JournalTOCs

Journal of Water Chemistry and Technology
Number of Followers: 8

Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1934-936X - ISSN (Online) 1063-455X
Published by Springer-Verlag

[2469 journals]

Cloud Point Extraction Coupled with Laser Thermal Lens Spectrometry for
Determination of Trace Palladium in Environmental Water Samples
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  Abstract: A highly sensitive, simple and safe method has been developed for the determination of trace palladium by cloud point extraction (CPE) combined with thermal lens spectrometry (TLS). The method is based on the fact that formation of the stable hydrophobic complex of palladium(II) with a newly synthesized reagent 2-(5-iodo-2-pyridylazo)-5-dimethylaminoaniline (5-I-PADMA), and then extraction into the micellar phase of non-ionic surfactant octylphenoxypolyethoxyethanol (Triton X-114) as extracting agent at pH 4.8. Parameters that affect extraction efficiency, such as solution pH, concentration of 5-I-PADMA and Triton X-114, and equilibration temperature and time on CPE, were investigated and optimized. The results showed that an efficient extraction of palladium could be achieved with the following conditions were as follows: pH = 4.8 acetic acid-sodium acetate (HAc-NaAc) buffer solution, 100 μL 5 × 10–4 mol/L 5-I-PADMA, 800 μL 1.0% (w/v) Triton X-114, and heat-assisted at 60°C for 20 min. After phase separation, the surfactant-rich phase containing palladium complex was dissolved in 450 μL 2 mol/L HClO4-ethanol solution prior to its determination by TLS. A single mode He–Ne laser with 632.8 nm was employed for both excitation and probe beams. Under optimum experimental conditions, the calibration graph was linear over the range 0.1–7.5 ng/mL with a correlation coefficient of 0.9986. The detection limit was 1.0 ng/mL for palladium. The sensitivity enhanced by 558 times compared to that of the conventional spectrophotometry. The relative standard deviation (RSD) for elven replicate measurements of 1.0 ng/mL of palladium was 3.2%. The proposed method was applied to the determination of trace palladium in water samples.
  PubDate: 2022-02-01
A Multivariate Statistical Approach to Pollution Source Identification in
Cauvery River, South India
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  Abstract: This paper proposes the multivariate statistical methods, in particular, factor analysis and cluster analysis to assess and interpret the surface water quality of Cauvery River, South India. For this purpose, the surface water samples were obtained from the 50 monitoring stations along the 50 km river stretch during the periods of January 2018 and June 2018. In this approach, 23 parameters were used to measure the quality of collected water samples. The measured levels of turbidity, total dissolved solids, pH, ammonia and fecal coliforms exceed the Bureau of Indian Standards (BIS) for drinking water quality in 58, 35, 12, 11, and 30 samples, respectively. This shows that the surface water of Cauvery River is contaminated by pollutants from catchment area. The factor analysis infers that four principal components represent 71.78% of the total variance in the data set. Nutrient factor, organic factor, chemical factor, and mixed factor were identified as four principal components as per the factored loadings of variables. The agglomerative hierarchical grouping of 50 monitoring stations was carried out by cluster analysis, and these clusters were recognized subject to the spatial variation in surface water quality. Majority of locations (31 sites) fall under low pollution cluster and are influenced by runoff from catchment. The second cluster comprises 14 sampling sites influenced by domestic/urban sewage discharge and comes under moderately polluted category. The high pollution of third cluster is due to the industrial wastewater contamination in 5 monitoring stations. The study indicates that runoff contribution from catchment, urban sewage discharge, industrial wastewater discharge, and natural weathering processes are influencing the quality of Cauvery River water in the selected region. These primary sources are responsible for the abundant ionic concentrations and biological impurities in the Cauvery River. The legitimate treatment of urban and industrial wastewater and governance of anthropogenic activities in the Cauvery River catchment are essential for controlling the potential contamination of surface water.
  PubDate: 2022-02-01
About the Mechanisms of Formation of the Chemical Composition of the
High-Mountain Rivers of Central Asia: The Shakhdara River and its
Contribution to the Hydrochemistry of the Transboundary Panj River
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  Abstract: Agriculture still predominates in the use of water resources in Central Asia. About 90% of the water resources generated in the region are used for irrigation. The quality of irrigation water is an important element in obtaining ecological and safe varieties of crops because, according to the data of IAEA, the transfer of radionuclides to the human body is carried out along a water–soil–plant–human body chain. Although such a chain explains the movement of radionuclides, it will also probably be implemented when pollutants enter the human body. The aim of this work is to determine the origin of the chemical composition of the Shakhdara River and its contribution to the enrichment of the main river Panj with chemical elements. Water sampling from the rivers Shakhdara and Panj is carried out in accordance with the guidelines of Sanitary Regulation “Sanitary and Epidemiological Requirements for Water Sources, Water ion Points for Economic and Potable Purposes, Economic and Potable Water Supply, Places of Recreational Water Uses and Safety of Waterbodies,” The elemental analysis is performed in the United States at the Laboratory of Ambient Environment and Geology of the Department of Geological Sciences of the University of Colorado (Boulder) as well as at the Laboratory of Moisture Chemistry of the Institute of Arctic and Alpine Studies. It is found upon comparing the results of chemical analyses with the criteria of various types of weathering (carbonate, silicate, evaporation of evaporites) that the formation of the chemical composition of the Shakhdara River occurs as a result of weathering of silicate rocks with the active participation of H2CO3 and H2SO4. It is established that the Shakhdara River makes a significant contribution to the enrichment of the Panj River with 3d (Fe, Co, Ni) elements as well as arsenic, vanadium, and scandium in addition to the alkaline (K, Na) and alkaline earth (Mg, Sr) elements.
  PubDate: 2022-02-01
Influence of Natural Water Components on the Sorption of Dodecyl Sulfate
Anions on Kaolinite
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  Abstract: To better understand the physicochemical processes occurring in natural reservoirs upon their contamination with the most common organic pollutants (anionic surfactants), the interaction of sodium dodecyl sulfate (DDSNa), sodium humate (HNa), and kaolinite from the Glukhiv deposit in distilled and natural artesian water is investigated. The influence of the natural water components on the states of the sorbent and sorbate is determined by a set of methods. The influence of Ca2+ ions and pH on the mechanism and value of adsorption of HNa on kaolinite is discussed. Increases in the adsorption capacity of the monolayer and the specific surface area of kaolinite are detected during the adsorption of humates from both distilled and artesian water. The influence of the formation of more surface-active than DDSNa but less soluble dodecyl sulfate salts with double-charged cations on the colloidal chemical properties of a solution of DDSNa in artesian water is demonstarted. Substantial leveling of the influence of mineral components on the surface activity and solubility of DDSNa upon the introduction of humates (natural polyelectrolytes) is established. The concentration ranges of the existence of different forms of the anionic surfactant (anions, insoluble salts, self-associates, intermolecular associates with humates, and micelles) in the studied systems and their influence on the sorption of the anionic surfactant on natural kaolinite are determined. It is shown that the isotherm of adsorption of anionic surfactants from artesian water is characterized by the presence of a maximum, which indicates a substantial effect of the precipitation of sparingly soluble salts of the dodecyl sulfate anion with doubly charged cations from artesian water. Moreover, the stepwise nature of the isotherm of adsorption of the anionic surfactant from artesian water in the presence of 5 mg/dm3 HNa may indicate the occurrence of multilayer adsorption, which is associated with following changes in the state of dodecyl sulfate upon changing its concentration in a solution: intermolecular associates with HNa and polyvalent ions with different DDSNa/HNa ratios in the surfactant associates and micelles. It is found that the addition of 5 mg/dm3 HNa to solutions of DDSNa in artesian water almost doubles the adsorption of DDSNa from its micellar solutions. It is established that low residual concentrations of DDSNa at the level of maximum permissible concentration (MPC) in water (DDSNa = 0.5 mg/dm3) ensure almost complete (R = 97%) removal of the humate from natural water, which is very important from the standpoint of environmental safety for understanding the influence of anionic surfactant pollutions on the state of aquatic ecosystems.
  PubDate: 2022-02-01
Dairy Effluent Biodegradation by Endogenous Fungal Isolates in the
Integrated Wastewater Treatment System
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  Abstract: The dairy industry is the fastest growing industry in the world. Discharged water is more easily contaminated with high levels of organic substances, pollutants and microbes. Consuming raw milk effluents can cause disease transmission to living beings and can be harmful to the environment. The present investigation was carried out for the characterization and its biodegradation process of dairy effluents using locally selected isolated fungi. For the biodegradation process, three species of fungi such as ASP, ALT, FUS were isolated and identified from dairy wastewater using the CFU method. During the monsoon, the dairy farm (CMP) collected the seasonal milk effluent. Aeration followed by filtration for degradation was performed. During the research some physicochemical parameters such as pH, BOD, COD, TDS, TSS, TKN, etc., were analyzed. Effluents from milk processing and ASP fungal isolate have been found to have a high capacity to break down organic matter. The BOD5 and COD value of the crude effluent improved by 87.75 and 81.02%, respectively, after 5 days. Biodegradation with fungal isolates can be a perfect method for treating dairy wastewater. This treatment technique can be used for industrial purposes, starting from selected fungal isolates, Aspergillus was more vital than Alternaria and Fusarium species for the biodegradation of organic content in dairy effluents. After studying all the aspects considered, aeration followed by filtration was extremely effective in reaching the most notable level of contamination present in wastewater. The possible reason could be related to the high adsorption capacity of activated carbon and assimilation by sawdust. Activated coal and sawdust can remove an assortment of organic matter from contaminated water. At long last, biodegradation of dairy wastewater by chosen fungal isolates is viable treatment technology, particularly on account of using locally isolated fungal strains.
  PubDate: 2022-02-01
Determination of the Toxicity of Petroleum Products for Aquatic Organisms
Using Comprehensive Bioassay
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  Abstract: We present the experimental results of the toxicity of the aquatic environment polluted with petroleum products (diesel fuel and AI-95 gasoline), obtained using complex bioassay of standard test organisms: daphnia Daphnia magna, freshwater hydra Hydra attenuate, and zebrafish Brachidanio rerio. Petroleum products have acute toxicity for all types of test organisms at a concentration of 0.1 cm3/dm3 for diesel fuel and 0.2 cm3/dm3 for AI-95 gasoline. The mechanisms of the toxic effect of petroleum products on hydrobionts are discussed. An ingress of a large amount of oil products into a natural reservoir threatens the functioning of the aquatic ecosystem due to a decline or disappearance of sensitive species of aquatic organisms, primarily invertebrates. Under these conditions, a film of insoluble fractions of oil products is formed on the water surface, the access of oxygen from the air to the water is disrupted (falls to 2–3 cm3 O2/dm3), and hydrobionts die from hypoxia. Water-soluble fractions of petroleum products enter organisms and poison them. The initial stages of development of aquatic organisms—fish embryos and fry or invertebrate nauplii—are the most sensitive to the toxic effects of petroleum products. Petroleum products caused an increase in the frequency of nuclear disorders in fish blood cells in surviving individuals, which indicates a genotoxic effect compared to the cytological parameters of the control group of fish.
  PubDate: 2022-02-01
TiO2 Nanoparticles Effect on PVDF Membrane Filterability in Membrane
Bioreactors: Fouling Reduction and Critical Flux Enhancement
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  Abstract: One of the important operational factors affecting the fouling of membrane bioreactors (MBR) is the critical flux which is defined as the flux above which the cake layer formation on the membrane surface is seen. So, to prevent severe fouling in MBR, it is important to determine the critical flux and operate at a flux below it. The evaluation of critical flux and pollutant removal in a lab-scale submerged membrane bioreactor was performed for a real oil refinery wastewater. Transmembrane pressure (TMP) and flux behavior in a period of time via a so-called flux step method were studied to determine the critical flux of the membrane and to investigate of the effect of TiO2 nanoparticles (NPs) incorporation into Polyvinylidene fluoride (PVDF) matrix, on the membrane filterability. The effectiveness of MBR for treating effluent stream of Dissolved Air Floatation (DAF) unit of Tehran oil refinery wastewater plant has been studied and the results showed that TiO2 NPs improved the phenol removal efficiency in such wastewater. About 70% enhancement in critical flux of PVDF/TiO2 membrane was observed as a result of TiO2 NPs tendency to reduce fouling of PVDF membranes. It was concluded that the effect of TiO2 incorporation in the membrane matrix is more significant in fouling reduction than permeability improvement and that the surface charge of the membrane plays much more important role than other surface modification strategies such as hydrophilicity enhancement, in fouling mitigation of MBRs. The results also demonstrated that TiO2 has no significant effect on the microorganism destruction or growth, since the amount of total soluble microbial products (SMP) and extracellular polymeric substance (EPS) remained almost stable during MBR operation for both membranes.
  PubDate: 2022-02-01
Determination of Zn, Mn, and Cd in Strata Water
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  Abstract: The effect produced by the Triton X-100 concentration and ultrasonic treatment time on the value of an analytical signal during the atomic absorption and inductively coupled plasma atomic emission determination of analytes in strata water was studied. When Triton X-100 was used, the sensitivity of atomic absorption analysis grew by 1.5 times for manganese, 1.6 times for zinc, and 1.8 times for cadmium. As a result of atomic absorption analysis with the use of a surfactant, atomization completeness was attained. Using the methods of atomic absorption and inductively coupled plasma atomic emission, the content of manganese, zinc, and cadmium in strata water was determined. The precision of analysis results was improved by using acetyl acetonates of metals, as the reference samples must be similar to the analyzed samples in their chemical composition. Using the standard addition method at a varied water sample volume, the systematic error was shown to be negligible at a relative standard deviation sr of less than 0.03. The consistency of results obtained by two independent methods was estimated by F- and t-criteria. The results were shown to have a uniform variance by the F-cirterion, and the average results could be summarized by the t-criterion. The developed method excluded the use of toxic and expensive reagents to be competitive by the atomic absorption detection limits: cmin for Cd, Mn, and Zn was found to be 0.002 µg/mL.
  PubDate: 2022-02-01
A Two-Stage Batch System for Phosphate Removal from Wastewater by
Iron-Coated Waste Mussel Shell to Assess the Optimum Adsorbent Dosage
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  Abstract: High amounts of phosphate discharged in receiving water can lead to eutrophication. Once a water body is enriched with phosphate, it can prompt the growth of plants and cause algal blooms. The water body may also lose its important functions and cause adverse effects on the environment and human health. In this study, removal of phosphate from domestic wastewater treatment plant effluent was elucidated using iron-coated waste mussel shell. The phosphate adsorption by iron-coated waste mussel shell was examined with respect to initial phosphateconcentration (7 mg L–1), solution volume (0.2 L), adsorbent dosage (4–20 g), and contact time (1–5 day). The chemical composition of iron-coated waste mussel shell was analyzed using energy dispersive X-ray fluorescence spectrometer. The measurement of the specific surface area of iron-coated waste mussel shell was performed by multiple-point method according to the Brunauer, Emmett, and Teller theory. Several kinetic models (i.e., pseudo-first order and pseudo-second order) and isotherm models (i.e., Freundlich and Langmuir) were used to describe the adsorption behavior. The optimum removal efficiency of phosphate can reach at 95.7% after 120 h with the amount of iron-coated waste mussel shell used to run the experiment was 20 g and the treated effluent phosphate concentration of 0.3 mg L–1, was verified. Experimental data can be well described by pseudo-second order kinetic model (R2 > 0.99) and Freundlich isotherm model (R2 = 0.93), suggesting that chemisorption and multilayer adsorption occurred. Furthermore, a two-stage batch system was proposed to assess the optimum adsorbent dosage for phosphate removal. The two-stage system has contributed to reduce iron-coated waste mussel shell dosage by 56.94%, as compared to one-stage and thus reduced the operating cost of iron-coated waste mussel shell.
  PubDate: 2022-02-01
Potential Risks Assessment of Trihalomethanes in Drinking Water Supply
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  Abstract: Chlorine is widely used in the disinfection process of water supply systems to eliminate pathogens. However, a complication that occurs during the disinfection process is the formation of by-products that include volatile organic compounds such as chloroform and other trihalomethanes. This study is intended to assess the risk of trihalomethanes in tap water. Water samples were taken from end-user tap water near wastewater treatment plants in various locations in Perlis, Malaysia. Following the standard procedure and calculation method proposed by the US EPA, the exposure dose (mg/kg day)) for oral ingestion, dermal absorption and inhalation was calculated. A total of 90 independent data were obtained from the Perlis regions. Risk assessments were calculated and three groups were formed to represent three separate waste water treatment plants. The assessment of cancer risk in the Timah Tasoh area by ingestion routes for dibromochloromethane, bromo-dichloromethane and chloroform was 3.04 × 10–5, 1.73 × 10–4, and 2.67 × 10–5, while for the dermal pathway it was 6.65 × 10–4, 3.97 × 10–4, and 7.19 × 10–5 and inhalation for dibromochloromethane, bromodichloromethane, bromoform and chloroform—1.33 × 10–3, 1.02 × 10–3, 1.38 × 10–3, and 6.32 × 10–5. Another study area, Kuala Sungai Baru, has the lowest trihalomethane content. Obviously, the lowest risk as some of the compounds were found to be below the US EPA limit. The combined risk of cancer in these three study areas for the ingestion method was 1.23 × 10–5, 1.07 × 10–4, and 1.11 × 10–5. The results showed that the carcinogenic risk assessed for chloroform, bromodichloromethane and dibromochloromethane was within the established limit in some areas, but exceeded the acceptable level in other areas of the study. In addition, the greatest risk from trihalomethanes appears to arise from inhalation followed by ingestion and skin contact. This study made the Perlis Exploration Area Warning as a reference point for other nearby areas.
  PubDate: 2021-11-01
  DOI: 10.3103/S1063455X21060060
The Ecotoxicity of Nanoparticles Co2O3 and Fe2O3 on Daphnia magna in
Freshwater
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  Abstract: Despite all advantages of nanoparticles and their widespread utilization, the potential contamination caused by nanoparticles should be considered. They may enter aquatic media and cause the environmental concerns and adverse effects on living organisms, especially the aquatic animals. Iron oxide and cobalt oxide NPs are among the most widely used metal nanoparticles by the useful properties in wastewater treatment, biomedicine, sensors. There is the possibility to enter the environment and cause toxicity and interaction with ecosystem organisms. This study investigates the acute toxicity of iron oxide and cobalt oxide NPs on Daphnia magna which is the source of food chain after phytoplankton in aquatic ecosystems and the biological indicator in bioassay tests. Using OECD method (202), the different concentrations of Fe2O3 and Co2O3 nanoparticles were exposed to D. magna in the periods of 24, 48, 72, and 96 h at the temperature of 20–24°C. LC50 of iron oxide and cobalt oxide NPs were analyzed by Probit method for the determination of D. magna proportion in each solution following 96 h and respectively the following amounts of 163.21 and 121.04 mg L–1 were observed, affected by concentration and time (p < 0.05). According to aquatic hazard classification of USEPA, nanoparticles with LC50 value above 100 mg L–1 have lower acute toxicity for aquatic animals. Still, they may have a more negative impact on ecosystems and aquatic organisms in long run. However, they were less toxic than other nanoparticles, but with a certain trend in different environments and combined with other substances. The results of the study showed the lower rate of toxic effect in nano-iron oxide compared to nano-cobalt oxide in D. magna. Finally, proposed two new values for SAR and SAFE Coefficients.
  PubDate: 2021-11-01
  DOI: 10.3103/S1063455X21060023
Scale Inhibitors for Industrial Circulating Water Systems: A Review
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  Abstract: Presence and deposition of sparingly soluble salts, known as scale, has been one of utmost damaging problems of circulating water. In industry, the scaling phenomenon may cause technical problems such as reduction of heat transfer efficiency in cooling systems and obstruction of pipes. Therefore, adding scale inhibitors that exhibit desired efficiencies to control scale is so important to mitigate adverse effect in water circulation systems because of their high tolerance for cations, such as Ca2+, Mg2+, and their ability to efficiently dissolve the unstable polymorphs of inorganic salts at the early stages of crystallization, thus impairing scaling. This paper reviews the research progress and state-of-the-art developments of scale inhibitors, including natural scale inhibitors and synthetic scale inhibitors. Natural scale inhibitors, including natural organic and plant extract scale inhibitors, are non-toxic, inexpensive, widely used, biodegradable and in line with the characteristics of green chemistry. Synthetic scale inhibitors mainly composed of phosphorous, polycarboxylic acid and polyaspartic acid are widely used due to their excellent performance. Detailed comparison between natural scale inhibitors and synthetic additives alongside future directions towards antiscalant are also discussed. The former are less water-soluble, while the latter require a large dosage, which causes a great burden to the environment. In particular, the need for developing green, efficient, easy preparation, and pollution-free scale inhibitors, studying the interactions between scale inhibitors and metal ions is stressed. It is expected that this paper could offer an insight in deeper understanding the scale inhibitors in industry and provide some clues for exploring more advanced scale inhibitors technologies.
  PubDate: 2021-11-01
  DOI: 10.3103/S1063455X21060102
Elimination of Petroleum Contaminants Simultaneously by Pseudomonas
aeruginosa and Cladophora glomerata in the Caspian Sea Coastline Waters
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  Abstract: Extensive use of petroleum has caused many habitats to be contaminated in sea worldwide. Oil pollution impacts the environment and poses a direct or indirect health treats to different forms of life. In order to reduce the dangers and threats of these pollutions, it is important to choose a suitable method for purification and removal of petroleum compounds. There is an urgent need to clean up the waters with environmentally friendly and inexpensive methods. This study investigated the biodegradation of total petroleum hydrocarbons (TPH) using simultaneously Pseudomonas aeruginosa and Cladophora glomerata in southern Caspian Sea coastline. Coastline sediment samples were collected, with P. aeruginosa being the predominant strain. Afterwards gathered purified algae were placed in a lattice basket. Then bacteria and algae were cultured in triplicates in the presence of gasoline concentrations and under specific experimental conditions of varying temperature, pH, salinity, dissolved oxygen and incubation periods in aquariums of sea water. The data representing the gasoline biodegradation in the samples were statistically analyzed. In containing varying concentrations of gasoline and optimized experimental conditions for temperature, pH, salinity, dissolved oxygen and incubation period, maximum biodegradation of TPH was achieved by culturing P. aeruginosa strains and C. glomerata with the sea water samples of gasoline. Based on the results of statistical analysis the gram-negative bacteria, P. aeruginosa and the green algae C. glomerata almost completely biodegraded TPH contaminants from the samples’ culture media it was able to decompose almost 95% of crude oil over 28 days of incubation. It is concluded that the use of P. aeruginosa and C. glomerata together is an efficient method for the biodegradation of Caspian coastal waters contaminated with TPH.
  PubDate: 2021-11-01
  DOI: 10.3103/S1063455X21060072
A Novel Explanation for the Arrangement of the Universe–Solar
System–Planets–Earth. Part 3
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  Abstract: Abstract New ideas are presented about the nature of the evolution of the Universe, which call for a deeper scientific understanding and reassessment of the existing views on the so-called Big Bang cosmological model. According to this model, the Universe has now been expanding for ~20 Ga, with the lightest elements forming during the first few seconds at T ~ 109 K as a result of nuclear fusion. These elements are H, D, and 3,4He; at first, hydrogen turns into helium, and then helium transforms into carbon, oxygen, nitrogen, etc., up to iron group elements. The probability is examined of the action of attraction forces due to electromagnetic interaction of rotating charged baryonic particles, instead of the classical Newton theory of gravitation, i.e., the law describing gravitational interaction in classical mechanics. A discussion is provided of the nature and role of black holes in the Universe, which are seen as an integral and obligatory part of all physical structures of the Cosmos. So far, no theory has been able to fully describe the internal structure of black holes; however, as follows from the Planck and Boltzmann laws, these holes are a perpetuum mobile of evolution for the entire Universe, controlling the transformation mechanism through electromagnetic resonance oscillations of the entire cosmic ether (like the human brain), which propagate across all structures of the Universe. Space objects are Earth-like planets with a solid core, liquid mantle, and a hard crust, above which the atmosphere immediately begins; gas giants with no solid surface (a substantial part of them is the atmosphere, which at low altitudes turns into a liquid due to increased pressure, while there is no clear boundary between the liquid ocean and the atmosphere); and stars, all of which have a solid core and poles synchronized with black holes. Although our conceptions about the existence of dark matter and dark energy in the Universe still remain the most mysterious ones, we argue that the bulk of matter and energy is concentrated in cosmic–plasma electromagnetic fields (>95%). All stars and planets must be increasing in volume with time while retaining their angular momentum and position in space. Both space and time are equivalent to each other and are the most uncertain and multivector universal functions of the Universe. They change simultaneously and proportionally with the form of existence of matter, which inevitably leads to the emergence of a fundamentally new quality—life. Living beings evolve and acquire spirituality, i.e., the ability to cognize not only themselves but the surrounding world. However, space–time is an extremely complex system, yet to be understood by new generations of scientists: physicists, cosmologists, and others.
  PubDate: 2021-11-01
  DOI: 10.3103/S1063455X21060035
Polyvinylpyrrolidone/Single-Walled Carbon Nanotubes Incorporated Polyhipe
Monoliths Followed by HPLC for Determination of Tetracycline Antibiotics
in Water Samples
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  Abstract: In this work, a porous polyvinylpyrrolidone/single-walled carbon nanotube incorporated polymerized high internal phase emulsion (PVP/SWCNT-polyHIPE) monolithic column was fabricated and developed as a solid phase extraction (SPE) adsorbent coupled with high performance liquid chromatography-fluorescence detection (SPE-HPLC-FLD) for the determination of tetracycline (TC), oxytetracycline (OTC), chlorotetracycline (CTC), and doxycycline (DC) in environmental water samples. The proposed monolithic sorbent was easily produced by in-situ polymerizing of high internal phase emulsions (HIPEs), and performed high extraction ability to the four tetracycline antibiotics (TCs). The extraction conditions including sample pH, sample flow rate, sample volume, desorption solvent and its volume were studied by investigating the recoveries of the four TCs, and the optimal extraction conditions were obtained. Under the optimized conditions, the PVP/SWCNT-polyHIPE based SPE-HPLC-FLD method exhibited good linearity in the range of 20–800 ng/mL for four tetracycline antibiotics with correlation coefficients higher than 0.9996. For water samples, the detection limits (LODs, S/N = 3) ranged from 1.0–2.5 ng mL−1 for four tetracycline antibiotics. The intra-day (n = 15) and inter-day (n = 5) precisions (expressed in terms of relative standard deviation (RSD %) were in the range of 0.5–2.2 and 1.3–5.7%, respectively. The spiked recoveries were in the range of 85.0–101.7 % with RSDs lower than 4.0%. Furthermore, the prepared polyHIPE monoliths allowed more than 100 extraction cycles without any loss in the extraction efficiency. The developed method enables us to detect trace tetracycline antibiotics in water samples. The method can be useful in the extraction and determination of antibiotics in all kinds of environmental water samples.
  PubDate: 2021-11-01
  DOI: 10.3103/S1063455X21060114
Disinfection of Swimming Pool Water by UV Irradiation and Ozonation
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  Abstract: The paper discusses the current trends in water disinfection technologies in the operation of swimming pools. Organic substances added to water by personnel or users, when interacting with a disinfectant, are transformed into disinfection by-products (DBPs), the toxicity of which is often unknown. Oxidative technologies are helpful to disinfect water, decrease the concentration of DBPs, and remove already formed compounds. Among the existing methods of water disinfection in swimming pools, the most effective methods are ultraviolet (UV) irradiation in combination with the technology of oxidation of organic compounds. This approach not only comprehensively disinfects the water in the pool but also limits the appearance of disinfection. In this work, we used ultraviolet disinfection of water together with ozonation. The UV dose was measured using a Tensor-31 radiometer. Colony-forming bacteria were controlled according to the requirements of SanPIN 2.1.2.1183-03. The experimental results showed that disinfection of water in the pool using prefiltration and UV irradiation does ensure inactivation of microorganisms, since the total microbial count and total coliforms CFU/cm3 exceed the permissible limits after 48 h. We developed an effective technology for disinfecting water in swimming pools, including an installation of combined action of UV irradiation and ozonation implemented by low-pressure lamps. The installation ensures the necessary irradiance of water at a level of >250 W/m2 and additional ozonation with a dose of ~0.1 g of introduced ozone per 1 m3 of water. Additional ozonation keeps the total microbial number below 24 CFU/cm3, and the residual ozone concentration in water did not exceed 0.015 mg/dm3. For a 75-m3 pool, two installations with a capacity of 8 m3/h ensure the bacteriological purity of water, yielding an irradiance of >250 W/m2 and injecting 0.1 g/m3 of ozone. The concentration of ozone in water does not exceed 0.015 mg/dm3.
  PubDate: 2021-11-01
  DOI: 10.3103/S1063455X21060084
Influence of PDS Loading Upon Type CD1–xZNxS Photocatalysts
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  Abstract: In the last years, up to 90% of global energy demand for industrial and transportation sectors are supplied with fossil fuels, causing a high emission of greenhouse gases, including carbon dioxide and leading to a substantial depletion of carbon-based resources. A potential fuel for renewable energy is considered to be the hydrogen, besides to use of renewable energy based on solar, wind, geothermal and biomass. Up to now, CdS is the most important semiconductors with the 2.4 eV direct band gap that corresponds well with the maximum irradiation in the solar spectrum, and also has the advantage of a more negative conduction band edge compared to the H+/H2 redox potential. In this paper, we reported the synthesis of Zn2+ doped CdS with polymorphic crystallization using hydrothermal method at low temperature, without organic precursor used for water splitting. The products were characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy and UV-visible diffuse reflectance spectra. From Tauc plot the optical energy gap for undoped CdS was found to be nearly to 2.28 eV and increase to 2.44 eV for Cd0.5Zn0.5S. From photoluminescence spectroscopy measurements showthe two broad emission peaks located at ~535 and ~595 nm which is high for samples Cd0.8Zn0.2S and Cd0.8Zn0.5S compared with samples CdS, Cd0.7Zn0.3S and Cd0.6Zn0.4S. The PL peaks indicates defects, however, the increment in the photoluminescence spectroscopy intensity indicates the higher amount of defects. The higher amount of defects and vacancies present in samples Cd0.8Zn0.2S and Cd0.8Zn0.5S is beneficial for the H2 production rates. The H2 production after 12 h of Cd1–xZnxS samples is 204 (μmol for undoped CdS and increase to 277 μmol for Cd0.6Zn0.4S and 384 μmol for Cd0.5Zn0.5S respectively. The effect of PdS on the photocatalytic properties of Zn2+ doped CdS was investigated for hydrogen evolution under visible light from water containing Na2S and Na2SO3 as sacrificial reagents. To our knowledge, the effect of PdS on the photoactivity of Zn2+ doped CdS with polymorphic crystallization has not been reported before.
  PubDate: 2021-11-01
  DOI: 10.3103/S1063455X22010106
Synthesis of Clay-Based Adsorptive Microfiltration Membranes
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  Abstract: Chromium is one of the most hazardous inorganic water pollutants which is constantly released into water resources by natural and industrial processes. Microfiltration membranes (with pore sizes between 0.1–10 μm) cannot separate chromium ions and hence nanofiltration membranes (with pore sizes between 0.5–2 nm) are necessary which need high pressure pumps. Using adsorptive membranes, i.e. membranes which can adsorb impurities without using any extra adsorptive particles, is a new and developing method for water treatment which can be considered as a combination of adsorption and membrane technology. In this paper, clay-based adsorptive microfiltration membranes were successfully synthesized for chromium removal from water. 80 wt % of bentonite and 20 wt % of carbonates (calcium, magnesium and their mixture) were mixed, uniaxially pressed, dried, and fired at 1100°C for 3 h. Then, phase analyses of the samples, their physical and mechanical properties, microstructure, mean pore size and also their ability for chromium removal from water were studied. Results showed that the addition of carbonates lead the porosity to increase while contrary to organic pore formers like starch, due to the formation of phases like wollastonite, the mechanical strength not only didn’t collapse but also improved. It was seen that Cr3+ ions were removed from water up to 95% and regarding that the mean pore sizes of the microfiltration membranes used in this work (0.6–2.5 μm) were 10 000 times bigger than the size of Cr3+ ions (0.615 A), it was deduced that Cr3+ ions were removed through adsorption mechanism and the microfiltration membrane prepared the media for adsorption. By analyzing the filtered water and observation of Ca2+ ions in it, it was concluded that ion exchange was the main mechanism. Hence, a combination of membrane filtration and adsorption was achieved for water treatment which made microfiltration membranes act as nanofiltration ones and considering that the concentration of Cr3+ ions in real drinking water resources is less than 5 ppm (which is regarded in this research), it can be said that these low-cost adsorptive microfiltration membranes can be used to gain high quality drinking water.
  PubDate: 2021-11-01
  DOI: 10.3103/S1063455X21060047
Mass Balance Study on Domestic Wastewater Treatment Using Constructed
Wetlands
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  Abstract: Mass Balance is the application of conservation of mass to the analysis of physical systems by accounting for material entering and leaving the system. For this analysis mass can be flows and identified which might have been known through this technique. A mass balance study was conducted to know about the soil, plant and water relationship in the CW unit. The mass balance calculations comprised water and nutrient budget calculations to show the percentage distribution of water and nutrients such as N, P and K in constructed wetland. The distribution of water from the constructed wetland unit was observed to be contributed by evapotranspiration, outflow from the wetland and storage in soil with 1.78; 62.61 and 35.61% respectively. The reduction percentage of nutrient content (macro elements like nitrogen, phosphorous and potassium) present in domestic wastewater after treatment using constructed wetlands was observed to be 53% (total nitrogen) and out of this, 32% reduction is due to plant uptake (Phragmites australis) and 6% absorption is contributed by soil. For phosphorous, the results obtained from the analysis showed 52.6% soil accumulation and 49% plant uptake. For potassium 4% plant uptake and 46.9% soil accumulation was observed respectively. The pH in the range around 7.1 to 7.8 and so the contribution of ammonia volatilization low is observed. The water distribution in the CW unit was contributed by Input and output. Input in the unit comprised precipitation and wastewater inflow which contributes 2.6 and 97.39% respectively and the output comprised evapotranspiration and outflow of treated water from the wetland unit which contributes 1.78 and 62.61% respectively. 35.61% of water was observed to be stored in the soil of the constructed wetland unit.
  PubDate: 2021-11-01
  DOI: 10.3103/S1063455X21060096
Peculiarities of Preparation of Drinking Water from Surface Sources with
High Contents of Natural Organic Compounds, Iron, and Manganese
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  Abstract: The peculiarities of the Dnieper river water that contains natural organic compounds of allochthonous origin, in the composition of which fulvic acids with a molecular mass of about 1.0 kDa predominate, are investigated. It is established that the use of iron-containing coagulants in the process of purification of such water leads to its enrichment with iron compounds and a corresponding increase in its color intensity. Comparison of the effectiveness of aluminum and iron coagulants showed that both reagents lead to a stable decrease in Dnieper water coloration caused by humic acids. However, the use of iron(II) sulfate does not reduce water coloration caused by fulvic acids because of the formation of stable soluble hydroxofulvate complexes. It is shown that the redox system of Dnieper water is at the transition boundaries between Fe2+ and hydroxide Fe(OH)3 and between Mn2+ and oxides MnO2 and Mn2O3. The replacement of the standard chlorine agent with chlorine dioxide results in moving this boundary with the formation of finely dispersed flakes of iron hydroxide and particles of manganese oxides. As a result, the use of chlorine dioxide (ClO2) in doses of 0.2–1.25 mg/dm3 in the final stage of water purification leads to an increase in water coloration intensity, which can be successfully reduced by filtration. With an increase in the dose of ClO2, an inverse relationship is established between the dynamics of water colorarion intensity growth and the decrease in the Mn content during filtration. The correlation coefficient between these factors is r = –1, which indicates that the presence of manganese is the main factor for increasing the color intensity upon the treatment of water with chlorine dioxide in the summer season. On the basis of the obtained results, a flexible scheme is proposed for chlorine dioxide supply with the following stages: primary treatment at the entrance to water treatment facilites, secondary treatment after coagulation and settling of water before fast filtration, and final disinfection before supplying drinking water to the city.
  PubDate: 2021-11-01
  DOI: 10.3103/S1063455X21060059