.89% and 99.97%, respectively. Realizing the heavy metal ions and organic matter pollution coexisting systems purification. The manganese-iron cycle mediated by oxidized low-valent manganese functional bacteria has a dual effect on the pollutant’s degradation process through MFC. Firstly, the synergistic redox cycle transformation of iron and manganese promoted the production of OH and accelerated the degradation of organic matter. Secondly, the ferromanganese oxidation products and bio-nanowires enhance material oxidation and electron transfer, improving the organic pollution oxidation and heavy metal ions fixation efficiency. This study provides a new idea for the heavy metal ions and organic matter pollution coexisting systems remediation and MFC degradation efficiency optimization.

Evaluation of the distribution of N, P and organic matter in sediment and the pollution status of Lakes in southeastern Hubei Province, China

Eutrophication caused by nutrients and organic matter (OM) pollution is a common problem in the world. The contents of total nitrogen (TN), total phosphorus (TP) and OM in sediments were determined in four typical lakes in southeastern Hubei, China, in the spring of 2019, and their pollution status was evaluated by organic and comprehensive pollution indexes to identify pollution sources and provide specific directions for the pollution control in key areas of the lakes. We found the following: (1) Both nutrients and OM in Cihu Lake and Bao’an Lake were relatively high. Cihu Lake had the highest nutrient and OM in both surface and core sediments. TN, TP and OM in the surface sediments of Cihu Lake reached 700.9 mg/kg, 1668.8 mg/kg and 62.8 kg/g, respectively. The contents of nutrients and OM in Daye Lake and Liangzi Lake were relatively low. OM in these two lakes was significantly lower than that in the Cihu Lake (p < 0.05). (2) The organic pollution and comprehensive pollution revealed that the pollution level of Cihu Lake and Bao’an Lake was moderate to severe. The level of pollution in Daye Lake and Liangzi Lake was mainly mild and moderate. (3) TN pollution was the main factor affecting sediment pollution in the four lakes compared to TP. The risks associated with N pollution merit increased attention. (4) Correlation analysis showed that there was not always a significant correlation between nutrients and OM in surface sediments (p > 0.05). It indicated that the sources of nutrients and OM in sediments were not identical but were affected by many factors. However, the relationship between nutrients and OM was closer in core sediments. In the future, targeted measures should be taken to reduce sediment pollution based on specific pollution sources and pollution conditions in the four lakes, especially Cihu Lake.

Odour mapping and air quality analysis of a wastewater treatment plant at a seaside tourist area.

Although wastewater treatment plants (WWTPs) play a fundamental role in protecting the aquatic environment as they prevent organic matter, nutrients and other pollutants from reaching the natural ecosystems, near residential areas they can generate unpleasant smells and noise. The plant studied in the present work is in a seaside tourist area in the Valencian Community, Spain. The main aim was to detect any possible perceptible H2S concentrations from the WWTP by experimental measurement campaigns (including sensor readings and olfactometry measurements by two experts) plus mathematical modelling. After a thorough data analysis of the essential variables involved, such as wind speed, wind direction and H2S concentrations (the main odorant) and comparing their temporal patterns, it was found that the probability of affecting the residential area was highest from June to August before noon and in the late evening. The hourly H2S concentration, influent flow rate and temperature showed a positive correlation, the strongest (R2 = 0.89) being the relationship between the H2S concentration and influent flow rate. These two variables followed a similar daily pattern and indicated that H2S was emitted when influent wastewater was being pumped into the biological reactor. The H2S median concentration at the source of the emission was below 1393.865 μg/m3 (1 ppm), although concentrations 10 times higher were occasionally recorded. The observed H2S peak-to-mean ratio (1 min to 1 h of integration times) ranged from 1.15 to 16.03. This ratio and its attenuation with distance from the source depended on the atmospheric stability. Both H2S concentrations and variability were considerably reduced after submerging the inlet. The AERMOD modelling framework and applying the peak-to-mean ratio were used to map the peak H2S concentration and determine the best conditions to eliminate the unpleasant odour.

Planktonic algoflora of small rivers in urban conditions (on the example of the Mirozhka and Pskova rivers, Pskov, the Pskov Region)

The paper studies the planktonic algoflora of the Mirozhka and the Pskova Rivers. The research was carried out in the early autumn period of 2019. The taxonomic composition of the Mirozhka River included 107 species and intraspecific taxa of microalgae, the Pskova river 76 species taxa of algae from 7 phylums: Bacillariophyta, Cyanobacteria, Chlorophyta, Ochrophyta, Cryptophyta, Euglenozoa, Miozoa. The basis of the floral complex in both rivers were diatoms and green algae. The representatives of the Ochrophyta department also made a visible contribution to the species richness of the algoflora of the Mirozhka River. The degree of floral similarity of phytoplankton communities of the Mirozhka and Pskova rivers, calculated using the Sorensen-Chekanovsky index, was 55,7% (51 species of microalgae were common to the rivers). The average phytoplankton abundance in the Mirozhka River was 891,9 thousand cells/l, and in the Pskova river 199,6 thousand cells/l, biomass 366,9 micrograms/l and 79,6 micrograms/l, respectively. According to ecological and geographical analysis, freshwater widespread planktonic forms of microalgae predominated in both rivers, preferring slightly alkaline waters. Beta-mesosaprobionts prevailed in relation to organic matter pollution in rivers (38,5% the Mirozhka River; 41,8% the Pskova River), which indicates moderate pollution of the studied watercourses. The average saprobity index of the Mirozhka River and the Pskova River was 2,1 and 1,9, respectively, which makes it possible to attribute the waters of the studied watercourses to the 3rd class of quality moderately polluted.

Solar-Assisted-Self-Healing N-Doped MXene Quantum Dots-Based Membrane with Protein Resistance for Seawater Desalination.

Membrane-based air humidification-dehumidification desalination (MHDD) technology is an effective way to ease fresh water shortage owing to its excellent salt rejection. However, industrial applications pose higher requirements on membrane life expectancy. Membrane cleaning is considered as a potentially sustainable approach to prolong the operation time. Traditional cleaning methods are limited due to the poor recovery efficiency and the introduction of impurities. Here, a novel solar-assisted-self-healing N-doped MXene quantum dots (NMQDs)/ZnO-based membrane was fabricated to repair the water production capability of membranes contaminated by proteins from seawater. On the one hand, NMQDs with up-conversion properties absorb visible light and emit ultraviolet light, under which ZnO could be excited to form electron/hole pairs that help to degrade organic matter pollutants. On the other hand, the addition of NMQDs could improve the charge separation efficiency of ZnO. The synergistic effect of the two enhances the light absorption capacity of ZnO. The as-designed membrane exhibited excellent repair ability. The moisture permeation rate of the healed membrane reached 99.8% of the initial membrane after illumination. The self-healing membrane with solar energy is promising advances in sustainable desalination.

IMPROVING THE WASTE WATER QUALITY OF CATFISH FARMING POND THROUGH PHYTOREMEDIATION PROCESS BATCH CULTURE SYSTEM USING VARIOUS TYPES OF LOCAL HYDROMACROPHYTES

This study aimed to determine the effectiveness of the batch culture phytoremediation model conducted in a 30 L bucket with sand and gravel as a substrate in reducing pollutants from post-harvest catfish farming ponds. This true experimental study used a completely randomised design with the treatments of hydromacrophytes of emergent, floating, submerged, and polycultures of the three hydromacrophytes and controls without hydromacrophytes. Each treatment was repeated three times. The effectiveness of this model was monitored using physicochemical water parameters, Chironomidae density, and the biotic index of diatom [Trophic Diatom Index (TDI) and Percentage of Pollution Tolerant Value (%PTV)]. After incubation, monitoring was done on days 10, 15, 20, and 25. The results showed that the phytoremediation process had successfully reduced the suspended solid and nitrate levels in the water starting from day ten after incubation. The levels of Biochemical Oxygen Demand (BOD) and Total Kjeldahl Nitrogen (TKN) decreased significantly after 25 days. The level of organic matter pollution based on the %PTV and density of Chironomidae was significantly reduced after 15 days of incubation. However, the phosphate level was still high, and the water trophic status was hypereutrophic. The most effective treatment for the phytoremediation process in this study is submerged hydromacrophytes.

The Antibiotics Degradation and Its Mechanisms during the Livestock Manure Anaerobic Digestion.

Antibiotics are administered to livestock at subtherapeutic levels to promote growth, and their degradation in manure is slow. High antibiotic concentrations can inhibit bacterial activity. Livestock excretes antibiotics via feces and urine, leading to their accumulation in manure. This can result in the propagation of antibiotic-resistant bacteria and antibiotic resistance genes (ARGs). Anaerobic digestion (AD) manure treatment technologies are gaining popularity due to their ability to mitigate organic matter pollution and pathogens, and produce methane-rich biogas as renewable energy. AD is influenced by multiple factors, including temperature, pH, total solids (TS), substrate type, organic loading rate (OLR), hydraulic retention time (HRT), intermediate substrates, and pre-treatments. Temperature plays a critical role, and thermophilic AD has been found to be more effective in reducing ARGs in manure compared to mesophilic AD, as evidenced by numerous studies. This review paper investigates the fundamental principles of process parameters affecting the degradation of ARGs in anaerobic digestion. The management of waste to mitigate antibiotic resistance in microorganisms presents a significant challenge, highlighting the need for effective waste management technologies. As the prevalence of antibiotic resistance continues to rise, urgent implementation of effective treatment strategies is necessary.

Heterotrophic aquatic metabolism and sustained carbon dioxide emissions in a mineral-soil wetland restored with treated effluent

Wetlands are economically valuable ecosystems, in part because they purify wastewater by retaining and processing nutrients, organic matter (OM), and other pollutants. While natural wetlands are highly productive and sequester large pools of carbon (C), it is unclear whether the C cycle of restored treatment wetlands is functionally consistent with natural systems. This knowledge gap limits our appreciation for the role that wetland restoration can play as a natural solution to climate change. Here, we quantified metabolic and C cycling patterns of a restored, multi-basin wetland (Frank Lake, Alberta, Canada) receiving municipal and beef processing plant effluents rich in nutrients and OM. We conducted metabolic measurements in all three basins using dissolved oxygen sensors deployed under ice and in open water. Extreme production and respiration indicated that effluent was largely mineralized and replaced with wetland OM in transit. The heterotrophic status of all basins aligned with a published mass budget demonstrating the aquatic habitat of the wetland was an OM sink under current drought conditions that lengthen effluent processing time. Floating chamber measurements in open water zones confirmed that the wetland was a source of CO2 to the atmosphere. From input to outflow, sustained emissions led to declining pCO2 and a decline in the ratio of dissolved inorganic to organic C. Over 30 years post-restoration, the open water habitats in Frank Lake remain heterotrophic and a net source of CO2, suggesting that the trajectory of aquatic C cycling may be distinct from wetlands restored with non-effluent water sources.

Analytical applications of smartphones for agricultural soil analysis

Soil is one of the most important farming resources. Appropriate managing of its quality promotes productive and sustainable agriculture. The valuable farm practice in soil quality managing is based on regular soil analysis with the aim of determining the exact amount of nutrients or other chemical, physical, and biological soil properties. Soil analysis usually requires sample collection at the desired sampling depth followed by sample delivery to chemical laboratories. However, laboratory analyses are resource-intensive and costly, and require a lot of time, effort, and equipment. A low-cost, fast, and effective alternative for soil quality control is the application of smartphones to perform chemical analyses directly in the field or on the farm. In this paper, an overview of recent developments on smartphone-based methodologies for agricultural purposes and portable evaluation of soil quality and its properties is presented. The discussion focuses on recent applications of smartphone-based devices for the determination of basic soil parameters, content of organic matter, mineral fertilizers, and organic or inorganic pollutants. Obvious advantages of using smartphones, such as convenience and simplicity of use, and the main shortcomings, such as relatively poor precision of the results obtained, are also discussed. The general trend shows the huge interest from researchers to move the technology into the field with the aim of providing cost-effective and rapid soil analysis. This paper can broaden the understanding of using smartphones for chemical analysis of soil samples, as it is a relatively new area and is expected to be developed rapidly.Graphical

Two decades of the EU Water Framework Directive: Evidence of success and failure from a lowland arable catchment (River Wensum, UK)

The EU Water Framework Directive (WFD) is widely regarded as a seminal piece of environmental legislation. However, two decades since its inception, many European waterbodies are failing to meet its ambitious goal to ensure ‘good’ quantitative and qualitative status. Here, we investigate the impact of the WFD upon the environmentally sensitive yet heavily impacted River Wensum, a lowland arable catchment in eastern England. Compiling a dataset of 10,950 water quality samples collected from 57 sites across the catchment at approximately monthly intervals during 2000–2022, we assess the spatio-temporal dynamics of 12 priority pollutants, identify the major drivers of water quality change, and evaluate current and future compliance with WFD goals. Our analysis reveals improvements in wastewater treatment initiated significant declines (11–50 %) in the concentration of key sewage pollution indicators (phosphorus, ammonium, biological oxygen demand (BOD)) during the early 2000s. Conversely, agricultural pollution indicators (nitrogen, suspended solids, pesticides) displayed either limited change or a deterioration in water quality, with oxidised nitrogen concentrations in particular having increased 23 % during 2015–2022. Concentration spikes of organic chemical contaminants in recent years (propyzamide, tetrachloroethylene) raise concerns about increased riverine pollution from hazardous substances. Similarly, changes in winter (+13 %) and summer (−7 %) discharge over the past two decades have increased the risk of diffuse pollution mobilisation and reduced the dilution of point source pollutants, respectively. By 2022, ‘good’ or ‘high’ water quality status for organic matter pollution indicators (dissolved oxygen, BOD, ammonium) was achieved for >98 % of samples, however WFD compliance fell to just 46 % for phosphorus and 1.8 % for nitrogen. Projections to the end of the third River Basin Management Plan cycle (2027) reveal that whilst phosphorus compliance is likely to improve, nitrogen compliance failure will persist due to the existence of catchment legacy stores and climate change induced impacts on nitrogen mobilisation.

The causal links between long-term exposure to major PM2.5 components and the burden of tuberculosis in China

BackgroundWe aimed to estimate the causal impacts of long-term exposure to major PM2.5 components - including black carbon, organic matter, sulfate, nitrate, and ammonium - on the incidence and mortality of tuberculosis in China. MethodsWe collected annual and provincial-level tuberculosis incidence and mortality, concentrations of PM2.5 components, and socioeconomic indicators from between 2004 and 2018 in mainland China. We used the difference-in-differences (DID) causal inference approach with a generalized weighted quantile sum (gWQS) regression model to estimate the long-term effects and relative contributions of PM2.5 components' exposure on tuberculosis incidence and mortality. ResultsWe found that long-term multi-components exposure was significantly associated with tuberculosis incidence (WQS index IR%:8.34 %, 95 % CI:4.54 %–12.27 %) and mortality (WQS index IR%:19.49 %, 95 % CI: 9.72 %–30.13 %). Primary pollutants, black carbon and organic matter, contributed most of the overall mixture effect (over 85 %). Nitrate showed a critical role in tuberculosis burden in not-aging provinces and in regions at the Q3 stratum (i.e., the 3rd quartile) of GDP per capita and urbanization rate. Meanwhile the contribution of sulfate to tuberculosis burden in regions at the Q1 stratum of GDP per capita and urbanization rate was the largest among the effect of secondary pollutants (i.e., sulfate, nitrate, and ammonium). ConclusionThe mitigation of black carbon and organic matter pollution may significantly reduce the tuberculosis burden in China. Controlling nitrate emissions and increasing clean energy (i.e., energy sources with limited pollution emissions, such as natural gas and clean coal) may also be effective in certain regions.

The trophic status and estimation of fish potential production in Batur Lake, Indonesia: A preliminary study

Lake Batur is a type of volcanic lake in Bangli Regency, Bali, Indonesia. The main problems in Lake Batur are no outlet, organic matter pollution from accumulated waste from the human population, cages, and agriculture. This study intends to investigate and evaluate the existing trophic status, the condition of the water, and fish production potential in Batur Lake. Observations were conducted at six stations in March 2023 using random purposive sampling. The status of water was calculated using the Trophic State Index (TSI), and fish yield was estimated using the Morphoedaphic Index (MEI). The findings showed that the TSI measurements of Batur Lake ranged from 54.07 to 75.25. In this condition, the lake is categorized as eutrophic. The annual fish production potential ranges from 109.9 to 210.5 kg/ha, with an average of 120.4 kg/ha. With 1600 hectares, the lake can produce 109-130 tons of fish. Based on captured fisheries statistic data in 2022, the potential value of fish production was relatively lower than the fishery production, which amounted to 576 tons. To suggest sustainable fisheries in Batur Lake, we need to maintain the existing fishing regulations and keep stabilizing the water quality.

A quick review on the mechanism and applications of microbial mediated fuel cells

A Microbial Fuel Cell (MFC) is a bio electrochemical device that can generate electricity by the use of electrons obtained from the anaerobic oxidation of substrates. Generally, the MFC consists of two parts, an anode and a cathode, which are separated by a Proton Exchange Membrane (PEM). This review was investigated to study MFC and its operational physiochemical, microbial and bioelectrical parameters. Microbial electrochemical technologies constitute a relatively recent innovative approach for wastewater treatment where a laboratory-scale level shows remarkable results in terms of the removal of organic matter and other pollutants of interest, as well as for the recovery of potential energy store in chemical form in wastewaters. It is of interest to invest efforts in systems that take advantage of bio electrochemical principles without simultaneous power generation. An option for this would be to invest higher efforts on the research of sewage operating with MFCs setups, systems operating in short-circuit mode.

Exploring controls on perfluorocarboxylic acid (PFCA) gas-particle partitioning using a model with observational constraints.

The atmospheric fate of perfluorocarboxylic acids (PFCAs) has attracted much attention in recent decades due to the role of the atmosphere in global transport of these persistent chemicals. There is a gap in our understanding of gas-particle partitioning, limited by availability of reliable atmospheric measurements, partitioning properties, and models of gas-particle interactions. The gas-particle equilibrium phase partitioning of C2-C16 PFCAs in the atmosphere were modeled here by taking account of both deprotonation and phase partitioning equilibria among air, aerosol liquid water, and particulate water-insoluble organic matter using a range of available PFCA partitioning properties. We systematically varied water and organic matter content to simulate the full range of atmospheric conditions. Except in severe organic matter pollution episodes, shorter-chain PFCAs are predicted to mainly partition between air and aqueous phase, while for PFCAs with carbon chains longer than 12, organic matter is more likely to be the dominant particle phase reservoir. The model framework underestimated the particle fraction of C2-C8 PFCAs compared with several ambient observations, with larger discrepancies observed for longer-chain PFCAs. The discrepancy could result from externally mixed dust components, non-ideality of aerosol liquid water, surfactant descriptions at phase boundaries, and missed interactions between organic matter and charged PFCA molecules. Reliable measurements of ambient PFCAs with high time resolution and the measurement of uptake parameters by particle-relevant components will be beneficial to more reliable environmental fate modeling of ambient PFCAs.

Carbon-based nanomaterial intervention and efficient removal of various contaminants from effluents – A review

Water treatment is a worldwide issue. This review aims to present current problems and future challenges in water treatments with the existing methodologies. Carbon nanotube production, characterization, and prospective uses have been the subject of considerable and rigorous research around the world. They have a large number of technical uses because of their distinct physical characteristics. Various catalyst materials are used to make carbon nanotubes. This review's primary focus is on integrated and single-treatment technologies for all kinds of drinking water resources, including ground and surface water. Inorganic non-metallic matter, heavy metals, natural organic matter, endocrine-disrupting chemicals, disinfection by-products and microbiological pollutants are among the contaminants that these treatment systems can remediate in polluted drinking water resources. Significant advances in the antibacterial and adsorption capabilities of carbon-based nanomaterials have opened up new options for excluding organic/inorganic and biological contaminants from drinking water in recent years. The advancements in multifunctional nanocomposites synthesis pave the possibility for their use in enhanced wastewater purification system design. The adsorptive and antibacterial characteristics of six main kinds of carbon nanomaterials are single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene, graphene oxide, fullerene and single-walled carbon nanohorns. This review potentially addressed the essential metallic and polymeric nanocomposites, are described and compared. Barriers to use these nanoparticles in long-term water treatment are also discussed.

Efficiency and mechanism of ozonated microbubbles for enhancing the removal of algae and algae-derived organic matter

The effective control of eutrophication caused by algae blooms is still the focus of global attention. The traditional dissolved air floatation process for algae removal has a low adhesion efficiency between bubbles and algal cells and a low removal efficiency of organic pollutants. Aiming to address these defects, this study set up an ozone microbubble-enhanced air flotation experiment to explore the removal trends of algal cells and algal organic matter (AOM) pollution. In contrast to traditional air flotation, this approach targets the removal of various forms of AOM after algal cell damage. The highest removal rates of algal cells, extracellular microcystin (Mc), intracellular Mc-lr and total Mc-lr were 96.6%, 60.1%, 95.2% and 93.7%, respectively. Compared with the traditional process, the absorption rate and utilization rate of ozone were increased by 41.9% and 46.2%, respectively. The removal effect of AOM was also greatly improved, and ozone microbubbles enhanced the removal of aromatic protein-like substances and high-molecular-weight fulvic acid, humic acid and humic substances. The advantageous synergistic effect of ozone and microbubbles on algae removal was analyzed by exploring the enhanced air flotation removal mechanism of ozone microbubbles' enhanced air floatation removal. Good vacuole adhesion and strong oxidation caused by ozone microbubbles jointly guaranteed a good removal rate of AOM. The enhanced air flotation process with ozone microbubbles has high feasibility and a good effect, can effectively remove algal cells and algal pollutants, and has great potential in algal removal and control of water eutrophication.

Impact of biochar, fertilizers and cultivation type on environmentally persistent free radicals in agricultural soil.

Environmentally persistent free radicals (EPFRs) have been considered as emerging contaminants due to their detrimental effects on human health. The adverse health impacts are attributed to oxidative stress induced by EPFRs through the formation of reactive oxygen species (ROS). In soils, it may also increase the degradation process of polymeric organic matter and/or undesired organic pollutants through hydroxyl radical activity. The biochar pyrolysis process entails the thermal decomposition of organic compounds in the biomass, with the carbonization conditions and feedstock type facilitating the formation of EPFRs. When biochar is used to amend soil, these radicals may promote the formation of ROS, and thus influence the transformation of organic and inorganic contaminants in soil and impact the rhizosphere. Agricultural soils are being amended with biochar to mainly increase carbon content and facilitate the plant growing conditions. Therefore, agricultural soils may become a source of EPFRs. However, the fate and transformations of EPFRs in soils after biochar amendment are not well understood or studied. This paper presents the first (to our knowledge) studies of EPFRs behaviour in agricultural soil with different input of biochar, cultivation types and residence time period. Different cultivation types, addition of fertilisers and variation in biochar input, on the one hand, and presence of metals in soil, biochar and fertilizers, on the other hand, provide different conditions for EPFRs formation, accumulation and fate in agricultural soils. Two significant factors have been found to determine the fate of EPFRs in soil: transition metal content (particularly those in reaction available form) and cultivation level of soil. Cultivation significantly decreased presence of EPFRs, both carbon-centered and oxygen-centered, in relatively short periods of time, while metal presence (and particularly through fertilizer supplementation) increases the half-life of radicals and transforms organic matter to more oxygen-centered EPFRs. The amount of biochar addition plays a secondary role as the EPFRs content in the soils is in a longer term primarily controlled by the other two factors.