Journal of Water Chemistry and Technology最新文献

The diffusion of o-chlorotoluene (OCT), a hydrophobic organic compound, solubilized by means of the Triton X-100 surfactant from the region of local contamination into adjacent pure layers has been experimentally studied in a model kaolin based dispersion. The study is aimed at clarifying the factors influencing the motion of impurities in a dispersion medium with and without an electrical field. The theoretical analysis of obtained experimental data makes it possible to establish the effective diffusion coefficients of formed OCT/surfactant complexes in the pore space, which demonstrate the acceleration of the spread of contamination due to the influence of an electrical field. It has been shown that the diffusion coefficients of these complexes grow due to electroosmosis and hydrodynamic flows induced by it. Electroosmosis along negatively charged kaolin particles promotes the transport of impurities towards the cathode. At the same time, local narrowing of pores with a closed experimental cell leads to the pore solution hydrodynamic flows, which transport the impurities in the direction opposite to electroosmosis. Hence, due to a complicated interparticle space configuration, the electrical field actually results in pore solution mixing, which affects the character of the diffusion flows of impurities. Mixing may also be additionally intensified due to the heterogeneous charge of kaolin particles, which causes local changes in the direction of electroosmosis. At the same time, not only the fact of mixing as such is important, but also its specific features caused by different characters of electroosmotic and hydrodynamic flows and, correspondingly, by an sharp change in the direction of liquid flow near the surface of kaolin particles. As a consequence, the desorption of OCT/surfactant complexes from the surface of particles into the pore solution should be intensified and, correspondingly, the efficiency of their removal from the disperse systems should increase.

A new method for the determination of ultra-trace cobalt by ionic liquid-dispersive liquid-liquid microextraction (IL-DLLME) and graphite furnace atomic absorption spectrometry (GFAAS) was developed. The trace cobalt was extracted by DLLME using the homemade reagent 2-(5-bromo-2-pyridylazo)-5-dimethylaminobenzenamine (5-Br-PADMA) as chelating agent, the ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate ([C₆mim][PF₆]) as extractant, and acetonitrile (CH₃CN) as dispersing agent, and then determined by GFAAS. The factors affecting the cobalt extraction efficiency: the type and volume of extraction solvent and dispersive solvent, the concentration and dosage of chelating agent, and the pH of the solution, were explored using the one-way rotation method. Under the optimized conditions, the cobalt concentration showed excellent linearity in the range of 0.05–1.50 ng/mL with the detection limit of 0.026 ng/mL; the relative standard deviation (RSD) for the determination of the cobalt standard solution with the mass concentration of 1.0 ng/mL was 4.83% (n = 9). From the slope of the linear regression equation for the determination of cobalt obtained after extraction compared with that before extraction, the enrichment factor of the method was found to be 62, and the spiked recoveries were in the range of 94.0–104.4%. The method is characterized by low detection limit, high sensitivity, and environment friendliness as well as convenient and rapid operation for the determination of trace cobalt in water samples. The results of this method are satisfactory.

This study aims to investigate the effect of different seasons (where the temperature would be different) on the performance (phosphorous, nitrogen, and organic matter removal) of sequencing batch reactor (SBR) based wastewater treatment plants. The modified activated sludge model 2D (ASM2d) module, including the microbial kinetics is used to simulate the enhanced biological phosphorus removal (EBPR) SBR process and the temperature is chosen between 10 and 33°C. Influent data from two distinct wastewater treatment plants located in India and Europe are considered. The investigation of the kinetic variables is performed over a wide temperature range, and significant increases are seen as the temperature rises. The effluent parameters are within the government regulations. It is clear that an increase in temperature results in better effluent quality with reduced values of chemical oxygen demand (COD), biological oxygen demand (BOD), ammonium nitrogen and ammonium ions (NH₄), and total nitrogen (TN) and a slight increase in total phosphorus (TP) and total suspended solids (TSS). According to the current findings, as the temperature changes from low to high levels, the values of COD, BOD, TN, and NH₄ decreased by 2.50, 14.92, 5.80, and 9.90% respectively, for Indian data. There is a slight increase of 1.07% in the TSS profile. In conclusion, this study highlights the importance of considering the effect of different climatic conditions on the performance of SBR-based wastewater treatment plants.

Incorporating nano phase change materials (NPCMs) into the basin material helps improve the productivity and the evaporation rate in a solar still. Setting heat extraction rate as a standard, a comparative study was made with the yield of a single basin solar still by a phase change material (PCM) and NPCM. To counteract the low thermal conductivity of paraffin wax, metallic nanoparticles of cobalt oxide (CoO) were added. These CoO nanoparticles were found to be attractive for mixing with PCM to increase thermal conductivity. The impact of heat flux, flow rate and metal oxide particles on the flow and heat transfer behaviour of slurries was investigated. The X-ray diffraction (XRD) analysis showed the predominant peak (200) of CoO at 42.3°, with an average CoO nanoparticle size of 6 nm. The FESEM analysis revealed homogeneously aggregated spherical/platelet-shaped CoO nanoparticles ranging within 5–30 nm in size. Solar radiation increases linearly with time, reaching its maximum between 12:00 and 2:00 p.m. The use of NPCM increases the efficiency (12–25%) of the basin material due to its thermal properties and also the water output with an average yield rate of 3.5 L. Finally, the results indicate that the incorporation of CoO nanoparticles into paraffin wax increases the performance of the solar still and improves the water quality parameters.

In this study, a series of organic amine-intercalated α-ZrP were prepared. The crystal phase, structures and properties of these intercalated compounds were analyzed and characterized using several analysis methods. The interlayer distance of organic amine-intercalated α-ZrP has increased regularly along with the increase of chain elongation of organic amine. The composites were applied to adsorb phenol from wastewater. The adsorption equilibrium, kinetics, and dynamic adsorption of phenol onto intercalated α-ZrP were studied. Adsorption isotherms of phenol were determined at different temperatures, and they were well fitted to the Freundlich equation (R² > 0.99), and the corresponding maximum adsorption capacity of phenol was 0.832 mmol/g. Batch kinetic experiments revealed that the adsorption process followed a quasi-second-order kinetic model. The dynamic adsorption revealed that the adsorption capacity for phenol increased with the increase in temperature. The adsorption process was rapid and equilibrium was reached within 30 min. When the adsorption dosage is 0.1 g/15 mL, the adsorption yield for 10 mmol/L phenol solution can reach 61.2%.

The synergy effect between adsorption and solar photocatalysis to remove Cr(VI) is a new approach which is environmentally friendly and sustainable development technology. The choice of photocatalyst is crucial for achieving better performance in adsorption and photocatalytic reactions. The CuFe₂O₄ catalysts with a spinel structure were synthesized by co-precipitation and sol-gel methods, and characterized by X-ray diffraction, BET surface area, Scanning electron microscopy, Raman and Fourier-transform infrared spectroscopy (FTIR). The results of this study show that the CuFe₂O₄-co is an excellent adsorbent and photocatalyst simultaneously for Cr(VI) removal, this activity is correlated to its structural, and textural properties and a relatively narrow band gap. The catalyst is mainly crystallized in cubic inverse spinel structure and exhibits a large pore size that facilitates the accessibility of active sites by chromium ions on the surface, which can also improve absorbed light penetration. Moreover, the UV-Vis diffuse reflectance spectrum shows that the catalyst has a low band gap energy (1.2 eV), allowing a broader absorption spectrum, which enhances its capability to generate electron−hole pairs under visible light of solar irradiation. The effects of oxalic acid as a reducing agent, preparation technique, catalyst concentration, and initial dose of Cr(VI) were studied in this research. 100% reduction of Cr(VI) to Cr(III) is achieved within 1 h in the presence of small quantities of oxalic acid to maintain the рН 3 at an optimal concentration of catalyst (0.25 g/L).

Due to the rapid growth of industries, and population the water shortage has become a global problem. The most hazardous organic contaminants found in textile wastewater are dyes. There are several techniques for removing dyes from wastewater, but the majority of them are costly and time-consuming. The most practiced technique for removing dyes is adsorption. Carbon nanotubes (CNTs) are employed extensively in the water treatment industry because of their superior mechanical strength, high aspect ratio, toughness, and defined cylindrical hollow structure. The hydrophobic wall and cost of CNTs restrict their usage on a commercial scale, however, this problem has been partially alleviated by altering their surfaces or doping with other metal oxides. The effect of surface alteration, on the adsorption potential, characterization, and removal effectiveness of CNTs are discussed in detail. The market value and overall demand for CNTs are thoroughly explored. The process variables influencing the sorption mechanism and removal efficiencies such as adsorbent dose, pH, contact time, and temperature are discussed in detail. The economic viability of CNTs is checked by the desorption and reusability of adsorbents. The literature supports the claim that surface modification significantly increased adsorption capacity and removal efficiency. However, more research should be needed to explore non-toxic modifiers for improved surface activation.

The aim of this study is to explore the primary factors influencing water quality in Wadi Guebli (Northeastern Algeria) and evaluate its suitability for irrigation by employing a combination of hydrochemical examination and multivariate statistical methods. Throughout the year 2023, water samples were collected from seven sampling locations and analysed for sulfate ⁽({text{SO}}_{4}^{{2 - }})), sodium (Na^+), potassium (K⁺), calcium (Ca²⁺), bicarbonate (({text{HCO}}_{3}^{ - })), chloride (Cl^–) and magnesium (Mg²⁺) ions. The hydrochemical properties of water samples were determined using the Piper diagram, with the K⁺-({text{HCO}}_{3}^{ - }) water type being the dominant facies. Magnesium ratio (MR), Kelly index (KI), sodium absorption ratio (SAR), sodium percentage (Na⁺%), residual sodium carbonate (RSC) and permeability index (PI) values were employed to assess the suitability of the water for irrigation purposes. Calculated values of these parameters show that the Wadi Guebli waters present a danger for irrigation.

Mineral exchange is a crucial factor for all functions within the organisms of living beings. Chemical elements are integral components of cellular structures, organs, and tissues, as well as the blood and lymph. Together with water, they maintain osmotic pressure, support acid–base balance, and participate in various metabolic reactions within the body. Calcium and magnesium ions are also involved in metabolic interactions. The absorption of calcium by the organism requires magnesium, with magnesium reserves being drawn from various organs and tissues. Therefore, the ratio of calcium-to-magnesium ion concentrations in water is of significant importance. In this study, the results of a chronic experiment demonstrated that desalinated water, devoid of macroelements, affected the vitality of the organisms, even when the test crustaceans were fed. According to experimental data, the maximum survival duration of the experimental group of crustaceans was observed in a water environment with a calcium-to-magnesium ion ratio of 4 : 1. Given the nontoxicity of the water environment, it can be concluded that at such a ratio of these elements, metabolic processes within the organism operate optimally, thereby prolonging the lifespan of the test organisms.

The present research aims to investigate the biosorption capacity of microbial biomass supported onto granular pozzolana toward Chlortetracycline hydrochloride (CTC). Biosorption studies were carried out in a discontinuous system and various experimental conditions that may affect the biosorption process were evaluated including particle size of the support, the speed of agitation, the mass of the support, contact time, initial pH of the solution, and the initial concentration of CTC. At 25°C, the optimum conditions for maximum removal of CTC by immobilized microbial cells were as follows: grain size of pozzolana was between 4 and 5 mm, a stirring speed (SS) was 160 rpm, pozzolana masse was 45 g, initial pH was 7.44, the initial CTC concentration was 40 mg/L, and the equilibrium time was 5 h. Under the optimal process parameters, a maximum CTC removal rate of 93.76% was obtained. Langmuir, Freundlich and Temkin models have been applied to describe isothermal equilibrium studies of biosorption. The Freundlich model was well-fitted with the equilibrium data (R² = 0.99). The isotherm behaviour indicated that the biosorbent surface was heterogeneous, and the biosorption capacity of the microbial biomass calculated from the Langmuir model was 118.98 mg/g. The kinetic behaviour showed that the CTC biosorption followed pseudo-second-order kinetics, which suggested a chemisorption process.