Concentrations Of Different Anions Research Articles

Evaluation of Drinking Water Quality and Treatment from Coolers in Public Places in Madinah City, Saudi Arabia

The aim of this work is to prevent the public drinking from water coolers, by using an auto-detection process, if the quality of water is low. Therefore, the proposed water treatment management system for allows the activation of dispensers to provide the best-quality water coolers. The objective is to investigate the quality of the drinking water from coolers in public places in Madinah and to provide clean, safe, and healthy drinking water for the general public. The methodology consisted of performing different analyses, tests, and water treatments, such as physicochemical analyses of the water samples, measurements of the different concentrations of anions, measurements of the concentrations of heavy metals, and bacteriological tests of the water samples. Therefore, 66 water samples were tested, and the experimental values were compared with the reference values given by the World Health Organization (WHO) and Saudi Standards, Metrology, and Quality Organization (SASO) for drinking water. The tests revealed that the physicochemical parameters (pH, EC, TDS, and TH) of different water sources (95.5%) were in accordance with the SASO and WHO values. In addition, all the analyzed water samples (100%) contained permissible levels of nitrates, sulfates, nitrites, and free residual chlorine, as indicated by the results. However, 68.2% of the samples studied had fluoride concentrations below the standard limits. Furthermore, heavy metals such as lead, iron, and others were tested for all water coolers. The measured findings indicated that just one cooler exceeded the permissible limit of 0.3 mg/L for Fe, and the biological contamination testing revealed that 4.5% of the coolers were infected with coliforms. Finally, this research suggests that water coolers should be regularly maintained. Additionally, using the best design for the water desalination process is very important to give the best drinking water quality.

Machine learning assisted modeling of interfacial tension in the system N2/Brine

The CO2 rising in the atmosphere causes serious greenhouse effects on severe and sustainable global warming. Carbon capture is one of the most viable approaches accepted to achieve sustainable development goals. On the other hand, flue gases contain large amounts of CO2 and N2. For the purpose of CO2 sequestration in depleted reservoirs or saline aquifers, a deep understanding about the interaction between these components with brine is vital. Among the most important parameters, which can be investigated for such applications, is interfacial tension (IFT) in these systems. In the current study, we have measured IFT between N2 and different brines including monovalent and divalent ions at various temperatures and pressures at different salinity ranges. Various brines containing different salts such as NaCl, Na2SO4, KCl, MgCl2, and CaCl2 were synthesized in the range of salinity between 10000 ppm and 50000 ppm. The temperature and pressure ranges of our study were 30–70 °C, and 0.1–30 Mpa, respectively. IFT700 (Vinci, France) instrument was used for our experiments. The obtained experimental data were then analyzed using different machine learning algorithms. The prediction of IFT as a response variable (in the range of 31.39–74 mN/m) with independent variables including temperature (K), pressure (Mpa), and molar concentrations of different anions and cations (M) was carried out using adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network (ANN) with feed-forward architecture models which was trained using particle swarm optimization (PSO) algorithm as an evolutionary algorithm. Based on the present study results, the IFT was predicted accurately by ANFIS + PSO and ANN + PSO endorsed with good performance parameters. The coefficient of determination (R2), mean squared error (MSE), mean absolute error (MAE), and average absolute relative deviation (AARD%) were calculated to assess the accuracy of the models. Both models showed very good performance, with R2 coefficient 0.9898 and 0.9938 for test data of ANN + PSO and ANFIS + PSO, respectively. As it can be seen from the results, ANFIS and ANN methods were very successful for predicting the behavior of the complex systems studied in this work, while the ANFIS + PSO model had a better predictive power. It can be explained by the fact that ANFIS is a modeling technique that combines the power of artificial neural network with fuzzy logic theory techniques. It can apply FIS to define hidden layers and improve its predictive ability.

Kinetics of zero-valent iron-activated persulfate for methylparaben degradation and the promotion of Cl−

Methylparaben (MP) is an emerging pollutant, and the optimal conditions and kinetics of MP degradation using nano-zero-valent iron-activated persulfate (nZVI/PDS) need to be further investigated. This paper firstly investigated the response surface methodology (RSM) analysis of MP degradation by the heterogeneous system nZVI/PDS and concluded that the initial pH had the most significant effect on MP degradation. The optimal experimental conditions predicted by the RSM were as follows: initial pH 2.75, [nZVI]0 = 2.87 mM, [PDS]0 = 2.18 mM (MP degradation level of 95.30%). First- and second-order kinetic fits were performed for different initial pH levels and different concentrations of MP, nZVI, and PDS. It was determined that k = 0.0365 min−1 (R2 = 0.984) when the initial pH was 3, [PDS]0 = 2 mM, [MP]0 = 20 mg L−1, and [nZVI]0 = 3 mM (MP degradation level of 94.25%). The rest of the conditions were more closely fitted to the second-order reactions. The effects of different concentrations of anions and humic acid (HA) on the MP degradation level and k were examined, and it was found that Cl− could promote MP degradation to 97.69% (increased by 3.65%) and increase the k in accordance with the first-order reaction kinetics (0.0780 min−1, R2 = 0.991). Finally, the analysis of intermediates revealed 5 reaction pathways and 7 reaction intermediates, which inferred a possible reaction mechanism with the recycling performance of nZVI. In this paper, the superiority of nZVI/PDS for the purposes of activating MP degradation was affirmed. The presence of Cl− can enhance the level of MP degradation was confirmed, which provides a new direction for future practical engineering applications.

Chemical and Bacteriological Assessment of Groundwater in Tathleeth Region of Asir

The current study aims to identify and assess the validity of groundwater in Tathleeth Region of Asir, Saudi Arabia for human and irrigation uses. The efforts, in this work, included a collection of different groundwater samples from Tathleeth area. After collection, the samples were put in appreciate containers, transferred to laboratory and kept for further analysis. The collection, preservation and analysis were done according to the standard methods. Then after, the physico-chemical proprieties of the collected groundwater samples as well as the concentration of different anions and cations were determined. Further, a bacteriological analysis was performed to evaluate the possible use of the groundwater, in this area, for human use. Finally, the obtained results were compared with the allowed limits set by Gulf Standard Specification (GSS). Experimentally, many groundwater samples were collected from different wells, have different depths and distributed throughout the area of study. From all these groundwater samples, only nine samples were selected, to exclude repetition, and subjected to chemical and bacteriological analysis. The physical characteristics including: odor, color, turbidity and conductivity of the collected samples were determined. The values of different chemical parameters as: pH, total dissolved salts (TDS), total hardens, total alkalinity were measured according to the standard methods of analysis. In addition, the concentration of many anions (chloride, fluoride, nitrite, nitrate, ammonia and sulphate) and some major cations (iron, magnesium and calcium) were determined. Finally, a bacteriological analysis for E.coli, and T. coliform were performed for all collected samples. The revealed results showed that pH has values ranged from 7.3 to 8.5 and the electrical conductivity exhibited values between 754 - 8944 µS cm-1 while the total dissolved salts between 520 to 6171 mg L-1. The results demonstrate the validity of certain samples for human uses and the suitability of most of samples for irrigation purposes.

Speciation distribution of uranium in Tamusu groundwater calculated by CHEMSPEC

CHEMSPEC was used to study the speciation distribution of U in Tamusu groundwater and the effects of Eh, pH, different ions and concentrations and temperature. The calculation results indicate that uranium mainly exists as UO2(OH)2(aq) in Tamusu groundwater. Under strong acidic conditions, uranium mainly exists as UO22+, while in weak acidic, neutral or weak alkaline conditions, the main species is UO2(OH)2(aq). When the solution is in strong alkaline conditions, most of uranium exists as UO2(OH)3−, with the possible generation of CaUO4. U(IV) is stable in the reduction condition, while U(VI) is stable in the oxidic condition. The concentration of different anions also has influence on the speciation distribution of uranium in the order of HCO3−>F−>SO42−>Cl−. Increasing UO22+ concentration promotes the generation of CaUO2(CO3)32− and Ca2UO2(CO3)3(aq). As temperature increases from 5 to 80 degree centigrade, the concentration of UO2OH+ increases significantly.

Uticaj anjona na dekolorizaciju tekstilne boje Reactive Orange 16 UV/H2O2 procesom

The effects of various organic and inorganic anions on decolorization of textile dye Reactive Orange 16 by means of hydroxyl radicals have been studied. These anions are commonly present in wastewaters from textile industry and include chloride, sulfate, carbonate/bicarbonate, nitrate and acetate anions. The experiments were conducted in the presence of different concentrations of anions and at different initial pH values in a batch photoreactor equipped with UV-C (254 nm) lamps in the presence of hydrogen peroxide. It was obtained that decolorization efficiency was significantly affected by nature and concentration of the investigated anions. An inhibitory effect of acetate anions increased with increasing in their concentration and depended on whether protonated or deprotonated forms are favored. Carbonate anion showed specific, both positive and negative influence, depending on its concentration. Influence of bicarbonate, nitrate and chloride was more prominent at their higher initial concentrations. The presence of sulfate did not have noticeable impact on decolorization of RO16 dye under investigated conditions.

Effects of radical scavengers on humic acid removal by electron beam irradiation

Despite many efforts to remove humic acid (HA) in water resources, this problem is not overcome, especially in underdeveloped countries. The aim of this study is to evaluate the effects of inorganic anions (Cl−, HCO3-, SO42-, and NO3-) as radical scavenger on the efficacy of electron beam (EB) irradiation for the removal of HA from aqueous solutions. In this study, stock HA solution was prepared in alkaline condition; furthermore, different concentrations of anions were added to all HA samples. Here, the effect of different electron beam absorbed doses (1, 3, 6, 9, and 15 kGy) on the removal of HA is studied. HA concentration was measured using UV–vis spectrophotometer at 254 nm. The results showed that by increasing absorbed dose from 1 to 15 kGy, HA removal efficiency increased from 28.2 to 77.7%, respectively. While, by increasing different inorganic anion concentrations from 25 to 100 mg/L, the removal efficiency decreased. According to the results, nitrate has more inhibitory effect on the hydroxyl free radicals and HA removal efficiency in the presence of EB irradiation compared with chloride, bicarbonate, and sulfate anions. Furthermore, the kinetic model fitted the pseudo-second-order kinetics well.

Specific ion effects on the electrokinetic properties of iron oxide nanoparticles: experiments and simulations.

We report experimental and simulation studies on ion specificity in aqueous colloidal suspensions of positively charged, bare magnetite nanoparticles. Magnetite has the largest saturation magnetization among iron oxides and relatively low toxicity, which explain why it has been used in multiple biomedical applications. Bare magnetite is hydrophilic and the sign of the surface charge can be changed by adjusting the pH, its isoelectric point being in the vicinity of pH = 7. Electrophoretic mobility of our nanoparticles in the presence of increasing concentrations of different anions showed that anions regarded as kosmotropic are more efficient in decreasing, and even reversing, the mobility of the particles. If the anions were ordered according to the extent to which they reduced the particle mobility, a classical Hofmeister series was obtained with the exception of thiocyanate, whose position was altered. Monte Carlo simulations were used to predict the diffuse potential of magnetite in the presence of the same anions. The simulations took into account the ion volume, and the electrostatic and dispersion forces among the ions and between the ions and the solid surface. Even though no fitting parameters were introduced and all input data were estimated using Lifshitz theory of van der Waals forces or obtained from the literature, the predicted diffusion potentials of different anions followed the same order as the mobility curves. The results suggest that ionic polarizabilities and ion sizes are to a great extent responsible for the specific ion effects on the electrokinetic potential of iron oxide particles.

Studies of anions sorption on natural zeolites

This work presents results of FT-IR spectroscopic studies of anions–chromate, phosphate and arsenate – sorbed from aqueous solutions (different concentrations of anions) on zeolites. The sorption has been conducted on natural zeolites from different structural groups, i.e. chabazite, mordenite, ferrierite and clinoptilolite. The Na-forms of sorbents were exchanged with hexadecyltrimethylammonium cations (HDTMA+) and organo-zeolites were obtained. External cation exchange capacities (ECEC) of organo-zeolites were measured. Their values are 17mmol/100g for chabazite, 4mmol/100g for mordenite and ferrierite and 10mmol/100g for clinoptilolite. The used initial inputs of HDTMA correspond to 100% and 200% ECEC of the minerals. Organo-modificated sorbents were subsequently used for immobilization of mentioned anions.It was proven that aforementioned anions’ sorption causes changes in IR spectra of the HDTMA-zeolites. These alterations are dependent on the kind of anions that were sorbed. In all cases, variations are due to bands corresponding to the characteristic Si–O(Si,Al) vibrations (occurring in alumino- and silicooxygen tetrahedra building spatial framework of zeolites). Alkylammonium surfactant vibrations have also been observed. Systematic changes in the spectra connected with the anion concentration in the initial solution have been revealed.The amounts of sorbed CrO42–, AsO43– and PO43– ions were calculated from the difference between their concentrations in solutions before (initial concentration) and after (equilibrium concentration) sorption experiments. Concentrations of anions were determined by spectrophotometric method.

Concentration sensor based on a tilted fiber Bragg grating for anions monitoring

The ubiquity and importance of anions in many crucial roles accounts for the current high interest in the design and preparation of effective sensors for these species. Therefore, a tilted fiber Bragg grating sensor was fabricated to investigate individual detection of different anion concentrations in ethyl acetate, namely acetate, fluoride and chloride. The influence of the refractive index on the transmission spectrum of a tilted fiber Bragg grating was determined by developing a new demodulation method. This is based on the calculation of the standard deviation between the cladding modes of the transmission spectrum and its smoothing function. The standard deviation method was used to monitor concentrations of different anions. The sensor resolution obtained for the anion acetate, fluoride and chloride is 79×10−5mol/dm3, 119×10−5mol/dm3 and 78×10−5mol/dm3, respectively, within the concentration range of (39–396)×10−5mol/dm3.

Application of Ion Chromatography for the Determination of Nitrate in Process Streams of Thermal Denitration Plant

A simple, accurate, and rapid analytical methodology for the determination of nitrate content in process streams of thermal denitration plant has been developed. The nitrate content in these process streams varies over a wide range of concentration (0.1–150 g L−1). Quantitative determination of nitrate was accomplished by anion exchange chromatography with conductometric detection in suppressed mode. The method requires a simple sample dilution step. A Metrosep A supp 3 analytical column connected in series with a Metrosep RP guard column was used for nitrate separation. A solution containing a mixture of 1.8 mM Na2CO3 and 1.7 mM NaHCO3 was used as eluent. The limit of detection for the determination of nitrate is 0.02 µg mL−1 and the relative standard deviation was 5% for the overall method. No interference was observed from either the chloride or closely eluting “system peak” in the determination of nitrate. The method was validated using an ion selective electrode based determination. The method has a high throughput and 6 samples were analyzed per hour to provide the data on the process parameters. No interference was observed from the other anionic impurities, namely chloride and sulphate. In the case of process streams from thermal denitration of Zr raffinate the method requires a sample pretreatment for the removal of large excess of zirconium from the sample matrix. Onguard-H cartridges were found most suitable for this purpose. The concentration of different anions could be measured simultaneously.

A promising gold nanocluster fluorescent sensor for the highly sensitive and selective detection of S2−

Bright red-emissive gold nanoclusters (AuNCs) were synthesized by a facile one-pot approach in aqueous solution using bovine serum albumin (BSA) as a protecting agent. A new BSA-AuNC fluorescent sensor for the detection of S2− has been designed based on the sharp fluorescence quenching of BSA-AuNCs, which results from the degradation of its structure due to the formation of Au2S by the reaction between Au and S2−. The proposed highly sensitive (the detection limit [LD] was 0.029μM) and selective sensor was applied to the detection of S2− in the presence of high concentrations of different anions in aqueous solution, and the results were in good agreement with those determined by electrochemical methods. The sensor is shown to be environmentally friendly, simple, responsive and practical. Meanwhile, the morphological changes of BSA-AuNCs and BSA-AuNCs-S2− were characterized by high-resolution transmission electron microscopy (HRTEM). Furthermore, the sensing mechanism for the detection of S2− is discussed.

Corrosion Behavior of Aluminum Alloy for Heat Exchanger in an Exhaust Gas Recirculation System of Diesel Engine

This study examines the corrosion behavior of aluminum alloys in condensed water containing different concentrations of anions for a heat exchanger in an automotive exhaust gas recirculation (EGR) system of a diesel engine. Electrochemical measurements and bulk analyses revealed that the aluminum alloy is protected by the adsorption of increased nitrite and nitrate ions contained in condensed water, despite increased detrimental sulfate ions at high EGR rates. The mechanism of the beneficial anions, which are nitrite and nitrate on aluminum alloy in condensed water, was spontaneous physical adsorption (physisorption).

IR spectra in the studies of anion sorption on natural sorbents

This work presents the results of FT-IR spectroscopic studies of anions – chromates, phosphates, arsenates, sulfates and nitrates – sorbed from aqueous solutions (different concentrations of anions) on natural sorbents. The sorption has been conducted on zeolite (clinoptilolite) and smectite (mixtures of clay minerals containing mainly montmorillonite and kaolinite) which have been separated from natural Polish deposit. The Na-forms of sorbents were exchanged with hexadecyltrimethylammonium cations (HDTMA +). Cation exchange capacities (CEC) of clinoptilolite and smectite were measured. Their values are 23 mmol/100 g and 41 mmol/100 g respectively. The used initial inputs of HDTMA correspond to 100% (1.0) and 200% (2.0) CEC of the minerals. Organo-modified sorbents were subsequently used to immobilization mentioned anions. It was proven that those anions’ sorption causes changes in IR spectra of the HDTMA-zeolite and smectite. These alterations are dependent on the kind of anions that were sorbed. In both cases, variations are due to bands corresponding to the characteristic Si–O(Si,Al) vibrations (occurring in alumino- and silicooxygen tetrahedra building spatial framework of zeolite or layer structure of smectite), OH group vibrations and alkylammonium surfactant vibrations have been observed. Systematic changes in the spectra connected with the anion concentration in the initial solution have been revealed. The amounts of sorbed CrO 4 2 - , AsO 4 3 - , PO 4 3 - , SO 4 2 - , and NO 3 - ions were calculated from the difference between their concentrations in solutions before (initial concentration) and after (equilibrium concentration) sorption experiments. Concentrations of chromates were determined by colorimetry using the biphenylocarbazide method. For phosphates and arsenates molybdenum blue method, turbidimetric method for sulfates and hydrazine reduction method for nitrates was used.

Influence of anions on the adsorption kinetics of salicylate onto α-alumina in aqueous medium

The adsorption kinetics of salicylate on α-alumina surfaces were studied at 25 °C and pH 6 in the presence of 0.05 mM concentration of different anions (Cl −, Br −, I −, SCN −, HCOO −, CH 3COO −, S 2O 2− 3, CO 2− 3, and SO 2− 4) as a function of time. The experimental data were significantly better fitted to a pseudo-second-order kinetics equation of nonlinear form in the entire time duration and are in excellent agreement with corresponding estimated values. Considering adsorption data for salicylate in the presence of Cl − as the face value, all the monovalent anions (Br −, I −, SCN −, HCOO −, CH 3COO −) promote the adsorption of salicylate onto α-alumina surfaces while the divalent anions (S 2O 2− 3, CO 2− 3, and SO 2− 4) have the reverse effect under similar conditions. DRIFT spectra of α-alumina treated with salicylate reveal that the symmetric peak ν s( COO −) is shifted by ∼40 cm −1 to a lower wavelength region, which implies that salicylate forms an inner-sphere complex with α-alumina surface in the presence of both mono- and divalent anions.

LIX 84 as an extractant for throium(IV), uranium(VI) and molybdenum(VI)

The extraction order of Th(IV), U(VI) and Mo(VI) based on pH0.5 values is Mo(VI)>U(VI)>Th(IV). Quantitative extraction has been observed for U(VI) by mixture of 10% (v/v) LIX 84 and 0.1M dibenzoylmethane at pH 4.2 and by mixture of 10% LIX 84 and 0.05M HTTA in the pH range 5.5–7.3 and for Mo(VI) by 10% LIX 84 from chloride media at pH 1.5. The order of extraction of Mo(VI) from 1N acid solutions is HCl>H2SO4>HNO3>HClO4 and extraction decreases very rapidly with increase in the concentration of HCl as compared to that from H2SO4, HNO3 and HClO4 acid solutions. The diluents C6H6, CCl4 and CHCl2 are found to be superior ton-butyl alcohol and isoamyl alcohol for extraction of Mo(VI). Influence of concentration of different anions on the extraction of U(VI) and Mo(VI) has been studied. Very little extraction has been observed in case of Th(IV) by LIX 84 or its mixtures with other chelating extractants or neutral donors.

POTENTIAL DIFFERENCES ACROSS THE CHORION OF THEFUNDULUSEGG

1. Potential differences were measured across the chorion of single eggs of Fundulus heteroclitus. The chorion was shown by three lines of evidence to be more permeable for cations than for anions:a. Concentration potentials were of such a sign that the dilute solution was positive to the concentrated.b. Concentration potentials with K salts of divalent and univalent anions were equal, whereas concentration potentials with chlorides of divalent cations were about half of those with K.c. Equal concentrations of different anions were eqipotential against the egg, whereas equal concentrations of different cations gave various potential differences whose magnitudes were in the same order inverted as the mobilities of those cations in free diffusion.2. The difference between the permeability of the chorion for anions and its permeability for cations increased with dilution of the solution in which the egg was immersed.3. In KCl and CaCl2 solutions the ratio of chorion permeability for anions to permeability fo...