Removal of antibiotics with different charges in water by graphene oxide membranes

Antibiotics are a large group of emerging organic pollutants with low concentration levels in the water. The presence of antibiotics will affect the ecological environment and human health. The removal of trace organic compounds by graphene oxide (GO) membranes has attracted extensive attention. This study investigated the removal of three differently charged antibiotics by GO membranes and the influence of water quality on the removal of antibiotics. It showed that a crosslinked ethylenediamine-GO (EDA-GO) membrane had better stability and higher antibiotic removal performance than a non-crosslinked GO membrane. Among the three antibiotics, penicillin (PNC) was negatively charged and had the highest removal efficiency due to steric effect and electrostatic repulsion. A low concentration (10 mmol L−1) of Na+ in water could increase the membrane flux but had no significant effect on the removal of antibiotics. Ca2+ could reduce the membrane flux and improve the removal of chloramphenicol (CAP) and PNC. The removal efficiencies of low-concentration antibiotics (500 μg L−1) were higher than those of high-concentration antibiotics (10 mg L−1). Furthermore, the removal of antibiotics under the condition of actual wastewater quality was higher than those in solutions prepared with ultrapure water. The EDA-GO membrane has great potential in the removal of antibiotics in wastewater. HIGHLIGHTS The removal of three differently charged antibiotics by GO membranes was studied.; Crosslinked EDA-GO membrane had higher removal performance and better stability.; The removal of PNC with a negative charge was higher than CAP and ERY.; Ca2+ could reduce the membrane flux and increase the removal of antibiotics.; The removal of antibiotics under the condition of actual wastewater quality was higher.

Incorporation of Pb(ii) into hematite during ferrihydrite transformation

Ferrihydrite is ubiquitous in natural environments, and its transformation significantly influences the fate of heavy metals. Although Pb(ii) adsorption on iron oxides has been extensively studied, there is still a knowledge gap on the fate of Pb during the dynamic processes of iron oxide transformation. In this study, a set of wet chemistry experiments, spherical aberration corrected scanning transmission electron microscopy (Cs-STEM) integrated with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and X-ray absorption spectroscopy (XAS) were used to unravel Pb interactions with iron oxides during ferrihydrite transformation processes under abiotic conditions. Wet chemistry experiments, STEM-EDS elemental mapping and line scans, and quantitative analysis suggested that Pb penetrated into hematite nanoparticles during the transformation processes. STEM analysis at sub-nanoscales, XRD fine scans, and XAS analysis provided evidence of Pb incorporation into the crystal structures of hematite nanoparticles, in which Pb distributed along the zone axis and enlarged the lattice distance of hematite. These results advanced our understanding of the dynamic interactions of Pb with iron oxides by offering new perspectives about the critical roles of chemical speciation, nano-scale spatial distribution, and atomic coordination environments in controlling the geochemical dynamics of heavy metals

Gut Microbiome and Serum Metabolome Profiles of Capsaicin with Cognitive Benefits in APP/PS1 Mice

Capsaicin, a natural bioactive component, has been reported to improve cognition and ameliorate the pathology of Alzheimer’s disease (AD). Studies have linked AD to alterations in gut microbiota composition and serum metabolites. In the present study, we examined the alterations in serum metabolome and gut microbiome in APPswe/PS1dE9 (APP/PS1) mice treated with capsaicin. Capsaicin treatments resulted in a significant increase in the abundance of Akkermansia, Faecalibaculum, Unclassified_f_Atopobiaceae, and Gordonibacter and a significant decrease in the abundance of Adlercreutzia, Peptococcaceae, Alistipes, Oscillibacter and Erysipelatoclostridium. Furthermore, the species Akkermansia muciniphila (A. muciniphila) was significantly enriched in capsaicin-treated APP/PS1 mice (p = 0.0002). Serum metabolomic analysis showed that capsaicin-treated APP/PS1 mice had a significant higher level of tryptophan (Trp) metabolism and a significantly lower level of lipid metabolism compared with vehicle-treated mice. Capsaicin altered serum metabolites, including Kynurenine (Kyn), 5-Hydroxy-L-tryptophan (5-HIT), 5-Hydroxyindoleacetic acid (5-HIAA), indoxylsulfuric acid, lysophosphatidyl cholines (LysoPCs), and lysophosphatidyl ethanolamine (LysoPE). Significant correlations were observed between the gut bacteria and serum metabolite. With regard to the increased abundance of A. muciniphila and the ensuing rise in tryptophan metabolites, our data show that capsaicin alters both the gut microbiota and blood metabolites. By altering the gut microbiome and serum metabolome, a diet high in capsaicin may reduce the incidence and development of AD

Sulfolane Crystal Templating: A One-Step and Tunable Polarity Approach for Self-Assembled Super-Macroporous Hydrophobic Monoliths

Freeze-casting (ice templating) is generally used to prepare super-macroporous materials. However, water solubility limits the application of freeze-casting in hydrophobic material fabrication. In the present work, inexpensive and low-toxic sulfolane was used as a novel crystallization-induced porogen (sulfolane crystal templating) to prepare super-macroporous hydrophobic monoliths (cryogels) with tunable polarity. The phase transition of sulfolane consisted of reversible processes in the liquid, semi-crystalline, and crystalline states. Because of the density change during phase transition, liquid sulfolane experienced a 16.4% volume shrinkage per unit mass. Thus, the cryogels obtained using the conventional freezing method contained obvious hollow-shaped defects. Furthermore, a novel route of pre-cooling, pre-crystallization, crystal growth, freezing, and thawing (PPCFT) was employed to prepare cryogels with defect-free macroscopic morphology and uniform pore structure. The as-obtained cryogels were composed of a super-macroporous structures and interconnected channels, and their porosity ranged between 85 and 97%. Moreover, the cryogels manifested good hydrophobicity (contact angle = 120–130°) and had absorption capacities greater than 10 g g–1 for oils and organic liquids. The maximum absorption capacities of the resultant cryogels in dichloromethane, ethyl acetate, and liquid paraffin were 60.3, 35.8, and 15.2 g g–1, respectively. Moreover, sulfolane could conveniently dissolve hydrophobic and hydrophilic monomers to generate amphiphilic cryogels (contact angle = 130–0°). Therefore, sulfolane crystal templating is a potential fabrication method for super-macroporous hydrophobic materials with tunable polarity

Two-dimensional semiconducting SnP2Se6 with giant second-harmonic-generation for monolithic on-chip electronic-photonic integration

Abstract Two-dimensional (2D) layered semiconductors with nonlinear optical (NLO) properties hold great promise to address the growing demand of multifunction integration in electronic-photonic integrated circuits (EPICs). However, electronic-photonic co-design with 2D NLO semiconductors for on-chip telecommunication is limited by their essential shortcomings in terms of unsatisfactory optoelectronic properties, odd-even layer-dependent NLO activity and low NLO susceptibility in telecom band. Here we report the synthesis of 2D SnP2Se6, a van der Waals NLO semiconductor exhibiting strong odd-even layer-independent second harmonic generation (SHG) activity at 1550 nm and pronounced photosensitivity under visible light. The combination of 2D SnP2Se6 with a SiN photonic platform enables the chip-level multifunction integration for EPICs. The hybrid device not only features efficient on-chip SHG process for optical modulation, but also allows the telecom-band photodetection relying on the upconversion of wavelength from 1560 to 780 nm. Our finding offers alternative opportunities for the collaborative design of EPICs

Epitaxial Ferroelectric Hf0.5 Zr0.5 O2 with Metallic Pyrochlore Oxide Electrodes.

The synthesis of fully epitaxial ferroelectric Hf0.5 Zr0.5 O2 (HZO) thin films through the use of a conducting pyrochlore oxide electrode that acts as a structural and chemical template is reported. Such pyrochlores, exemplified by Pb2 Ir2 O7 (PIO) and Bi2 Ru2 O7 (BRO), exhibit metallic conductivity with room-temperature resistivity of <1 mΩ cm and are closely lattice matched to yttria-stabilized zirconia substrates as well as the HZO layers grown on top of them. Evidence for epitaxy and domain formation is established with X-ray diffraction and scanning transmission electron microscopy, which show that the c-axis of the HZO film is normal to the substrate surface. The emergence of the non-polar-monoclinic phase from the polar-orthorhombic phase is observed when the HZO film thickness is ≥≈30 nm. Thermodynamic analyses reveal the role of epitaxial strain and surface energy in stabilizing the polar phase as well as its coexistence with the non-polar-monoclinic phase as a function of film thickness

Epitaxial Ferroelectric Hf0.5 Zr0.5 O2 with Metallic Pyrochlore Oxide Electrodes.

Adv. Mater. 2021, 33, 2006089 DOI: 10.1002/adma.202006089 Aviram Bhalla-Levine is hereby added as an author of the article. Avi was an undergraduate student who did some of the piezoresponse force microscopy (PFM) experiments in the work. He left the group in the summer of 2019. When preparing the figures for the submission, the authors overlooked the fact that Avi had acquired that data. To give proper credit, they are added as an author of the paper as given above in the correction author list. The author name is associated with affiliation 1: Z. Zhang, A. Bhalla-Levine, Dr. L. Xie, Dr. M. Kumari, Dr. S. Das, Z. Leng, Prof. L. W. Martin, Prof. R. Ramesh Department of Materials Science and Engineering University of California Berkeley, CA 94720, USA E-mail: [email protected]

Epitaxial Ferroelectric Hf0.5 Zr0.5 O2 with Metallic Pyrochlore Oxide Electrodes.

The synthesis of fully epitaxial ferroelectric Hf0.5 Zr0.5 O2 (HZO) thin films through the use of a conducting pyrochlore oxide electrode that acts as a structural and chemical template is reported. Such pyrochlores, exemplified by Pb2 Ir2 O7 (PIO) and Bi2 Ru2 O7 (BRO), exhibit metallic conductivity with room-temperature resistivity of <1 mΩ cm and are closely lattice matched to yttria-stabilized zirconia substrates as well as the HZO layers grown on top of them. Evidence for epitaxy and domain formation is established with X-ray diffraction and scanning transmission electron microscopy, which show that the c-axis of the HZO film is normal to the substrate surface. The emergence of the non-polar-monoclinic phase from the polar-orthorhombic phase is observed when the HZO film thickness is ≥≈30 nm. Thermodynamic analyses reveal the role of epitaxial strain and surface energy in stabilizing the polar phase as well as its coexistence with the non-polar-monoclinic phase as a function of film thickness