Search Results (109)

An inorganic–organic hybrid nano-adsorbent was prepared by chemical immobilisation of an organic Schiff base Cu (II) ion receptor, DHB ((E)-N-(1-(2-hydroxy-6-methyl-4-oxo-4H-pyran-3-yl) ethylidene) benzohydrazide), a selective dehydroacetic acid-based chemosensor, onto a mesoporous silica support. In order to prepare the sorbent, the silylating agent was anchored onto the silica. During this procedure, 3-Chloropropyl trimethoxy silane (CPTS) was attached to the surface, increasing hydrophobicity. By immobilising DHB onto the CPTS platform, the silica surface was activated, and as a result the coordination chemistry of the Schiff base generated a hybrid adsorbent with the capability to rapidly sequestrate Cu (II) ions from wastewater, as an answer to combat growing Waste Electrical and Electronic Equipment (WEEE) contamination in water supplies, in the wake of a prolonged consumerism mentality and boom in cryptocurrency mining. The produced hybrid materials were characterised by FTIR, proximate and ultimate analysis, nitrogen physisorption, PXRD, SEM, and TEM. The parameters influencing the removal efficiency of the sorbent, including pH, initial metal ion concentration, contact time, and adsorbent dosage, were optimised to achieve enhanced removal efficiency. Under optimal conditions (pH 7.0, adsorbent dosage 3 mg, contact time of 70 min, and 25 °C), Cu (II) ions were quantitatively sequestered from the sample solution; 93.1% of Cu (II) was removed under these conditions. The adsorption was found to follow pseudo-second-order kinetics, and Langmuir model fitting affirmed the monolayer adsorption. Full article

Microplastics (MPs) are recognised as emerging vectors for hydrophobic organic contaminants in aquatic environments due to their relatively large surface area and the diversity of their polymer chemistries compositions. This study investigates the sorption behaviour of two priority polycyclic aromatic hydrocarbons (PAHs), pyrene (PYR) and fluoranthene (FLU), onto six common MPs: poly(m-xylene adipamide) (PA-MXD6), high- and low-density polyethylene (HDPE, LDPE), polypropylene (PP), polyethylene terephthalate (PET), and polylactic acid (PLA). Sorption isotherms and kinetics were evaluated under simulated freshwater conditions at environmentally relevant concentrations (1–50 µg·L⁻¹). Despite the low MP concentration used (0.2 g·L⁻¹), over 80% of the initial PAH content was removed by polyolefins, and more than 50% by all other MPs. Sorption capacity was strongly dependent on particle surface area. Langmuir, Henry, and Freundlich isotherms models were fitted, with linear behaviour prevailing at low concentrations. Analysis using the Dubini–-Radushkevich model confirmed that sorption involves chemisorption contributions, mainly through π–π interactions and hydrophobic interactions (polyolefins). Mechanistically, molecular diffusion within the MP matrix was not governing the sorption process, as diffusion coefficients varied with particle size instead of polymer chemistry. Instead, sorption appears to be governed by PAH diffusion through the hydrodynamic boundary layer and subsequent retention on the MP surface. Empirically, kinetic data fitted the pseudo-second-order model, further supporting that the sorption process involves chemisorption. These findings highlight the role of MPs as vectors for PAHs in freshwater systems and their potential application in contaminant removal. Expressing sorption per unit surface area is recommended for accurate assessment. This work contributes to understanding the environmental behaviour of MPs and their implications for pollutant transport and toxicity. Full article

Bentonite is the most widely used raw material for producing organoclays, which have numerous industrial and environmental applications. Due to their hydrophobicity, high swelling, and strong affinity for organic compounds, organoclays are effective in removing organic solvents from contaminated water originating from pipeline leaks, oil spills, traffic accidents, and industrial discharges. Such contamination not only degrades water quality but also forms surface films that hinder oxygen transfer, threatening aquatic ecosystems. In this study, two sodium bentonites with different specific surface areas (30 and 50 m²/g) were modified with three quaternary ammonium salts of varying molar masses and alkyl chain lengths (Sun, Arq, and Arm) to evaluate their performance in organic solvent sorption (gasoline, diesel, and kerosene). The materials were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), scanning electron microscopy (SEM), and swelling capacity and sorption efficiency. The swelling capacity was determined according to ASTM D5890-19 (Foster method) using gasoline, diesel, kerosene, toluene, and xylene, while the sorption efficiency was assessed following ASTM F726-17 in gasoline, diesel, and kerosene, chosen due to their high potential for water contamination and frequent occurrence in oil spill and leakage scenarios. These solvents also differ in polarity and aromatic content, providing a relevant model for hydrocarbon mixtures commonly found in the environment. Results showed that the interaction between the clay and the surfactant depended strongly on the modifier’s chemical structure. The sorption capacity increased with greater interlayer expansion, surfactant molar mass, and specific surface area of the clay. Among all samples, the Arm-modified natural bentonite (VLArm) exhibited the best performance, with adsorption capacities of up to 6 g/g for diesel, 5 g/g for gasoline, and 5 g/g for kerosene. These values exceeded most previously reported organoclays. These findings demonstrate that optimizing the combination of clay properties and surfactant chemistry can yield highly efficient, low-cost organoclays for environmental remediation of organic contaminants. Full article

Carbonaceous amendments are widely proposed to sequester hydrophobic organic contaminants in sediments, yet their effectiveness for alkylphenolic endocrine disruptors in organic-rich freshwater systems—and its time dependence—remains poorly constrained. Here, we compared activated carbon (AC), biochar (BC), and humic compost (HC) for reducing desorption and maize phytoexposure to 4-octylphenol (4-OP) and 4-nonylphenol (4-NP) in canal sediment from the Jegrička River. Sediment was spiked (~1.1 mg kg⁻¹ 4-OP; 1.2 mg kg⁻¹ 4-NP), amended with 0.5–10% (w/w) AC, BC, or HC, and aged for up to 180 days prior to multi-step XAD-4 desorption tests. A two-compartment first-order model resolved fast- and slow-desorbing pools, while a 10-day maize (Zea mays L.) pot experiment quantified early phytoextraction and sediment–plant–loss mass balances for AC and HC treatments. The unamended sediment exhibited high operational bioavailability: ~98% of both alkylphenols were XAD-4-extractable, and 83–89% of the desorbable pool was released within 24 h. AC produced the most rapid immobilization; at 0.5–1%, it halved XAD-4-extractable fractions within weeks and reduced them to near-zero within months, whereas BC and HC achieved comparable reductions only after longer aging. Plant uptake was a minor sink: in the control, shoots accumulated ~21 µg kg⁻¹ sediment of 4-OP and 65 µg kg⁻¹ sediment of 4-NP (≈2% and 5% of the initial inventory). HC generally lowered uptake, and high AC doses kept plant burdens consistently low. Overall, amendment-enhanced sorption and sequestration dominated attenuation, with AC delivering the fastest risk reduction and HC representing a more plant-compatible amendment option. Full article

The pervasive presence of nanoplastics (NPs) in the soil environment has been widely documented. However, the mechanisms governing their transport through soil remain poorly understood. This study investigated the migration and vertical distribution of NPs under simulated rainfall, examining the effects of NP properties (concentration, polymer type, aging) and rainfall conditions (duration, pH). The results demonstrated that rainfall facilitated the entry and retention of NPs in soil, with long-term rainfall promoting gradual migration to deeper layers or groundwater. NP mobility was inversely related to their contamination levels. Lower concentrations enhanced downward transport, while higher concentrations led to preferential retention in the topsoil. Due to its hydrophilicity, polyamide (PA) exhibits greater mobility in soil than hydrophobic polystyrene (PS). Both UV aging and acidic rainfall conditions inhibited the migration of NPs, which increased their long-term retention in soil, thereby elevating ecological risk. These results highlight the need for increased attention to the risk of groundwater contamination posed by hydrophilic NPs following long-term rainfall, as well as the threat posed by hydrophobic NPs, particularly after aging and under acidic rainfall conditions, to soil organisms and food safety. Our findings provide critical insights for assessing NP risks in soil environments. Full article

Studies have shown that natural organic matter can regulate pollutant behavior through multiple pathways; however, research on the environmental behavior of veterinary antibiotics (VAs) in typical alkaline calcareous loess soil under the influence of exogenous organic matter remains limited. This study investigated the influence of humic acid (HA), as a representative of natural organic matter, on the sorption behavior of ciprofloxacin (CIP) in sierozem—a typical alkaline calcareous loess soil. Using the batch equilibrium method, we examined how HA affects CIP sorption under various environmental conditions to better understand the environmental fate of VAs in soil–water systems with low organic matrix content. Results showed that CIP sorption onto sierozem involved both fast and slow processes, reaching equilibrium within 2 h, with sorption capacity increasing as HA concentration increased. Kinetic data were well described by the pseudo-second-order model regardless of HA addition, suggesting multiple mechanisms governing CIP sorption, such as chemical sorption reaction, intraparticle diffusion, film diffusion, etc. Sorption decreased with increasing temperature both before and after HA amendment, indicating an exothermic process. Isotherm analysis revealed that both the Linear and Freundlich models provided excellent fits (R² ≈ 1), implying multilayer sorption dominated by hydrophobic distribution. In ion effect experiments, cations at concentrations above 0.05 mol/L consistently inhibited CIP sorption, with inhibition strength following the order: Mg²⁺ > K⁺ > Ca²⁺ > NH₄⁺, and intensifying with increasing ionic strength. However, HA addition significantly mitigated this inhibition, likely due to complexation between HA’s functional groups (e.g., carboxyl and hydroxyl) and cations, which reduced their competitive effect and enhanced CIP sorption. pH-dependent experiments indicated stronger CIP sorption under acidic conditions. HA addition increased soil acidity, further promoting CIP retention. In summary, HA enhances CIP sorption in sierozem by providing additional sorption sites and modifying soil surface properties. These findings improve our understanding of how exogenous organic matter influences the behavior of emerging contaminants such as antibiotics in soil–water systems, offering valuable insights for environmental risk assessment in semi-arid agricultural regions. Full article

Wastewater-derived microplastics (WW-MPs) are increasingly recognised as reactive vectors for aromatic organic contaminants (AOCs), yet their role in contaminant fate remains insufficiently constrained. This review synthesises current knowledge on the transformation of microplastics in wastewater treatment plants, including fragmentation, oxidative ageing, additive leaching, and biofilm formation, and links these processes to changes in sorption capacity toward phenols, PAHs and their derivatives, and organochlorine pesticides (OCPs). We summarise the dominant adsorption mechanisms-hydrophobic partitioning, π-π interactions, hydrogen bonding, and electrostatic and, in some cases, halogen bonding-and critically evaluate how wastewater-relevant parameters (pH, ionic strength, dissolved organic matter, temperature, and biofilms) can modulate these interactions. Evidence in the literature consistently shows that ageing and biofouling enhance WW-MP affinity for many AOCs, reinforcing their function as mobile carriers. However, major gaps persist, including limited data on real wastewater-aged MPs, lack of methodological standardisation, and incomplete representation of ageing, competitive sorption, and non-equilibrium diffusion in existing isotherm and kinetic models. We propose key descriptors that should be incorporated into future sorption and fate frameworks and discuss how WW-MP-AOC interactions may influence ecological exposure, bioavailability, and risk assessment. This critical analysis supports more realistic predictions of AOC behaviour in wastewater environments. Full article

Microplastics (MPs) and nanoplastics (NPs) are emerging aquatic contaminants that pose environmental and public health risks due to their persistence, ubiquity, and ability to adsorb co-contaminants. This scoping review synthesises findings from 57 experimental studies and five review studies published between 2019 and 2025 on the use of biochar-based materials for the removal of microplastics from water and wastewater. Guided by the hypothesis that surface-modified biochars, such as magnetised, surfactant-coated, or chemically activated forms, achieve high removal efficiencies through multimodal mechanisms (e.g., electrostatic attraction, hydrophobic interactions, π–π stacking, and physical entrapment), this review applies PRISMA-based protocols to systematically evaluate biochar feedstocks, pyrolysis conditions, surface modifications, polymer types, removal mechanisms, and regeneration approaches. Scopus, Web of Science, and PubMed were searched until 30 May 2025 (English-only), and 62 studies were included. The review was not registered, and no protocol was prepared. The results confirm a high removal efficiency (>90%) in most experimental studies, particularly under controlled laboratory conditions and using pristine polystyrene. However, the performance declines significantly in complex matrices (e.g., wastewater and surface water) owing to dissolved organic matter, ionic competition, and particle heterogeneity, thus supporting the guiding hypothesis. This review also identifies critical methodological gaps, including narrow plastic typologies, a lack of standardised testing protocols, and limited field-scale validation. Addressing these gaps through environmentally realistic testing, regeneration optimisation, and harmonised methods is essential for transitioning biochar from a promising sorbent to a practical water treatment solution. Full article

Mycotoxins commonly contaminate grains and traditional Chinese medicinal materials, posing serious health risks to humans and animals. To address this issue, a magnetic microporous organic network (MMON) was synthesized via an in situ growth method and Sonogashira–Hagihara coupling for the simultaneous adsorption of seven mycotoxins, followed by UPLC-MS/MS detection. The optimized MMON featured a high surface area, uniform micropores, and rapid magnetic separation within 5 s. Structural and compositional analyses confirmed its tailored architecture, while DFT calculations revealed a pore confinement effect, π–π stacking, and hydrophobic interactions as the primary adsorption mechanisms. A magnetic solid-phase extraction (MSPE) method using 8 mg of MMON achieved adsorption equilibrium within 10 s in 5 mL of a 4 mg/L mycotoxin standard solution. The material maintained over 95% efficiency across ten reuse cycles at a low cost. Under optimal conditions, an MSPE-UPLC-MS/MS method with a low detection limit (0.002–0.15 μg/L), wide linear range (0.01–100.0 μg/L), large enrichment factor (20.1–21.9), low adsorbent dosage, and short extraction time was developed. The determination of mycotoxins in complex grain-based foods and herbal products was also realized with recoveries of 81.32% to 116.10%. This work offers a rapid, cost-effective, and high-throughput approach for mycotoxin detection, supporting quality control in food and herbal product safety. Full article

Water resource management and agricultural practices in the Mediterranean region, characterised by the excessive use of pesticides, pose significant environmental and human health challenges. As they can be easily and inexpensively produced from various biomass sources, biochars are frequently recommended as a low-cost secondary decontamination strategy to address soil contamination problems. This study investigates the properties and sorption behaviours of biochars produced in a low-cost metallic kiln using local rosemary, giant reed, St. John’s wort, olive, cypress, and palm tree biomass residues to evaluate their potential for environmental remediation, with a special focus on the mobility and retention of contaminants. Analytical and experimental techniques were employed to characterise the biochars’ physicochemical attributes and sorptive capacities. The core analyses included measurement of basic physicochemical properties, including pH, electrical conductivity, functional group identification via Fourier transform infrared (FTIR) spectroscopy, and the molarity of ethanol droplet (MED) test to assess the surface hydrophobicity. Batch sorption experiments were conducted using methylene blue (MB) and two fluorescent tracers—uranine (UR) and sulforhodamine-B (SRB)—as proxies for organic contaminants to assess the adsorption efficiency and molecule–biochar interactions. Furthermore, the adsorption isotherms at 20 °C were fitted to different models to assess the biochars’ specific surface areas. Thermodynamic parameters were also evaluated to understand the nature and strength of the adsorption processes. The results highlight the influence of feedstock type on the resulting biochar’s properties, thus significantly affecting the mechanism of adsorption. Rosemary biochar was found to have the highest specific surface area (SSA) and cation exchange capacity (CEC), allowing it to adsorb a wide range of organic molecules. Giant reed and palm tree biochars showed similar properties. In contrast, wood-derived biochars generally showed very low SSA, moderate CEC, and low hydrophobicity. The contrasting properties of the three dyes—MB (cationic), UR (anionic), and SRB (zwitterionic)—enabled us to highlight the distinct interaction mechanisms between each dye and the surface functional groups of the different biochars. The reactivity and sorption efficiency of a biochar depend strongly on both the nature of the target molecule and the intrinsic properties of the biochar, particularly its pH. The findings of this study demonstrate the importance of matching biochar characteristics to specific contaminant types for optimised environmental applications, providing implications for the use of tailored biochars in pollutant mitigation strategies. Full article

Per- and polyfluoroalkyl substances (PFASs) are a broad group of synthetic chemicals characterized by strong carbon–fluorine bonds, making them highly persistent and widely distributed in the environment. Their chain length and functional head groups, such as sulfonate and carboxylate groups, determine key molecular properties like hydrophobicity, acidity, and sorption behavior. These properties significantly impact the effectiveness of PFAS removal from water systems. This review provides a structural classification of PFASs and explores removal strategies, with a particular emphasis on adsorption. It examines sustainable adsorbents, including both natural materials (e.g., cellulose, chitosan, lignin, and cyclodextrins) and engineered synthetic materials (e.g., covalent organic frameworks, metal–organic frameworks, and molecularly imprinted polymers). The discussion highlights important parameters such as chain length and functional chemistry, as these can greatly influence removal efficiency. Furthermore, the discussion addresses the adsorption mechanisms-such as electrostatic attraction, hydrophobic interaction, and fluorophilic interactions-to show how they contribute in different systems. By combining structural insights with adsorption performance data, this review aims to help design and select sustainable, high-performance adsorbents for efficiently reducing PFASs in contaminated water. Full article

The inherent hydrophobicity of poly(vinylidene fluoride) (PVDF) ultrafiltration membranes leads to severe membrane fouling when processing proteinaceous solutions and organic contaminants, significantly limiting their practical applications. This study presents a novel metal-ion mediated co-deposition strategy for fabricating high-performance antifouling poly(vinylidene fluoride) (PVDF) hollow fiber ultrafiltration membranes. Through Zn²⁺ coordination-driven self-assembly, a uniform and stable composite coating of dopamine (DA), tannic acid (TA), and ZIF-8 nanoparticles was successfully constructed on the membrane surface under mild conditions. The modified membrane exhibited significantly enhanced hydrophilicity, with a water contact angle of 21° and zeta potential of −29.68 mV, facilitating the formation of a dense hydration layer that effectively prevented protein adhesion. The membrane demonstrated exceptional separation performance, achieving a pure water permeability of 771 L/(m²∙h∙bar) and bovine serum albumin (BSA) rejection of 97.7%. Furthermore, it showed outstanding antifouling capability with flux recovery rates exceeding 83.6%, 74.7%, and 71.5% after fouling by BSA, lysozyme, and ovalbumin, respectively. xDLVO analysis revealed substantially increased interfacial free energy and stronger repulsive interactions between the modified surface and protein foulants. The antifouling mechanism was attributed to the synergistic effects of hydration layer formation, optimized pore structure, additional water transport pathways from ZIF-8 incorporation, and electrostatic repulsion from negatively charged surface groups. This work provides valuable insights into the rational design of high-performance antifouling membranes for sustainable water treatment and protein separation applications. Full article

Commercial hydrophobic membranes encounter severe problems such as membrane wetting and membrane fouling under extreme conditions, which affect membrane separation performance. To enhance the anti-fouling abilities of hydrophobic membranes, a composite membrane with omniphobic characteristics was fabricated successfully in this paper. Titanium dioxide (TiO₂) nanoparticles were in-situ grown via the hydrothermal synthesis method, and then fluorosilane with low surface energy was grafted on polyvinylidene fluoride (PVDF) membranes. Subsequently, the morphologies, chemical compositions, wetting properties and structural parameters of composite membranes were characterized systematically. Various contaminants were added to the feed to investigate the anti-fouling and anti-wetting performances of the composite membrane in membrane distillation tests. The results showed that butyl titanate was first hydrolyzed to form titanium hydroxide (Ti(OH)₄) and then it was dehydrated to form TiO₂ in the hydrothermal environment. TiO₂ crystals continued to grow and formed rough morphology with micro-nano synergistic distribution, which is similar to a “sunflower” disk composed of cubic clusters and nanopillars. Meanwhile, fluorosilane successfully was grafted onto TiO₂. The contact angles of deionized water, 0.4 mM sodium dodecyl sulfate (SDS) solution and 0.2% v/v mineral oil emulsion on the composite membrane surface were 167.3°, 162.0° and 158.5°, respectively, endowing the composite membrane with excellent omniphobic features. In direct contact membrane distillation (DCMD) tests, the composite membrane exhibited a relatively stable membrane permeate flux, and the salt rejection rate almost reached 100%. The mixture, consisting of inorganic salts, organic substances, surfactants and oil emulsions, was used as feed. In contrast, the commercial PVDF membrane flux decreased drastically and even dropped to 0 due to the membrane fouling and wetting. As for the pristine PVDF membrane, the membrane surface was covered with pollutants and membrane pores were blocked. Therefore, it was proved that the omniphobic composite membrane possesses outstanding anti-fouling and anti-wetting performance. Full article

The biological aging of titanium implants, marked by increased surface hydrophobicity and organic contamination, reduces bioactivity and delays osseointegration. A major challenge in implant dentistry is determining how to preserve surface hydrophilicity during storage, as conventional atmospheric conditions accelerate surface degradation. This pilot in vivo study aimed to evaluate ozone nanobubble water (NBW3) as a storage medium to prevent biological aging and enhance the early-stage osseointegration of glow discharge-treated titanium implants. Screw-type implants were stored in either NBW3 or atmospheric conditions and then implanted into femoral bone defects in Sprague Dawley rats. Removal torque testing, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and histological analysis of bone-to-implant contact (BIC) were performed 14 and 28 days post-implantation. At 14 days, the NBW3-stored implants demonstrated significantly higher removal torque (2.08 ± 0.12 vs. 1.37 ± 0.20 N·cm), BIC (65.74 ± 12.65% vs. 44.04 ± 14.25%), and Ca/P atomic ratio (1.20 ± 0.32 vs. 1.00 ± 0.22) than the controls. These differences were not observed at 28 days, indicating NBW3’s primary role in accelerating early osseointegration. The findings suggest that using NBW3 is a simple, effective approach to maintain implant surface bioactivity during storage, potentially improving clinical outcomes under early or immediate loading protocols. Full article

Background/Objectives: Antibiotic contamination in water sources is a growing global concern, contributing to environmental degradation and the proliferation of antimicrobial resistance. Traditional treatment methods, such as advanced oxidation or high-pressure membrane processes, are often energy-intensive and economically unsustainable for large-scale or decentralized applications. This study explores the potential of two cost-effective, commercially available metal–organic frameworks (MOFs), ZIF-8 and F300, to improve the performance of membrane-based filtration–adsorption systems for removing tetracycline and sulfadiazine from water. Methods: Batch adsorption experiments were performed to evaluate the uptake capacities, kinetics, and isotherms of both MOFs toward the selected antibiotics. The membranes were modified using a low-cost silane-assisted deposition of MOF particles and tested in a microfiltration system. Removal efficiencies and water permeability were assessed and kinetic and isotherm models were applied to understand the adsorption mechanisms. Results: ZIF-8 showed superior adsorption performance, with maximum capacities of 442.2 mg/g for tetracycline and 219.3 mg/g for sulfadiazine. F300 was effective only for tetracycline. Membranes modified with ZIF-8 improved pharmaceutical removal by 187% (tetracycline) and 224% (sulfadiazine) compared to unmodified membranes. Although permeability decreased due to increased hydrophobicity, the materials and processes remained economically favorable. Conclusions: This study demonstrates that MOF-modified ceramic membranes, particularly those incorporating ZIF-8, offer a low-cost, scalable, and energy-efficient alternative for pharmaceutical removal from water. The approach combines strong environmental impact with economic viability, making it attractive for broader implementation in water treatment systems. Full article