Nitrate Ion Concentration Research Articles

A Co3O4 Nanoparticle-Modified Screen-Printed Electrode Sensor for the Detection of Nitrate Ions in Aquaponic Systems

In this study, a screen-printed electrode (SPE) modified with cobalt oxide nanoparticles (Co3O4 NPs) was used to create an all-solid-state ion-selective electrode used as a potentiometric ion sensor for determining nitrate ion (NO3-) concentrations in aquaculture water. The effects of the Co3O4 NPs on the characterization parameters of the solid-contact nitrate ion-selective electrodes (SC-NO3--ISEs) were investigated. The morphology, physical properties and analytical performance of the proposed NO3--ion selective membrane (ISM)/Co3O4 NPs/SPEs were studied by X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), potentiometric measurements, and potentiometric water layer tests. Once all conditions were optimized, it was confirmed that the screen-printed electrochemical sensor had high potential stability, anti-interference performance, good reproducibility, and no water layer formation between the selective membrane and the working electrode. The developed NO3--ISM/Co3O4 NPs/SPE showed a Nernstian slope of -56.78 mV/decade for NO3- detection with a wide range of 10-7-10-2 M and a quick response time of 5.7 s. The sensors were successfully used to measure NO3- concentrations in aquaculture water. Therefore, the electrodes have potential for use in aquaponic nutrient solution applications with precise detection of NO3- in a complicated matrix and can easily be used to monitor other ions in aquaculture water.

The problem of pollution of drinking water with nitrate ions and modern methods of its solution

The article discusses various regulatory documents that regulate the content of nitrate ions in drinking water, as well as the impact of nitrates on human health and safety. The results of studies on nitrate ion contamination of sources of drinking water supply in 5 regions of Ukraine are presented. Physico-chemical analysis was carried out for water sources from wells in rural areas, city limits and in the territories adjacent to cities. The relevance of the problem of water pollution with nitrate ions, which requires the search, implementation and improvement of water purification methods from nitrates, has been proven. A comparative analysis of the advantages, disadvantages and features of the use of various methods of removing nitrate ions from drinking water, including water from non-centralized sources of water supply, was carried out. Biological, ion-exchange, adsorption, electrochemical methods, as well as baromembrane methods, in particular the reverse osmosis method, are used to purify water from nitrate ions. The regularities of the reverse osmosis process during the removal of nitrate ions from model solutions and water from wells were studied. Reverse osmosis membranes manufactured in the USA by Filmtec type TW30-1812-50 were used for experimental studies. Model solutions of Mg(NO3)2, Zn(NO3)2 and, directly, water from non-centralized sources of water supply were used as the tested water. Membrane selectivity and permeate selection coefficient were determined according to the known method. Parametric curves of the dependence of the selectivity of the membrane in relation to NO3- on the increase of the working pressure from 0.5 MPa to 1.9 MPa for model solutions of different concentrations were constructed. The dependences of the change in the concentration of nitrate ions in well water and the selectivity (φ, %) of the membrane in relation to NO3- on the working pressure were obtained. On the basis of the research results, a conclusion was made about the high efficiency of water purification from nitrates by low-pressure reverse osmosis (in the range from 0.5 MPa to 1.9 MPa) and the parameters of the researched process were determined, which would allow reaching the MPC standards for nitrates in drinking water.

Seasonal and Spatial Variability of Dissolved Nutrients in the Yenisei River

The accelerated rates of warming in high latitudes lead to permafrost degradation, enhance nutrient cycling and intensify the transport of terrestrial materials to the Arctic rivers. The quantitative estimation of riverine nutrient flux on seasonal and spatial scales is important to clarify the ongoing changes in land–ocean connectivity in the Arctic domain. This study is focused on a multiyear (2015–2021) analysis of concentrations of dissolved nutrients in the Yenisei River. Applying stationary water sampling, we studied seasonal variations in concentrations of phosphate, nitrate, nitrite and ammonia ions in the Yenisei River in the upper (56.0° N), middle (60.9° N) and lower (67.4° N) sections of the river. The waters of the upper river section demonstrated significant and steady nutrient enrichment throughout the hydrological year, reflecting the influence of the Krasnoyarsk reservoir. The downstream reaches of the Yenisei River had more apparent seasonal patterns of nutrient concentrations. Particularly, winter-season nutrient levels in the middle and lower river sections were the highest during the hydrological year and close to the upper section. At snowmelt, and especially the summer–fall seasons, all inorganic nutrient concentrations dropped dramatically after the inflow of the Angara River. On the other hand, the peak nitrite content observed during the early spring flood was most pronounced in the lower section of the river basin, reflecting the specific characteristics of the nitrogen cycle in permafrost soils. The spring flood plays the major role in the annual nutrient fluxes, except for nitrates, for which the maximum occurred in the winter season. The summer–fall season, despite its duration and considerable water runoff, demonstrated the lowest fluxes of dissolved inorganic phosphorus and nitrogen in comparison to other periods of the hydrological year, suggesting strong biological uptake and chemostasis.

A New Partially Phosphorylated Polyvinyl Phosphate-PPVP Composite: Synthesis and Its Potentiality for Zr (IV) Extraction from an Acidic Medium

A newly synthesized partially phosphorylated polyvinyl phosphate derivative (PPVP) was functionalized to extract Zirconium (IV) from Egyptian zircon sand. The specifications for the PPVP composite were approved effectively via different techniques, namely, FT-IR, XPS, BET, EDX, TGA, 1H-NMR, 13C-NMR, GC-MS, XRD and ICP-OES analyses, which demonstrated a satisfactory synthesis of PPVP and zircon dissolution from Egyptian zircon sand. Factors controlling parameters, such as pH values, shaking time, initial zirconium concentration, PPVP dose, nitrate ions concentration, co-ions, temperature and eluting agents, have been optimized. At 25 °C, pH 0, 20 min shaking, 0.05 mol/L zirconium ions and 0.5 mol/L nitrate ions, PPVP has an exciting preservation potential of 195 mg/g, equivalent to 390 mg/L zirconium ions. From the extraction–distribution isotherm, the practical outcomes of Langmuir’s modeling are better than the Freundlich model. With a theoretical value of 196.07 mg/g, which is more in line with the experimental results of 195 mg/g. The zirconium ions adsorption onto the PPVP composite follows the pseudo-second-order kinetics with a theoretical capacity value of 204.08 mg/g. According to thermodynamic potential, the extraction process was expected to be an exothermic, spontaneous and beneficial extraction at low temperatures. The thermodynamic parameters ΔS (−0.03 kJ/mol), ΔH (−12.22 kJ/mol) and ΔG were also considered. As the temperature grows, ∆G values increase from −2.948 kJ/mol at 298 K to −1.941 kJ/mol at 338 K. Zirconium ions may be eluted from the working loaded PPVP by 0.025M HNO3, with a 99% efficiency rate. It was found that zirconium ions revealed good separation factors towards some co-ions such as Hf4+ (28.82), Fe3+ (10.64), Ti4+ (28.82), V5+ (86.46) and U6+ (68.17). A successful alkali fusion technique with NaOH flux followed by the extraction with PPVP is used to obtain a high-purity zirconia concentrate with a zircon content of 72.77 % and a purity of 98.29%. As a result of this, the improved factors could finally be used.

Electrochemical Denitrification of Synthetic Aqueous Solution and Actual Contaminated Well Water: RSM Modeling, Kinetic Study, Monte Carlo Optimization, and Sensitivity Analysis

The process of electrochemical denitrification is applied with the aim of converting nitrate ( NO 3 − ) to N2 gas by reducing nitrate and oxidizing by-products such as ammonia ( NH 4 + ). In this study, Ti/RuO2 and graphite were used as anode and cathode electrodes, respectively, to treat synthetic aqueous solutions containing different concentrations of nitrate ions. Nitrate initial concentration (2.75–55 mg NO3-N/lit), voltage (2.5–30 V), pH (3–13), electrode distance (ED = 0.5–3.5 cm), and reaction time (10–180 min) were the main studied operating parameters for the electrochemical denitrification (ECD) reactor. The experiments were designed using the central composite design (CCD) method. The experimental results were modeled with the response surface methodology (RSM) technique. Scanning electron microscope (SEM), X-ray diffraction analyzer (XRD), and Fourier transform infrared spectroscopy (FTIR) characterized electrodes were performed before and after all experiments. Optimization and sensitivity analysis was performed using the Monte Carlo simulation (MSC) approach. The energy consumption and current efficiency were calculated for the ECD reactor. Kinetic models of zero, first, and second order were evaluated, and the second-order model was selected as the best kinetic model. Also, the effect of adding monovalent, divalent salts, and organic compounds to the process was evaluated. Finally, three nitrate-contaminated water wells were selected near agricultural lands as real samples and investigated the performance of the ECD process on the samples. The performance of the ECD reactor for the real samples showed some decrease compared to the synthetic samples.

PSII-8 Impact of Grazing High Nitrate Forages on Serum Nitrate Concentration and Production Performance in Beef Heifers

Abstract The objective of this study was to compare nitrate concentrations in soil, forage, and the serum of animals grazing high (HNO3) and low (LNO3) nitrate forages. The fall before the study began one-half of a 6-ha field was amended with manure to increase nitrate levels in the soil. Forage barley (Hordeum vulgare L. var. Vernal) was planted in spring at 45 kg/ha. The 6-ha field was divided into twenty-seven 0.2-hectare paddocks (n = 13 HNO3; n =14 LNO3). Twenty-four crossbred yearling heifers were stratified by body weight (389.8 ± 2.8 kg) and randomly assigned to HNO3 (n = 12) or LNO3 (n = 12) with three replicates per treatment. Heifers entered paddocks when forage was 30 to 46 cm tall and removed when residual height was 10 cm. Heifers grazed for a total of 58 days. Each grazing period lasted 7-8 d. Soil samples were collected at the beginning of the study and sent to a commercial laboratory for soil analyses. Forage samples were collected prior to animal introduction to each grazing paddock, and before re-grazing. Heifers were weighed on d1 and every 14 d. Serum samples for nitrate analysis were collected on d 28, 42 and 57 of the trial. Forage samples were analyzed by near infrared spectrometry. Serum samples were analyzed for nitrate concentrations by ion chromatography. Data were analyzed using PROC GLM of SAS. Analysis of body weights and average daily gain included repeated measures. Soil, nitrate-nitrogen (ppm) and nitrate-nitrogen content (kg/ha) were greater (P < 0.001) in HNO3 compared to LNO3 paddocks. Soil P (P < 0.03) and K (P = 0.0002) levels were also greater in HNO3 than LNO3 paddocks. Average forage nitrate ion concentrations were greater (P < 0.0001) for HNO3 (1.58%) compared to LNO3 paddocks (0.42%). Forage nitrate ion concentrations increased (P < 0.002) with increasing grazing days. Peak nitrate ion concentration in HNO3 paddocks was 2.45%. Forage ADF, TDN, NDF, NEm, NEg were similar (P ≥ 0.07) between treatments. Forage crude protein was greater in HNO3 compared to LNO3 paddocks (P < 0.0001). Serum nitrate levels were undetectable (< 2 ppm) regardless of treatment. Heifer bodyweight and average daily gain were similar (P > 0.7) across treatments. Heifers gained an average of 1.1 kg/d resulting in a linear increase (P < 0.04) in body weight. In summary, grazing vegetative forage containing toxic concentrations of nitrate did not result in an increase in the serum nitrate concentration. Animal performance also did not differ across dietary treatments. This is suggestive of adaptive changes that prevented toxicity and compromised production performance for heifers grazing high nitrate forages. Supported by the Mary A. Turner Research Endowment

Photobiomodulation therapy protects red blood cells against nitrative stress during streptozotocin-induced diabetes

Background. According to the International Diabetes Federation Diabetes Atlas, 10th edition, diabetes is responsible for 6.7 million deaths in 2021. Diabetes mellitus is a group of metabolic disorders characterized by hyperglycemia secondary to either resistance to insulin, insufficient insulin secretion, or both. Oxidative and nitrative stress is a vital part of the complex mechanism by which diabetes and its complications develop. It is known that Photobiomodulation therapy accelerates diabetic wound healing, treats relegated inflammation, and increases oxygen availability for cells. Although some basic molecular mechanisms caused by photobiomodulation therapy in different cell types are already known, they have not been studied in erythrocytes and are different due to the absence of central organelles such as nucleus and mitochondria. The aim of the study was to investigate the effect of photobiomodulation therapy on the development of nitrative stress in blood plasma and erythrocytes of rats from different experimental groups. Materials and Methods. The study was performed on white outbred male rats weighing 130–180 g. The diabetes mellitus was induced by intraperitoneal injection of streptozotocin (60 mg/kg). Rats were exposed to photobiomodulation with light-emitting diodes at a wavelength of 630–660 nm daily for 10 days. The irradiation time was 5 minu­tes. The content of nitrite and nitrate anions, total NO synthase activity, as well as the activity of its endothelial and inducible isoforms in red blood cells of rats were determined spectrophotometrically. Results and Discussion. Under streptozotocin-induced diabetes mellitus, the content of nitrite and nitrate anions and NO synthase activity increased in the rats’ red blood cells, as well as in blood plasma. Moreover, we found an increase in inducible NO synthase activity and nitrate ion content in red blood cells of irradiated healthy rats. Also, there was an increase in nitrite and nitrate ion content after photobiomodulation therapy in the blood plasma of healthy animals. On the other hand, irradiation caused a decrease in NO synthase activity with a parallel reduction in both nitrite and nitrate anions content in erythrocytes and blood plasma of rats with experimental diabetes. Conclusion. Photobiomodulation therapy protects rats’ red blood cells from nitrative stress during streptozotocin-induced diabetes mellitus.

Characteristic analysis of cabbage cultivated or stored under snow cover and prototype development of its processed products

Yukishita kyabetsu, cabbage (Brassica oleracea L. var. capitata L) that is cultivated or stored under snow cover for several months, was analyzed before and after snowfall; the sugar content, which imparts sweetness, was mostly retained. Meanwhile, the nitrate nitrogen (nitrate ion) concentration, which causes astringency, was decreased. In the analysis using a taste sensing system, the astringency and bitterness decreased because of the decrease in nitrate ions; thus, it was speculated that the sweetness increased in comparison. For cabbage stored in the snow room, we conducted a 5-day distribution test using three temperature groups (1, 10, and 20 °C) to clarify the effect of distribution temperature following shipment. The results showed that the sugar content was unchanged for almost 5 days in the 1 and 10 °C temperature groups, while it decreased in one day in the 20 °C temperature group. In the 20 °C temperature group, the nitrate ion concentration, which is responsible for bitterness, more than doubled in one day of distribution storage.

Reactive Nitrogen Hotspots Related to Microscale Heterogeneity in Biological Soil Crusts.

Biocrusts covering drylands account for major fractions of terrestrial biological nitrogen fixation and release large amounts of gaseous reactive nitrogen (Nr) as nitrous acid (HONO) and nitric oxide (NO). Recent investigations suggested that aerobic and anaerobic microbial nitrogen transformations occur simultaneously upon desiccation of biocrusts, but the spatio-temporal distribution of seemingly contradictory processes remained unclear. Here, we explore small-scale gradients in chemical concentrations related to structural characteristics and organism distribution. X-ray microtomography and fluorescence microscopy revealed mixed pore size structures, where photoautotrophs and cyanobacterial polysaccharides clustered irregularly in the uppermost millimeter. Microsensor measurements showed strong gradients of pH, oxygen, and nitrite, nitrate, and ammonium ion concentrations at micrometer scales in both vertical and lateral directions. Initial oxygen saturation was mostly low (∼30%) at full water holding capacity, suggesting widely anoxic conditions, and increased rapidly upon desiccation. Nitrite concentrations (∼6 to 800 μM) and pH values (∼6.5 to 9.5) were highest around 70% WHC. During further desiccation they decreased, while emissions of HONO and NO increased, reaching maximum values around 20% WHC. Our results illustrate simultaneous, spatially separated aerobic and anaerobic nitrogen transformations, which are critical for Nr emissions, but might be impacted by future global change and land management.

From Photocatalysis to Photo-Electrocatalysis: An Innovative Water Remediation System for Sustainable Fish Farming

In this study, the effects of photo-electrocatalysis (PEC) were evaluated as an innovative application of conventional photocatalysis (PC) to remediate water in a recirculating system for rainbow trout (Oncorhynchus mykiss) culture, in relation to fish welfare and health, with a multidisciplinary approach. Three tanks were employed, equipped with conventional biological filters as a control system, and three tanks equipped with the PEC purification system. The concentrations of ammonia, nitrite and nitrate ions in water were monitored, and the fish’s oxidative damage and stress response were evaluated in parallel. The water of the PEC-treated experimental group showed lower ammonia (TAN) and nitrite concentrations and higher nitrate concentration, possibly deriving from TAN oxidation through PEC, also leading to gaseous N2. Histological analysis did not reveal any pathological alteration in the gills and liver of both groups. The superoxide dismutase (sod1), glutathione reductase (GR), glutathione peroxidase (GPx1), and Tumor necrosis factor (TNFα) gene expressions were significantly higher in the control group than in the PEC-treated group, while the Heat shock protein 70 (Hsp70) expression did not show any difference in the two groups. These results indicate that the use of PEC filters has a positive effect on water quality, compared to the use of conventional biological filters, inducing a high level of welfare in O. mykiss.

Behavior of Ni20Cr Alloy in Molten Nitrate Salts.

This study reports the behavior of the Ni20Cr alloy in molten nitrate salts. Its behavior was evaluated in the eutectic mixture called Solar Salt (binary salt) and in a ternary mixture (90% Solar Salt and 10% lanthanum nitrate). The addition of lanthanum nitrate was performed to determine if the presence of the La3+ cation could act as a corrosion inhibitor. Through mass loss and potentiodynamic polarization studies, the effects of both electrolytes on the corrosion resistance of the alloy at 300, 400, and 500 °C and at exposure times of 250, 500, 750, and 1000 h were determined. The results showed an increase in the corrosivity of the ternary salt, due to a decrease in its melting point and an increase in the concentration of nitrate ions. However, it was observed that the La3+ cations formed a protective layer (La2O3) on the alloy surface. In both corrosive media, the Ni20Cr alloy showed excellent corrosion resistance, due to its ability to form protective layers of Cr2O3, NiO, and NiCr2O4, in addition to the presence of a layer of La2O3 in the case of the ternary salt.

РОЛЬ ОКСИДАТИВНОГО СТРЕССА В РАЗВИТИИ ВНУТРИПЕЧЁНОЧНОГО ХОЛЕСТАЗА БЕРЕМЕННЫХ И ЕГО АКУШЕРСКИХ И ПЕРИНАТАЛЬНЫХ ОСЛОЖНЕНИЙ

Objective. To determine the significance of oxidative stress in the pathogenesis of obstetric and perinatal complications in pregnant women with different course of intrahepatic cholestasis (IHC). Material and methods. 59 women with IHC of pregnancy and 30 patients without IHC were examined. The total concentration of nitrite and nitrate ions and thiobarbituric reactive substances (TBARS) in the blood serum of women with IHC was determined, their prognostic significance as predictors of maternal and perinatal complications was analyzed. Results. IHC is accompanied by the development of oxidative stress (Р<0.0001) and endothelial dysfunction (Р(U)=0.013). Determination of the concentration of TBARS in the blood serum of women with IHC allows predicting meconium staining of amniotic fluid (TBARS>17.64 µmol/l, Se=75.0%, Sp=84.3%; AUC=0.820; 95% CI 0,698- 0,908; p=0.0007), preterm labour with a symptomatic course of IHC (TBARS>14.25 µmol/l, Se=100.0%, Sp=71.4%; AUC=0.875; 95% CI 0.635-0.979; p=0.002) and the development of respiratory distress-syndrome in children born to patients with IHC (TBARS>17.32 µmol/l, Se=71.4 %, Sp=75.6%; AUC=0.775; 95% CI 0.648-0.874; p=0.0005). Conclusion. Oxidative stress is an essential link in the pathogenesis of IHC and its obstetric and perinatal complications.

2,4,6-trinitrotoluene (TNT) degradation by Indiicoccus explosivorum (S5-TSA-19).

2,4,6-trinitrotoluene (TNT), a nitro-aromatic explosive commonly used for defense and several non-violent applications is contributing to serious environmental pollution problems including human health. The current study investigated the remediation potential of a native soil isolate, i.e., Indiicoccus explosivorum (strain S5-TSA-19) isolated from collected samples of an explosive manufacturing site, against TNT. The survivability of I. explosivorum against explosives is indirectly justified through its isolation; thus, it is being chosen for further study. At a TNT concentration of 120mg/L within an optimized environment (i.e., at 30°C and 120rpm), the isolate was continually incubated for 30days in a minimal salt medium (MSM). The proliferation of the isolate and the concentration of TNT, nitrate, nitrite, and ammonium ion were evaluated at a particular time during the experiment. Within 168h (i.e., 7days) of incubation, I. explosivorum co-metabolically degraded 100% TNT. The biodegradation procedure succeeded the first-order kinetics mechanism. Formations of additional metabolites like 2,4-dinitrotoluene (DNT), 2,4-diamino-6-nitrotoluene (2-DANT), and 2-amino-4,6-dinitrotoluene (2-ADNT), were also witnessed. TNT seems to be non-toxic for the isolate, as it reproduced admirably in TNT presence. To date, it is the first report of Indiicoccus explosivorum, efficiently bio-remediating TNT, i.e., a nitro-aromatic compound via different degradation pathways, leading to the production of simpler as well as less harmful end products. Further, at the field-scale application, Indiicoccus explosivorum may be explored for the bioremediation of TNT (i.e., a nitro-aromatic compound)-contaminated effluents.

Predictive capability evaluation and mechanism of Ce (III) extraction using solvent extraction with Cyanex 572

Owing to the high toxicity of cerium toward living organisms, it is necessary to remove cerium from aqueous solutions. In this regard, the extraction of cerium (Ce (III)) from nitrate media by Cyanex 572 under different operating conditions was examined in this study. The effect of contact time, pH, extractant concentration, and nitrate ion concentration were investigated to characterize the extraction behavior of cerium and based on these outcomes, an extraction mechanism was suggested. The analysis of infrared spectra of Cyanex 572 before and after the extraction of cerium indicated that cerium extraction was performed via a cation-exchange mechanism. Then, the predictive models based on intelligent techniques [artificial neural network (ANN) and hybrid neural-genetic algorithm (GA-ANN)] were developed to predict the cerium extraction efficiency. The GA-ANN model provided better predictions that resulted higher R2 and lower MSE compared to ANN model for predicting the extraction efficiency of cerium by Cyanex 572. The interactive effects of each process variable on cerium extraction were also investigated systematically. pH was the most influential parameter on cerium extraction, followed by extractant concentration, nitrate ion concentration and contact time. Finally, the separation of cerium from other rare earth elements like La (III), Nd (III), Pr (III), and Y (III) was conducted and observed that the present system provides a better separation of cerium from rare heavy earth than light rare earths.

Durability degradation of tunnel-lining-shotcrete exposed to nitric acid: Neutralization and nitrate ion migration

The tunnel-lining-shotcrete, in the long highway tunnel, was usually neutralization jeopardized by NxOy attack caused by automobile exhaust. To investigate the neutralization process of lining shotcrete, the nitrate acid solution, simulated NxOy gas, with the pH value of 1, 2 and 3 were used as aggressive medium. Meanwhile, the pH value and nitrate ion content in shotcrete neutralization zone were measured using potentiometry method. After that, the composition and relative content of mineral phases and microstructure were charactered via X-ray diffraction (XRD), thermogravimetric-differential thermal scanning (TG-DSC) and scanning electron microscope (SEM). With increased of the hydrogen ion concentration on nitric acid solution, the pH value and nitrate ion content in neutralization zone were decreased and increased respectively. Meanwhile, those of shotcrete were higher and smaller than those of normal concrete. The loss rate of weight, relative compressive and splitting tensile strength of shotcrete was lower than that of normal concrete as the pH value of 1, while that of shotcrete was higher when the nitric acid pH value of 2 and 3. The neutralization process of nitric acid-exposed-shotcrete was divided into three stages, namely, neutralization reaction, hydration product decomposition, and concrete surface spalling off. The pH value of concrete declined, whereas nitrate ion content in the neutralization zone increased with prolonged immersion time. Moreover, the maximum depth of nitrate ion content was deeper. The yellow-white spongy corrosion product layer formed and covered the specimen surface. Additionally, crisscross macro-cracks appeared on the concrete specimen surface, which caused large amount of aggregates was peeled off.

Synthesis and characterization of polyimidazolium species on silica nanoparticles: Study on cytotoxicity and removal of nitrate from water

AbstractA nanocomposite containing imidazolium based on modified silica nanoparticles (polyimidazolium based on nano silica particles [PIZNS]) was prepared to remove nitrate from water. The prepared compounds were fully characterized by Fourier transform infrared, 1H‐NMR, field emission scanning electron microscopy, energy dispersive X‐ray (EDX) and thermogravimetric analyzes. The ability of PIZNS in nitrate ions adsorption was tested under different operating conditions. The maximum removal efficiency and adsorption capacity (Qmax) of the PIZNS were obtained 90.56% and 37.73 mg g−1, respectively (initial nitrate ion concentration of 50 mg/L, at pH = 7, 30 mg adsorbent, contact time of 30 min). To evaluate the selectivity coefficient, the removal of nitrate ion was determined in the presence of competitive sulfate, bicarbonate, chloride, and phosphate ions by adsorbent. Further, kinetic and isotherm investigation showed best fit by second order and Langmuir models, respectively. In addition, the anti‐cancer properties and subsequently the cytotoxicity effect of the PIZNS was assayed in vitro using cisplatin as a standard against three cancer cell lines including PC12, HL60, and βTC. The most potent inhibition effect was observed toward HL60 cells by PIZNS. Thus, the collapse of mitochondrial membrane potential was evaluated in these cells. In addition, the cytostatic effect of this polymer was depicted in the HL60 3D spheroid model.

Evaluation and improvement of the WWTP performance of an agricultural cooperative by adsorption on inert biomaterial: case of orthophosphate, nitrate and sulfate ions

The study is carried out at the wastewater treatment plant (WWTP) of an agricultural cooperative that operates according to the activated sludge process. Dairy industry is enlisted as one of the top-most industries in the food industry. Dairy wastewater treatment is a big issue as dairy wastewater releases a high amount of chemical oxygen demand, inorganic and organic particles, biological oxygen demand, and nutrients. But, these processes partly degrade wastewater containing fats and nutrients as dairy wastewater. The aim of this study was to evaluate the purification performance of this treatment process. The qualitative analysis of decanted raw wastewater (DRWW) and purified wastewater (PWW) shows that the concentration of orthophosphate, nitrate and sulfate ions is slightly higher. Such contaminated water if not handled appropriately, it pollutes water bodies and largely affects our ecosystem and biodiversity. Hence, our proposal is to improve the WWTP performances by using the adsorption process onto dried Carpobrotus edulis as an inert biomaterial. This adsorption process is recognized as one of the best water treatment techniques, more and more works are oriented towards the search for new materials, cheaper and having a good adsorbent potential. This study opens the path for the use of natural and abundant local material to remove orthophosphate, nitrate and sulfate ions using the C. edulis plant particles shred. The surface micromorphology of the biomaterial was investigated using a scanning electron microscope; while the qualitative element composition was analyzed using energy dispersive X-ray and infrared spectroscopies. The found results of DRWW was about 57% for orthophosphates, 67% for sulfates and 73% for nitrates ions. For PWW, the percentage removal was found to be 62%, 73% and 84% for orthophosphates, sulfates and nitrates respectively. These results indicate that dried C. edulis plant, as an environmentally friendly adsorbent could be recommended for the removal of mineral pollutants. In conclusion, the C. edulis adsorbent can be integrated into the activated sludge process for wastewater treatment after identifying the optimal hydraulic loads, associated sizes, and shapes in continuous operations.

Fluorine tin oxide-supported copper nanofilms as effective and selective de-nitration electrocatalysts

• Copper nanofilms are electrodeposited directly on FTO/Glass. • Catalyst can re-designed and scaled-up for continuous-flow rate water de-nitration. • Cu@FTO is more efficient and nitrogen-selective than Cu or FTO. • Cu@FTO lowers nitrate to acceptable levels. Due to widespread water pollution with nitrate ion, methods to remove or lower the nitrate concentrations in water are needed. A novel route to reproducibly electro-deposit copper nano-films, with no need for additional treatments or additives, from acidic media onto fluorine-doped tin oxide/glass (Cu@FTO) is described. The films involve elemental copper nanoparticles inside copper agglomerates of larger sizes. Within 2 h, at ambient potential (−1.8 V), the Cu@FTO electrode reduces aqueous nitrate ions (∼40%) more effectively than the benchmark bare Cu metal sheet (∼11%). The Cu@FTO is also more selective to N 2 production (∼30%) compared to bare Cu sheet with only (∼1.1%). Furthermore, the Cu@FTO effectively functions for 7 h and continues to bring down the nitrate ion concentration from 200 ppm to acceptable levels (less than 60 ppm), reproducibly in 5 attempts. The results are promising for future water de-nitration processes using easy-to-prepare Cu@FTO electrodes, aiming at producing electrodes for continuous flow reactors at larger scale.

Optically “silent” neptunium(V)-nitrate complex in ionic liquid

The complexation of pentavalent neptunium, Np(V), with nitrate ion in an ionic liquid solution has been studied spectroscopically for the first time. The characteristic f-f transition absorption band of Np(V) in the NIR region changes significantly upon the titration of nitrate ion into the solution, revealing strong complexation of Np(V) with nitrate ion in the ionic liquid. Most notably, the absorption band of Np(V) almost disappears when a sufficiently high concentration of nitrate ion is present in the solution. Such a rare optically “silent” species can be assigned to the 1:2 Np(V)/nitrate complex with a centrosymmetric coordination environment where Np sits at the inversion center.

Optimization of cerium extraction from aqueous solutions by response surface methodology employing 4‐factor Box‐Behnken design

AbstractIn this research, the solvent extraction of Cerium (III) using Cyanex 572 has been investigated under variations of the pH, extractant concentration, nitrate ion concentration, and contact time. Box‐Behnken design and analysis of variance were applied to determine the main effects and their interactions. The high R2 value obtained from the developed model indicated a good correlation between the predicted and measured data. Contact time had no significant effect on the extraction of cerium. pH and extractant concentration were the most significant parameters affecting the cerium extraction under the examined conditions. The developed model was applied to find out the optimum values of the selected variables for the maximum extraction of cerium. The nature of diluent influences the extraction efficiency of Cerium (III). Kerosene was found to be efficient diluent for the extraction of cerium in terms of better extraction capability as investigated.