Search Results (656)

Metal contamination poses serious environmental and human health risks, which results in the need for low-cost remediation approaches. The utilization of agricultural byproducts for the removal of metal contaminants is considered cost-effective and environmentally sustainable. Garlic byproducts are rich in sulfur-containing compounds, and various functional groups contribute to metal binding. This study aimed to evaluate the potential of garlic stem and peel for the removal of cadmium (Cd), lead (Pb), and arsenic (As) from aqueous solutions and for their immobilization in contaminated soils. Batch sorption experiments conducted at pH 7 for 24 h showed that garlic stem removed 71.5% of Cd and 70.8% of Pb, while garlic peel achieved 65.4% and 79.4% removal, respectively. The higher Pb removal by garlic peel might be attributed to its higher sulfur content. However, both byproducts were less effective in removing As(III) and showed negligible removal of As(V), as these species predominantly occur in neutral or negatively charged species at neutral pH, resulting in weak interactions with negatively charged surface functional groups. Soil incubation experiments were conducted using 1% and 5% amendments of garlic stem and peel in Pb- and As-contaminated soils. Extractable Pb concentrations significantly increased in soils treated with 1% garlic peel because of the formation of labile complexes of Pb with dissolved organic carbon. However, a column experiment to evaluate the impact on Pb mobility under saturated and unsaturated conditions showed that Pb concentration in soil pore water decreased with garlic stem. Pb concentration was lower under saturated conditions, possibly due to the precipitation of Pb as PbS. Although the short-term application of raw agricultural byproducts increased extractable metal concentrations, long-term incubation reduced Pb levels in pore water. These findings suggest that unmodified garlic stem is a promising, cost-effective amendment for Pb immobilization in soil. Nevertheless, caution is needed in its application to prevent unintended metal mobilization in soil. Full article

Tomato leaves, typically discarded during harvest, are a rich yet underutilized source of bioactive compounds. This study aimed to valorize tomato leaves by optimizing the extraction of their phenolic compounds using a water-based method and response surface methodology. The optimal conditions, notably heating a mixture of 1:50 solid-to-liquid ratio at 71 °C for 29 min, yielded the most total phenolic content and antioxidant activity. The biological activities of the lyophilized tomato leaf extract (TLE) were then assessed. TLE showed dose-dependent antimicrobial activity against Escherichia coli and Candida albicans, but neither against Pseudomonas aeruginosa nor Staphylococcus aureus. In addition, it demonstrated moderate cytotoxicity against MCF-7 breast cancer cells with an IC₅₀ value of 114.5 µg/mL. Interestingly, the extract significantly reduced intracellular reactive oxygen species levels in RAW 264.7 macrophages, supporting its anti-inflammatory potential. LC-MS analysis identified rutin (45.21%), 4-hydroxycoumarin (13.60%), and α-tomatine (12.37%) as the major chemical constituents in TLE, suggesting contributing effects behind the observed bioactivities. These results support the potential of tomato leaf extract as an eco-friendly source for functional ingredients, transforming agricultural waste through green extraction into valuable applications for nutraceuticals and sustainable product development. Full article

This article presents the results of a comprehensive investigation into geopolymer composites synthesized from fly ash, incorporating ground asphalt derived from reclaimed road pavement and quartz sand. The primary objective of this study was to elucidate the influence of mixture composition on the mechanical, physical, and microstructural characteristics of the developed materials. The innovative aspect of this research lies in the integration of two distinct filler types—mineral (quartz sand) and organic-mineral (milled asphalt)—within a single geopolymer matrix, while preserving key performance parameters required for engineering applications, including compressive and flexural strength, density, water absorption, and abrasion resistance. The experimental methodology encompassed the characterization of the raw materials by X-ray diffraction (XRD), chemical composition analysis via X-ray fluorescence (XRF), and assessment of particle size distribution. Additionally, the produced geopolymer materials underwent density determination, compressive and flexural strength measurements, abrasion testing, and mass water absorption evaluation. The chemical composition was further examined using XRF, and the surface morphology of the specimens was analyzed by scanning electron microscopy (SEM). The findings demonstrate that the incorporation of quartz sand enhances the density and mechanical strength of the composites, whereas the addition of recycled asphalt, despite causing a modest reduction in mechanical performance at elevated dosages, augments water resistance. Moreover, ternary composite material provide an optimal compromise between mechanical strength and durability under humid conditions. Overall, the results substantiate the feasibility of utilizing asphalt waste for the fabrication of functional and sustainable geopolymer materials suitable for construction applications. Full article

The inevitable ubiquity of natural organic matter (NOM) in all waters presents a challenge to the proper functioning of water treatment processes. Therefore, minimizing NOM in raw water is crucial to avoid operational issues in subsequent treatment steps. In this experimental study, we aimed to maximize the degradation of NOM using UV/H₂O₂ advanced oxidation, employing design of experiments (DoE) and response surface methodology (RSM) for process optimization. Experiments were carried out on synthetic water, and the effects of dissolved organic carbon (DOC) content and hydrogen peroxide concentration on DOC removal at neutral pH were examined. NOM isolated from the Suwannee River was used as a representative model. The process was modeled and optimized using Design-Expert 14.0.7.0 software. The highest DOC removal of approximately 34% was observed at a DOC level of ~8 mg L⁻¹ and an H₂O₂ concentration just below 250 mg L⁻¹. Degradation products were analyzed by ultra-high-performance liquid chromatography coupled with hybrid quadrupole time-of-flight mass spectrometry, revealing sixteen compounds, mostly long-chain saturated fatty acids. Finally, the energy efficiency of the experimental setup was assessed and discussed. Full article

(1) Background: The impact of different drying methods on the functional properties and microstructure of milk powders was analyzed in this study. (2) Methods: Whole milk, skim milk, and buttermilk powders were obtained by freeze drying, spray drying, and roller drying. (3) Results: The examined powders differed in chemical composition, and these differences were attributed mainly to their fat content. The functional properties of the studied powders were determined mainly by the drying method and were less influenced by their composition. Loose and tapped bulk density was highest in roller-dried powders and lowest in freeze-dried powders. The flowability of milk powders was determined by calculating the Carr index and the Hausner ratio, and the results were used to classify the analyzed powders into the following groups: poorly flowing and cohesive (spray-dried samples), passable (roller-dried samples), and fair (freeze-dried samples). The volume of insoluble particles was highest in roller-dried powders and much lower in spray-dried powders, whereas freeze-dried powders were 99.8–99.9% soluble in water. Whole milk powder was characterized by low wettability (>180 s) regardless of the drying method. Powder morphology was influenced mainly by the drying method. (4) Conclusions: The fractal analysis demonstrated that spray-dried powders had the smallest fractal dimensions, which implies that their surface was least complex (most uniform). Regardless of the drying method, fractal dimensions were highest in whole milk powder, which could suggest that fat affects the microstructure of powders. The color parameters of milk powders were determined mainly by the drying method and were less influenced by the type of raw material used in powder production. Full article

Recycled aggregate concrete refers to concrete made by using recycled aggregates produced from construction waste to replace natural aggregates. The performance of recycled aggregate concrete is extremely unstable. Internal factors such as water–cement ratio, porosity, and the properties of recycled aggregates, as well as external factors like temperature, humidity, environmental erosion, and the addition of improvement materials, may all have an impact on its mechanical properties. The response surface analysis method was employed to investigate the impact of three key factors—the number of dry–wet cycles, the content of stainless steel fibers, and the concentration of Na₂SO₄—on the mechanical properties of stainless steel fiber recycled aggregate concrete (SSFRAC) under dry–wet cycling conditions in the study. By incorporating stainless steel fibers into the cementitious gel network, SSFRAC is conceptualized as a composite material where the metal fibers are integrated into the gel matrix, forming a hybrid system akin to metallogels. The response models for compressive strength durability coefficient S_c and flexural strength durability coefficient S_f are established using Design-Expert software to evaluate the significance of these factors and their interactions. The version of Design-Expert used in this study is Design Expert 13.0. The results demonstrated that both S_c and S_f models exhibit high fitting accuracy, effectively capturing the relationships among the factors. The number of dry–wet cycles exhibit the highest significance, followed by Na₂SO₄ concentration and stainless steel fiber content. The interaction between dry–wet cycle number and Na₂SO₄ concentration has a particularly significant impact on S_c. For S_f, stainless steel fiber content is the most significant factor, followed by dry–wet cycle number and Na₂SO₄ concentration, with the interaction between fiber content and Na₂SO₄ concentration exerting a notably strong influence. This study highlights the potential of cement-based gels as raw materials for synthesizing functional composite materials, where the incorporation of metal fibers enhances mechanical performance and durability under aggressive environmental conditions. The findings provide insights into the design and optimization of hybrid gel–metal systems for advanced construction applications. Full article

Zoonotic Campylobacter species (ZCS), particularly C. jejuni and C. coli, cause major foodborne gastroenteritis and poultry is the principal reservoirs. However, there is limited data on Campylobacter transmission risk practices and antimicrobial resistance (AMR) in Nigeria. Therefore, this study determined the prevalence, AMR, and risk practices aiding Campylobacter transmission in two major slaughterhouses processing poultry carcasses in Enugu State, Nigeria. Four hundred poultry faecal samples were analysed for zoonotic Campylobacter organisms using standard protocols. Antimicrobial resistance was profiled via Kirby–Bauer disk diffusion technique, against eight antimicrobial agents. Risk practices were assessed through slaughterhouse observations and interviews with 56 workers. The overall prevalence of Campylobacter infections was 14.5% (58/400), while the species-specific prevalence were 13% (52/400) and 1.5% (6/400) for C. coli and C. jejuni, respectively. Campylobacter colonisation was significantly higher (p < 0.05) in broilers, and during the wet season. The AMR profile of the isolates against the eight antibiotics tested was: Amoxicillin/clauvlanic acid (100%), vancomycin (100%), tetracycline (96.6%), ciprofloxacin (55.2%), chloramphenicol (44.8%), ceftazidime (10.3%), azithromycin (3.4%) and streptomycin (3.4%). All the 58 Campylobacter isolates were multidrug-resistant. The multiple antibiotic resistance indices ranged from 0.4 to 0.9, with a mean of 0.7. Major risk practice associated with ZCS transmission include non-use of personal protective equipment (100%), slaughtering on unsanitary surfaces (100%), using visibly unclean water for meat processing (100%), improper manual evisceration (75%), eating or drinking during processing (64.4%), slaughtering sick animals (37.5%), inadequate cleaning of surfaces and equipment after use (21.4%) and consuming raw meat during carcass processing (19.6%). The findings reflect critical gaps in food safety, occupational health, prudent antimicrobial use in poultry farming and zoonotic disease control, emphasizing the need for antibiotic regulation, training on hygienic meat processing, public education, infrastructural development of slaughterhouse facilities, and inter-sectorial collaboration to curb Campylobacter contamination and spread of antimicrobial resistance. Full article

Manganese (Mn) has emerged as a contaminant of concern due to its occurrence at concentrations exceeding regulatory limits in various environmental matrices, driven by both anthropogenic activities and natural geochemical processes. Although Mn is an essential micronutrient, excessive exposure poses risks to human health and ecosystems. This study investigates the potential application of Moringa oleifera seed pods, an agro-industrial byproduct, as low-cost biosorbents for Mn ion removal from aqueous solutions. Biosorbents were prepared from raw seed pods and chemically modified using NaOH and HCl. Surface characterization was performed using SEM, EDS, and FTIR techniques. Kinetic analysis indicated that Mn ion adsorption by all biosorbents followed a pseudo-second-order model, with equilibrium reached within 30 min. Among the tested materials, the alkali-treated biosorbent exhibited the highest removal efficiency (94%) under optimal conditions (288 K, pH 6.0, 60 min). Equilibrium data fitted both Langmuir and the Freundlich isotherms, with a maximum adsorption capacity of 7.64 mg g⁻¹ for alkali-treated pods and 6.00 mg g⁻¹ for the unmodified pods. Thermodynamic analysis revealed negative Gibbs free energy values, confirming the spontaneous nature of the biosorption process. Enthalpy values below 40 kJ mol⁻¹ (Pod_NA: 11.88 kJ mol⁻¹; Pod_AC: 1.08 kJ mol⁻¹; Pod_BA: 8.94 kJ mol⁻¹) suggest that physisorption is the predominant mechanism. These findings demonstrate the viability of Moringa oleifera pods as effective biosorbents for Mn ion remediation, supporting the valorization of agricultural waste within sustainable water treatment strategies. Full article

Oily wastewater is a critical environmental concern, and the high costs and fouling of conventional membranes drive the search for low-cost, efficient alternatives. This study evaluates surface-modified quartz particles for oil–water separation, focusing on hydrophilic and hydrophobic coatings. Quartz samples underwent washing, hydrophobic coating, and hydrophilic coating, with morphological and elemental changes assessed using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM–EDS). Oil and grease (O&G) content was determined via the EPA 1664 method under high-solids conditions. The untreated oil–water mixture contained 142,955.9 mg/L O&G. Hydrophilic-coated quartz achieved the greatest reduction, producing water with only 751.3 mg/L O&G, indicating excellent oil rejection and water selectivity. Washed quartz performed similarly at 837.1 mg/L. Hydrophobic-coated quartz, while yielding higher residual oil in water (64,198.9 mg/L), demonstrated strong oil affinity, making it more suitable for oil recovery applications. Raw quartz, tested without heavy oil loading, showed a baseline of 13.4 mg/L. These results confirm that surface engineering of quartz enables tunable separation properties, where hydrophilic surfaces favor water purification and hydrophobic surfaces enhance oil capture. The findings provide a pathway for scalable, cost-effective, and application-specific oily wastewater treatment solutions. Full article

Background: Staphylococcus aureus is a major zoonotic and foodborne pathogen with substantial One Health implications, yet its prevalence, resistance, and virulence potential within the aquaculture sector in Nigeria remains poorly characterized. Objectives: To supplement existing information, this current study investigated the prevalence, clonal distribution, antimicrobial resistance, and virulence gene profiles of S. aureus isolates from fish, fish water, and occupationally exposed fish handlers in Anambra State, Southeast Nigeria. Methods: A total of 607 samples—comprising 465 surface swabs from raw and processed fish, 36 fish water samples, and 106 nasal swabs from fish handlers—were processed using selective culture, biochemical tests, antimicrobial susceptibility testing, DNA microarray analysis, spa typing, and SCCmec typing. Results: S. aureus was recovered from 16.5% (100/607) of the samples. Fourteen (14%) isolates were methicillin-resistant (MRSA), harboring mecA and SCCmec types IV and V, with a combined MRSA prevalence of 2.3%. Multidrug resistance was observed in 52.2% of isolates (mean Multiple Antimicrobial Resistance index: 0.23), with 19 resistance genes spanning nine antimicrobial classes—including heavy metal and biocide resistance. Twenty-eight spa types across 13 clonal complexes (CCs) were identified, with CC1, CC5, and CC8 predominating. The detection of shared spa types between fish and handlers indicates potential cross-contamination. Detected virulence genes included those for accessory gene regulators (agrI-IV), Pantone–Valentine leucocidin (lukFS-PV), toxic shock syndrome (tsst-1), hemolysins (hla, hlb, hld/hlIII, hlgA), biofilm formation (icaA, icaD), immune evasion (chp, scn, sak), enterotoxins (sea, seb, sec, sed, egc, and others), exfoliative toxins (etA, etB), epidermal cells differentiation (edinA, edinB), and capsular types (cap5, cap8). Conclusions: This study reveals that the aquaculture sector in Southeast Nigeria serves as a significant reservoir of genetically diverse, multidrug-resistant S. aureus strains with robust virulence profiles. These findings highlight the necessity of integrated One Health surveillance and targeted interventions addressing antimicrobial use and hygiene practices within aquatic food systems. Full article

The energy transition is an issue of fundamental importance in the current global context, as an increasing number of countries are committed to searching for minerals and elements essential for the storage, distribution, and supply of energy derived from new renewable and sustainable sources. In some countries, these elements (such as boron, lithium, and strontium) are considered to be critical raw materials (CRMs) because of their limited occurrence within their own borders and are commonly found in minerals and geothermal–formation waters, especially in brackish to brine waters. In the Italian territory, CRM-rich waters have already been identified by previously published studies (i.e., with mean concentrations in the Salsomaggiore Terme of 390 mg/L of boron, 76 mg/L of lithium, and 414 mg/L of strontium); however, their extraction is hampered by several knowledge gaps. In particular, a comprehensive understanding of the origin, accumulation processes, and migration pathways of these CRM-rich waters is still lacking. These factors are closely linked to the geological framework and evolutionary history of each specific area. To address these gaps, we investigated the Salsomaggiore Structure that is located at the northwestern front of the Apennine in Italy by integrating geological data with hydrogeochemical results. We constructed new preliminary distribution maps of the most significant CRMs around the Salsomaggiore Structure, which can be used in the future for the National Mineral Exploration Program drawn up in accordance with the European Critical Raw Materials Act. These maps, combined with the interpretation of seismic reflection profiles calibrated with surface geology and wells, allowed us to establish a close relationship between water geochemistry/CRM contents and the geological evolution of the Salsomaggiore Structure. This structure can be considered representative of the frontal ranges of the Northwestern Apennine and other mountain chains associated with the foreland basin systems. Full article

This study evaluates Fe₃O₄ magnetic biochar synthesized from pecan nutshells for arsenic removal. Surface modification with Fe₃O₄ significantly enhanced arsenic adsorption selectivity and efficiency compared to raw biomass (PM). Synthesis variables (precursor type, particle size, Fe/precursor ratio, N₂) and adsorption conditions (such as concentration, pH, agitation) were investigated. The modified biochar achieved >90% arsenic removal efficiency under various conditions, demonstrating the modification’s critical role. A fuzzy decision network was employed to analyze experimental results and identify optimal conditions for maximizing performance. This approach effectively leverages knowledge for scenario-specific optimization, offering a sustainable strategy for advanced water treatment materials. Full article

Adsorption is a common method for solving the contamination of methylene blue (MB) in dyeing wastewater. Aerogel adsorbents with high porosity and specific surface areas have attracted increasing attention. However, the high costs of raw materials for aerogel preparation restrict their large-scale production and application. Fly ash (FA), a by-product of coal-fired power plants, is rich in silica and aluminum elements and has the potential to prepare aerogel adsorbents. This study proposed a modified recycling route for FA to synthesize silica–alumina composite aerogel with high specific surface area. FA was pretreated by three steps of alkali fusion, water leaching and acid leaching to obtain a solution rich in silicon and aluminum elements, with a total leaching efficiency of 96.92% and 91.36% for silicon and aluminum, respectively, under optimized alkaline fusion conditions of FA:NaOH mass ratio of 1:1.2, calcination time of 2 h, and calcination temperature of 550 °C. Silica–alumina aerogel with a specific surface area of 661.3 m²/g was then synthesized from the leaching solution through a sol–gel method, exhibiting well-developed mesopores and achieving an adsorption capacity of 52.22 mg/g for MB. The adsorption kinetics and isotherms of MB adsorption by FA-derived silica–alumina composite aerogel was investigated. FTIR characterization confirmed that the adsorption of MB by FA-derived aerogel was mainly physical adsorption. This study provides a new approach for the resource utilization of FA, and the high-specific-surface-area FA-derived aerogel holds potential as an alternative adsorbent for the removal of dyes in wastewater. Full article

Dairy wastewater is highly polluting and requires treatment before being discharged into receiving surface waters or destined for reuse. This study aimed to evaluate the performance of a wastewater treatment plant (WWTP) at a dairy facility, which includes the following treatment stages: screening, grease trap, and an upflow anaerobic filter (UAF). Monitoring data from a WWTP at a dairy situated in the southern region of Minas Gerais, Brazil, were assessed based on pollutant removal efficiency in accordance with Brazilian environmental regulations. The results showed that the WWTP achieved average removal efficiencies of 96.2% for COD and 97.1% for BOD₅. The BOD₅/COD ratio of raw and treated wastewater averaged 0.46 and 0.30, respectively, indicating preferential removal of the biodegradable organic fraction. The treated wastewater complied with legal standards for pH, settleable solids, and total suspended solids. However, at least one sample did not meet regulatory limits for discharge into water bodies regarding surfactants and oils & greases. Strong linear correlations (R²~0.8) between COD and BOD₅ data were observed for both raw and treated wastewater. While the treated wastewater was not suitable for use in the facility’s wood-fired boiler, it may be reused for agricultural irrigation. Full article

Blueberries are in high demand worldwide because of their taste and functional components. However, the shelf life of blueberries is short owing to their perishability and rapid quality deterioration. Therefore, a sterilization technology must be developed that can extend the shelf life of blueberries while maintaining their appearance and taste. As such, we verified the effectiveness of three pre-storage sterilization treatments (UV-C, ozone gas, and ozone water) using mercury-free excimer UV lamps that did not adversely affect the environment. We then created a device that continuously treated blueberries with approximately 2.57 ppm of ozone gas to ensure sterilization during the storage period, and we verified the effectiveness of the device. We found that the pre-storage ozone treatment reduced the number of fungi on the blueberry surface without adversely affecting fruit quality. The continuous ozone treatment suppressed the decrease in anthocyanin content, further reduced the number of fungi on the fruit surface and maintained fruit appearance for a longer period compared with the control. This suggests that continuous low-concentration ozone treatment suppresses the decay and extends the storage period of blueberries intended for raw consumption. Full article