Water Components Research Articles

Performance and mechanistic studies of rapid atenolol degradation through peroxymonosulfate activation by V, Co, and bamboo carbon catalyst.

Developing the Co-based catalysts with high reactivity for the sulfate radical (SO4-·)-based advanced oxidation processes (SR-AOPs) has been attracting numerous attentions. To improve the peroxymonosulfate (PMS) activation process, a novel Co-based catalyst simultaneously modified by bamboo carbon (BC) and vanadium (V@CoO-BC) was fabricated through a simple solvothermal method. The atenolol (ATL) degradation experiments in V@CoO-BC/PMS system showed that the obtained V@CoO-BC exhibited much higher performance on PMS activation than pure CoO, and the V@CoO-BC/PMS system could fully degrade ATL within 5min via the destruction of both radicals (SO4-· and O2-··) and non-radicals (1O2). The quenching experiments and electrochemical tests revealed that the enhancing mechanism of bamboo carbon and V modification involved four aspects: (i) promoting the PMS and Co ion adsorption on the surface of V@CoO-BC; (ii) enhancing the electron transfer efficiency between V@CoO-BC and PMS; (iii) activating PMS with V3+ species; (iv) accelerating the circulation of Co2+ and Co3+, leading to the enhanced yield of reactive oxygen species (ROS). Furthermore, the V@CoO-BC/PMS system also exhibited satisfactory stability under broad pH (3-9) and good efficiency in the presence of co-existing components (HCO3-, NO3-, Cl-, and HA) in water. This study provides new insights to designing high-performance, environment-friendly bimetal catalysts and some basis for the remediation of antibiotic contaminants with SR-AOPs.

Influence of synthesis conditions and raw materials on the properties of N‐chlorosulfonamides immobilized on granular styrene–divinylbenzene polymer carriers

AbstractPolymer materials with immobilized functional groups–donors of active chlorine are widely used to create products with a microbiocidal effect and increased resistance to microbial contamination. In this work, various methods for the synthesis of granular styrene–divinylbenzene polymers with N‐chlorosulfonamide groups were investigated. It has been shown that the synthesis of polymers with chlorine‐active SO2NNaCl groups from a non‐functionalized styrene–divinylbenzene polymer matrix through the stage of its sulfochlorination with chlorosulfonic acid in dichloromethane for 6–7 h is optimal. These products contain approximately 11% of active chlorine and maintain a stable particle size distribution. When cation exchangers such as Purolite C100 are used as the initial polymer carrier, the content of chlorine‐active groups in the target product is approximately 9%, and an increase in the content of the dust fraction is observed. The obtained samples, regardless of the synthesis method, are capable of releasing active chlorine into solutions containing amino compounds. The microbial impurities in water also cause the emission of active chlorine in an amount that does not depend on the loading of the polymer, but is determined by the concentration of microbes, due to which a pronounced antimicrobial effect is observed. In this case, the resulting products do not cause further decomposition of the functional groups of the polymer, which indicates the high service life of the latter. The availability of raw materials, relative ease of synthesis, stability, possibility of regeneration and microbiocidal properties of the studied polymers make them promising for use as components of water and air purification systems and other products for medical and industrial purposes. © 2024 Society of Chemical Industry.

An assessment of the water footprint of the population and agricultural crops in the natura 2000 site ROSCI0434 siretul mijlociu, Romania

The designation of a Natura 2000 site ROSCI0434 Siretul Mijlociu for the protection of habitats and species, whose development is closely tied to the aquatic environment, signifies that the management of water resources, and implicitly, the water footprint, has contributed to maintaining a balanced and favorable status for biodiversity conservation. Given that the Natura 2000 site was declared based on older studies, and the Management Plan for the protected natural area was not yet developed, we are now conducting an assessment of the impact of the water footprint in the current climatic conditions. This includes considering other predominant types of agricultural crops and changes in food habits. This evaluation aims to understand the relationship between the water footprint and the conservation status of species and habitats in light of these new circumstances.The blue and grey water components of the water footprint are the ones that directly affect the natural protected area out of the three components of the water footprint: green, blue, and grey water. The ecological impact of water use in ROSCI0434 Siretul Mijlociu is extensive, affecting both terrestrial and aquatic ecosystems. Pollutants can harm habitats and species, while agricultural water usage alters habitats and disrupts hydrological patterns, impacting breeding and foraging grounds. Additionally, changes in water quantity and quality diminish ecosystem services like water purification and habitat provision, affecting biodiversity and human well-being.

Research Note: Relationships between texture and water property measurements in raw intact broiler breast fillets with the wooden breast condition

Relationships between texture measurements and meat water properties were investigated in raw intact broiler breast fillets with the wooden breast (WB) condition. Texture measurements included subjective WB scores and blunt Meullenet-Owens Razor Shear (BMORS). Water properties were determined with low-field nuclear magnetic resonance (LF-NMR). Spearman correlation was used to estimate relationships between WB scores and water properties, while Pearson correlation was used for relationships between BMORS force and water properties. LF-NMR measurements exhibited 3 water components: protein-associated or hydration water T2b, intra-myofibrillar water or immobilized water T21, and extra-myofibrillar water or free water T22 in chicken breast meat. Significant and strong Spearman correlations were found between the WB scores and T21 time constant, the abundance (normalized areas) of T22, and the proportion of T21 and T22 (rs > 0.60, P < 0.001). Strong Pearson correlations (r = 0.72) were noted only between the T21 time constant and BMORS force. These results demonstrate that water may contribute to the specific texture characteristics measured with subjective WB scoring (palpable hardness and rigidity) and BMORS (hardness and share force) in raw broiler breast fillets with the WB condition.

Materials and Designs for Extremely Efficient Encapsulation of Soft, Biodegradable Electronics

AbstractEffective encapsulation is essential for reliable operation of bio‐integrated electronics, particularly those containing dissolvable elements, under humid environments for desired periods of time; however, conventional inorganic or organic encapsulants often suffer from tissue‐incompatible mechanical rigidity and insufficient water‐barrier performance. Here, a mechanically resilient and efficient encapsulation strategy is proposed that can exceed a functional lifetime of state‐of‐the‐art soft encapsulations by several tens of magnitudes. The exceptional protection arises from the high aspect ratio of dissolvable yet impermeable inorganic fillers embedded within biodegradable polymers, which significantly extend the diffusion length of biofluids or water components. Theoretical modeling and experimental analysis elucidate the effects of types, shapes, and concentrations of the fillers on encapsulation performance, as well as mechanical/physical properties. The operation of electronic components under aqueous solutions for prolonged periods demonstrates the practical feasibility of the encapsulation approach for versatile types of soft, biodegradable electronics.

Mathematical Modeling of Drinking Water Losses Management Case Study – Cairo - Egypt

Water, As A Precious natural resource, necessitates sustainable management to minimize wastage. Excessive leakage, particularly in regions confronting water scarcity such as Egypt, directly undermines environmental objectives and principles of cost recovery. Effective water management is pivotal for reducing losses and optimizing efficiency. Accurate measurement of water production and distribution is essential to identify losses and assess water utilities' performance. This data aids in pinpointing the root causes of losses, whether physical or commercial, facilitating targeted reduction strategies. Forecasting supply-demand balance is critical for planning water networks and treatment facilities. Detailed infrastructure information enables decision-makers to discern areas experiencing water shortages and those with surplus resources. Our aim is to probe the causes of water losses in Cairo's drinking water network, the capital of Egypt, and propose managerial solutions. Operational efficiency relies on minimizing labor, material, and energy costs. Water loss poses a significant operational challenge, as components of non-revenue water can significantly impact utilities' financial stability. The IWA Water Balance offers a standardized approach to water audits, facilitating a comprehensive analysis of water production, storage, and distribution. This analysis aids in quantifying the magnitude of the water loss problem and prioritizing corrective actions based on revenue and non-revenue water components. The Cairo Water Company is entrusted with producing 5.5 million cubic meters of purified drinking water per day from 11 treatment plants, serving a network spanning 13,307 kilometers and supported by 20 maintenance centers. With a focus on serving 1.1 million citizens in compliance with Egyptian regulations, our study encompasses various metrics, including billed and unbilled consumption, unauthorized usage, and metering inaccuracies, to calculate commercial losses. Additionally, we evaluate main and storage leakages, as well as service connection leakages up to the customer meter, to determine technical losses. Through a mathematical module, we compute non-revenue water (NRW) and infrastructure leakage index (ILI) metrics. Performance indicators are utilized to assess the effectiveness of water utilities in managing losses and asset maintenance. Our designed module empowers decision-makers to evaluate and enhance asset methodologies for water loss management.

PENGARUH PERBEDAAN KONSENTRASI SOURDOUGH TERHADAP SIFAT FISIK DAN MIKROBIOLOGI PADA ROTI TAWAR

Sourdough is a mixture of wheat flour, water and other components processed by fermentation. Sourdough, in other terms, is natural yeast which can be used as a food additive for starters in making bread, cakes and other bakery products. The process of making sourdough can take place naturally through a fermentation process, resulting in a unique taste and aroma of bread and better nutritional content. However, currently natural sourdough yeast is being developed as a bread developer. This is because some Istan yeast can cause allergens if they enter the body and are consumed directly. The use of natural sourdough yeast is an alternative for developing whitebread. This research aims to determine the effect of different sourdough concentrations on the physical and microbiological properties of white bread. The method used in this research used a Completely Randomized Design (CRD) with one factor, namely sourdough concentration of 0%, 30%, 60% and 90%. Apart from that, the proofing time has been determined at around 135 minutes. The parameters observed were physical quality (expandability, texture), microbiology (total number of lactic acid microbes), and water content analysis. Data analysis uses ANOVA and if there is a significant difference then proceed with the Least Significant Difference test (LSD). The results of the study showed that the addition of sourdough had a significant effect on the physical, microbiological and water content of white bread. In addition, fermentation time has a significant effect on the number of natural sourdough yeast microbes. The natural sourdough yeast used to make white bread with a fermentation time of 16 days.

Tidal Characteristic Analysis Utilizing Radar Tide Gauge in Cirebon Seawater

Radar-based tide gauges are one approach in measuring water level offering easier installation and maintenance. Tidal data recording that has been done commonly applies tide staff or pressure tide gauge. In this study, a radar tide gauge was installed at Cirebon port, northern part of Java island, to determine the tidal characteristics in Cirebon seawaters. Water elevation data was recorded every 15 minutes from July 2022 to November 2023. The tidal component is calculated using least squares method while the tidal type is determined using the Formzahl number. The dominant tidal component known consists of semidiurnal component i.e. M2, S2, N2, K2, 2N2; diurnal component, K1, O1, P1, Q1, J1, TAU1; and shallow water component SSA components with a height of 11.98, 5.58, 2.91, 2.11, 1.45, 11.80, 3.89, 6.11, 2.08, 1.56 and 3.11 (in cm), respectively. Tidal type in the study area is mixed type prevailing Semidiurnal. The tidal range is around 0.8-1 m high with high tide conditions at 6.00-9.00 and 18.00 - 21.00, while low tide conditions are within 11.00 - 14.00 and 01.00 - 04.00. Elevation height calculation based on datum is done by combining the tidal components. Tidal measurement data using radar can be an alternative data to support and complement data recorded in Cirebon and may become a consideration for development and other maritime activities.

ZIF-8 functionalized S-tapered fiber-optic sensor for polystyrene nanoplastics detection by electrostatic adsorption

Microplastic (MP) residues in marine have become an increasingly serious environmental pollution issue, and in recent years the detection of MPs in marine started to attract worldwide research interests. Optical-fiber-based environmental sensors have been extensively employed for their several merits such as high sensitivity, pressure resistance, compactness and ease of constructing communication networks. However, fiber-optic refractive index sensors are not specifically developed for distinguishing MPs from other inorganic particles suspended in water. In this paper, an metal-organic framework (MOF) ZIF-8 functionalized S-tapered fiber (STF) sensor is proposed for specific detection of polystyrene nanoplastics (PSNPs) in aqueous environment. ZIF-8 coordination nanoporous polymers with different film thickness were immobilized over the surface of the fabricated STF structure based on self-growth technique and yielding a large surface area over the sensor surface. High sensitivity detection can be achieved by converting the concentration perturbation of PSNPs into evanescent waves over the ZIF-8 functionalized STF surface through the strong electrostatic adsorption effect and π-π stacking, while the fabricated sensor is insensitive to gravels with silica as the primary component in water. It is found that the proposed detector with 18 film layers achieves a sensitivity up to 114.1353nm/%(w/v) for the PSNPs concentration range of 0.01 %(w/v) to 0.08 %(w/v).

Control of Biological Surface States on Chlorine-Doped Amorphous Silica Particles and Their Effective Absorptive Ability for Antibody Protein.

Amorphous silica particles (ASPs) have low biotoxicity and are used in foodstuffs; however, the adsorption states of proteins on their surfaces have not yet been clarified. If the adsorption states can be clarified and controlled, then a wide range of biological and medical applications can be expected. The conventional amorphous silica particles have the problem of protein adsorption due to the strong interaction with their dense silanol groups and denaturation. In this study, the surfaces of amorphous silica particles with a lower silanol group density were modified with a small amount of chlorine during the synthesis process to form a specific surface layer by adsorbing water molecules and ions in the biological fluid, thereby controlling the protein adsorption state. Specifically, the hydration state on the surface of the amorphous silica particles containing trace amounts of chlorine was evaluated, and the surface layer (especially the hydration state) for the adsorption of antibody proteins while maintaining their steric structures was evaluated and discussed. The results showed that the inclusion of trace amounts of chlorine increased the silanol groups and Si-Cl bonds in the topmost surface layer of the particles, thereby inducing the adsorption of ions and water molecules in the biological fluid. Then, it was found that a novel surface layer was formed by the effective adsorption of Na and phosphate ions, which would change the proportion of the components in the hydration layer. In particular, the proportion of the free water component increased by 21% with the doping of chlorine. Antibody proteins were effectively adsorbed on the particles doped with trace amounts of chlorine, and their steric adsorption states were evaluated. It was found that the proteins were clearly adsorbed and maintained the steric state of their secondary structure. In the immunoreactivity tests using streptavidin and biotin, biotin bound to the chlorine-doped particles showed efficient reactivity. In conclusion, this study is the first to discover the surface layer of the amorphous silica particles to maintain the steric structures of adsorbed proteins, which is expected to be used as a carrier particle for antibody test kits and immunochromatography.

Modeling the Subpixel Land-Use Dynamics and Its Influence on Urban Heat Islands: Impacts of Factors and Scale, and Population Exposure Risk

Urban heat islands (UHIs) has been proven firmly related to the land use structure. Identifying interactions between UHIs and multiple land use components is a crucial step to obtain human heat welfare information. However, few studies have predicted sub cell scale land use structure dynamics on UHIs due to the lack of subpixel simulation methods. Herein, we present an integrated framework coupling subpixel unmixing and mixed-cell simulation methods to predict fine-scale land-use structural changes. A widely used XGBoost was used to determine the optimal scale for future UHIs prediction. This framework explores how multiscale changes in land use structure will affect future UHIs intensity, taking Wuhan, China as a study area. The results reveal that most influence comes from the scale below the 330-m grid, while the fine-scale land use components of a given position show limited impact on the UHI intensity. Impervious surfaces contribute more than 55% of the importance, while bare soil and water components within the 270-m grid also significantly affect UHIs. We also find that optimizing the structure of land use components can potentially release approximately 599,000 people from high-UHI regions in the study area.

Comprehensive evaluation of the aggressive certain degree of the chemical components in water to concrete

Evaluation and research on the aggressive degree to concrete were done in the previous research. However, the evaluation of aggressive certain degree in water to the concrete was experimented comprehensively in the laboratory by the Viet Nam Standard “TCVN 3994:1985” and ISO 14911:1998. In addition, this paper considers water with the chemical name “Chlorite-Bicarbonate-Sodium-Magnesium” by the Kurlov formula and “TCVN 81:1981”. Especially, comprehensive consideration of chemical analysis that includes Cation (Ca2+; Mg2+; ∑(Fe2+; Fe3+; Na+; K+; and NH4+); Anion (Cl−; SO42−; HCO3−; CO32− and OH−); and the other special items analysis which includes Permanent and Temporary hardness; Alkalinity; CO2 free; CO2 corrosive; Total mineralization; pH value; Nitrite (NO2−); and Nitrate (NO3−). The research results presented “water with chemical characteristics can’t create the aggression in concrete,“ which shows pH concentration is 5 and CO2 corrosion is 20 mg/l (approximately 0.04%); whereas ion Mg2+ is 1.5 g/l (approximately 3%) and SO42− is 0,25 g/l (approximately 0.5%). The total salt content in the presence of an evaporating surface obtains 12,5 g/l (approximately 25%). So research results can be used safely for the design or construction of the reinforcement concrete structures in My Thai Canal Bridge, Rach Gia town, Kien Giang province, Viet Nam, and Construction or Geotechnical as good reference documents in the future.

Numerical Study on Heat Transfer and Release Characteristics of Key Components in Electrically Heated Tobacco Products

Electrically heated tobacco products (EHTPs) could release effective aerosol components from tobacco materials at relatively low temperatures without a burning phenomenon. It is essential to grasp the temperature distribution and release mechanism of key components in heated tobacco materials. The existing experimental studies have provided initial insights into the thermodynamic behavior of tobacco materials under various conditions. However, current numerical models are still in their early stages of development, with the majority failing to correlate heat transfer with component release. Based on this, a coupled numerical model of gas flow, heat transfer, and the release of key components in the electrically heated tobacco product is established in this study, which exhibits improvements in revealing the internal heat and mass transfer characteristics in the porous media of tobacco and is capable of evaluating the influence of component contents and product design parameters. The release rates of water, glycerol, and nicotine components are quantitatively described by the first-order Arrhenius formula, and the transport of heat and gas flow is simulated using the Navier-Stokes equation. The accuracy of the model is validated through experiments, including temperature monitoring at multiple measurement points and determination of residual contents in the tobacco substrate after each puff. The simulation results suggest that an appropriate component ratio and tobacco filler mass can enhance both the release amount and release efficiency of key components, and reducing either the diameter or length of the tobacco section can help to improve the heat transfer performance. A slower heating rate matched with longer preheating times enables the complementary release of water and glycerol components, which helps to regulate the uniformity of component content in the aerosol to some extent. This study helps to provide suggestions for the design and optimization of electrically heated tobacco products.

Influence of stratification and wind forcing on the dynamics of Lagrangian residual velocity in a periodically stratified estuary

Abstract. Wind and stratification play pivotal roles in shaping the structure of the Lagrangian residual velocity (LRV). However, the intricate dynamics by which wind and stratification modify the LRV remain poorly studied. This study derives numerical solutions of LRV components and eddy viscosity subcomponents to elucidate the dynamics within the periodically stratified Pearl River estuary. The vertical shear cross-estuary LRV (uL) is principally governed by the interplay among the eddy viscosity component (uLtu), the barotropic component (uLba), and the baroclinic component (uLgr) under stratified conditions. During neap tides, southwesterly winds notably impact uL by escalating uLtu by an order of magnitude within the upper layer. This transforms the eastward flow dominated by uLtu under wind influence into a westward flow dominated by uLba in upper shoal regions without wind forcing. The along-estuary LRV exhibits a gravitational circulation characterized by upper-layer outflow engendered by a barotropic component (vLba) and lower-layer inflow predominantly driven by a baroclinic component (vLgr). The presence of southwesterly winds suppresses along-estuary gravitational circulation by diminishing the magnitude of vLba and vLgr. The contributions of vLba and vLgr are approximately equal, while the ratio between uLba and uLgr (uLtu) fluctuates within the range of 1 to 2 in stratified waters. Under unstratified conditions, LRV exhibits a lateral shear structure due to differing dominant components compared to stratified conditions. In stratified scenarios, the eddy viscosity component of LRV is predominantly governed by the turbulent mean component, while it succumbs to the influence of the tidal straining component in unstratified waters.

Deuterium enrichment by proton exchange membrane water electrolysis with electrolyte circulation

Hydrogen isotopes will be new energy sources in nuclear fusion. In this study, a batch system for producing heavy water was developed in which pure water with deuterium (D) was circulated during proton exchange membrane water electrolysis. Deuterium was enriched by up to 94.7 at.% from 51.1 at.%. The D components of water and gas were analyzed during electrolysis. The relationship between the concentration of D (CD) and the electrolytic consumption ratio (R) was evaluated. This relationship was simulated using a mass balance model. From the gas analysis, the separation factor α was calculated. It was found that α depended on the ratio among H2O, HDO, and D2O to maintain the equilibrium state of the chemical exchange reaction.

Natural deep eutectic solvents (NADES) for the extraction of bioactives: emerging opportunities in biorefinery applications

Natural deep eutectic solvents (NADES) have emerged as an eco-friendly alternative for extracting bioactives, avoiding the use of flammable organic solvents and extreme temperatures and pH conditions. NADES rely on intermolecular interactions between hydrogen bonding donors (HBD) and hydrogen bonding acceptors (HBA) to form eutectic mixtures with significantly lower melting points than their individual components. These matrices are influenced by factors like water content, temperature, and component ratios. NADES high viscosity can hinder extractive efficiency, which can be mitigated by adding water or working at higher temperatures. However, excessive dilution with water may disrupt the supramolecular structure of NADES, reducing extraction efficiency. A notable feature of NADES is their fine-tunability for specific purposes. Adjusting physicochemical properties such as polarity, pH, and viscosity optimizes extraction efficiency by promoting the solubility of target molecules and interactions between the NADES and target molecules. NADES, unlike organic solvents, can partially disrupt plant and microalgae cell walls, enhancing permeability and extraction efficiency. Moreover, NADES can have a stabilising effect on bioactives and can enhance their biological activity and bioavailability. These attributes, coupled with their low environmental impact in terms of low toxicity and high biodegradability, make NADES attractive for biorefinery applications.

Automated approach for recovering modal components in shallow waters.

This paper proposes a fully automated method for recovering modal components from a signal in shallow waters. The scenario involves an unknown source emitting low-frequency sound waves in a shallow water environment, and a single hydrophone recording the signal. The proposed automated algorithm is based on the warping method to separate each modal component in the time-frequency space. However, instead of manually choosing a single arrival time for extraction, the method performs successive extractions with automated time selection based on an explicit quality factor. Modal component separation is achieved through a watershed algorithm, streamlining the process and eliminating the need for manual intervention. The proposed method is tested on experimental data of a right whale gunshot, a combustive sound source, and a bowhead whale upsweep, demonstrating its effectiveness in real-world scenarios.

Simultaneous and on-line detection of organic and heavy metal components in water using a novel nebulization-assisted injection plasma ionization triple quadruple mass spectrometry instrument

BackgroundThe global release of organic and heavy metal components into natural water bodies is a major concern for the environment and human health. The assessment of water quality relies on analyzing organic and heavy metal components qualitatively and quantitatively. Real-time identification of organic and metal components in water systems requires different analytical techniques due to varying measurement requirements. Thus, on-line detecting both organic compounds and heavy metals in ambient water systems simultaneously using a single instrumentation setup presents a significant challenge. ResultsIn this study, an analytical technique of nebulization-assisted injection plasma ionization mass spectrometry (NI-PIMS) was developed. This novel method enables the simultaneous detection of heavy metals and organic compounds in water system with high sensitivity, which has been demonstrated by the limit of quantification (LOQ) values below 1.0 μg/L for the three sterols (Enrofloxacin, ciprofloxacin, and clenbuterol) and three heavy metals (Pb, Ba, and Cd). Moreover, the method was successfully applied to rapidly analyze real water samples from urban and rural areas in China. The analytical results are available in less than 0.5 min, and only a few microliters of sample are required for each analysis. Significance and noveltyAs far as we know, this is the first report of on-line simultaneous analysis of organic compounds and heavy metals in a water system using a single mass spectrometry instrument. Compared to traditional methods, NI-PIMS demonstrates higher efficiency, sensitivity, no or lower sample preparation, and less sample consumption. The advancement and widespread use of this technology are expected to enhance the effectiveness of mass spectrometers, broaden the applications, and play an important role in complex sample analysis in fields such as atmospheric science, environmental science, and earth science.

Rhodamine B for Probing the Effects of Modifications in Cetrimonium Bromide Counter-anions by Transition Metals on CTAB/Butanol/n-hexane/water Microemulsion.

Dye solubilization in microemulsion based on Cetyltrimethylammonium bromide (CTAB) and its modified forms (counter-anions based upon Zn2+, Cu2+ and Fe3+) is comparatively innovative and not explored in existing literature. Here, surfactant with modified counterions (SMCs) were used to study the effects of metal chlorides (ZnCl2, CuCl2 and FeCl3) modifications on the comparative solubilization of Rhodamine-B (RB) by Cetyltrimethylammonium bromide (CTAB) and its modified forms. The solubility of RB in different microemulsions were studied using UV-Visible spectroscopy and phase diagrams of CTAB with modified counter ions CTA+[ZnCl2.Br]- named as CZN-1, CTA+[CuCl2.Br]- named as CCU-1 and CTA+[FeCl3.Br]- named as CFE-1 based upon surfactant with modified counter ions (SMCs). Four different points in microemulsion region of phase diagram were selected with different percentage composition of Smix (surfactant and co-surfactant), oil and RB (taken as water component). The interaction of RB, CCU-1, CFE-1 and CZN-1 within microemulsion environment were studied using Fluorescence spectroscopy. Emission spectra of RB in CCU-1 and CFE-1 based microemulsion confirmed that RB formed complexes with Cu and Fe ions. It was also found that RB was less soluble in CTAB based microemulsion as compared to microemulsions based on SMCs. This novel research study will expose new path for future research work related to microemulsion.

Oxidation of branched chain amino acids by HOCl: Kinetics and mechanism

The kinetics of the chlorination of leucine, isoleucine, and valine (BCAAs) was studied in excess HOCl by stopped-flow and spectrophotometric methods (25 ◦C, I = 1.0 M NaClO4). The intermediates and products were identified and monitored by 1H NMR spectroscopy. It was established that these reactions are fully analogous and proceed according to distinct mechanisms under alkaline and neutral conditions. At high pH, the formation and subsequent rate determining decomposition of N-monochloroamino acid control the process. The decomposition occurs via competing pH-independent and OH−-assisted reaction paths and the sequence of chlorination, dichlorination and decarboxylation steps leads to the formation of N-chloroimines and their carbanionic forms, which are in fast acid – base equilibria. The dechlorination of the carbanions yields nitriles as the main products. The hydration of the N-chloro imines produces chloramine and aldehydes which are involved in further oxidation reactions with HOCl. The formation of chloroform and chloroacetaldehyde was confirmed in each system. At pH 7.0, the N-chloro derivatives of BCAAs form immediately and are converted into the corresponding N,N-dichloro species within a few seconds after mixing the reactants. In this reaction, the reactive form of the oxidant is Cl2O. The first-order decomposition of the dichloroamino acids occurs on stopped-flow timescale (k = 0.5 – 0.7 s−1) and yields N-chloroimines which slowly decompose with a characteristic first-order rate constant on the order of a few times 10−5 s−1. The main products are the corresponding nitriles that account for about 80% and 60% of the original amounts of amino acids under neutral and alkaline (cOH− = 5.00 × 10−2 M) conditions, respectively. Aldehydes, carboxylic acids, chloroform and NCl3 were also identified as by-products. The results unequivocally confirm that harmful chlorinated species may form from amino acids long after the chlorination step in water treatment technologies that deteriorates the quality of the finished water. Environmental implicationIn source waters, amino acids account for about 75% of the total dissolved nitrogen. Therefore, it is an essential issue how the reactions of these compounds with hypochlorite ion can be controlled to avoid the formation of toxic compounds. The compounds formed from BCAAs are considered to be harmful both under alkaline and neutral conditions (chloroacetaldehyde, chloroform, nitriles). However, some of the intermediates have extended lifetime in these systems and they may also react with other components of raw water during water treatment processes.