Preparation of adsorptive polyethyleneimine/polyvinyl chloride electrospun nanofiber membrane: Characterization and application

Optimized design of quaternary amino-functionalized chitosan fibers for ultra-high diclofenac adsorption from wastewater

The extraction of non-steroidal anti-inflammatory drugs (NSAIDs) from water bodies is imperative due to the potential harm to humans and the ecosystem caused by NSAID-contaminated water. Quaternary amino-functionalized epichlorohydrin cross-linked chitosan fibers (QECFs), an economical and eco-friendly adsorbent, were successfully prepared using a simple and gentle method for efficient diclofenac (DCF) adsorption. Additionally, the optimized factors for the preparation of QECFs included epichlorohydrin concentration, pH, temperature, and (3-chloro-2-hydroxypropyl) trimethylammonium chloride (CHTAC) concentration. QECFs demonstrated excellent adsorption performance for DCF across a broad pH range of 7-12. The calculated maximum adsorption capacity and the amount of adsorbed DCF per adsorption site were determined to be 987.5 ± 20.1 mg/g and 1.2 ± 0.2, respectively, according to the D-R and Hill isotherm models, at pH 7 within 180 min. This performance surpassed that of previously reported adsorbents. The regeneration of QECFs could be achieved using a 0.5 mol/L NaOH solution within 90 min, with QECFs retaining their original fiber form and experiencing only a 9.18% reduction in adsorption capacity after 5 cycles. The Fourier transform infrared spectrometer and X-ray photoelectron spectroscopy were used to study the characterization of QECFs, the preparation mechanism of QECFs, and the adsorption mechanism of DCF by QECFs. Quaternary ammonium groups (R4N+) were well developed in QECFs through the reaction between amino/hydroxyl groups on chitosan and CHTAC, and approximately 0.98 CHTAC molecule with 0.98 R4N+ group were immobilized on each chitosan monomer. Additionally, these R4N+ on QECFs played a crucial role in the removal of DCF.

Achieving Cross Time-Domain Multiplexed Signal Cascade and Cancer Exosomes Identification by Bridging Long Lifetime Phosphor to NIR-II Lanthanide Energy Transfer

Designing lanthanide luminescence lifetime sensors in the second near-infrared (NIR-II) window holds great potentials for physiological studies. However, the single lifetime signal is confined to one or two orders of magnitude of signal variation, which limits the sensitivity of lifetime probes. In this study, a lifetime cascade system, i.e., ZGO:Mn, Eu-DNA-1/TCPP-PEI70K @Yb-AptEpCAM , with a variety of signals (τm , τn , τµ , τm /τn and τm /τµ ) is constructed for exosome identification using time-domain multiplexing. The sensitized ligand TCPP acts as both target-modulated switch and a bridge for connecting long lifetime ZGO:Mn, Eu-DNA-1 emitter to lanthanide Yb3+ . This drives successive dual-path energy transfer and forms two D(donor) -A(acceptor) pairs. The lifetime variation is dominantly modulated by arranging TCPP as energy intermediate relay to covert milliseconds to nanoseconds to microseconds. It enables a broad lifetime range of six orders of magnitude. The presence of exosome specifically recognizes aptamers on TCPP-PEI70K @Yb-AptEpCAM to impede D-A pairs and reverse multiplexed response signals of the lifetime cascade system. The ratio lifetime signals τm /τn and τm /τµ achieve prominent exosome quantification and exosome type differentiation attributed to signal amplification. The cascade system relying on lifetime criteria can realize precise quantization and provide an effective strategy for subsequent physiological study.

Concentration analysis of metal-labeled nanoplastics in different water samples using electrochemistry

Despite the threats posed by nanoplastics to the environment and human health, little was known about the occurrence, formation, migration, and environmental impacts of nanoplastics due to the lack of quantitative and sensitive detection techniques. In this work, an electrochemical strategy for the detection of nanoplastics based on Ag labeling was proposed. Positively charged silver ions were attached to negatively charged polystyrene nanoplastics (PSNPs), and then the silver ions on the surface of PSNPs were reduced to Ag by sodium borohydride. Subsequently, the concentration of PSNPs was determined by identifying the signal of Ag by differential pulse voltammetry. The method showed different sensitivity for PSNPs of different sizes (100, 367, 500 nm). For tap water samples, the reason for the change in Ag electrochemical signal was discussed. The sensitivity of the method to PSNPs in tap water was investigated. The feasibility of the method for environmental water samples was verified using spiked lake water and spiked seawater, and satisfactory recoveries (93-112 %) were obtained for PSNPs of different sizes and concentrations. This study provided a sensitive, low-cost, and simple method without complex instrumentation, which was important for the determination of PSNPs in environmental water samples.

Chemiluminescence sensing for Hg2+ in environment water using carbon materials from PVC dechlorination as signal initiator

Chemiluminescence (CL) sensing with good performance remains a challenge. The utilization of secondary residues from polyvinyl chloride (PVC) treatment is the key to improve PVC recycling rate. Herein, dechlorinated carbon materials from PVC/iron scrap co-treatment in subcritical water were used as CL sensing element. It was found that tiny changes in the spatial structure of aptamer could cause huge changes in CL signal of the residue-luminol system. A CL biosensor was constructed for mercury in environment water for the first time. The detection limit was estimated to be 0.37 pM. High sensitivity was mainly due to strong CL triggering and signal amplification from residues and effective regulating residue activity by aptamer space dimension. For real water samples, the results by residue CL analysis were consistent with that by cold vapor atom adsorption spectroscopy (CVAAS). Most strikingly, the used material was secondary residues from the treatment of PVC waste, which reduced the time and energy consumption of CL sensing. This research proposed the approach for routine monitoring mercury in environment but also provided the reference for developing other environmentally beneficial analysis platforms.