Low sulfur fuel oils (LSFOs) with less than 0.5% sulfur content have been mandated for marine vessels by the International Maritime Organization since 2020. However, owing to the low dispersibility and high viscosity of LSFOs, their oceanic spills are difficult to clean using conventional response systems. In this study, we propose a superhydrophilic and hygroscopic ramie to clean spilled LSFO. To this end, a raw ramie fiber, which is intrinsically hydrophobic, was treated using a mild alkali to remove its waxy, rough, and gummy veneer and reveal a smooth surface. This substantially improved its hygroscopic nature, superhydrophilicity, and water-retention, while preserving its mechanical durability in dry and wet environments. The hygroscopic ramie exhibited underwater superoleophobicity and self-cleaning abilities against highly adhesive LSFOs. Two proofs-of-concept are demonstrated in this study—an oil-proof glove for maximizing oil repellency and a direct oil-scooping device for simple and continuous recovery of spilled oil with high efficiency.

Aquatic particles and organic carbon (OC) regulate the occurrence and transport of hydrophobic organic contaminants such as polycyclic aromatic hydrocarbons (PAHs) in water-suspended particle-sediment interfaces. Conventional studies on the mechanisms regulating the relationships between PAHs and total particles/OC have ignored micro-scale regulatory factors such as particle size and OC composition. Field research in the eutrophic shallow Lake Taihu, China, revealed that the fine particle fractions 2.7–10 μm in diameter had stronger PAH adsorption capacity and significantly regulated PAH particle size distribution and water-particle partitioning. Selective PAH biodegradation by planktonic microorganisms probably significantly weakened the capacity of the coarse fractions to regulate PAHs. OC fragments at different temperature gradients had markedly different influences on the particle size distribution of PAHs. High-temperature pyrogenic OC fractions (part of black carbon) were the principal OC regulatory factors for medium-to high-molecular-weight PAHs. However, the OC fragments did not directly affect the particle distribution of low-molecular-weight PAHs. During particle deposition and burial, microbial PAH utilization and efficiency probably regulated the burial potential of various hydrophobic PAH species. Biodegradation of relatively less hydrophobic PAHs with octanol-water partition coefficients (log Kₒw) < 5.8 showed an increasing trend with decreasing PAH hydrophobicity. Biological pump action of the relatively higher hydrophobic PAH species (log Kₒw > 5.8) showed a decreasing trend with increasing PAH hydrophobicity. The discoveries of the present work further clarified the mechanisms of PAH partitioning and burial in a eutrophic shallow lake and collectively provides a valuable reference for modeling the transport and dispersal mechanisms of hydrophobic, particle-bound organic contaminants in other aquatic ecosystems.

In this study, magnetic biochar (MAB) and humic acid (HA)-coated magnetic biochar produced from apple branches without and after cellulase hydrolysis (HMAB and CHMAB, respectively) were prepared and tested as adsorbents of enrofloxacin (ENR) and moxifloxacin (MFX) in aqueous solution. Compared with MAB and HMAB, novel adsorbent CHMAB possessed a superior mesoporous structure, greater graphitization degree and abundant functional groups. When antibiotic solutions ranged from 2 to 20 mg L⁻¹, the theoretical maximum adsorption capacities of CHMAB for ENR and MFX were 48.3 and 61.5 mg g⁻¹ at 35 °C with adsorbent dosage of 0.4 g L⁻¹, respectively, while those of MAB and HMAB were 39.6 and 54.4 mg g⁻¹, and 44.7 and 59.0 mg g⁻¹, respectively. The pseudo-second-order kinetic model and Langmuir model presented a better fitting to the spontaneous and endothermic adsorption process. The maximum adsorption capacity of ENR and MFX onto CHMAB was achieved at initial pH values of 5 and 8, respectively. Additionally, the adsorption capacity of ENR and MFX decreased with increasing concentrations of K⁺ and Ca²⁺ (0.02–0.1 mol L⁻¹). Synergism between the pore-filling effect, π-π electron-donor-acceptor interactions, regular and negative charge-assisted H-bonding, surface complexation, electrostatic interactions and hydrophobic interactions may dominate the adsorption process. This study demonstrated that a novel magnetic biochar composite prepared through pyrolysis of agricultural waste lignocellulose hydrolyzed by cellulase in combination with HA coating was a promising adsorbent for eliminating quinolone antibiotics from aqueous media.

Multiwalled carbon nanotubes (MWCNTs) were oxidized using a mixture of H₂SO₄ and HNO₃, and the oxidized MWCNTS were decorated with magnetite (Fe₃O₄). Finally, poly-N-isopropyl acrylamide-co-butyl acrylate (P-NIPAM) was added to obtain P-NIPAM/Fe/MWCNT nanocomposites. The nanosorbents were characterized by various techniques, including X-ray diffraction, transmission electron microscopy, scanning electron microscopy, thermogravimetric analysis, and Brunauer–Emmett–Teller analysis. The P-NIPAM/Fe/MWCNT nanocomposites exhibited increased surface hydrophobicity. Owing to their higher adsorption capacity, their kerosene removal efficiency was 95%; by contrast, the as-prepared, oxidized, and magnetite-decorated MWCNTs had removal efficiencies of 45%, 55%, and 68%, respectively. The P-NIPAM/Fe/MWCNT nanocomposites exhibited a sorbent capacity of 8.1 g/g for kerosene removal from water. The highest kerosene removal efficiency from water was obtained at a process time of 45 min, sorbent dose of 0.005 g, solution temperature of 40 °C, and pH 3.5. The P-NIPAM/Fe/MWCNTs showed excellent stability after four cycles of kerosene removal from water followed by regeneration. The reason may be the increase in the positive charge of the polymer at pH 3.5 and the increased adsorption affinity of the adsorbent toward the kerosene contaminant. The pseudo second-order model was found to be the most suitable model for studying the kinetics of the adsorption reaction.

Polycyclic aromatic hydrocarbons (PAHs) are hazardous toxic contaminants and considered as primary pollutants due to their persistent nature and most of them are carcinogenic and mutagenic. The key challenge in PAHs degradation is their hydrophobic nature, which makes them one of the most complex materials and inaccessible by a broad range of microorganisms. This bioavailability can be increased by using a biosurfactant. In the present study mixed PAHs were degraded using the biosurfactant producing bacterial strains. In addition, iron nanoparticles were synthesized and the impact of iron nanoparticles on the growth of the mixed bacterial strains (Pseudomonas stutzeri NA3 and Acinetobacter baumannii MN3) was optimized. The mixed PAHs (anthracene, pyrene, and benzo(a)pyrene) degradation was enhanced by addition of biosurfactant (produced by Bacillus subtilis A1) and iron nanoparticles, resulting in 85% of degradation efficiency. The addition of the biosurfactant increased the bioavailability of the PAHs in the aqueous environment, which might help bacterial cells for the initial settlement and development. The addition of iron nanoparticles increased both bacterial biomass and PAHs adsorption over their surface. These overall interactions assisted in the utilization of PAHs by the mixed bacterial consortia. This study illustrates that this integrated approach can be elaborated for the removal of the complex PAHs pollutants from soil and aqueous environments.

Recalcitrant plastics in the environment are gradually fragmented into weathered debris distinguished from their original state by the integrative action of influencing factors, such as UV light, heating and physical abrasion. As new artificial carbon-source substrates in aquatic ecosystems, plastic products can be colonized by biofilms and even utilized by microorganisms. To investigate the influences of weathering of plastics on the colonized biofilms, freshwater samples from the Yangtze River (Nanjing, China) were collected for biofilm incubation. Based on the characterization of plastics and biofilms, the effects of plastic surface properties on biofilm characteristics were revealed by the analysis of partial least squares regression (PLSR). Roughness was the principal influencing factor, while rigidity had the opposite effect to it. 16S rRNA gene high-throughput sequencing results indicated the high relative abundance of Cyanobacteria and rising proportion of harmful components (e.g., Flavobacterium) on photoaged polyethylene plastics. The microbial functional profiles (KEGG) predicted by Tax4Fun showed that the functions (e.g., membrane transport, energy metabolism, etc.) of biofilm on photoaged plastics were dissimilar with those on original ones. These findings suggested that the distinct microbial community and the adverse functional changes in biofilms on photoaged plastics potentially enhanced their environmental risks. On the other hand, 28-day cultured biofilms on original low-density polyethylene (LDPE) films were dominated by Exiguobacterium. The previously ignored potentials of this microorganism in rapidly accommodating to a hydrophobic substrate and its plastic degrading ability were both worthy of attention. Therefore, it is necessary to consider the weathering process of plastics in exploring the “plastisphere”, and to give further insights into the double-edged nature of the “plastisphere".

The unified bioaccessibility method (UBM) was harnessed to assess in vitro oral bioaccessibility pools of dialkyl phthalate congeners (with methyl, –ethyl, –butylbenzyl, –n-butyl, –2-ethylhexyl, and –n-octyl moieties) and bisphenol A at the 17 μg g⁻¹ level in beach sand contaminated with polyethylene microplastics. A variety of sample preparation approaches prior to the analysis of the UBM gastrointestinal extracts, including traditional methods (protein precipitation, liquid-liquid extraction, and solid-phase extraction) and dispersive liquid-liquid microextraction (DLLME) were comprehensively evaluated for clean-up and analyte enrichment. DLLME was chosen among all tested approaches on account of the high extraction efficiency (73–95%, excluding bis(2-ethylhexyl)phthalate and di-n-octyl phthalate), high sample throughput (∼7 min per set of samples), and environmental friendliness as demonstrated by the analytical eco-scale score of 83, and the green analytical procedure index pictogram with green/yellow labeling. The release of the less hydrophobic plastic-laden compounds (dimethyl phthalate, diethyl phthalate and bisphenol A) from the contaminated sample into the body fluids was significant, with bioaccessibility values ranging from 30 to 70%, and from 43 to 74% in gastric and gastrointestinal fluids, respectively, and with relative standard deviation < 17% in all cases. The majority of the compounds were leached during gastric digestion, likely as the combined action of the low pH and the gastric enzymes. The risk exposure analysis revealed that accumulation/concentration in the body fluids is potentially relevant for dimethyl phthalate, diethyl phthalate and bisphenol A, with relative accumulation ratios ranging from 1.1 ± 0.1 to 2.6 ± 0.4. The average daily intake values for the suite of compounds, corrected with the bioaccessibility fraction, ranged from 60 to 430 ng kg of body weight⁻¹·day⁻¹, in all cases, far below the tolerable daily intakes, thus indicating the lack of children health risk by ingestion of microplastic-laden sand with elevated concentrations of plasticizers.

The robust and eco-friendly super-hydrophobic sponge with remarkable performances has been potential adsorption material for the treatment of offshore oil spills. In this work, the durable PDMS@SiO₂@WS₂ sponge was fabricated via a green and facile one-step dipping method. The mixed tungsten disulfide (WS₂) microparticles and hydrophobic SiO₂ nanoparticles were immobilized on the sponge by non-toxic polydimethylsiloxane (PDMS) glue tier, which featured the hierarchical structure and extreme water repellency with the water contact angle of 158.8 ± 1.4°. The obtained PDMS@SiO₂@WS₂ sponge exhibits high oil adsorption capacity with 12–112 times of its own weight, and oil/water selectivity with separation efficiency over 99.85%. Notably, when subjected to the complex marine environment including high temperature, corrosive condition, insolation, and strong wind and waves, the modified sponge can maintain sable super-hydrophobicity with water contact angle over 150°. Moreover, it possesses superior mechanical stability for sustainable reusability and oil recovery. The sponge fabricated by non-toxic modifiers along with its sable super-hydrophobicity in complex marine environment makes it a potential material for practical applications.

Discharged carbon nanotubes (CNTs) likely interact with co-existing organic contaminants (OCs) and pose joint toxicity to environmental microbes. Herein, hydrophobic pentachlorophenol (PCP) and hydrophilic ciprofloxacin (CIP) were used as representative OCs and their joint toxicities with CNTs to Bacillus subtilis were systematically investigated at cellular, biochemical, and omics levels. The 3-h bacterial growth half inhibitory concentrations of CNTs, PCP, and CIP were 12.5 ± 2.6, 3.5 ± 0.5, and 0.46 ± 0.03 mg/L, respectively, and they all could damage cell membrane, increase intracellular oxidative stress, and alter bacterial metabolomics and transcriptomics; while CNTs-PCP and CNTs-CIP binary exposures exhibited distinct additive and synergistic toxicities, respectively. CNTs increased bacterial bioaccumulation of PCP and CIP via destabilizing and damaging cell membrane. PCP reduced the bioaccumulation of CNTs, while CIP had no significant effect; this difference could be owing to the different effects of the two OCs on cell-surface hydrophobicity and CNTs electronegativity. The additive toxicity outcome upon CNTs-PCP co-exposure could be a result of the balance between the increased toxicity from increased PCP bioaccumulation and the decreased toxicity from decreased CNTs bioaccumulation. The increased bioaccumulation of CIP contributed to the synergistic toxicity upon CNTs-CIP co-exposure, as confirmed by the increased inhibition of topoisomerase Ⅳ activity and interference in gene expressions regulating ABC transporters and lysine biosynthesis. The findings provide novel insights into environmental risks of CNTs.

Toxicokinetic studies appertain to the fundamental research of soil bioavailability. However, the research outcomes of aspects influencing uptake and elimination of hydrophobic organic compounds have not been summarized so far. In our review, a recapitulation of available toxicokinetic data (i.e. experimental conditions, if the steady state was reached, uptake and elimination rate constants, and bioaccumulation factors) is presented in well-arranged tables. Further, toxicokinetic models are overviewed in the schematic form. In the review, the required information could be quickly found and/or the experimental gaps easily identified. Generally a little is known about the effects of soil properties other than soil organic matter. Limited or no data are available about soil treatment, food supply during laboratory exposure, and metabolization in oligochaeta. The impact of these factors might be important especially for arable soils with typically low organic matter content but high consequences on humans. Besides these circumstances, other uncertainties between published studies have been found. Firstly, the scientific results are provided in heterogenous units: bioaccumulation factors as well as the rate constants are reported in dry or wet weight of soil and earthworms. The steady state is another critical factor because the time to reach the equilibrium is influenced not only by soil and compound characteristics but for example also by aging. Nevertheless, toxicokinetic studies bring irreplaceable information about the real situation in soil and our review help to define missing knowledge and estimate the scientific priorities.