Electrospinning fabrication of magnetic nanoparticles-embedded polycaprolactone (PCL) sorbent with enhanced sorption capacity and recovery speed for spilled oil removal

Upcycling of PVC waste to high-value sorbent with KOH-activation for efficient removal of organic dyes

Polyvinyl chloride (PVC), known for its chemical stability and flame-retardant qualities, has many uses in various fields, such as pipes, electric wires, and cable insulation. Research has established its potential recovery as a fluidic fuel through pyrolysis, but the use of PVC pyrolysis oil, which is tainted by chlorine, is constrained by its low heat value and harmful environmental effects. This study engineered a layered double hydroxide (LDH) to tackle these challenges. The LDH facilitated dechlorination during PVC pyrolysis and bolstered thermal stability via cross-linking. During pyrolysis with LDH, PVC was transformed into carbon-rich precursors to sorbents. Chemical activation of these residues using KOH created sorbents with a specific surface area of 1495.4 m2 g⁻1, rendering them hydrophilic. These resulting sorbents displayed impressive adsorption capabilities, removing up to 486.79 mg g⁻1 of methylene blue and exhibiting the simultaneous removal of cations and anions.

Carbon dot/polylactic acid nanofibrous membranes for solar-mediated oil absorption/separation: Performance, environmental sustainability, ecotoxicity and reusability

Carbon dots (CDs) are promising photothermal nanoparticles that can be utilized in environmental treatments. They exhibit favorable physicochemical properties, including low toxicity, physical and chemical stability, photo-dependant reversible behaviour, and environmentally friendly synthesis using benign building blocks. Here, we synthesized innovative CDs/polylactic acid (PLA) electrospun composite membranes for evaluating the removal of hydrophobic compounds like long-chain hydrocarbons or oils in biphasic mixtures with water. The ultimate goal was to develop innovative and sustainable solar-heated oil absorbents. Specifically, we fabricated PLA membranes with varying CD contents, characterized their morphology, thermal, and mechanical properties, and assessed the environmental impact of membrane production according to ISO 14040 and 14044 standards in a preliminary "cradle-to-gate" life cycle assessment study. Solar radiation experiments demonstrated that the CDs/PLA composites exhibited greater uptake of hydrophobic compounds compared to pure PLA membranes, ascribable to the CDs-induced photothermal effect. The adsorption and regeneration capacity of the new CDs/PLA membrane was demonstrated through multiple uptake/release cycles. Ecotoxicity analyses confirmed the safety profile of the new adsorbent system towards freshwater microalgae, further emphasizing its potential as an environmentally friendly solution for the removal of hydrophobic compounds in water treatment processes.

Enhancement of AFB1 Removal Efficiency via Adsorption/Photocatalysis Synergy Using Surface-Modified Electrospun PCL-g-C3N4/CQDs Membranes

Aflatoxin B₁ (AFB₁) is a highly toxic mycotoxin produced by aspergillus species under specific conditions as secondary metabolites. In this study, types of PCL (Polycaprolactone) membranes anchored (or not) to g-C₃N₄/CQDs composites were prepared using electrospinning technology with (or without) the following surface modification treatment to remove AFB₁. These membranes and g-C₃N₄/CQDs composites were characterized by SEM, TEM, UV-vis, XRD, XPS and FTIR to analyze their physical and chemical properties. Among them, the modified PCL-g-C₃N₄/CQDs electrospun membranes exhibited an excellent ability to degrade AFB₁ via synergistic effects of adsorption and photocatalysis, and the degradation rate of 0.5 μg/mL AFB₁ solution was observed to be up to 96.88% in 30 min under visible light irradiation. Moreover, the modified PCL-g-C₃N₄/CQDs electrospun membranes could be removed directly after the reaction process without centrifugal or magnetic separation, and the regeneration was a green approach synchronized with the reaction under visible light avoiding physical or chemical treatment. The mechanism of adsorption by electrostatic attraction and hydrogen bonding interaction was revealed and the mechanism of photodegradation of AFB₁ was also proposed based on active species trapping experiments. This study illuminated the highly synergic adsorption and photocatalytic AFB₁ removal efficiency without side effects from the modified PCL-g-C₃N₄/CQDs electrospun membranes, thereby offering a continual and green solution to AFB₁ removal in practical application.

Ultrafast and on-demand oil/water separation with vertically aligned cellulosic smart sponge

Slow oil sorption speed of commercial non-woven polypropylene (PP) sorbent remains a major challenge for efficient clean-up of oil spillage. Adsorption-based polymeric sponge oil removing offers an appealing way to solve this challenge by increasing surface area. However, the tortuous oil sorption path and plastic waste after oil uptake are two long-standing bottlenecks for realizing efficient oil spill removal. Here, we report a vertically aligned-biomass fiber junctioned sorbents (a-BFJS), by confining delignified biomass with carbon nanotube (CNT), polyvinyl alcohol (PVA), and methyltrimethoxysilane (MTMS). The sorbent shows an excellent performance towards xylene sorption capacity with uptake about 50 g g^-1 within 10 s. This is due to the wide and short pathway of their aligned channels, which improves the capillary effect and fast oil transport in the oriented channels. Moreover, the sponge exhibits fast oil sorption-desorption kinetics enabled by simple mechanical squeezing. We further engineered a scalable rapid continuous oil skimming with simple peristaltic pump. The oil recovering using a-BFJS realized high oil selectivity from xylene/water emulsion. Our demonstration of the high-performance aligned channel sorbent and scalable oil removing sponge offers an eco-friendly and promising strategy for efficiently removing oil from oil spills from water.