Oxidation-reduction Potential Research Articles

Study on the factors of hydrogen sulfide production from lignite bacterial sulfate reduction based on response surface method

Bacterial sulfate reduction (BSR) is one of the key factors leading to the anomalous accumulation of hydrogen sulphide in coal mines. Environmental factors such as temperature and pH play a crucial role in the metabolism and degradation of coal by sulfate-reducing bacteria (SRB). In this study, coal samples were selected from Shengli Coal Mine, and SRB strains were isolated and purified from mine water using a dilution spread-plate anaerobic cultivation method. Based on single-factor experiments and response surface methodology (RSM), the impact of temperature, pH, oxidation–reduction potential (ORP), chemical oxygen demand to sulfate ratio (COD/SO42−) on the generation of hydrogen sulphide during brown coal BSR was analyzed. The results showed that the anaerobic degradation of coal by SRB was inhibited by either too high or too low a temperature to produce hydrogen sulfide, and the greatest production of hydrogen sulfide occurred at a temperature of about 30 °C; The greatest production of hydrogen sulfide occurred at an initial ambient pH of 7.5; COD/SO42− ratio of around 2.0 is most conducive to hydrogen sulphide generation; the lower ORP value is more favorable for hydrogen sulfide generation. The optimal conditions obtained by RSM were: temperature of 30.37 °C, pH of 7.64 and COD/SO42− of 1.96. Under these conditions, the hydrogen sulfide concentration was 56.79 mg/L, the pH value was 8.40, the ORP value was −274 mV, and the SO42− utilization rate was 58.04%. The RSM results showed that temperature, ambient pH and COD/SO42− had a significant effect on hydrogen sulfide production, and the degree of effect was: ambient pH > temperature > COD/SO42−.

Unsuitability of the Oxidation-Reduction Potential Measurement for the Quantification of Fecal Redox Status in Inflammatory Bowel Disease.

Oxidative stress is a key pathophysiological process associated with the development and progression of inflammatory bowel disease (IBD). Biomarkers for oxidative stress, however, are scarce, as are diagnostic tools that can interrogate an individual's gut redox status. This proof-of-concept study aimed to evaluate the potential utility of an oxidation-reduction potential (ORP) measurement probe, to quantify redox status in the feces of both patients with IBD and healthy controls. Previous studies using this ORP measurement probe demonstrated promising data when comparing ORP from severely malnourished individuals with that of healthy controls. To date, ORP analyses have not been performed in the context of IBD. We hypothesized that measuring the ORP of fecal water in patients with IBD might have diagnostic value. The current study, however, did not show significant differences in ORP measurement values between patients with IBD (median [IQR] 46.5 [33.0-61.2] mV) and healthy controls (25 [8.0-52.0] mV; p = 0.221). Additionally, ORP measurements were highly unstable and rapidly fluctuated throughout time, with ORP values varying from +24 to +303 mV. Due to potential biological processes and limitations of the measuring equipment, this study was unable to reliably measure ORP. As a result, our findings indicate that ORP quantification may not be a suitable method for assessing fecal redox status and, therefore, does not currently support further exploration as a diagnostic or monitoring tool.

Remediation of diesel-oil contaminated soils using an innovative nanobubble and electrolyzed catalytic system

Soil contamination resulting from petroleum hydrocarbons poses a significant environmental challenge. In this research, an innovative electrolyzed catalytic system was devised to produce nanobubble-enriched catalytic water, which was employed for remediating soils contaminated with diesel oil. This novel system harnessed high voltage (220 V) via direct current, utilizing titanium electrodes coated with iridium dioxide. The inclusion of iron-copper hybrid oxide catalysts between the electrodes was instrumental in enhancing the efficiency of radical generation. The study employed the electron paramagnetic resonance (EPR) technique and the Rhodamine B (RhB) method to analyze the species and concentration of the generated radicals. EPR is a versatile tool for investigating materials with unpaired electrons and is capable of quantifying reaction kinetics for transition metals. RhB can be used as a probe for hydroxyl radical concentration determination. The addition of an electrolyte (NaCl or K2SO4) could enhance the electrolytic reaction and improve radical production rate. By incorporating 20 mM of K2SO4 and utilizing 75 g of catalyst per 500 mL batch of nanobubble-contained electrolyzed catalytic water (NECW) production, with a current density of 20 mA/cm2, a highly oxidized nanobubble-infused electrolyzed catalytic water was successfully generated. This water exhibited an oxidation-reduction potential of 887 mV and contained a radical concentration of 7.6 × 10−13 M, encompassing hydroxyl, superoxide, and sulfate radicals. Furthermore, it displayed a negative zeta potential of −39.8 mV, along with nanobubbles averaging 28 nm in diameter and a nanobubble density of 3.7 × 109 particles per milliliter. The presence of nanobubbles in electrolyzed catalytic water, owing to their negative zeta potential and nano-scale attributes, imparts a repulsive force that hinders bubble aggregation and prolongs their existence. When these nanobubbles burst, the resulting radicals contribute to an augmented radical concentration, which, in turn, facilitates the oxidation of petroleum hydrocarbons. Approximately 72.4% of the total petroleum hydrocarbon in soils could be removed (dropped from 3230 mg/kg to 892 mg/kg) after five batches of NECW washing (10 min of each washing time) via the desorption and extended chemical oxidation mechanisms. The total petroleum hydrocarbons in the water phase could be removed entirely after pumping the polluted water into the electrolyzed catalytic system for immediate treatment, indicating that the electrolyzed catalytic system could oxidize the desorbed total petroleum hydrocarbon effectively. The findings demonstrate that the nanobubble-infused catalytic water generated by the innovative electrolyzed system effectively and efficiently remediates petroleum-hydrocarbon-contaminated soils and water, all while minimizing the risk of secondary pollution.

Evaluation of High Stocking Densities on the Water Quality and Growth Performance of Pacific White Shrimp Litopenaeus vannamei Reared in a Mixotrophic Biofloc Nursery System

The present study aimed to explore the effects of intensive culture densities on the water quality and growth performance of the Pacific white shrimp Litopenaeus vannamei reared in a mixotrophic biofloc system (heterotrophic/chemoautotrophic) at three stocking rates of 5,000, 4,000, and 3,000 PL/m3 (namely G5000, G4000, and G3000, respectively) for 21 days. At the end of the study, the mean values of water temperature, dissolved oxygen, dissolved oxygen saturation level, pH, oxidation-reduction potential, free carbon dioxide, alkalinity, total ammonia nitrogen (TAN), nitrite-nitrogen (NO2-N), nitrate-nitrogen, and settleable solids did not substantially differ among study groups ( p > 0.05 ). In addition, the highest mean levels of TAN and NO2-N recorded were 1.27 mg/l (G4000) and 9.23 mg/l (G3000), respectively. The results of growth performance revealed that final body weight, weight gain, weekly growth rate, and specific growth rate were not affected by the studied densities ( p > 0.05 ). Although no significant differences were observed ( p > 0.05 ), the G3000 treatment exhibited the highest survival rate (80.66% ± 8.56%), followed by G4000 (75.05% ± 0.31%) and G5000 (71.63% ± 2.11%). However, the shrimp yield was meaningfully higher for G5000 treatment (1.72 ± 0.0.09 kg/m3, 0.69 ± 0.03 kg/m2) compared with G3000 group (1.27 ± 0.0.12 kg/m3, 0.48 ± 0.04 kg/m2) ( p < 0.05 ). Our results indicate L. vannamei can be reared at intensive nursery densities of up to 5,000 PL/m3 (2,000 PL/m2) until reaching 0.5 g without significant retardation in water quality, growth, and survival.

Strategies for the Biotransformation of Tung Leaves in Bioethanol Fermentation

The tung tree (Vernicia fordii Hemsl.), as a woody oilseed crop, has been cultivated in China for thousands of years, and its leaves are rich in cellulose and proteins. The tung leaf is an alternative raw material for the traditional ethanol fermentation of food crops. In this work, the effects of the simultaneous saccharification fermentation of tung leaves at different substrate concentrations on gas production characteristics, reducing sugars, pH, oxidation–reduction potential (ORP), and ethanol yield were investigated during bioethanol production. In addition, the effect of the initial fermentation pH on the ethanol fermentation of tung leaves was explored. The results showed that during bioethanol production from tung leaves, the pH of the fermentation broth showed a continuous decreasing trend. Moreover, the ORP showed a decreasing trend and then rebounded, and the concentration of reducing sugars initially increased and then decreased. The optimal ethanol yield of 4.99 g/L was obtained when the substrate concentration was 100 g/L. Changes in the initial pH have little effect on yeast activity, but such changes can affect the yeast cell wall structure and substance transport, leading to differences in the ethanol yield. When the initial pH is 7, the maximum ethanol yield is 5.22 g/L. The experimental results indicate that the utilization of tung leaves for bioethanol production has a good potential for development.

SOME EXPERIMENTS WITH ELECTROCHEMICALLY ACTIVATED WATER

Experiments on the physical properties of the Electrochemically Activated water carried out in the last few years are present. During the electrolysis of tap water with a semipermeable membrane two fractions – catholyte and anolyte are obtained with different values of the physical and chemical parameters. Power hydrogen and oxidation-reduction potential have been investigated by many researchers, but without precise evaluation of their changes at different intervals of time. Here, tables for the values of these parameters are present. New results, difficult to explain, are obtained in the following aspects: 1) Double activation with reversed electrodes; 2) Electroosmosis at different types of water, including tap water, distilled and de-ionized ones, and 3) Evaluation of the quantity of heavy metals in the water before and after activation. Since no description of the potential of the electrical field, produced by the electrodes of the electrolyzer, was found in the literature, measurement of the field between and around the electrodes in case of presence and absence of membrane have been carried out. The results could be of interest to the researchers trying to understand some of the anomalous properties of the electrolyzed water.

Nitrite production mechanism and microbial evolution characteristic influenced by pH during partial denitrification (PD) process

Partial denitrification (PD) has been proved technically feasible and economically favorable to produce nitrite (NO2--N) for anammox. To obtain stable NO2--N accumulation, the effects of pH (6.0, 7.5, 9.0, 10.0) on nutrient removal mechanism and microbial community evolution were investigated. Higher pH benefited PD performance with the optimal NO2--N and nitrate-to-nitrite transformation ratio (NTR) reaching to 43.50 mg/L, 81.64% at pH= 9.0 although slight NO2--N inhibition occurred caused by biomass loss and proton deficiency at pH= 10.0. Batch testes showed the same change trends of NTR (pH=9.0 >pH=7.5 >pH=6.0 >pH=10.0), where pH and oxidation reduction potential (ORP) also proved the “NO2--N knee” as pH varied around 7.5–9.0. The denitrification kinetic proved the closely relationship among carbon consumption rate (CCR), poly-β-hydroxyalkanoates transformation rate (PTR), NO2--N accumulation rate (N2AR), NO2--N reduction rate (N2RR) and nitrate (NO3--N) reduction rate (N3RR) although COD release, nitrogen loss and floc disintegration were observed under different pH conditions. Meanwhile, more aggregated microbial compositions formed (562–605 OTUs) at the optimal pH range of 7.5–9.0, where Terrimonas, norank_f_A4b, Defluviicoccus, Hyphomicrobium, norank_f_Blastocatellaceae, and OLB13 were the main contributors for NO2--N maintenance, with the proportions accounting for 35.29–39.60%.

Exploiting the Electrical Nature of Biofilms for Long-Term Monitoring of Quiescent Aquatic Environments via Open-Circuit Microbial Potentiometric Sensors: Evidence of Long-Distance Electrical Signaling

This study was based on the hypothesis that spatial–temporal characterization of contaminant-affected redox gradients in a quiescent system could be measured by microbial potentiometric sensor (MPS) arrays incorporated in large, natural biofilm networks. Two experimental chambers, each containing at least 48 equidistantly located MPS electrodes, were fabricated to examine reproducibility of the patterns. The MPS electrodes were exposed to biofilm growth conditions by introducing high dissolved organic carbon (DOC) and dechlorinated tap water at the bottom of the experimental chamber; and the spatial–temporal changes in the MPS array signals were recorded, which showed that signal trends were correlated to the induced changes in DOC. The results indicated that MPS arrays measured the spatial–temporal changes in the aqueous solution caused by an influx of carbon rich water, which could not be detected by conventional oxidation-reduction potential (ORP) electrodes. Interestingly, the experiments conducted over long time periods revealed unusual behaviors like electrical signaling and possible potentiometrically driven communication within the biofilm. These observed behaviors suggest that biofilms may create a large network through which communication signals can be generated and propagated by inducing changes in electric potentials similar to a sophisticated electronic device.

Groundwater quality assessment of aba urban area

This work presents groundwater quality assessment of Aba Urban area and its sources of Contaminants within Aba Urban Area. Aba area was divided into nine parts using a 3x3 grid. Water samples were taken from each of these 9 parts of Aba. Five water samples were taken from household boreholes while four samples were taken from boreholes drilled and cased at the remaining four parts in the course of carrying out this research. Site and laboratory tests were conducted to determine the values water parameters in the samples. The parameters analysed in the laboratory include the Phosphate, ammonium, Lead, cadmium, Manganese, Copper, Mercury, Chromium, and magnesium, Electric conductivity (EC), Dissolved oxygen (DO), Total dissolved solid (TDS), Acidity, Turbidity, Alkalinity, oxidation- reduction potential (ORP), Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD) and E-Coli. It was discovered that more than 75% of the water samples are contaminated by EColi. Umuagu sample has Manganese value of 0.775mg/l. This more than the limiting value of 0.4mg/l. The values 252, 524 and 472 mg/l of Magnesium in samples from Estate, Abia Polytechnic and Osisio Ngwa respectively are more than the limiting value of 150mg/l. The DO (mg/l) values of 6,4 and 9 from Ariaria Junction and Abia Polytechnic are outside the range limiting of 6.5mg/l – 8.0 mg/l. The values of TDS, ORP and BOD recorded in all the samples are below the limiting values of 600 mg/l, 357 mV and 1mg/l respectively.

Combined cluster and discriminant analysis based on hydrochemical and isotopic evidence: A case study of the Yellow River Delta in China

Groundwater serves as an indispensable resource, fundamental for both sustaining life and underpinning various human endeavors. However, escalating demands, coupled with climate change, have given rise to significant water scarcity in numerous areas, including the Yellow River Delta (YRD) in China. This study aims to characterize the hydrochemical composition and stable isotopes (δ2H and δ18O) of groundwater in YRD and identify spatial clustering patterns using combined Hierarchical Cluster Analysis (HCA) and Discriminant Analysis (DA). Comprehensive analyses were conducted on the major ions (i.e., K+, Na+, Ca2+, Mg2+, Cl-, SO42-, and HCO3-), water quality indicators (i.e., pH, electrical conductivity (EC), and oxidation-reduction potential (ORP)) and isotopic composition of groundwater samples. Applying HCA on a collection of 38 water samples, the study delineated six distinct clusters, each bearing unique hydrochemical characteristics. DA was used to establish a discriminant model, achieving a classification accuracy of 80% for new groundwater samples. The study underscores that there are localized variations in the hydrochemical characteristics of groundwater in YRD, attributed to different geological conditions and anthropogenic influences. Such insights are instrumental in crafting effective strategies for water resource management, environmental conservation, and sustainable development in YRD and other analogous regions confronted with groundwater challenges.

Assessment of lead heavy metal pollution in Ciliwung River

Heavy metal contributed in bio-magnification process. So, its presence needs to be monitored and evaluated to prevent and control its hazards to human health and sustainability river ecosystem. One of that heavy metal is lead. This study aims to assessment the lead metal pollution in Ciliwung River because one of its uses is as water resources for Regional Drinking Water Company (PDAM). This study used a survey and analytical method. There were 12 samples of water column and 10 samples of sediments that distributed from upstream to the beginning of downstream. The parameters determined in site used water checker included temperature, pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Dissolved Oxygen (DO), and Oxidation Reduction Potential (ORP). While the lead contained in sample used Automatic Absorption Spectrophotometric (AAS). The result showed that lead content in all samples exceeded the quality standards and the lead on sediment were more than in water column. Lead in the Ciliwung River is mostly due to anthropogenic sources because it occurred naturally in small amounts. Downstream, the EC, TDS, and ORP values increase, while the pH and DO value decreases. The ORP values at all sampling points were positive. It means that deoxygenation occurred along the Ciliwung River. The implication is needed the additional raw water processing that accompanied further economic analysis to make sure the water availability for the community sustained.

Heavy metal content in estuaries water and sediment of Banten Bay, Indonesia

The primary economic activity in the estuaries of Banten Bay is fisheries. To maintain their productivity, it is essential to ensure good water quality, which requires monitoring of heavy metal content in both water and sediment. Therefore, this research aimed to investigate heavy metal content in estuaries’ water and sediment of Banten Bay. A survey was conducted in four estuaries, namely Karangantu, Wadas, Cengkok, and Pamong. Heavy metal content in estuaries water was analyzed in April and October 2021, while heavy metal content in estuaries sediment was analyzed in October 2021. Other parameters were analyzed in the laboratory or in situ. The analysis showed that the lead (Pb) content in the estuaries’ water exceeded the standard in April but met the standard in October, while the iron (Fe) and cadmium (Cd) content in the water fulfilled the standard in both months. The Pb, Fe, and Cd content in the estuaries’ sediment also met the standard. The Principal Component Analysis (PCA) indicated that the Pb content in the water was influenced by organic carbon (C organic), while the Cd content was affected by total suspended solids (TSS), oxidation-reduction potential (ORP), salinity, and water depth. Furthermore, the Pb and Fe content in the sediment was influenced by pH, while the Cd content was affected by C organic.

Efficient separation of Li and Mn from spent LiMn2O4 cathode materials by NH4HSO4 reduction roasting-selective ammonia leaching

With the imminent peak in the retirement of rechargeable lithium-ion batteries worldwide, the development of efficient methods for recycling valuable elements from LIBs has attracted considerable attention. In this work, a novel method of NH4HSO4 reduction roasting-selective ammonia leaching was proposed to thoroughly separate Li and Mn from the spent LiMn2O4 cathode materials. Using the TG-DSC-FTIR, XRD, SEM-EDS and ICP methods, the detailed mechanism of reduction roasting process was revealed, showing that the Mn4+ and Mn3+ in the spinel structure of LiMn2O4 were reduced by the NH4+ from the molten ammonium salt, and transformed into water-soluble MnSO4 and Li2Mn2(SO4)3. According to the water-leaching performance of the roasting products, the sulfation conversion rate of Mn reaches 98.1 %, while Li is almost completely transformed under the optimal roasting conditions (475 ℃, 60 min). Using the NH3·H2O-air leaching-system, complete separation of Li and Mn can be achieved. It was shown that the introduction of air into the ammonia solution at a rate of 0.2 L/min under the optimal leaching condition leads to Mn precipitation in the form of nanoscale Mn3O4 particles with a precipitation rate of over 99.99 %, while Li still remains completely leached. Based on the in situ detection of the oxidation reduction potential and pH during the selective leaching, the key mechanism of efficient Mn precipitation was revealed. that is, the increasing potential accelerates the oxidation of Mn(OH)2, and the rapid consumption of Mn(OH)2 promotes the hydrolysis of Mn2+, thereby achieving a significant improvement in the separation efficiency of Li and Mn.

Waterlogging increases greenhouse gas release and decreases yield in winter rapeseed (Brassica napus L.) seedlings

A sustainable future depends on increasing agricultural carbon (C) and nitrogen (N) sequestration. Winter rapeseeds are facing severe yield loss after waterlogging due to the effects of extreme rainfall, especially in the seedling stage, where rainfall is most sensitive. Uncertainty exists over the farming greenhouse gas (GHG) release of rapeseed seedlings following the onset of waterlogging. The effect of waterlogging on GHG release and leaf gas exchange in winter rapeseed was examined in a pot experiment. The experiment included waterlogging treatments lasting 7-day and 21-day and normal irrigation as a control treatment. According to our findings, (1) The ecosystem of rapeseed seedlings released methane (CH4) and nitrous oxide (N2O) in a clear up change that was impacted by ongoing waterlogging. Among them, N2O release had a transient rise during the early stages under the effect of seedling fertilizer. (2) The net photosynthetic rate, transpiration rate, stomatal conductance, plant height, soil moisture, and soil oxidation–reduction potential of rapeseed all significantly decreased due to the ongoing waterlogging. However, rapeseed leaves showed a significant increase in intercellular carbon dioxide (CO2) concentration and leaf chlorophyll content values after waterlogging. Additionally, the findings demonstrated an extremely significant increase in the sustained-flux global warming potential of the sum CO2-eq of CH4 and N2O throughout the entire waterlogging stress period. Therefore, continuous waterlogging can increase C and N release from rapeseed seedlings ecosystem and decrease yield. Therefore, we suggest increasing drainage techniques to decrease the release of agricultural GHGs and promote sustainable crop production.

The Use of Apple Vinegar from Natural Fermentation in the Technology Production of Raw-Ripened Wild Boar Loins.

Wild boar meat is difficult to process, mainly due to its hardness and stringiness. Three types of raw-ripened wild boar loins were produced (C-control treatment, R1 and R2-treatments with the addition of apple vinegar in various production variants). The research aimed to develop a new innovative technology for the production of wild boar loin using apple vinegar for marinating and to determine the impact of apple vinegar on the microbiological and sensory quality, and physico-chemical parameters of the product. As part of the research, a technology for the production of ripened wild boar products was developed and the composition of fatty acids, cholesterol content, pH value, oxidation-reduction potential, thiobarbituric acid reactive substances (TBARS) index, color, microbiological, sensory, and statistical analysis were determined. It was found that the loins were characterized by a high content of saturated, monounsaturated, and polyunsaturated fatty acids (20.18-43.37%), a low content of trans fatty acids (0.30-0.57%), and a high cholesterol content (75.13-85.28 mg/100 g of the product). Samples with apple vinegar (R1 and R2) were characterized by a lower pH value (5.10-5.70; p < 0.05), a comparable oxidation-reduction potential (409.75-498.57 mV), and a low TBARS index (0.461-1.294 mg malondialdehyde/kg of product). Their color was lighter (L* 38.25-40.65). All the tested loins were characterized by appropriate microbiological quality guaranteeing the storage durability of the product. R1 and R2 treatments were characterized by the greatest juiciness. The highest overall quality was achieved by R1 loins (7.36-7.76 c.u.). The apple vinegar used to marinate the loins had a positive effect on their microbiological and sensory quality as well as physico-chemical parameters. Moreover, the technology guarantees the appropriate quality and health safety of the products.

Nitrous oxide emissions from two full-scale membrane-aerated biofilm reactors

The upcoming change of legislation in some European countries where wastewater treatment facilities will start to be taxed based on direct greenhouse gas (GHG) emissions will force water utilities to take a closer look at nitrous oxide (N2O) production. In this study, we report for the first time N2O emissions from two full-scale size membrane aerated biofilm reactors (MABR) (R1, R2) from two different manufacturers treating municipal wastewater. N2O was monitored continuously for 12 months in both the MABR exhaust gas and liquid phase. Multivariate analysis was used to assess process performance. Results show that emission factors (EFN2O) for both R1 and R2 (0.88 ± 1.28 and 0.82 ± 0.86 %) were very similar to each other and below the standard value from the Intergovernmental Panel on Climate Change (IPCC) 2019 (1.6 %). More specifically, N2O was predominantly emitted in the MABR exhaust gas (NTRexh) and was strongly correlated to the ammonia/um load (NHx,load). Nevertheless, the implemented Oxidation Reduction Potential (ORP) control strategy increased the bulk contribution (NTRbulk), impacting the overall EFN2O. A thorough analysis of dynamic data reveals that the changes in the external aeration (EA)/loading rate patterns suggested by ORP control substantially impacted N2O mass transfer and biological production processes. It also suggests that NTRexh is mainly caused by ammonia-oxidizing organisms (AOO) activity, while ordinary heterotrophic organisms (OHO) are responsible for NTRbulk. Different methods for calculating EFN2O were compared, and results showed EFN2O would range from 0.6 to 5.5 depending on the assumptions made. Based on existing literature, a strong correlation between EFN2O and nitrogen loading rate (R2 = 0.73) was found for different technologies. Overall, an average EFN2O of 0.86 % N2O-N per N load was found with a nitrogen loading rate >200 g N m−3 d−1, which supports the hypothesis that MABR technology can achieve intensified biological nutrient removal without increasing N2O emissions.

Enhancing Ecological Efficiency in Biological Wastewater Treatment: A Case Study on Quality Control Information System

This study aimed to improve the control system of the biological stage of wastewater treatment using the quality control information system to support the concept of environmental efficiency management. In this case, the object of the study was the treatment facilities of Sumy city (Ukraine). For automatic control of wastewater quality, pH, oxidation reduction potential (ORP), electrical conductivity, and temperature indicators were taken, as well as hydrobiological analysis of activated sludge and mathematical modelling. The pH of wastewater at the input system has systematically unacceptable values (above 8.5 were recorded). Unacceptable concentrations of sulphur-containing toxicants arrive at the entrance of treatment facilities (0.22–1.3 mg/L). The response of activated sludge biocenosis to increasing concentrations of hydrogen sulphide in wastewater was analysed. Furthermore, a mathematical model of monoculture population growth, with two factors that affect population growth (nutrient concentration and monoculture production concentration), was implemented for the initial assessment of possible negative effects on wastewater treatment. The differential equation of the population dynamics of the i-th species of microorganisms in activated sludge was described. The applied system of automated monitoring of wastewater parameters with expert assessment of activated sludge and a unified mathematical model of approaches allows for a complex system of decision-making support to be realised. However, this requires the construction of mathematical models that would take into account the cause–effect relations that operate under conditions of incomplete technological information and the potential presence of emergencies due to natural disasters and military activities.

A Study on Syrup of Juniperus excelsa Cones Grown in Türkiye

For beverage products, some analytical tests are conducted prior to packaging and distribution. However, physicochemical properties may affect product quality adversely in a number of ways. Liquids with high dissolved solids may impact inferior palatability and may induce an unfavorable physiological reaction in the transient consumer. In this study, it was to evaluate some certain physicochemical properties of syrup which was made from Juniperus excelsa’s berries collected from four different geographical locations managed by the Regional Directorate of Forestry authorities in Turkiye. Considerable physicochemical variations were found among Juniperus excelsa’s berry-based syrup products. The lowest value of pH: 5.46 was found with syrup prepared from Yalvaç-Isparta, (sample C), followed by pH: 5.75 from Hisarcık-Kütahya, (sample D), pH: 5.80 Ağlasun-Burdur (sample B), and pH: 6.32 Gazipaşa-Antalya (sample A), respectively. However, syrup prepared from sample C showed the highest values of electrical conductivity (EC), total dissolved solids (TDS), sugar content (Brix), and also distinguished from the others by highest oxidation-reduction potential (ORP). It was found to be 3136.1 uS/cm for EC, 1568 ppm for TDS, 1.90 °Bx for Brix and 188.6 mV for ORP. However, the highest turbidity value of 67.6 NTU was found with sample D while the lowest with sample A (39 NTU). These values may be good criteria for the botanical origin of syrup and therefore, it may be used in syrups prepared from Juniperus excelsa’s berries.

Intensification of opening a thrust alloy based on platinum and rhodium

A high chemical resistance inherent in the alloys based on platinum group metals is one of the reasons for a number of difficulties that arise when dissolving such materials. Nowadays, the dissolution in aqua regia is one of the most effective methods for dissolving corrosion-resistant alloys. The main disadvantage of this method is a release of toxic gaseous substances such as nitrosyl chloride and nitrogen oxides. To decrease the volume of gases thus released without reducing the redox potential of the system, we proposed a method of dissolving a Pt – Rh alloy in HCl-HNO3 with a controlled dosed supply of HNO3 at a given value of the oxidation-reduction potential (ORP) of the system. The potential of the system has been chosen proceeding from the potential for HNO3 – HCl – Pt and HNO3 – HCl-Rh systems and amounted to 0.85 and 0.9 V. The impact of the dispersion and the inherent flaw of PtRh alloys on the dissolution indices of the alloy was also considered. It is shown that the dissolution of a Pt – Rh alloy with a rhodium content of 15 % in HCl – HNO3 at a constant value of ORP = 0.9 V compared to the use of the classic mixture (HCl:HNO3 = 1:3 vol.) provides a decrease in nitric acid consumption by 40%, reduction of the process time, increase in the recovery factor for both platinum and rhodium, and a two-fold reduction of the volume of released nitrogen oxides (theoretical calculation). It is also revealed that the process of mechanical activation of the alloy reduces the dissolution time and leads to almost quantitative dissolution of the sample.

Anticorrosion and Hydrophobic Surface Protection Inducing Dendrite‐Free Zn Anode for Aqueous Zn‐Ion Batteries

Zinc is widely used as an anode in zinc‐ion batteries (ZIBs) due to its nontoxicity, favorable theoretical specific capacity, and low oxidation–reduction potential. Nevertheless, irreversible Zn dendritic growth and unavoidable side reactions limit its cyclic stability and high‐rate capability. This research puts forward a surface protection strategy by introducing a hydrophobic polyvinylidene fluoride and carborundum nanocoating (PVDF‐SiC) coating on the surface of Zn anode to synergistically restrain side reactions and Zn dendrites. PVDF improves the hydrophobicity of Zn anode at the solid–liquid interface, which can avoid side reactions between Zn anode and water. SiC nanoparticles with high porosity and small size pore can also homogenize the Zn2+ flux, which can cause uniform Zn deposition and inhibit Zn dendrite growth. The hydrophobic PVDF‐SiC@Zn symmetric battery accordingly exhibits an invariable overvoltage (&lt;40 mV) after 780 h at 1 mA cm−2 with 0.25 mAh cm−2. Simultaneously, constant and convertible Zn deposition in PVDF‐SiC@Zn//Ti asymmetric battery is implemented. The PVDF‐SiC@Zn//V2O5 full battery exhibits 68% capacity retention after 400 cycles. The porous/hydrophobic PVDF‐SiC composite modification efficiently restrains the side reactions and Zn dendrite growth on the Zn anode, providing an innovative idea for achieving long‐life ZIBs.