A Novel Magnetic ß-Cyclodextrin-Modified Graphene Oxide and Chitosan Composite as an Adsorbent for Trace Extraction of Four Bisphenol Pollutants from Environmental Water Samples and Food Samples.

In this study, a novel functionalized magnetic composite (MNCGC) for magnetic solid-phase extraction of bisphenols from environmental and food samples was developed, featuring a multistep synthesis with Fe3O4, chitosan, graphene oxide, and ß-cyclodextrin, crosslinked by glutaraldehyde. Characterization confirmed its advantageous morphology, intact crystal structure of the magnetic core, specific surface area, and magnetization, enabling efficient adsorption and separation via an external magnetic field. The optimized MSPE-HPLC-FLD method demonstrated excellent sensitivity, linearity, and recovery rates exceeding 80% for bisphenol pollutants, validating the method's effectiveness in enriching and detecting trace levels of bisphenols in complex matrices. This approach offers a new avenue for analyzing multiple bisphenol residues, with successful application to environmental water and food samples, showing high recovery rates.

Adsorption behavior and interaction mechanism of microplastics with typical hydrophilic pharmaceuticals and personal care products.

Microplastics (MPs) and pharmaceuticals and personal care products (PPCPs) are two types of emerging contaminants widely present in the global aquatic ecosystem. The ecological risks associated with the coexistence of these two contaminants have garnered increasing attention from researchers. In this study, we selected 15 typical hydrophilic PPCPs, including Sulfacetamide (SA), Thiamphenicol, Florfenicol, Chloramphenicol (CHL), Ampicillin, Cephalexin, Ofloxacin, Fluorouracil, Phenytoin, Theophylline, Cimetidine, Methylparaben, Diethyltoluamide, Benzophenone-2 (BP-2), and Benzophenone-4, as adsorbates. We evaluated the adsorption potential of five traditional plastics (TPs), namely Polyamide 6 (PA6), Polystyrene (PS), Polyethylene terephthalate (PET), Polyvinyl chloride (PVC), and Polyurethane (TPU), as well as three biodegradable plastics (BDPs), including Polylactic acid (PLA), Polybutylene succinate (PBS), and Poly (ε-caprolactone) (PCL), for these adsorbates. Out of the 120 combinations of MPs and PPCPs tested, only 24 exhibited significant adsorption behavior. Notably, the adsorption performance of the three BDPs was stronger than that of the three typical TPs (PS, PET, and PVC). Based on their adsorption potential, PA6, BDPs, phenytoin, and BP-2 were identified as potential sources of high ecological risk. To further explore the adsorption mechanism, we investigated the adsorption behaviors of SA, BP-2, and CHL on PA6. The conclusions were as follows: SA, BP-2, and CHL all reached adsorption equilibrium within 24 h, with the partition coefficient (Kd) following this order: BP-2 (8.051) â‰« SA (0.052) > CHL (0.018). The primary forces of adsorption were electrostatic interactions, intermolecular hydrogen bonding, and hydrophobic interaction, respectively. Additionally, weak electrostatic effects were observed in the adsorption of CHL and BP-2. The effects of pH, ionic strength, and fulvic acid on adsorption capacity varied. These results highlight a complex adsorption mechanism between MPs and hydrophilic contaminants in the aquatic environment. This study provides a basis for further evaluating the ecological risks of MPs and PPCPs combined pollution.

Degradation pathway of triazole fungicides and synchronous removal of transformation products via photo-electrocatalytic oxidation tandem MoS2 adsorption.

A simple and effective tandem process of photo-electrocatalytic oxidation (PECO)-MoS2 adsorption was developed for the synchronous removal of triazole fungicides (TFs) and toxicological transformation products (TPs). In order to accurately identify trace TPs and evaluate degradation pathway during water treatment, a sensitive analytical method was developed on the basis of the stir bar sorptive extraction (SBSE) pretreatment tandem LC-MS/MS technique. Firstly, the typical TFs (PRO, TET, and DIN, C0 = 1.0 mg/L) in actual water samples were treated under the optimal process (bias voltage 1.8 V, pH 4, irradiation intensity 50 mW/cm2, 0.05 g MoS2/100 mL, 350 rpm, adsorption of 5 min). The result indicated that the residues of PRO, TET, and DIN in secondary effluent were 0.0973, 0.0617, and 0.0012 mg/L, respectively, with the removal rates of 90.3%, 93.8%, and 99.9%, respectively, undergoing 30-min photo-electrocatalysis and 5-min adsorption. The alkaline medium was favorable for the adsorption of MoS2 to TFs. The assessment results of potential cancer risk indicated that the residues of TFs in secondary effluent were safe for drinking water consumption. Besides, the major TPs were identified via the SBSE-HRLC-MS/MS technique, and one possible transformation pathway of TFs was proposed. TFs mainly underwent dehydrochlorination, cyclization, hydroxylation, etc. to produce a series of nitrogenous heterocyclic compounds that possess higher polarity than parents, hinting that TPs might pose potential aquatic toxicity. However, TPs can be removed synchronously by this tandem technique. The current study can provide a theoretical basis for the harmless treatment of TFs in the water environment.

Fabrication and Adsorption Optimization of Novel Magnetic Core-shell Chitosan/Graphene Oxide/ß-cyclodextrin Composite Materials for Bisphenols in Aqueous Solutions.

A novel magnetic composite material, Fe3O4@SiO2/chitosan/graphene oxide/ß-cyclodextrin (MCGC), was prepared by multi-step methods. Various methods were used to systematically characterize the morphology, composition, structure, and magnetic properties of MCGC. The results obtained show that the composite material has good morphology and crystal structure and can be separated quickly by an external magnetic field. The operation is relatively easy, and the raw materials used to prepare this material are economical, easy to obtain, and environmentally friendly. The performance and adsorption mechanism for using this material as an adsorbent to remove bisphenol A (BPA) and bisphenol F (BPF) from water were studied. The adsorption parameters were optimized. Under optimal conditions, MCGC was found to remove more than 90% of BPA and BPF in a mixed solution (20 mg/L, 50 mL); the adsorption process for BPA and BPF on MCGC was found to follow a Redlich-Peterson isotherm model and Pseudo-second-order kinetic model. The adsorption mechanism for MCGC may involve a combination of various forces. Recycling experiments showed that after five uses, MCGC retained a more than 80% removal effect for BPA and BPF, and through real sample verification, MCGC can be used for wastewater treatment. Therefore, MCGC is economical, environmentally friendly, and easy to separate and collect, and has suitable stability and broad application prospects.

Residual levels and risk assessment of tetrabromobisphenol A in Baiyang Lake and Fuhe river, China.

Tetrabromobisphenol A (TBBPA) in water from Xiongan New Area was determined by gas chromatography-mass spectrometry (GC-MS), simultaneous with its risk assessment. The optimal extraction conditions, derivatization factors (such as derivation reagent amount, derivatization time and temperature), and dissolution solvent were determined by orthogonal experiment. These results indicated the optimum derivatization time and temperature were 70 °C and 30 min, respectively, whilst the amount of derivatization reagent (N,O-bis (trimethylsilyl) trifluoroacetamide) was 40 µL. The optimum extraction efficiency was obtained when using the mixture of hexane-dichloromethane (1:1, v:v) with salt concentration of 6 g/L. Using the sample of S9 as control, the recovery experiments were performed with three different spiked levels. The water samples of Baiyang Lake and Fuhe river were analyzed using the optimized conditions. Those results showed that the concentrations of TBBPA in samples ranged from 18.5 ng/L to 82.6 ng/L, which lies in the middle level of data previously published from other areas in China. The risk quotient (RQ) model was used to evaluate the above data. The results of exposure and risk assessment showed that the margin of exposure (MOE) was 1.28 × 107-2.5 × 107 and the RQmax was 0.0266. The European Food Safety Authority (EFSA) standard and categories of RQ indicates that the estimated dietary exposure to TBBPA is unlikely to raise significant health concerns. This is the first report on the occurrence and risk assessment of TBBPA in waters from Xiongan New Area, which will be helpful for further risk assessment of other persistent organic pollutants. At present, the toxicological data of TBBPA in the biological body of Baiyang Lake is limited. In addition, more accurate and convenient approaches for the risk assessment of TBBPA should be explored.

New insights into the photocatalytic activity of 3-D core-shell P25@silica nanocomposites: impact of mesoporous coating.

In this report, a three-dimensional (3-D) network of core-shell TiO2 (P25)-mesoporous SiO2 (P25@mSiO2) nanocomposites was prepared via a controllable surfactant-assisted sol-gel method. The nanocomposites were investigated for photocatalytic reactions of organic dye degradation, water splitting, and CO2 reduction to understand the roles of the mSiO2 shell in these photocatalytic reactions. It was found that the mSiO2 shell accelerates the photodegradation of the organic dye, but dramatically reduces the photocatalytic activity of P25 in water splitting and CO2 reduction. The roles played by the mSiO2 shell in the photocatalytic reactions are summarized as: (1) effective prevention of agglomeration of P25 nanoparticles, (2) facilitating the transfer of uncharged photo-generated ˙OH radicals via the abundant -OH groups on the mesoporous surface, (3) provision of increased reaction sites between ˙OH radicals and dye molecules by its mesoporous nanostructure and large surface area, and (4) prevention of diffusion of the photo-generated charge carriers (photoelectrons and photoholes) because of its insulating nature.

Fast crystallization of amorphous Gd2Zr2O7 induced by thermally activated electron-beam irradiation.

We investigate the ionization and displacement effects of an electron-beam (e-beam) on amorphous Gd2Zr2O7 synthesized by the co-precipitation and calcination methods. The as-received amorphous specimens were irradiated under electron beams at different energies (80 keV, 120 keV, and 2 MeV) and then characterized by X-ray diffraction and transmission electron microscopy. A metastable fluorite phase was observed in nanocrystalline Gd2Zr2O7 and is proposed to arise from the relatively lower surface and interface energy compared with the pyrochlore phase. Fast crystallization could be induced by 120 keV e-beam irradiation (beam current = 0.47 mA/cm2). The crystallization occurred on the nanoscale upon ionization irradiation at 400 °C after a dose of less than 1017 electrons/cm2. Under e-beam irradiation, the activation energy for the grain growth process was approximately 10 kJ/mol, but the activation energy was 135 kJ/mol by calcination in a furnace. The thermally activated ionization process was considered the fast crystallization mechanism.