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Abstract: In this study, nanoscale Fe0 was immobilized in and on poly(vinyl alcohol) (PVA) microspheres by the inverse suspension crosslinked method. Two different sizes of Fe0/PVA microspheres were synthesized in the presence and absence of dispersant. The chelating action between Fe2+ and PVA was identified by Fourier transform infrared and X-ray photoelectron spectroscopy. The morphology and distribution of the obtained Fe0/PVA microspheres were characterized by environmental scanning electron microscope, energy-dispersive X-ray spectrometry, and X-ray diffraction. Nanoscale Fe0 particles were mostly dispersed over the surface of the microspheres. They were distributed more homogeneously on the surfaces of Fe0/PVA microspheres with diameter of 600–700μm than those with diameter of 10–12μm. The nitrobenzene (NB) reduction reactions followed pseudo-first-order kinetics. The normalized surface rate constants (k SA) values were determined to be 0.162Lh−1 m−2 for L-Fe0/PVA microspheres, 0.098Lh−1 m−2 for S-Fe0/PVA microspheres, and 0.023Lh−1 m−2 for nanoscale Fe0 particles. Furthermore, with the analysis of the products by GC/MS, possible reductive pathways of NB by Fe0/PVA microspheres were suggested. The recovery rates of iron in microspheres were determined to be 81.17% for large Fe0/PVA and 60.31% for small Fe0/PVA. [Copyright &y& Elsevier]

More information is needed to fully comprehend how acid mine drainage (AMD) affects the phototransformation of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in karst water and sewage-irrigated farmland soil with abundant carbonate rocks (CaCO 3) due to increasing pollution of AMD formed from pyrite (FeS 2). The results showed FeS 2 accelerated the inactivation of ARB with an inactivation of 8.7 log. Notably, extracellular and intracellular ARGs and mobile genetic elements (MGEs) also experienced rapid degradation. Additionally, the pH of the solution buffered by CaCO 3 significantly influenced the photo-inactivation of ARB. The Fe2+ in neutral solution was present in Fe(II) coordination with strong reducing potential and played a crucial role in generating •OH (7.0 μM), which caused severe damage to ARB, ARGs, and MGEs. The •OH induced by photo-Fenton of FeS 2 posed pressure to ARB, promoting oxidative stress response and increasing generation of reactive oxygen species (ROS), ultimately damaging cell membranes, proteins and DNA. Moreover, FeS 2 contributed to a decrease in MIC of ARB from 24 mg/L to 4 mg/L. These findings highlight the importance of AMD in influencing karst water and sewage-irrigated farmland soil ecosystems. They are also critical in advancing the utilization of FeS 2 to inactivate pathogenic bacteria. [Display omitted] • Pyrite (FeS 2) accelerated the inactivation of ARB. • ARGs and MGEs underwent fast degradation due to •OH. • The most serious damage of ARB and ARGs were impacted by pH buffered by CaCO 3. • The •OH induced by FeS 2 caused the damage of cell membranes, proteins and DNA. • The resistance of bacteria was inhibited due to destruction of ARB, ARGs and MGEs. [ABSTRACT FROM AUTHOR]

Abstract: Batch sorption experiments were conducted using macroreticular poly(vinyl alcohol) (MR-PVA) beads as a adsorbent to adsorb Pb(II) from both single component system and multi-metal solution in which experimental parameters were studied including solution pH, contact time, adsorbent dose, initial concentration of metal ions and ionic strength. The equilibrium isotherms were determined at pH 6 under constant ionic strength and at different temperatures. The results showed that the maximum adsorption capacity of Pb(II) (213.98mgg−1) with 1gL−1 of adsorbent was observed at 300mgL−1 at an initial pH value of 6.0 under temperature of 288K. Removals of about 60% occurred in 30min, and equilibrium was attained at around 150min. The equilibrium data for the adsorption of Pb(II) on MR-PVA beads was tested with various adsorption isotherm models among which three models were found to be suitable for the Pb(II) adsorption. In addition, the kinetic adsorption fitted well to the pseudo-second-order model and the corresponding rate constants were obtained. Thermodynamic aspects of the adsorption process were also investigated. [Copyright &y& Elsevier]

Microplastics (MPs) are considered to influence the bioavailability of heavy metals through direct adsorption, but this neglects the distribution of heavy metal chemical speciation indirectly influenced by MPs by altering geochemical properties. The present study aims to explore the link between the fractionation distribution of cadmium (Cd 2+ ) and changes in geochemical properties in sediments induced by polyethylene terephthalate microplastics (PET-MPs). The PET-MPs reduced the acid-soluble fraction of Cd 2+ in sediments and increased its organically bound fraction. In addition, the concentration of bioavailable Cd 2+ in the sediment decreased by 4.09-25.96 % with increasing PET-MPs doses and aging. Whereas the thermal aging of PET-MPs led to a decrease in the molar ratio of oxygen-containing functional groups and the BET surface area, which is not favorable for improving the adsorption capacity of PET-MPs. On the other hand, the correlation analysis demonstrated the key role of PET-MPs in increasing the content of sediment organic matter and its humification level, which indirectly led to a decrease in Cd 2+ bioavailability. The microbial analysis demonstrated that PET-MPs increase the relative abundances of Chloroflexi, hexokinase, and 6-phosphofructose kinase in sediments, thereby increasing the humification level of sediment organic matter. The present study provides a new perspective for understanding the environmental risks of MPs-altered heavy metals., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The high-selectivity and high-sensitivity determination of trace concentrations of toxic gases is a major challenge when using semiconductor metal oxide (SMO) gas sensors in complicated real-world environments. In this study, by strategically combining a three-dimensional inverse opal (3DIO) macroporous ZnO substrate and a ZIF-8 outer filter membrane, two series of sensors with Pt NPs loaded at different locations are developed. In the optimal 3DIO ZnO@ZIF-8/Pt sensor, the existence of small Pt NPs in ZIF-8 cavities can effectively accelerate the absorption of H 2 S, capture electrons from the N site of ZIF-8, and donate the electron to the S site of H 2 S, as indicated by density functional theory simulations, leading to a significantly increased response to H 2 S. Together with the molecular-sieving effect that ZIF-8 exerts on gas molecules with larger kinetic diameters, the 3DIO ZnO@ZIF-8/Pt sensor exhibits a high response to H 2 S (118-5.5 ppm), a detection limit of 40 ppb, and importantly, a 59-fold higher selectivity to H 2 S against typical interference gases. In addition, the 3DIO ZnO@ZIF-8/Pt sensor is developed as a multi-platform sensor to evaluate trace concentrations of H 2 S in meat quality assessment, halitosis diagnosis, and automobile exhaust assessment., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The N-doped three-dimensional (3D) needle bridge connection core-shell structure N-CoS 2 @Co 3 O 4 synthesized in this work was prepared by simple hydrothermal and high-temperature vulcanization methods. The optimized N-CoS 2 @Co 3 O 4 -2 composite response to NO 2 is 62.3-100 ppm, a response time of 1.3 s, the recovery time of 17.98 s, the detection limit of 5 ppb and stability of as long as 10 weeks at room temperature (RT). Its excellent NO 2 sensing performance is attributed to the unique porous and bridge connection core-shell structure of the N-CoS 2 @Co 3 O 4 -2 with high specific surface area, interconnected internal channels, abundant exposed S edge active sites, and high catalytic performance promoted by N-doping. This simple manufacturing method of high-performance sensing materials paves the way for the design of N-doped bridge connection core-shell structures., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Simultaneous construction of porous and hollow adsorbent, especially from gas-in-water Pickering emulsion (PE) reactor, is vital for improving mass transfer kinetics and uptake amount. Inspired by the formation process of stalagmites in karst cave, amino and amidoxime bifunctionalized lotus root-type microsphere with porous surface (NH 2 @AO-PLRMS) is prepared by the silica nanoparticles (SPs)-stabilized CO 2 -in-water Pickering emulsion reactor and subsequent two-step grafting polymerization. The important roles of SPs acting as Pickering emulsifier, surface pore-forming agent, and adjusting internal lotus root structure are confirmed. Lotus root-type pores are dependent on the interface intensity and the permeability for compressed CO 2 bubbles in PE droplets. Benefitting from the lotus root-type structure and abundant affinity sites, the maximum uranium adsorption capacity of NH 2 @AO-PLRMS is 1214.5 mg·g -1 at 298 k, and an ultrafast uptake process can be achieved in the first 30 min. Both thermodynamic and kinetic studies indicate a spontaneous, entropy increased, and exothermic chemisorption process, and the synergies of amidoxime and amino groups can enhance the adsorption selectivity. Remarkably, NH 2 @AO-PLRMS displays a high uranium adsorption capacity and desorption efficiency after seven cycles. These findings provide a way to obtain adsorbents with enhanced uranium extraction performance from gas-in-water PE reactor., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The unique properties of heterostructure materials make them become a promising candidate for high-performance room-temperature (RT) NO 2 sensing. Herein, a p-n heterojunction consisting of two-dimensional (2D) MoS 2 nanoflakes vertically grown on one-dimensional (1D) SnO 2 nanotubes (NTs) was fabricated via electrospinning and subsequent hydrothermal route. The sulfur edge active sites are fully exposed in the MoS 2 @SnO 2 heterostructure due to the vertically oriented thin-layered morphology features. Moreover, the interface of p-n heterojunction provides an electronic transfer channel from SnO 2 to MoS 2 , which enables MoS 2 act as the generous electron donor involved in NO 2 gas senor detection. As a result, the optimized MoS 2 @SnO 2 -2 heterostructure presents an impressive sensitivity and selectivity for NO 2 gas detection at RT. The response value is 34.67 (R a /R g ) to 100 ppm, which is 26.5 times to that of pure SnO 2. It also exhibits a fast response and recovery time (2.2 s, 10.54 s), as well as a low detection limit (10 ppb) and as long as 20 weeks of stability. This simple fabrication of high-performance sensing materials may facilitate the large-scale production of RT NO 2 gas sensors., (Copyright © 2021 Elsevier B.V. All rights reserved.)

This work illustrates a simple polymer thermal treatment strategy to develop high-dispersed Fe 2 O 3 /Fe nanoparticles residing in honeycomb-like N-doped graphitic carbon (Fe 2 O 3 /Fe@N-GC). The as-prepared Fe 2 O 3 /Fe@N-GC composites consist of three-dimensional (3D) strutted interconnective graphitic carbon frame, which would not only refrain from restacking and facilitate the charge transfer, but also provide more reaction interface between gas molecules and materials. Benefiting from the synergistic merits of Fe 2 O 3 /Fe, N-doping graphitic carbon, high surface area and unique 3D architectures, the optimal Fe 2 O 3 /Fe@N-GC presents impressive sensitivity and selectivity for NO 2 gas detection at room temperature with the response of 25.48-100 ppm, response time of 2.13 s, recovery time of 11.73 s, detection limit of 10 ppb and as long as 60 days of stability. As a result, the present Fe 2 O 3 /Fe@N-GC composite with an easy fabrication method and high sensitivity, selectivity, stabitliy towards NO 2 at RT would inspire various designs based on the 3D honeycomb structure for more real applications in gas sensors., (Copyright © 2020 Elsevier B.V. All rights reserved.)

In this study, a novel TiO 2-x /rGO-PS-Vis process was developed, which utilizes the TiO 2-x /rGO (Ti 3+ and oxygen vacancies self-doped TiO 2 coupled with reduced graphene oxide) nanocomposite as a promising and efficient activator of persulfate (PS) for the enhanced oxidation of micropollutants under visible -light irradiation. TiO 2-x /rGO exhibited a significantly high activity for PS activation to produce more sulfate radicals (SO 4 - ) and hydroxyl radicals (OH). Therefore, almost 100% BPA (10 mg/L) and 80% TOC can be removed just within 12 min with 1.0 g/L TiO 2-x /rGO and 2 mM PS under visible light. Moreover, it was found that many other typical micropollutants, such as phenol, acetaminophen and sulfamethoxazole can also be effectively degraded by this process. Electron paramagnetic resonance (EPR) and radical quenching experiments indicated that both SO 4 - and OH contribute to the degradation of organics, and the radical process was the main degradation pathway. In addition, the effects of PS concentration, catalyst dosage, initial solution pH and inorganic anions were investigated systematically. Experiments carried out in the real background of water matrix with low-concentration of BPA indicated that the proposed TiO 2-x /rGO-PS-Vis process has strong non-selective photo-oxidative ability for the removal of micropollutants in water., (Copyright © 2018 Elsevier B.V. All rights reserved.)