Surface Water Quality Research Articles

Three visions about surface water quality

Water quality is a worldwide problem, especially in places where the growth of urban areas alters surface waters that can be analyzed in conjunction with legislation, bioindicators and emerging pollutants. However, the use of these three variables to determine water quality is still scarce. For this reason, the use of these three variables was the objective of this research, which sought answers as to their associative use for the analysis of surface waters such as the Paragominas Igarapé, in the municipality of the same name, Pará, Brazil. Investigative research with qualitative and quantitative scope was used with 72 selected publications, in seven types of publication, whose time frame was between 2005 and 2024.The data obtained and analyzed indicated that Conama Resolution 357 still needs changes and greater flexibility where bioindicators composed of Ephemeroptera, Plecoptera and Trichoptera (n= 8; 80%), and pollutants or contaminants such as microplastics (9.0 ± 6.6). This association was confirmed by principal component analysis (PCA): PC1 = 87%. PC2 = 12.8%. Thus, the use of the association between Conama Resolution 357/2005, with the EPT group and microplastics, may indicate greater veracity in the quality of urban surface waters, such as the Paragominas stream.

Simulating and predicting surface water quality for drinking and bathing purposes through combined approach of PCA, entropy-based WQI, and stochastic models

Simulating and predicting surface water quality for drinking and bathing purposes through combined approach of PCA, entropy-based WQI, and stochastic models

Youth Engagement in Water Quality Monitoring: Uncovering Ecosystem Benefits and Challenges

A youth-centric participatory mapping approach was employed to monitor the lower Mill Creek, an urban waterway located in Cincinnati, Ohio, by collecting geospatial data points on surface water quality and ecological assets. Utilizing the ArcGIS Field Maps application, a digital survey-based tool was developed to identify key areas related to ecological assets and urban water management challenges. The purpose of this citizen science approach was to allow researchers to capture and understand community perspectives and insights while engaging in scientific research that focuses on identifying geographic vulnerability areas and ecological assets. The primary objective was to empower local community groups and residents in an environmental justice neighborhood to understand the current opportunities and constraints of the adjacent waterbody, enabling informed decision-making for future planning initiatives that benefit both conservation and remediation efforts aligned with local values and needs. A youth-centric participatory mapping approach was employed to monitor the lower Mill Creek, an urban waterway in Cincinnati, Ohio, through the collection of geospatial data on surface water quality and ecological assets. The findings, based on hotspot analysis, revealed significant spatial clustering of heavy debris near the barrier dam and the lower portion of Mill Creek, where it converges with the Ohio River. This accumulation is attributed to the structural features of the barrier dam’s inner flood catchment area, which traps debris during rainfall events. Although no areas showed spatial significance for perceived ecological services, students identified specific areas with esthetic and biodiversity value, particularly at Mill Creek’s confluence with the Ohio River and along the northern stretch of the stream corridor. These findings provide valuable insights for guiding future conservation and remediation efforts that reflect both community values and environmental priorities.

Water quality assessment for aquacultivation in Quang Ngai city, Quang Ngai province

Aquatic product development and growth are significantly influenced by the water supply used for aquaculture. Evaluating the water quality available for this activity is vital since Quang Ngai city has been a major hub for the growth of aquaculture in Quang Ngai province. Twelve surface water quality parameters were monitored and analyzed at eight sampling points in the river basins of An Nghia and Tinh Khe communes from May to September 2023. The Water Quality Index (WQI) was calculated, and methods including Principal Component Analysis (PCA), calculation of environmental variable weights based on principal components (PC), and Pearson correlation were used to assess the correlation of the investigated factors. In the river basin of An Nghia and Tinh Khe communes, 12 criteria for the assessment of surface water quality were tracked and examined using 8 sampling locations between May and September in 2023. The degree of linkage was assessed using principal component analysis (PCA), weighting environmental factors based on principal components (PC), and Pearson correlation. The water quality index (WQI) was calculated between the factors of the research. The findings show that: (1) The parameters exceeded the permitted limit: DO, Alkalinity, NH4+, TP, Vibrio SPP, Coliform, TOC, and TN. The two metrics with the greatest levels of pollution among them are Vibrio SPP and NH4+. The WQI index ranges from 52-74 and is within the average water quality range (51-75); (2) PCA analysis reveals that only the first two principal components, PC1 and PC2 can account for 74.39% of the variance, with NH4+ (0.089) having the highest weight; (3) NH4+ and Vibrio SPP content have a strong correlation (r = 0.95), indicating that both of these parameters can be used to evaluate water quality in the study area in general.

An assessment of radiological risks and chemical toxicity due to naturally occurring radionuclides in surface waters of a semiarid region in Brazil

Santa Quitéria, a city in northeastern Brazil, faces significant challenges in ensuring the availability of potable water due to its semi-arid climate and limited water resources. This study investigates the radiological quality of surface waters commonly used by the population for drinking and by animals for hydration. Water samples were collected from six different locations over a 25-month period, and the concentrations of naturally occurring radionuclides were measured using spectrophotometric analysis, total alpha, and gross beta counting. The mean activity concentrations of Unat, 226Ra, 210Pb, 232Th, and 228Ra were determined to be 9.89∙10−2, 5.35∙10−2, 5.86∙10−2, 6.89∙10−3, and 2.81∙10−3 Bq∙L−1, respectively. Statistical methods, such as cluster and factor analysis, were applied to understand the distribution patterns of these radionuclides. The study also estimated dose rates from radionuclide intake, with a maximum value of 108.5 µSv·y−1, and compared the results against dose limits set by relevant organizations. Furthermore, the risks of morbidity and mortality from radionuclide intake were assessed, revealing the need for optimization at one sampling point where the health risks exceeded intervention thresholds.

Assessment of surface and groundwater quality in the Ctalamochita River basin, Argentina: hydrogeochemical characteristics and exploratory data analysis.

Freshwater and groundwater are important resources for the drinking water supporting agricultural and livestock activities in the Córdoba province, Argentina. The aim of this study was to assess the physicochemical and microbiological quality of surface water (n = 14) and groundwater (n = 17) sites in the middle-lower basin of the Ctalamochita River (Córdoba, Argentina) for human and animal consumption. A total of 18 physicochemical and five microbiological parameters were evaluated to determine the hydrogeological characteristics of both water resources and their suitability for human and animal consumption using the Water Quality Index (WQI). The results indicated that Na+ and HCO3- were the dominant cation and anion, respectively, in both water resources. Physicochemical and microbiological parameters values were compared with national and international guidelines. The WQI showed that groundwater samples exhibited poorer quality when compared to surface waters for human consumption, primarily due to elevated concentrations of major ions and the presence of total coliforms and Pseudomonas aeruginosa. Meanwhile, the WQI for animal consumption indicated that both surface and groundwater samples were suitable for this purpose. The Piper diagram showed that most of the surface water samples were classified as Na+-Cl--HCO3-, while groundwater samples were classified as Na+-HCO3-. This classification highlights the hydrogeochemical differences between the two water resources. TheGibbs diagram indicates that the chemical composition of both surface and groundwater sources is primarily controlled by processes of rock-water interaction and evaporation. The findings of this study will facilitate the development of a proactive plan to safeguard and sustain water resources in the middle-lower basin of the Ctalamochita River. This can be achieved through the implementation of preventive strategies and the introduction of innovative policies.

Watershed Grouping Based on Suspended Sediment Yield Using Morphological Criteria: A Comparison of Hierarchical and Nonhierarchical Techniques

ABSTRACTRegional sediment analysis methods have traditionally been used to reliably estimate sediment yield in ungauged watersheds with adequate hydrometric stations. Watershed‐grouping techniques are a suitable approach for estimating sediment load, which can be used to assess erosion processes, and surface water quality, and plan soil and water conservation measures. Additionally, the relationship between sediment yield and watershed characteristics can be used to identify different stages of erosion evolution and prioritize watersheds for conservation efforts. To this end, this study aimed to assess the applicability of various analytical hierarchy process (AHP) methods, including Ward's, Single linkage, and β‐flexible methods, as well as the nonhierarchical fuzzy C‐means (FCM) method in the Gorganroud and Qareh‐Sou watersheds of northern Iran based on hydrological, geological, climatic, physiographical, and land‐use characteristics. Furthermore, the study evaluated clustering methods to determine the optimal number of subwatershed clusters. The AHP methods identified two, three, or four clusters, while the FCM method identified three clusters as the best number of clusters. The results indicated that the FCM method had a well‐regionalized estimation in the study area with the maximum amount of validation indices (The highest Dunn coefficient 0.31–0.65, the lowest TESS 16.62–36.8, and acceptable Pseudo‐F coefficient 8.1–10.4). Notably, the fuzzy clustering methods associated each input sample with two or more clusters, which reduced the uncertainty of sediment yield estimation. The recommended clustering method can be used for regional sediment analysis in ungauged watersheds and evaluated against other hydrological variables in the study area.

Heating and ultraviolet irradiation: Gas pressure meter-based analytical system for on-site and rapid monitoring of permanganate index (CODMn)

Permanganate index (CODMn) is one of the important indicators of surface water quality measurement. Herein, a portable analytical system was developed for on-site and rapid analysis of CODMn, organic substances in water were oxidized and transformed into gases, so that CODMn concentration was converted into a change of gas pressure signal, the pressure signal change was further detected by a gas pressure meter. Heating method and ultraviolet (UV) irradiation method were used as assisting technologies for oxidization of organic substances by acidic KMnO4, a linear range of 2–150 mg l-1 and a detectable limit of 2 mg l-1 were obtained. Those methods were further applied to the detection of CODMn in various water samples (lake waters and domestic sewage) and certified reference water samples (BWZ 6974–2016C and BWZ 7617–2016), with recoveries of 89–111 %. Among them, a portable analytical system based on UV irradiation gas pressure meter was further established and used for the analysis of CODMn in field. It is a promising analytical system/device for CODMn monitoring in field, offering advantages of low-cost, easy-operation, portability and rapidness.

Surface water quality in Costa Rica: new initiatives and challenges

ABSTRACT Despite Costa Rica's reputation for being a leader in environmental policy and its thriving nature-based tourism industry, the nation has had poor surface water quality. Reasons for poor water quality include the lack of sewerage treatment, overuse of septic tanks, and the application of large quantities of agrichemicals. Although Costa Rica has policies to maintain surface water quality, they have not been sufficiently implemented. Recent initiatives have addressed surface water quality, including an ambitious plan to expand treated sewerage systems in all urban areas. Current efforts to meet this goal have focused on the San Jose metropolitan area and coastal communities. This paper reviews the advances and challenges to Costa Rica's efforts to improve water quality.

A Localized Evaluation of Surface Water Quality Using GIS-Based Water Quality Index along Satpara Watershed Skardu Baltistan, Pakistan

Surface water quality in Skardu, Gilgit-Baltistan, Pakistan, is of immense importance because of the city’s dependence on these resources for domestic uses, agriculture, and drinking water. The water quality index (WQI) was integrated with the Geographic Information System (GIS) to spatially envision and examine water quality data to facilitate the identification of pollution hotspots, trend analysis, and knowledge-based decision-making for effective water resource management. This study aims to evaluate the physiochemical and bacteriological parameters of the Satpara watershed and to provide the spatial distribution of these parameters. This study endeavors to achieve Sustainable Development Goal 6 (SDG 6) by identifying localities with excellent and unfit water for drinking, sanitation, and hygiene. A total of fifty-one surface water samples were collected from various parts of the Satpara watershed during the fall season of 2023. Well-established laboratory techniques were used to investigate water for parameters like Electrical Conductivity (EC), pH, turbidity, total dissolved solids (TDSs), major cations (K+, Na+, Mg2+, Ca2+), major anions (Cl−, SO42−, NO3−, HCO3−), and bacteriological contaminants (E. coli). Spatial distribution maps of all these parameters were created using the Inverse Distance Weighted (IDW) technique in a GIS environment. A significant variation in the quality of water was observed along the study area. The level of Escherichia coli (E. coli) contamination is above the permissible limit at various locations along the watershed, making water unsafe for direct human consumption in these areas. Some regions showed low TDS values, which could adversely affect human health and agricultural yield. From the WQI valuation, 58.82% of the collected samples were “Poor”, 31.8% were “Very poor” and 9.8% were found to be “Unfit for drinking”. The research findings emphasize the pressing need for consistent monitoring and adoption of water management strategies in Skardu City to warrant sustainable soil and water use. The spatial maps generated for various parameters and the water quality index WQI offer critical insights for targeted intercessions.

Cover crops and P‐fertilizer management affect microbial activity in a US Midwest corn and soybean rotation

AbstractMicroorganisms can have a substantial effect on labile phosphorus (P), which may be lost from the soil surface and impact water quality. Changes in nutrient availability and soil health from agricultural management can affect microbial biomass carbon (MB‐C), microbial biomass phosphorus (MB‐P), and the expression of P cycling enzymes. The objective of this research was to investigate biological mechanisms affecting P availability and potential loss to runoff in a no‐till, corn (Zea mays)–soybean (Glycine max) cropping system with two cover crops (cover crop [CC] and no cover crop [NC]) and three P management treatments (fall broadcast [FB], spring injected ammonium polyphosphate [SI], and no phosphorus application [NP]). Treatments were applied to a randomized block design with three replicates. Soil samples were analyzed for MB‐P, MB‐C, phosphatase activity, and Mehlich‐III P (PM). The P supply to the soil solution was measured using diffusive gradient thin film P (PDGT). In Spring 2018, Fall 2018, and Spring 2019, all phosphatase activity was greater in CC versus NC (p < 0.01). Microbial biomass C was greater in CC compared with NC in spring but not fall samplings. On average, MB‐P was fivefold greater in the P fertilized than unfertilized treatments (p < 0.001). CCs did not change MB‐P, PM, or PDGT within FB or NP, but did affect SI fertilizer treatments. Our results suggest CC can increase potential for organic P mineralization, application of P fertilizer increases MB‐P, and an interaction between SI P fertilizer management and CC may increase P supply to the soil solution.

Enhancing surface water quality prediction efficiency in northeastern thailand using machine learning

Enhancing surface water quality prediction efficiency in northeastern thailand using machine learning

Impacts of changing weather patterns on the dynamics of water pollutants in agricultural catchments: Insights from 11-year high temporal resolution data analysis

Widespread and long-term shifts in weather patterns are contributing to further degradation of surface water quality. This challenge caused by the increasing frequency of extreme weather events requires appropriate adaptation of current mitigation strategies. But to confirm the need to redesign such strategies, an understanding of the impacts of increasing weather extremes on pollutant losses in different catchment types is required. With this in view, this study investigated the impact of changing weather patterns on the inter-seasonal and inter-annual dynamics of nutrient losses in six agricultural catchments in Ireland over 11 years. The high temporal resolution data (10-min) from these intensively managed catchments represented different characteristics and management practices. Mann-Kendall Trend Analysis and Generalised Additive Models were used to study nutrient concentration trends, and to investigate the significance of water discharge, precipitation, potential evapotranspiration, soil moisture deficit, air temperature, and soil temperature on the losses of nutrients, respectively. The analysis of historical data revealed changes in the trends of daily average nitrate (NO3-N), phosphorus (P), and suspended sediment (SS) concentrations in association with significant increasing trends in air temperature, soil temperature, and precipitation across the same month over 11 years of monitoring. While discharge was significantly contributing to the concentrations of NO3-N, P, and SS across different catchments, air and soil temperature were significantly correlated to NO3-N losses, and precipitation was the major contributor to regulating P (total P and total reactive P) concentrations. In short, air temperature, soil temperature, soil moisture deficit, and precipitation were the main climatic drivers regulating the nutrient concentrations while the soil chemistry and drainage status were the non-climatically related drivers. The results revealed that the extent of the impact of climatic drivers depends on catchment characteristics. Therefore, expanding the application of this type of study would facilitate better understanding of current and future challenges to water management and provision of climate-resilient mitigation strategies for different catchment typologies.

Application of electrical resistivity tomography for groundwater evaluation in Yirgacheffe Town and its environs, Main Ethiopian Rift

Exploring groundwater is crucial in areas with poor surface water quality, such as Yirgacheffe Town and its surroundings. This study aims to assess aquifer materials and groundwater potential using Electrical Resistivity Tomography (ERT) in the region,within the Main Ethiopian Rift. Four electrical resistivity profiles were gathered using a Wenner array with a WDA-1 digital resistivity and induced polarization meter from Chongqing, China. Each profile extended 236 m with 4-m electrode spacing. Data were analyzed and inverted with Res2DinV software and validated against lithological logs. The ERT inversion revealed three subsurface geoelectric layers: (1) massive rhyolite ignimbrite and basalt (>2000 Ωm); (2) weathered rhyolite ignimbrite and basalt (200–2000 Ωm); and (3) topsoil (4–200 Ωm). These results are key for effective water resource management and highlight ERT's utility in similar geological settings.

The state of knowledge of freshwater resources in the U.S. Virgin Islands: Data scarcity and implications

AbstractLike many small island communities, the U.S. Virgin Islands (USVI), an unincorporated territory of the U.S., is naturally freshwater scarce. In recent decades, rapid land development in the USVI has increased water demand considerably, exerting extra pressure on freshwater resources. Freshwater quantity and quality data for the USVI are very scarce and scattered, which limits freshwater management capabilities. We draw attention to this information deficit and discuss its implications by reviewing the current state of knowledge of surface and groundwater quantity and quality for the USVI. Our review confirms that long‐term records of surface and groundwater quantity and quality are limited and unreliable. For example, streamflow was most recently monitored in 2006, and the most extensive surface water quality records are from the 1960s and 1980s. Since 2016, mean groundwater levels have been recorded daily, but only for three wells (one on each island of the USVI). Importantly, this lack of information threatens water security for the territory and limits our understanding of how development has impacted water quality and availability over time. This could be addressed using models, such as a groundwater recharge model, in combination with remote sensing and updated field data (i.e., streamflow, groundwater, and ecohydrological characterizations of land use change).

Analysis of groundwater and surface water quality using modelled water index and multivariate statistics in Kampala and Mbarara Districts, Uganda

The demand for domestic, public and industrial use of water increases with population growth. However, activities from humans and natural environment have resulted into decline in water quality. The aim of this study was to evaluate the quality of groundwater and surface water collected from Kampala and Mbarara districts of Uganda using water quality index and multivariate statistics. A total of 10 physicochemical parameters (pH, water temperature, chloride, sulphate, nitrate, electrical conductivity, total dissolved solids, total suspended solids, total solids, and phosphate) were measured monthly to evaluate the quality of water in the study districts. Results showed that sulphate, electrical conductivity and total dissolved solids were observed with significantly high values in surface water than the groundwater for both seasons. Among all the parameters measured, electrical conductivity was observed with the highest value (2129.67 ± 1.41 µS/cm) while nitrate concentration (0.57 ± 0.02 mg/L) was observed with the lowest during the wet season in surface water. In addition, the mean values of nitrate, electrical conductivity, total dissolved solids and sulphate detected in the groundwater and surface water were within the recommended limits, while phosphate and chloride were observed with mean concentrations above the regulatory limits in 50% of the samples. The correlation analysis revealed strong and positive association between electrical conductivity and total dissolved solids in groundwater and surface water for both seasons. Also, the chemical make-up of groundwater and surface water within the study districts revealed that the determination of water quality rests on two major indices (conductivity and anthropogenic-pollutants) based on the factor analysis. The two indices accounted for 0.619% in groundwater and over 0.70% in surface water, indicating more pollution in surface water. Moreover, the water quality index (WQI) values obtained ranged from 14.81 to 115.73 in dry season and 7.77 to 108.24 during the wet season. According to WQI classification, 42% of the samples collected fell within the “excellent” and “good” categories while others fell within “poor” and “unfit” categories (58%) during the dry season. Based on these findings, appropriate treatment methods, proper sanitation and waste management should be implemented in locations with critical water conditions. Also, frequent monitoring of groundwater and surface water quality by environmental protection agency is highly recommended.

Environmental Impact of Automobile Wastes on Surface Water Quality in Ebonyi State, Southeast Nigeria

ABSTRACTThe negative impact of operations in informal auto mechanic workshops is a major public health concern, and its effect on surface water pollution cannot be overlooked. This current work evaluates the environmental impact of automobile waste on surface water quality in Ebonyi State, Southeast Nigeria. A total of 108 surface water samples were taken in 2022 and 2023 from Abakaliki, Onueke, and Afikpo streams, and WHO as controls using standard analytical methods. Data sets were analyzed using Fisher's Significance Least Difference (F‐LSD) at the 0.05 probability level. The study showed that surface water appearance was slightly brown, and the observed upstream is acidic in nature, the midstream is alkaline, and the downstream is natural. Water samples from Abakaliki, Onueke, and Afikpo streams were observed to be hard since their concentration levels were above the WHO standard. Furthermore, the high concentrations of heavy metals (Pb and Mn) as well as the oil and grease content indicate that the surface water in the area of study is polluted and its overall quality is degraded. The study therefore concluded that automobile waste had a negative influence on the surface water quality in the study area. Based on these new findings, it is recommended that automobile waste be properly treated and disposed of to avoid their adverse effects on surface water quality. In addition, given the uncontrolled development of these informal auto workshops across the nation in recent years, there is a need for the execution of environmental standards connected to automobile service activities.

Optimizing surface water quality parameters in monitoring networks in a developing sub-tropical region with high anthropogenic pressure (São Paulo State Brazil).

Efficient water quality monitoring is a central aspect of water resources management, especially in developing countries, where water quality is under high anthropogenic pressure and resources for monitoring are usually limited. Here, we evaluated an alternative to optimize water quality parameters (WQPs) in the water quality monitoring network (WQMN) of the most populous state in Brazil (São Paulo State). We focused on the monitoring goal of identifying water quality temporal trends, selecting WQPs with high statistical explanatory power and those that were particularly sensitive to natural and anthropogenic perturbations. We considered 12 initial WQPs (dissolved copper, total zinc, total lead, total chromium, total mercury, total nickel, total cadmium, total iron, total manganese, total aluminum, total copper, and surfactant) with data from 2004 to 2018 for 56 monitoring sites distributed across four major watersheds with contrasting land uses in the state. We performed principal component analysis, followed by objective criteria to refine WQPs recommendation for the WQMN. Our results indicated the opportunity of reducing at least one parameter from the initial set of WQPs in all watersheds. Total iron, total manganese, and total aluminum were the most relevant initial WQPs, since their maintenance in monitoring were indicated in all the analyzed cases. Natural watershed conditions (e.g., geomorphology and water geochemistry) potentially governed their concentrations in surface water. On the other hand, total mercury, total chromium, and dissolved copper had the maintenance indicated in only one watershed, especially due to concentrations consistently below the respective limits of quantification (LoQs). Future investigations can complement our recommendations for these parameters, since changes in LoQs could throw another light on water quality spatial and temporal variations and the need for reference areas for assessing baseline conditions can also be relevant. Moreover, we argue that depending on the monitoring goals of the WQMN, additional sampling of biota and sediments could be useful as many of the studied WQPs' bioconcentrate. Our results illustrated an alternative approach towards adaptive monitoring in São Paulo state in accordance with the intended monitoring goal (i.e., water quality temporal trends), converging with the more flexible monitoring adopted in well-structured networks worldwide. While we did not cover other monitoring goals in our study (as the control of illegal discharge of effluents or industrial spills, for example), we expect our methodology can contribute to establishing technical guidelines for reviewing the existing WQMNs in Brazil and other developing countries with similar challenges.

Studying Surface Water Quality in the Upstream of Ba River Basin in Gia Lai Province

This study used two data sets to evaluate the surface water quality in the upstream of Ba River basin in Gia Lai Province in 2022. The first collected data set included six monitoring periods in April, May, July, September, November, and December in 2022 with 22 surface water samples each time at 22 points in Gia Lai. The second data set was monitored additionally, focused on the monitoring points in the Ba River basin in Gia Lai, including 38 monitoring points: 28 points on the Ba River and 10 points on 4 major river tributaries in the Ba River basin, with 10 samples for each point during the period from April 4th, 2022 to May 2nd, 2022. Results from processing the first data set showed that there were 4/22 points having water quality at the level from poor to very heavily polluted needing special attention, including: 3 points measured in the dry season (N1 - Tra Da Industrial Park, Pleiku City, N17 - receiving wastewater from Chu Se Industrial Park, and N23 - Phu Tuc town, Krong Pa) and 1 point measured in the rainy season in July (N11 -Yang Trung Bridge, Kong Chro district) where the water quality was heavily polluted with WQI = 8. Results from processing the second data set showed that the water quality of the Ba River tended to gradually degrade along the flow. There are 3 monitoring points in the upstream of Ba River with the water quality reaching level C (bad water quality): NN_Song Ba_1, NN_Song Ba_2, and NN_Song Ba_3. The remaining points reached level D (very poor water quality). These locations with poor water qualities need appropriate measures to improve water quality. This research results will be the basis for developing a surface water quality management plan in Gia Lai province and Ba River basin.

Fabrication of FeCu/CC Composite for Efficient Removal of Nitrate for Aqueous Solution Via Electrochemical Reduction Process

AbstractThe electrochemical nitrate reduction (ENR) for the conversion of nitrate to nitrogen gas is a significant strategy to remediate the eutrophication in surface water. However, the exploitations and practical applications of suitable electrocatalysts still face great challenges. In this study, FeCu bimetal microparticles were deposited onto surface of carbon cloth (CC) to fabricate the FeCu/CC electrocatalyst for the removal of nitrate. Among obtained catalysts, the sample with Fe/Cu molar ratio of 1 : 15 (Fe1Cu15/CC) exhibits the excellent electroreduction efficiency for nitrate removal (R(NO3−), >90 %) but an ineffective selectivity of N2 formation (S(N2), ~23 %). After the anchor of reduced graphite oxide (rGO) to surface of Fe1Cu15/CC, at the optimized condition without the assistance of chlorine oxidation, R(NO3−) and S(N2) of rGO/Fe1Cu15/CC catalyst reach 94.2 % and 72.8 %. After 5 day endurance test, the values of R(NO3−) and S(N2) are still 82.9 % and 62.8 %, demonstrating the promising durability of this catalyst electrode. Meanwhile, the potential application of rGO/Fe1Cu15/CC was explored for the treatment of simulated wastewater discharged by urban wastewater treatment plant, the concentration of total nitrogen (TN) decreases from 15–1.17 mg/L, and this value is lower than TN threshold limit in Class IV of Chinese surface water quality standard.