Journal of Water Chemistry and Technology最新文献

The production and application of activated biochar have demonstrated significant improvements in environmental conditions both locally and across Ukraine. Researchers have confirmed the viability of creating carbon adsorbents specialized for water purification from plant-based materials, streamlining the conversion of organic biopolymers into the final product. Enhancements to traditional pyrolysis technology included the implementation of wet cooling-activation, which facilitated the development of the porous structure in wood biochar. The study further compared the efficiency of various technological solutions by evaluating biochar samples across several criteria in water purification technology.

In this paper, a method is proposed for the complex treatment of technical waste water containing essential concentrations of organomineral impurities including 1 g/dm³ of copper ions. Plasma treatment decreases the chemical oxygen demand of a solution by 17 times, the content of salts by 34%, and the copper and iron concentration by 20%. Electrodialysis decreases the total salt content from 3 to 0.2 g/dm³ and brings the copper and iron content to 8 and 3 mg/dm³, respectively. The destruction of organic substances contained in the water under plasma treatment results in a carbon-containing precipitate studied by physicochemical methods to determine structural and sorption characteristics. The FTIR spectrum of the carbon-containing precipitate indicates the presence of hydrophilic groups and a great amount of uncompensated active sites and free radicals, which can be used in sorption processes. The prospects of using the carbon-containing precipitate as a filler for the desalination chambers of an electrodializer under electrical field application is shown.

A fixed-bed column study for the removal of malachite green (MG) from the aqueous phase was demonstrated using strategically dewaxed honeycomb powder (HCP). The removal efficiency was tested at several working parameters of the column, in particular, the column bed height, initial dye concentration, working pH, and the flow rate. Breakthrough curves have been plotted using the throughput volume versus concentration ratio for different parameters to identify the pathway of uptake. Thomas and bed depth service time (BDST) kinetic models have been applied to obtain the rate constants and the uptake capacity. The BDST model suggests an adsorption capacity of 196.28 mg L^–1. The column performance was seen to vary with solution pH and was found favourable at higher pH values. The adsorption rate decreases with increasing flow rate but increases with increasing concentration of the dye. Easy regeneration ensures multi-cycle operations. The mechanism of dye adsorption by HCP has been proposed as a blend of electrostatic attraction and weak forces. Henceforth, the use of HCP for the removal of MG in column mode may be extrapolated to serve as a promising agent in the treatment of dye-containing water and wastewater.

In this study, we aimed to fabricate a novel, completely natural antibacterial disinfectant material for environmental applications, such as treating drinking water. We created two different berberine−alginate (BerAlg) beads using the ionotropic gelation method, employing calcium and aluminium ions as cross-linkers. The materials were characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), swelling, and release kinetic studies. Antibacterial activity was assessed through time-kill analysis. Among the four release kinetics models tested, the BerAlg bead formulation showed the best fit with the Korsmeyer−Peppas model, having the highest R2 value (0.9757). The longest release of berberine (Ber) was observed over a 4-h period. The time-kill assay results revealed that BerAlg beads were effective in killing for up to 7 h. In conclusion, these results demonstrate the promising potential of BerAlg beads as an antibacterial delivery system for disinfecting various liquid environments, such as drinking water.

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).