Search Results (29)

Effective management of fecal pollutants in rural sanitation is crucial for environmental health and public safety, especially in developing regions. In this study, temporal and regional variations in nutrient elements, heavy metals, pathogenic microorganisms (PMs), and antibiotic resistance genes (ARGs) of fecal samples from rural toilets in China were investigated. The moisture contents of the fecal samples average 92.7%, decreasing seasonally from 97.4% in summer to 90.6% in winter. The samples’ pH values range from 6.5 to 7.5, with a slight decrease in winter (6.8), while their electrical conductivity varies from 128.1 to 2150 μs/cm, influenced by regional diets. Chromium (9.0–49.7 mg/kg) and copper (31.9–784.4 mg/kg) levels vary regionally, with higher concentrations in Anhui and Guangxi Provinces due to dietary and industrial factors. Zinc contents range from 108.5 to 1648.9 mg/kg, with higher levels in autumn and winter, resulting from agricultural practices and Zn-containing fungicides, posing potential health and phytotoxicity risks. Seasonal and regional variations in PMs and ARGs were observed. Guangxi Province shows the high PM diversity in summer samples, while Jiangsu Province exhibits the high ARGs types in autumn samples. These findings highlight the need for improved waste management and sanitation solutions in rural areas to mitigate environmental risks and protect public health. Continued research in these regions is essential to inform effective sanitation strategies. Full article

The disposal of wastewater resulting from petroleum industries presents a major environmental challenge due to the presence of hard-to-degrade organic pollutants, such as oils and hydrocarbons, and high chemical oxygen demand (COD). In this study, an efficient and eco-friendly method was developed to treat such wastewater using a photocatalyst composed of biochar derived from pistachio shells and loaded with zinc oxide (ZnO) nanoparticles. The biochar-ZnO composite was prepared via a co-precipitation-assisted pyrolysis method to evaluate its efficiency in the photocatalytic degradation of petroleum wastewater (PW). The synthesized material was characterized using various techniques, including scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy, to determine surface morphology, crystal structure, and functional groups present on the catalyst surface. Photocatalytic degradation experiments were conducted under UV and sunlight for 90 h of irradiation to evaluate the performance of the proposed system in removing oil and reducing COD levels. Key operational parameters, such as pH (2–10), catalyst dosage (0–0.1) g/50 mL, and oil and COD concentrations (50–500) ppm and (125–1252) ppm, were optimized by response surface methodology (RSM) to obtain the maximum oil and COD removal efficiency. The oil and COD were removed from PW (90.20% and 88.80%) at 0.1 g/50 mL of PS/ZnO, a pH of 2, and 50 ppm oil concentration (125 ppm of COD concentration) under UV light. The results show that pollutant removal is slightly better when using sunlight (80.00% oil removal, 78.28% COD removal) than when using four lamps of UV light (77.50% oil removal, 75.52% COD removal) at 0.055 g/50 mL of PS/ZnO, a pH of 6.8, and 100 ppm of oil concentration (290 ppm of COD concentration). The degradation rates of the PS/ZnO supported a pseudo-first-order kinetic model with R² values of 0.9960 and 0.9922 for oil and COD. This work indicates the potential use of agricultural waste, such as pistachio shells, as a sustainable source for producing effective catalysts for industrial wastewater treatment, opening broad prospects in the field of green and nanotechnology-based environmental solutions in the development of eco-friendly and effective wastewater treatment technologies under solar light. Full article

This study presents a sustainable and scalable biosynthesis method for zinc oxide (ZnO) nanoparticles using Bacillus subtilis, focusing on their application in photocatalytic cyanide degradation in aqueous solutions. The bacterial strain was molecularly identified through 16S rRNA gene sequencing and phylogenetic analysis. The optimized biosynthesis process yielded crystalline ZnO nanoparticles in the zincite phase with an average size of 21.87 ± 5.84 nm and a specific surface area of 27.02 ± 0.13 m²/g. Comprehensive characterization confirmed the formation of high-purity hexagonal ZnO (space group P63mc) with a bandgap of 3.20 eV. Photocatalytic tests under UV irradiation demonstrated efficient concentration-dependent cyanide degradation, achieving 75.5% removal at 100 ppm and 65.8% at 500 ppm within 180 min using 1.0 g/L ZnO loading. The degradation kinetics followed a pseudo-first-order model with rate constants ranging from 6.64 × 10⁻³ to 3.98 × 10⁻³ min⁻¹. The enhanced photocatalytic performance is attributed to the optimal crystallite size, high surface area, and surface defects identified through a microscopic analysis. These results establish biosynthesized ZnO nanoparticles as promising eco-friendly photocatalysts for industrial wastewater treatment. Full article

Water pollution caused by landfill leachate, which contains high concentrations of heavy metals and organic contaminants, poses a serious environmental threat. Among the potential remediation strategies, phytoremediation using Miscanthus x giganteus (giant miscanthus) has gained attention due to its strong resistance to harsh conditions and its capacity to accumulate heavy metals. This study evaluates the effectiveness of Miscanthus x giganteus in treating landfill leachate, with a focus on removing key pollutants such as zinc (Zn), nickel (Ni), and copper (Cu) by simulating wetland conditions. A pilot-scale experiment conducted at the Grebača landfill site assessed the plant’s ability to enhance metal bioavailability, stabilize contaminants, and limit their mobility within the leachate system. The results demonstrated that Miscanthus x giganteus effectively mobilized Zn and Ni through rhizospheric activity, whereas Cu remained largely immobile, indicating potential for phytostabilization. Sequential extraction analysis further confirmed that the plant significantly reduced the mobile fractions of Zn and Ni in the soil, highlighting its dual role in both phytoremediation and phytostabilization. These findings suggest that Miscanthus x giganteus offers a sustainable and cost-effective approach to landfill leachate treatment, serving as a viable alternative to conventional methods. By integrating this nature-based solution into industrial and municipal waste management, it promotes environmental sustainability while enhancing remediation efficiency. Full article

Environmental regulations on lead recycling are becoming increasingly stringent, prompting the search for sustainable alternatives to conventional high-temperature processes. Hydrometallurgical methods in chloride media have emerged as a viable option for recovering lead from mining and urban wastes, including lead anode corrosion residues, zinc leaching residues, and spent lead–acid batteries. This study reviews the key conditions for lead recovery in chloride media, highlighting the variables that optimize lead dissolution, and the potential challenges associated with these processes. The findings indicate that efficient lead recovery requires high chloride concentrations, with acidity playing a critical role depending on the relative concentrations of lead and sulfate in the solution. When lead and sulfate concentrations are similar, stable lead–chloride complexes form within a pH range of 0 to 6.0. However, at higher sulfate concentrations, the pH range narrows significantly to 0 to 2.0, necessitating a more acidic environment for effective dissolution. Chloride media offer a distinct advantage through the formation of stable lead–chloride complexes, whose stability is influenced by chloride concentration, sulfate concentration, pH, and redox potential. Moreover, this approach provides a sustainable alternative that could integrate seawater into industrial processes, particularly in regions facing water scarcity. Full article

Background/Objectives: Bee venom (BV), as a natural product, is one of the foundations of the pharmaceutical industry, through which many diseases, including serious ones, can be effectively treated. The BV nanofilm is an effective antidote delivered into the human body to target the affected area and address the issue without major side effects. In this study, we investigated the intriguing therapeutic effects of apitoxin (bee venom) used in isolation, combined with the powerful properties of zinc oxide nanoparticles. Methods and Results: BV nanofilm was evaluated using Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The BV extract was analyzed using mass spectrometry (MS), which identified 84 active components present at varying concentrations. BV was treated with both polyvinyl alcohol (PVA) and zinc oxide nanoparticles (ZNPs) to increase the intensity of OH and CH₂ groups and to enhance the dispersion of C=O. BV has demonstrated anti-type 2 diabetes activity by inhibiting α-amylase and α-glucosidase, which are starch-degrading enzymes. The nanofilm is an active mixture of BV, PVA, and ZNPs, which exhibited the highest antidiabetic activity with IC₅₀ values of 30.33 μg/mL and 5.55 μg/mL for the inhibition of α-amylase and α-glucosidase, compared to IC₅₀ of 51.69 µg/mL and IC₅₀ of 7.30 µg/mL for BV, respectively. The nanofilm also showed higher anti-inflammatory activity by inhibiting red blood cell (RBC) hemolysis, with an IC₅₀ of 16.99 μg/mL in comparison to IC₅₀ of 72.99 µg/mL for BV alone. The nanofilm demonstrated broad-spectrum antimicrobial activity, effectively targeting both Gram-positive (Staphylococcus aureus ATCC 6538 and Bacillus subtilis ATCC 6633) and Gram-negative bacteria (Salmonella typhi ATCC 6539, Escherichia coli ATCC 8739). Furthermore, increased antioxidant activity was recorded by inhibiting the 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging effect with an IC₅₀ of 4.26 μg/mL and 19.43 μg/mL for nanofilm and BV, respectively. BV was found to be more toxic to liver tissue (HepG2 cell line) than nanofilm, with IC₅₀ values of 18.5 ± 0.08 μg/mL and 52.27 ± 0.7 μg/mL, respectively. The BV extract displayed higher toxicity to liver tissue (2.3%) with 97.7% viability at 250 μg/mL, compared to nanofilm, which showed 0.09% toxicity and 99.9% viability at the same concentration. Conclusions: the BV nanofilm emerges as a promising alternative medicine, offering an innovative solution for treating various diseases through its high concentration of therapeutically active compounds and effortless targeting delivery. Full article

This paper presents the results of research on the possibility to obtain CRMs (REEs) and industrial metals (Zn) from slag as a waste generated as part of zinc and lead extraction processes. Physicochemical methods were used to separate CRM and Zn concentrates: magnetic separation, sintering with NaOH and leaching with selected mineral acids. After analysing the obtained results, it was found that the use of concentrated hydrochloric acid and a temperature of 363 K for leaching was effective in separating REEs from slags obtained from current production. The recovery rate in this case ranged from 83.73% for La to 98.03% for Eu. For slag samples (M1) obtained from current production from ZGH Bolesław S.A.(Poland) as well as HC Miasteczko Śląskie S.A. (Poland) and treated with concentrated HCl, the leaching level of Bi, Zn, Ni, Mn and P exceeded 90% compared to the content in the reference sample. For a historical slag sample from Ruda Śląska (Poland), treatment with concentrated HCl yielded a high leaching level of Cd (70.90%), Pb (78.66%), As (72.49%) and Mo (61.90%). A concentrate containing 1.64% of REEs and 67.1% of Zn was isolated from the solutions obtained after leaching by precipitation. An economic analysis of an REE concentrate extraction facility was also performed. For an operation of 17 years, the calculated NPV was −26,352,644 million EUR. The obtained results indicate that, for the analysed facility, recovering metals and critical raw materials from slag as a waste mass is not economically effective. Full article

Industrial wastewater discharge, tainted with hazardous substances, including dyes like methylene blue (MB) from the textile sector, further emphasizes the need for water treatment to produce safe drinking water. This study explores the potential of olive mill solid waste, an abundant and cost-effective agricultural waste in Mediterranean regions, to yield high-quality activated carbon (AC) with zinc chloride activation for MB adsorption. The activation process, carried out at a modest temperature of 500 °C without the need for an inert atmosphere, resulted in AC with remarkable characteristics, boasting a substantial surface area of 1184 cm²·g⁻¹ and a total pore volume of 0.824 cm³·g⁻¹. Extensive characterization of the AC was carried out through a large range of surface techniques. The pH of the solution had minimal influence on MB adsorption, the maximum removal was 95%, which was under slightly acidic pH conditions (5.8), and the adsorbent dose was 0.4 g·L⁻¹ for a 50 mg·L⁻¹ MB concentration. Equilibrium data pertaining to MB adsorption were subjected to fitting with different models, namely Langmuir, Freundlich, and Temkin. Notably, the Langmuir model exhibited the best fit, revealing a maximum monolayer adsorption capacity of 500 mg·g⁻¹ at 25 °C, and the adsorption kinetics closely followed a pseudo-second-order model. Full article

Rapid economic development and increased demand for mineral products in China have led to extensive extraction of various ores, resulting in significant environmental challenges associated with the generation of industrial solid waste, particularly iron tailings. Despite being a major mining nation, China faces issues of wasteful practices, with substantial amounts of valuable elements lost during the processing of iron ore. This study addresses the urgent need for sustainable solutions by proposing an innovative approach for the recovery of valuable elements from iron tailings. The proposed process involves a sequential application of acid leaching, chemical precipitation, and Metal-Organic Frameworks (MOFs) ion adsorption. The pre-treated iron tailings were leached in HCl solution with pH 1.5 at 70 °C for 2 h, and the co-leaching efficiency of 98.1% V, 98.2% Mo, 99.3% Fe, and 98.7% Mg was obtained. Chemical precipitation is then employed to isolate Fe, Mg V, and Mo and promote the formation of targeted compounds, ensuring concentration and purity. The integration of MOF ion adsorption, known for its high surface area and tunable pore structures, provides an efficient platform for selectively capturing and recovering target ions. 97.7% V and 96.3% Mo were selectively extracted from Zirconium 1,4-carboxybenzene metal-organic framework (UiO-66) adsorption system with pH 5.0 at 30 °C for 6 h, and 91.7% V and 90.3% Mo were selectively extracted from 2-methylimidazole zinc salt metal-organic framework (ZIF-8) adsorption system with pH 5 at 30 °C for 6.0 h. This three-stage process offers an efficient method for the recovery of valuable elements from iron tailings. Full article

Groundwater monitoring is critically important, even though it is costly and often neglected. In this study, a judgmental monitoring of groundwater offering solutions based on a cost and time-effective research approach is presented. The method was performed in three Mediterranean areas in Greece and Italy to examine its advantages and disadvantages. As a first step, a multi-statistical analysis was practiced to assess and apportion the potential contributions of pollution sources of groundwater. Pearson correlation, principal component analysis, and factor analysis were applied to groundwater samples to characterize the evolution of hydrochemical processes. High concentrations of chlorides and nitrates highlight that salinization and the extensive use of nitrate fertilizers dominate in the coastal part of Eastern Thermaikos Gulf, the dissolution of carbonate rocks and livestock/industrial activities drive the groundwater quality status in the Upper Volturno basin, while in the Mouriki basin thermal power plant and the use of zinc fertilizers are the main factors of groundwater quality degradation. The determination of the critical sampling points was applied, considering the land use and hydrogeological and morphological characteristics of the areas. The application of the judgmental sampling approach provides reliable results regarding groundwater evolution. These results were compared to previous works and found that a non-probability sampling technique can provide the same results as a more costly method in the Mediterranean region. Thus, judgmental sampling is crucial for the optimal application of water resource management and control techniques in basins to avoid gaps in data collection. Full article

Corrosion inhibitors represent one of the most commonly used methods for significantly reducing the corrosion rate of metals and alloys. Adsorption inhibitors have a wide range of applications in cooling water systems, deicing solutions for aircrafts, airports and ways, etching and degreasing solutions, oil pipelines, paints and coatings and metal processing solutions. Adsorption corrosion inhibitors of metals and alloys are generally organic compounds that contain structures with heteroatoms (N, P, S, As, O) in their molecules, having lone pair electrons or π electrons in aromatic rings or multiple bonds. They enable relatively strong interactions between the metal atoms and organic molecules, resulting in a protective layer of organic molecules adsorbed at the metal–corrosive solution interface. Most molecules of active substances from drugs contain similar structures, which is why many drugs have been already tested as corrosion inhibitors. One of the major disadvantages of using drugs for this purpose is their particularly high price. To overcome this impediment, the possibility of using expired drugs as corrosion inhibitors has been investigated since 2009. The present paper is an exhaustive compilation of the scientific published papers devoted to the use of expired drugs as corrosion inhibitors in various aggressive solutions. The inhibitory efficiencies of expired drugs are presented as a function of the studied metal or alloy and the nature of the aggressive solution, as well as the concentration of the inhibitor in such a solution. Research has especially been focused on mild and carbon steel and less on stainless steel, as well as on some metals such as copper, zinc, nickel, tin and aluminum and its alloys. The experimental methods used to assess the inhibitory efficiencies of expired drugs are briefly discussed. Also, the available information on the stability of the active substances in the drugs is presented, although most authors were not concerned with this aspect. Finally, several actions are revealed that must be undertaken by researchers so that the results obtained in the study of the anticorrosive action of expired drugs can be applied at the industrial level and not remain only an academic concern. Full article

The progress of the textile industry has led to a severe increase in the discharge of colored effluents, polluted with dyes and metal ions (non-biodegradable, carcinogenic to humans and environmental hazards). The implementation of effective methodologies and materials for the treatment of wastewater has become an urgent requirement. The present work describes the application of two samples of mineral materials—Ghidirim diatomite and modified diatomite—as adsorbents for the removal of dyes—Acid Blue 350, Methylene Blue, Basic Red 2—and of metal ions—copper, zinc, and lead—from aqueous solutions. In order to determine the optimal working conditions by which to ensure maximum removal efficiency, the influence of the nature and amount of the sorbent, the initial concentration of pollutant, and the temperature were studied. Working under normal conditions (room temperature, solution pH) efficiencies greater than 80% were obtained for the removal of dyes and metal ions. The adsorption fitted well with the pseudo-second order kinetic model, and the maximum adsorption capacities were determined from the Langmuir isotherm model. The adsorption of investigated pollutants is an endothermic and spontaneous process. The results indicate that Ghidirim diatomite and modified diatomite have potential applications in water purification management, providing high removal efficiency of both dyes and metal ions. Full article

Zeolitic imidazolate frameworks (ZIFs) have potential for various gas and ion separations due to their well-defined pore structure and relatively easy fabrication process compared to other metal–organic frameworks and zeolites. As a result, many reports have focused on preparing polycrystalline and continuous ZIF layers on porous supports with good separation performance in various target gases, such as hydrogen extraction and propane/propylene separation. To utilize the separation properties in industry, membrane is required to be prepared in large scale with high reproducibility. In this study, we investigated how humidity and chamber temperature influence the structure of a ZIF-8 layer prepared by the hydrothermal method. Many synthesis conditions can affect the morphology of polycrystalline ZIF membranes, and previous studies have mainly focused on reaction solutions, such as precursor molar ratio, concentration, temperature, and growth time. On the other hand, we found that the humidity of the chamber and the heating rate of the solution also lead to dramatic changes in the morphology of ZIF membranes. To analyze the trend between humidity and chamber temperature, we set up the chamber temperature (ranging from 50 °C to 70 °C) and relative humidity (ranging from 20% to 100%) using a thermo-hygrostat chamber. We found that as the chamber temperature increased, ZIF-8 preferentially grew into particles rather than forming a continuous polycrystalline layer. By measuring the temperature of the reacting solution based on chamber humidity, we discovered that the heating rate of the reacting solution varied with humidity, even at the same chamber temperature. At a higher humidity, the thermal energy transfer was accelerated as the water vapor delivered more energy to the reacting solution. Therefore, a continuous ZIF-8 layer could be formed more easily at low humidity ranges (ranging from 20% to 40%), while micron ZIF-8 particles were synthesized at a high heating rate. Similarly, under higher temperatures (above 50 °C), the thermal energy transfer was increased, leading to sporadic crystal growth. The observed results were obtained with a controlled molar ratio, in which zinc nitrate hexahydrate and 2-MIM were dissolved in DI water at a molar ratio of 1:45. While the results are limited to these specific growth conditions, our study suggests that controlling the heating rate of the reaction solution is critical for preparing a continuous and large-area ZIF-8 layer, particularly for the future scale-up of ZIF-8 membranes. Additionally, humidity is an important factor in forming the ZIF-8 layer, as the heating rate of the reaction solution can vary even at the same chamber temperature. Further research related to humidity will be necessary for the development of large-area ZIF-8 membranes. Full article

According to the idea of sustainable development, humanity should make every effort to care for the natural environment along with economic development. Decreasing water resources in the world makes it necessary to take action to reduce the consumption of this resource. This article presents the results of research conducted to improve the use of recyclable materials in line with the circular economy model. The research focused on the development of a technological solution for the recovery of raw materials from galvanic wastewater. The concept of a galvanic wastewater treatment system presented in the article includes wastewater pre-treatment in the ultrafiltration (UF) process and water recovery in the reverse osmosis (RO) process. In addition, the purpose of the work was to manage post-filtration waste (RO retentate) containing high concentrations of zinc in the process of galvanizing metal details. The obtained results indicate that it is possible to reduce the amount of sewage from the galvanizing industry by reusing the recovered water as technical water in the process line. The carried-out model tests of galvanizing confirmed the possibility of using RO retentate for the production of metal parts. The achieved results are a proposal to solve the problem of reducing the impact of galvanic wastewater on the environment and to improve the profitability of existing galvanizing technologies by reducing the consumption of water and raw materials. Full article

The direct and rapid determination of trace cobalt ion (Co²⁺) in the electrolyte of zinc smelting plants is urgently needed but is impeded by the severe interference of extremely high-concentration zinc ions in the solution. Herein, colorimetric detection of Co²⁺ by the polyvinylpyrrolidone functionalized silver nanoparticles (PVP-AgNPs) is realized in solutions with the Zn/Co ratio being high, up to (0.8–5) × 10⁴, which is located within the ratio range in industrial solution. The high concentration of Zn²⁺ induces a strong attenuation of Co²⁺-related signals in ultraviolet-visible (UV-vis) extinction spectra; nevertheless, a good linear range for detecting 1–6 mg/L Co²⁺ in 50 g/L Zn²⁺ solution is still acquired. The strong anti-interference toward other metal ions and the mechanism understanding for trace Co²⁺ detection in such a high-concentration Zn²⁺ solution are also revealed by systematic analysis techniques. The results extend the AgNPs as colorimetric sensors to industrial solutions, providing a new strategy for detecting trace-metal ions in industrial plants. Full article