Journal of Water Chemistry and Technology最新文献

Industrial effluents have caused water bodies to suffer from accumulation of heavy metals such as cadmium (Cd), lead (Pb), and mercury (Hg). This study focuses on determination of the potential use of mycofiltration in the removal of heavy metals, the effect of contact time, and the efficiency of mushroom species in mycofiltration from an artificial wet pond. In search of effective biosorbents, mycofilters were developed by adding spawns of P. ostreatus and A. bisporus, which were left for incubation and then installed in synthetic ponds for a certain period. Thereafter, mushrooms were harvested, post treated and their biosorption rate was analyzed through atomic absorption spectrophotometer. Significant differences were evaluated in the biosorption rate of mycofilters of P. ostreatus and A. bisporus. A dependent relationship was also established between biosorption and the temperature, namely, an increase in biosorption with an increase in temperature. The comparison of all results for the two species revealed that P. ostreatus showed superiority in the biosorption capacity for Pb 9–189 mg g^–1 and Cd 1–21.4 mg g^–1 over A. bisporus. However, A. bisporus has shown significant results in the case of Hg 0.6–10 mg g^–1 absorption. Overall, in this study, P. ostreatus demonstrated the highest range in biosorption efficiency for metals Pb 99–100% and Cd 97–100% as compared to A. bisporus. At the same time, A. bisporus showed a slightly higher level of removal efficiency in the case of Hg 85–100%. Considering these findings, industrialists may use this cheap and ecofriendly treatment technology for the uptake of heavy metals.

Seasonal and long-term changes in the quality parameters of water delivered to the Dnipro Water Supply Station (DWSS) in Kyiv after the Kyiv Reservoir were considered. The range of measured parameters covered the following periods: 1950–1962 until the creation of the Kyiv Reservoir, 1996–2006, and 2012–2022 after its creation. Water quality monitoring was performed by both the standard integral parameters (chromaticity, permanganate and bichromate oxidability, biological oxygen demand, and total organic carbon) and the ratios between them. The statistical analysis and graphic interpretation of data were carried out by Microsoft Excel tools. The correlations between the factors were estimated with the use of Pearson correlation coefficients r. Based on the determined correlations, the quality of water in the water reservoir and at the inlet to the DWSS water treatment facilities in Kiev was balanced between allochthonous and autochthonous sources of organic substances. The changes in water quality characteristics were noticed to be cyclic and correlate in a certain way with solar activity. The consideration for solar activity cycles provides a basis for predicting the Dnipro water quality and should facilitate the technological and logistic support of operation for the water treatment station in coming years.

Environmental pollution is a major global problem, which involves the pollution of food and drinking water, and the assessment of pollution levels is vital for the health of the community. The most significant part of this assessment is to determine the involvement of unintentional contamination (agricultural pesticides) and deliberate biological attacks of drinking water. The aim of this study was to detect water and food toxin contamination using Vibrio persian Bioluminescence Inhibition Assay (VPBIA) by optimizing the culture medium condition. To this end, the optimization of the growth and bioluminescence emission of the bacteria was carried out in four media cultures: photobacterium, Luria-Bertani (LB), and two seawater mediums (SWC#1, SWC#2). After determining SWC#1 as an optimum culture medium and optimizing the growth and emission of bioluminescence using response surface methodology (RSM), three factors (temperature variation, pH, and incubation time) were considered. The experimental design results indicated that the best conditions for the growth and distribution of the bacteria bioluminescence are pH 8.5, 20°C, and an incubation time of 20 h. Finally, the bioluminescent inhibitory bioassays for two food and water toxin (Staphylococcal enterotoxin B (SEB) and cholera toxin) were performed. The results show that cholera toxin had the most effect on V. persian light emissions. This new method could be used for the development of warning devices in order to detect water and food contamination.

The study illustrates the use of polyelectrolyte multilayer (PEM) membranes prepared with weak/strong polyelectrolyte combination of poly(ethyleneimine)/chondroitin sulfate A (PEI/CS) for the removal of metolachlor (MTR) from water samples. The proposed PEM membranes were characterized by chemical, physical, thermal, and morphological properties. The removal of MTR herbicide by PEI/CS multilayer deposited on a microfiltration polyamide membrane was found to be efficient with a retention rate of about 96.46% for 8 bilayers sat an excellent permeate flux of 6.27 m³/m² day. The photodegradation of metolachlor which got trapped in PEMs in the presence of riboflavin (Rb) sensitizer was investigated at various concentrations. A comparative study on photo-elimination of MTR without the presence of Rb was also done. The degradation time was greatly shortened from more than 1 h for direct photolysis to 5–15 min depending on the initial concentration of the sensitizer. The degradation of metolachlor in the presence of Rb as well as direct photolysis was also experimentally studied.

In this study, the eutrophication status of the Berdan and Göksu River Basins was determined by using recently obtained data between September 2021 and August 2022. Very high total phosphorus and trophic index (TRIX) values indicated that all stations visited in the Berdan, and Göksu River Basins were characterized as eutrophic (bad). The correlations between TRIX and eutrophication-related parameters showed strong and positive relations between TRIX and concentrations of Chlorophyll-a and total phosphorus strongly suggesting that the increase in total phosphorus concentrations highly enhanced primary productivity and eutrophication. The P-enrichment in the Berdan and Göksu River Basins caused eutrophication in these river waters, leading to the further development of coastal eutrophication in the P-limited Northeastern Mediterranean shelf waters.

The photocatalytic destruction of organic substances is an efficient method for the production of high-quality purified water for various applications. For photocatalytic purposes, titania is most widely studied due to its low cost, availability, untoxicity, and stable chemical structure. The combined application of a photocatalyst and hydrogen peroxide increases the degree of ecotoxicants destruction to CO₂, H₂O, and inorganic ions (mineralization) and shortens the reaction time to decrease the water treatment expenditures. Photocatalytic destruction kinetics was studied for a non-ionic surfactant, namely, octylphenol ethoxylate (Triton X-100) with hydrogen peroxide in an aqueous medium in reactors with immobilized TiO₂. The conditions for achieving a high degree of mineralization of Triton X-100 (84–88% for 4–5 h at C₀ = 50 mg/dm³) were established in the H₂O₂/TiO₂/UV (λ = 254 nm) system in a reactor with TiO₂ immobilized on a large-pore ceramic support alongside with its essential advantages as compared to the TiO₂/UV system, where the maximum degree of mineralization of Triton X-100 was 2.5 times lower. The possibility of attaining a high degree of mineralization with hydrogen peroxide for Triton X-100 (up to 92% on TOC basis of 2 h) was demonstrated in a quartz reactor with a Degussa P-25 TiO₂ film on its inner surface at the external irradiation mode (λ = 254 nm) without additional TiO₂ powder.

Liquid water is thought by many to be composed of a quasi-stable mixture of clusters that range in size from dimers to several hundred molecules and even to micrometer-size units [1–3]. The implications of such a three-dimensional structure, or whether it even exists, are often subject to debate. While many treatments (temperature change, shaking, electro-magnetic radiation, etc.) alter the physical-chemical properties of water, just how these interventions may affect the assemblage of clusters is often a matter of conjecture. The object of this study is to relate the effect of a weak, spinning, magnetic field to the assemblage of water clusters, and the subsequent changes in the chemical reactivity of bulk water. The results show that such a weak, rotating, magnetic field applied to water can either increase or decrease the spontaneous net rate of hydration of CO₂, depending on the direction of spin of the magnet and the history of a given water sample. The targets for a magnetic field applied in this way are chiral water clusters and their destruction, or the inter/intra-conversion of enantiomers, can change the reactivity of water. The conclusion is that samples of distilled water, under otherwise identical conditions, can have a range of chemical reactivities depending on their individual assemblage of clusters.

The role of bivalve molluscs in the biological treatment of polluted natural waters is considered. The anatomical structure and tissue composition of these hydrobionts enabling the effective filtration and purification of water from suspended pollutants are given. It is shown that molluscs simultaneously create a biogenic water circulation that mixes water masses. Water absorption and circulation within the mantle cavity provides bivalve molluscs with oxygen and food necessary for respiration, which has a substantial effect on the biogenic migration of chemical elements in aquatic ecosystems. These circumstances make it possible to design special bioreactors that can be used, together with other hydrobionts, such as algae and bacteria, for biological treatment of natural reservoirs polluted by sewage. A plan has been drawn up to conduct experiments to study the rate of filtration and purification of contaminated water by bivalve mollusks. In this regard, the use of a bioreactor with bivalve molluscs in drinking water purification systems at the first stage of water treatment is worthy of attention.

Heavy metals (HM) are among the most dangerous inorganic ecotoxicants that can have a mutagenic and toxic effect on all objects of the biosphere. Ingressing a living organism, heavy metals can accumulate in various tissues and organs, causing their dysfunction. Therefore, water contamination with heavy metals is among the most urgent problems of environmental safety in both our country and the whole world, and the development of modern, efficient, and cost-effective methods for purifying contaminated water from heavy metals is an essential and urgent task today. Baromembrane separation in combination with other physical and chemical processes is one of the effective methods for extracting heavy metal ions from contaminated waters. In this work, we studied the possibility of using an anionic surfactant sodium dodecyl sulfate (NaSDS) and nonionic polyethylene glycol tert-octylphenyl ether (Triton X-100) to purify contaminated waters from Co(II) by ultrafiltration. The main characteristics of the baromembrane process were determined: the retention factors of the ions of the tested metal and the volumetric flow rate through the polymeric ultrafiltration membrane. Ultrafiltration in combination with the use of surfactants is effective for water purification from heavy metal ions or radionuclides, as demonstrated by an example of Co(II). The process should be performed at concentrations of surfactants near the critical micelle concentration for optimal results.

We proposed to evaluate the performance of new adsorption materials in relation to existing commercial products by comparing the values of the standard molar adsorption energy of (Delta G_{{text{a}}}^{^circ }) of adsorbates. A typical error in the determination of (Delta G_{{text{a}}}^{^circ }) is due to the incorrect calculation of the adsorption equilibrium constant K_e. It is often calculated in isothermal regions that do not correspond to standard adsorption conditions, or the dimensional constant of the Langmuir model equation K_L is falsely used as a thermodynamic constant. The direct use of the Langmuir constant K_L as an equilibrium constant is a thermodynamically invalid approach; however, due to the simplicity of determining K_L, an estimate of the adsorption energy based on it can become an accessible and useful tool for adsorption studies. In this work, we examined two methods to transform the Langmuir constant into surrogate constants, which, according to formal features, are dimensionless quantities and reflect the conditional energy of adsorption. We selected 16 adsorption systems of activated carbon (F300, KAU, KAU/Fe, Akant) with aqueous solutions of sparingly soluble aromatic compounds of the phenol and aniline series. We compared the adsorption energy values obtained from the Langmuir constant and the thermodynamically verified constant of the partial adsorption isotherm, calculated by the procedure developed by A.M. Koganovskii (the Koganovskii method, KM). The deviations of the adsorption energy values calculated from the Langmuir constant are on average 10–15% compared to the results obtained by the Koganovskii method. To plot the adsorption isotherms of aromatic compounds, a simplified algorithm for calculating K_e according to the KM was proposed and tested (without considering the volume of the adsorption phase and the molar volume of adsorbents). Deviations in energy values were within 5% of the KM results. Thus, the considered simplified methods are easy to implement and accurate enough to estimate the standard adsorption energy; therefore, they can be recommended for the initial assessment of the effectiveness of new adsorption materials.