Journal of Water Chemistry and Technology最新文献

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.

Magnetically recyclable nanoparticle catalysts, in particular, Fe₃O₄, TiO₂@Fe₃O₄, SiO₂@Fe₃O₄, TiO₂–SiO₂@Fe₃O₄ and silver doped TiO₂–SiO₂@Fe₃O₄ (Ag–TiO₂–SiO₂@Fe₃O₄) were synthesized by sol-gel and modified sol-gel synthesis methods. These nanoparticle catalysts were prepared from metal salts and alkoxide precursor salts. Photocatalytic activity of these catalysts was studied in the degradation of organophosphorus pesticides Glyphosate, and Malathion in water. A detailed study of photodegradation of these organic compounds under UV radiation was performed. The physicochemical characterization of the synthesized nanoparticles was performed using TEM (Transmission electron microscopy), EDX (energy dispersive X-ray), ICP-AES (inductively coupled plasma−atomic emission spectroscopy), XRD (X-ray diffraction) and BET surface area measurement techniques. The degradation reactions of organic pesticides were performed in a specially designed photo-batch reactor. The use of H₂O₂ as an oxidant in the reaction was found to enhance the catalytic performance towards degradation and subsequent mineralization of the organophosphorus pesticides. Silver-doped nanocatalyst exhibits high recycling efficiency and stability over several subsequent runs. The course of the reactions was studied using COD (chemical oxygen demand) removal and HPLC (high-performance liquid chromatography) methods of water before and after the photodegradation reactions. More than 95% reduction in the COD was observed in the treated water sample using Ag–TiO₂–SiO₂@Fe₃O₄.

The method of isotherm simulation by approximating mathematical expressions that are valid for a small experimental section of the isotherm over the entire range of equilibrium concentrations is an important and useful tool in adsorption practice. Nine adsorption equilibrium systems of activated carbon (AC)–derivatives of aniline and phenol were examined. The adsorbent used was activated carbon obtained from fruit pits. The results of isothermal adsorption of aromatic substances with relatively small molecules on a microporous carbon adsorbent indicate the simultaneous adequacy of the Freundlich and Langmuir models to the experimental data in moderate concentration ranges ((0.1–100)n mg/dm³, where n = 1, 2, 3, 4, 5). Thus, the results of adsorption from the aqueous phase do not demonstrate the energy differences of the AC surface that are incorporated into the theoretical classical model isotherms. The isotherm reflects the adsorption process on both homogeneous and heterogeneous surfaces simultaneously. This may be due to the displacement nature of adsorption from the aqueous phase, where initial surface screening by water molecules occurs during adsorbent wetting, leading to the leveling of its energetic heterogeneity. In the next stage—displacement of some water molecules by the organic adsorbate—the energetic differences of the adsorption sites are not as clearly manifested as in gas-phase adsorption. Therefore, theorizing the nature of the AC surface based on the best model simulation of experimental isotherms using classical equations becomes questionable. Three-parameter equations (Langmuir–Freundlich, Redlich–Peterson) demonstrated a finer simulation of the experiment compared to the classical two-parameter models. The study emphasizes that the mathematical description of the isotherm is a convenient method for the efficient storage and use of information about the adsorption properties of the system. It serves to compare the effectiveness of new materials with commercial analogs and to predict the performance of real purification systems under dynamic conditions.

Industrialization has caused serious heavy metal pollution in water resources, which is harmful to human health. It is of great significance to use heavy metal removal technology to ensure water safety. In this study, a new kaolin/chitosan composite (TGL-CS) was prepared for the adsorption of lead-containing wastewater based on the mercapto-alkenyl base reaction strategy. The effects of pH, adsorbent dosage and ionic strength on the adsorption performance of TGL-CS were investigated. The adsorption process of Pb(II) on TGL-CS is consistent with the Langmuir isotherm and pseudo-second-order kinetic model. The maximum adsorption capacity of TGL-CS for Pb(II) was 87.72 mg/g. The adsorption mechanism of TGL-CS is mainly the coordination between Pb(II) and hydroxyl, amino and sulfur-containing groups. In particular, the click chemical reaction does not consume the amino group in chitosan but also introduces the sulfur-containing group to improve the adsorption capacity of heavy metals. In addition, the ionic strength in the environment system has little effect on the adsorption of Pb(II) by TGL-CS, and the reusability of TGL-CS is high. In summary, TGL-CS has the advantages of low cost, simple preparation, and broad application prospects in the treatment of heavy metal-polluted water bodies.

The possibility of extracting Cu compounds through adsorption using galvanic sludge modified with solutions of humic acids was investigated. The chemical and structural composition of rigid galvanic sludge from printed circuit board production was examined. The primary phase-forming element is Fe compounds in the form of β-FeOOH, constituting up to 45% of the sludge mass. X-ray phase analysis of the sludge revealed the presence of two main phases: akaganeite (β-FeOOH) and an atacamite-like crystalline phase of copper hydroxychloride (Cu(OH)₃Cl) in quantities exceeding 10%. The conditions for leaching Cu compounds from the sludge and the effect of thermal treatment on the sludge adsorption capacity were determined. Copper was leached from galvanic sludge using an H₂SO₄ solution within the pH range of the equilibrium solution of 3–5.5. This allowed for the leaching of up to 97% of copper, with minimal dissolution of Fe compounds. The Cu concentration in the leaching solution reached 10–15 g/dm³, while the concentration of Fe ions did not exceed 1 mg/dm³, enabling the subsequent utilization of these solutions for Cu electroextraction. The modification of the sludge with humic acid solutions increases its adsorption capacity for copper ions by more than threefold.