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a b s t r a c tFe 3 O 4 magnetic nanoparticles (MNPs) with diameters about 10 nm were synthesized successfully and used to remove phenol and aniline from aqueous solution. The results showed that phenol and aniline could be eliminated easily from solution under acidic and neutral conditions in the presence of MNPs and H 2 O 2 . When the concentrations of Fe 3 O 4 MNPs and H 2 O 2 were 5 g L −1 and 1.2 M, respectively, phenol and aniline could be removed completely after 6 h of reaction at 308 K, and the total organic carbon (TOC) abatement efficiency for phenol and aniline were 42.79% and 40.38%. Some intermediates such as formic acid, acetic acid, fumaric acid and hydroquinone were detected during reaction. Fe 3 O 4 MNPs exhibited good stability and reusability, also showed excellent catalysis ability to eliminate some substituted phenolic and aniline compounds from solution. Fe 3 O 4 MNPs had good superparamagnetism and was readily separated from solution by applying an external magnetic field. Finally we proposed that phenol and aniline might be degraded by the hydroxyl free radicals (·OH) released from H 2 O 2 in the presence of Fe 3 O 4 MNPs as catalysts.

The research presented in this paper investigates the adsorption of cation surfactantsscetyltrimethylammonium bromide (CTAB) and cetylpyridinium chloride (CPC)sonto magnetic nanoparticles and the application of this mixed hemimicelles solidphase extraction (SPE) method for the preconcentration of several typical phenolic compoundssbisphenol A (BPA), 4-tertoctylphenol (4-OP), and 4-n-nonylphenol (4-NP)sfrom environmental water samples. In this novel SPE method, the charged surfactants CTAB and CPC form mixed hemimicelles on Fe 3 O 4 nanoparticles (Fe 3 O 4 NPs), which causes retention of analytes by strong hydrophobic and electrostatic interactions. The SPE method combines the advantages of mixed hemimicelles and magnetic nanoparticles. In order to provide guidelines for the mixed hemimicelles SPE method development, surfactant adsorption isotherms and -potential isotherms were also investigated. The main factors affecting the adsolubilization of analytes, such as the amount of Fe 3 O 4 NPs and surfactants, the type of surfactants, the solution pH, the sample loading volume, and the desorption conditions, were investigated and optimized. A concentration factor of 800 was achieved by the extraction of 800 mL of several environmental water samples using this SPE method. Under the selected conditions, detection limits obtained for BPA, 4-OP, and 4-NP were 12, 29, 34 ng/L, respectively. The accuracy of the method was evaluated by recovery measurements on spiked samples, and good recoveries (68-104%) with low relative standard deviations from 2 to 7% were achieved. The advantages of this new SPE method include high extraction yields, high breakthrough volumes, short analysis times, and easy preparation of sorbents. To the best of our knowledge, this is the first time that a mixed hemimicelles SPE method based on magnetic separation and nanoparticles has been used for the pretreatment of environmental water samples.

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Wearing face masks has become the new normal worldwide due to the global spread of the coronavirus disease 2019. The inhalation of microplastics due to the wearing of masks has rarely been reported. The present study used different types of commonly used masks to conduct breathing simulation experiments and investigate microplastic inhalation risk. Microplastic inhalation caused by reusing masks that underwent various treatment processes was also tested. Results implied that wearing masks considerably reduces the inhalation risk of particles (e.g., granular microplastics and unknown particles) even when they are worn continuously for 720 h. Surgical, cotton, fashion, and activated carbon masks wearing pose higher fiber-like microplastic inhalation risk, while all masks generally reduced exposure when used under their supposed time (<4 h). N95 poses less fiber-like microplastic inhalation risk. Reusing masks after they underwent different disinfection pretreatment processes can increase the risk of particle (e.g., granular microplastics) and fiber-like microplastic inhalation. Ultraviolet disinfection exerts a relatively weak effect on fiber-like microplastic inhalation, and thus, it can be recommended as a treatment process for reusing masks if proven effective from microbiological standpoint. Wearing an N95 mask reduces the inhalation risk of spherical-type microplastics by 25.5 times compared with not wearing a mask.

A novel, simple and efficient strategy for fabricating a magnetic metal-organic framework (MOF) as sorbent to remove organic compounds from simulated water samples is presented and tested for removal of methylene blue (MB) as an example. The novel adsorbents combine advantages of MOFs and magnetic nanoparticles and possess large capacity, low cost, rapid removal and easy separation of the solid phase, which makes it an excellent sorbent for treatment of wastewaters. The resulting magnetic MOFs composites (also known as MFCs) have large surface areas (79.52 m2 g−1), excellent magnetic response (14.89 emu g−1), and large mesopore volume (0.09 cm3 g−1), as well as good chemical inertness and mechanical stability. Adsorption was not drastically affected by pH, suggesting π–π stacking interaction and/or hydrophobic interactions between MB and MFCs. Kinetic parameters followed pseudo-second-order kinetics and adsorption was described by the Freundlich isotherm. Adsorption capacity was 84 mg MB g−1 at an initial MB concentration of 30 mg L−1, which increased to 245 mg g−1 when the initial MB concentration was 300 mg L−1. This capacity was much greater than most other adsorbents reported in the literature. In addition, MFC adsorbents possess excellent reusability, being effective after at least five consecutive cycles.

Repairing peripheral nerve injury, especially long-range defects of thick nerves, is a great challenge in the clinic due to their limited regeneration capability. Most FDA-approved nerve guidance conduits with large hollow lumen are only suitable for short lesions, and their effects are unsatisfactory in repairing long gaps of thick nerves. Multichannel nerve guidance conduits have been shown to offer better regeneration of long nerve defects. However, existing approaches of fabricating multichannel nerve conduits are usually complicated and time-consuming. Inspired by the intelligent responsive shaping process of shape memory polymers, in this study, a self-forming multichannel nerve guidance conduit with topographical cues was constructed based on a degradable shape memory PLATMC polymer. With an initial tubular shape obtained by a high-temperature molding process, the electrospun shape memory nanofibrous mat could be temporarily formed into a planar shape for cell loading to realize the uniform distribution of cells. Then triggered by a physical temperature around 37 °C, it could automatically restore its permanent tubular shape to form the multichannel conduit. This multichannel conduit exhibits better performance in terms of cell growth and the repair of rat sciatic nerve defects. These results reveal that self-forming nerve conduits can be realized based on shape memory polymers; thus, the fabricated bioinspired multichannel nerve guidance conduit has great potential in peripheral nerve regeneration.

Mixed hemimicelles solid-phase extraction (SPE) based on cetyltrimethylammonium bromide (CTAB)-coated nano-magnets Fe 3 O 4 was investigated for the preconcentration of four chlorophenols (CPs) in environmental water samples prior to HPLC-spectrophotometry determination in this paper. By the rapid isolating (about 5 min) of Fe 3 O 4 nanoparticles (NPs) through placing a Nd-Fe-B strong magnet on the bottom of beaker, the time-consuming preconcentration process of loading large volume sample in conversional SPE method with a column can be avoided. The unique properties of Fe 3 O 4 NPs such as high surface area and strong magnetism were utilized adequately in the SPE process. This novel separation method produced a high preconcentration rate and factor. A comprehensive study of the adsorption conditions such as the Fe 3 O 4 NPs zeta-potential, CTAB added amounts, pH value, standing time and maximal extraction volume was also presented. Under optimized conditions, four analytes of 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (TCP) and pentachlorophenol (PCP) were quantitatively extracted. The method was then used to determine four CPs in five real environmental water samples. High concentration factors (700) were achieved for each of the analytes, with observed detection limits ranging between 0.11 and 0.15 g L −1 . The accuracy of method was evaluated by recovery measurements on spiked samples. Good recovery results (83-98%) with satisfactory relative standard deviation (RSD) were achieved. It is important to note that satisfactory preconcentration factors and extraction recoveries for the four CPs were obtained with only a little amount of Fe 3 O 4 NPs (0.1 g) and CTAB (60 mg). To the best of our knowledge, this was the first time a mixed hemimicelles SPE method based on Fe 3 O 4 NPs magnetic separation had been used for the pretreatment of environmental water samples.