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Arsenic–calcium residue (ACR) is one of the major hazardous solid wastes produced by the metallurgical industry that poses a serious threat to the environment. However, a suitable method for the effective treatment of ACR is still lacking. In this study, an alternative treatment method for ACRs via the immobilization of As as scorodite was proposed with the use of two types of ACRs (ACRreal directly collected from a Pb refinery and ACRlab precipitated from waste sulfuric acid in the lab). The treatment of ACR included preparing the As-enriched solution via H2SO4 dissolution–neutralization of ACR at pH < 2, As(III) was oxidized by H2O2, and As(V) was immobilized as scorodite. The results showed that gypsum produced from ACRlab in the dissolution–neutralization process contained 68 mg/kg of As, far below the Chinese national standard for hazardous solid wastes (

With the goal of improving the removal of anionic contaminants, copper oxide (CuO)-modified biochar (BC) nanocomposites were successfully prepared through simply ball milling CuO particles with BC. The physicochemical properties of the fabricated CuO/BC nanocomposites were systematically characterized by a series of techniques; their adsorption performances were assessed, and the main adsorption mechanism was revealed. X-ray powder diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy analyses of the nanocomposites showed the strong interaction between CuO and BC and confirmed the success of the ball-milling syntheses. Because of strong electrostatic attraction between the embedded CuO nanoparticles and reactive red (RR120), the composited adsorbents exhibited excellent RR120 removal. The 10%-CuO/BC nanocomposite achieved the best RR120 removal efficiency (46%), which is much higher than that of pristine BC (20%). In addition, the adsorption was insensitive to the change of solution initial pH (4-10). The 10%-CuO/BC also showed fast adsorption kinetics (equilibrium time < 3 h) and extremely high adsorption capacity (Langmuir maximum capacity of 1399 mg g-1) to RR120 in aqueous solutions. Findings from this study demonstrate not only the strong feasibility of ball-milling synthesis of BC-based nanocomposites but also the promising potential of the CuO/BC nanocomposites to remove aqueous anionic contaminants.

The ideal product of rare-earth-doped phosphors should have uniform particle size distribution and homogeneous doping ions in each particle, and therefore, intensified micromixing at mesoscale is highly required. In this article, inspired by the concept of "mesoscience", we demonstrate the tuning of Eu3+ doping in GdBO3 microparticles at mesoscale by a high-gravity-assisted reactive precipitation-coupled calcination process. The high-gravity environment and tiny droplets generated by the high-gravity rotating packed bed (RPB) reactor lead to significant intensification of mass transfer and micromixing, which are beneficial for the homogeneous doping of Eu3+ in the host material during reactive precipitation in liquid solution. Under excitation at 395 nm, the emission spectra of the Eu3+-doped phosphors exhibit a narrow-band red emission centered at 625 nm and the highest intensity was observed at x = 0.2. The RPB products show higher intensity than that of the control group even when the reaction time was shortened to 1/6. After calculation, the quenching in the sample most likely results from dipole-dipole interactions. The chromaticity coordinates for the RPB sample was measured as (0.598, 0.341) with a quantum yield of up to 78.11%, and the phosphors exhibit good thermal stability at 423 K. The phosphors were used as the luminescent materials for light-emitting diodes (LEDs), and the devices showed good performance. Our preliminary study illustrated that high-gravity-assisted approaches are promising for tuning the doping of rare-earth ions in microparticles at mesoscale toward efficient production of phosphors for LEDs.

The osmotic heat engine represents a new and promising technology for the harvesting of low-grade waste heat from various sources. However, the lack of an adequate semipermeable membrane hinders the technology’s advancement. In this study, we investigated the application of a freestanding graphene oxide membrane (GOM) for energy generation in an osmotic heat engine. The synthesized GOM has a water permeability coefficient of 4.4 L m–2 h–1 bar–1 (LMH-bar). The internal concentration polarization in the osmosis filtration system can be minimized because no membrane support layer is needed for the freestanding GOM. As a result, high water flux and high power density are obtained. For example, under an applied hydraulic pressure of 6.90 bar, with a 2 M draw solution of ammonium bicarbonate solution, a power density of 20.0 W/m2 is achieved. This study shows that the freestanding GOM is promising for application in the osmotic heat engine. Future research regarding improving the mechanical properties and water stability of the GOM is beneficial for further advancing the technology.

Fluorescent carbon dots (FCDs) have received considerable attention because of the great potential for a wide range of applications, from bioimaging to optoelectronic devices. In this work, we reported the synthesis of nitrogen-doped FCDs with an average size of 2 nm in a subcritical water apparatus by using biomass waste (i.e., expired milk) as the precursor. The obtained FCDs were highly dispersed in aqueous solution because of the presence of O-containing functional groups on their surfaces. Under the excitation of ultraviolet and blue light, the FCDs exhibited excitation wavelength-dependent fluorescence in the emission range of 400–550 nm. The FCDs could be easily taken up by HeLa cells without additional surface functionalization, serving as fluorescent nanoprobes for bioimaging. The applications of FCDs as sensing agents for the detection of Fe3+, solid-state fluorescent patterning, and transparent hybrid films were also performed, demonstrating their potential for solid-state fluorescent sensing, security labeling, and wearable optoelectronics.

In the present work, we selected hexamethylcucurbit[3,3]uril (Me6Q[3,3]) as a building block and obtained two Me6Q[3,3]-based porous supramolecular assemblies from neutral water (A) and aqueous HCl solutions (B), respectively. Both Me6Q[3,3]-based assemblies are constructed of Me6Q[3,3] molecules through the typical outer surface interaction of cucurbit[n]urils, as well as hydrogen bonding between latticed water molecules and portal carbonyl oxygens of Me6Q[3,3]. The assemblies present different porous structure features and exhibit different adsorption properties for eight common volatile organic compounds. However, the two porous assemblies exhibit similar adsorption properties for certain fluorophore dyes, including rhodamine B (G1), fluorescein (G2), and pyrene (G3), and form solid colored fluorescent compounds, some of which exhibit responses to the selected volatile organic compounds.

Y.X. W. was supported by the National Natural Science Foundation of China Number 81903281. C.M. is supported by the National Institute of Environmental Health Sciences of the National Institutes of Health under Award Number R01ES031657., Water chlorination can lead to the formation of disinfection byproducts, including trihalomethanes (THMs). However, few epidemiologic studies have explored associations between THM exposure and mortality. This study included 6720 adults aged >= 40 years from the National Health and Nutrition Examination Survey 1999-2012 who had blood THM concentrations quantified. A higher risk of all-cause mortality was found across increasing quartile concentrations of blood chloroform (TCM) and total THMs (TTHMs; sum of all four THMs) (both p for trend = 0.02). Adults in the highest quartile of TCM and TTHM concentrations had hazard ratios (HRs) of 1.35 (95% confidence intervals: 1.05-1.74) and 1.37 (1.05-1.79), respectively, for all-cause mortality, compared with adults in the lowest quartile. When cause-specific mortality was evaluated, a positive relationship was found between blood bromodichloromethane (BDCM), dibromochloromethane (DBCM), bromoform (TBM), total brominated THMs (Br-THMs; sum of BDCM, DBCM, and TBM), and TTHM concentrations and risk of cancer death and between blood TCM and TTHMs and risk of other cause (noncancer/nonheart disease) mortality. Our findings suggest that higher exposure to Br-THMs was associated with increased cancer mortality risk, whereas TCM was associated with a greater risk of noncancer/nonheart disease mortality., National Natural Science Foundation of China (NSFC) 81903281, United States Department of Health & Human Services National Institutes of Health (NIH) - USA NIH National Institute of Environmental Health Sciences (NIEHS) R01ES031657

[EN] A new method to significantly enhance the photoelectrochemical properties of phenyl-modified carbon nitride layers via the insertion of nickel ions into carbon nitride layers is reported. The nickel ions: are embedded within the carbon nitride layers by manipulating the interaction of Ni ions and molten organic molecules at elevated temperature prior to their condensation. A detailed analysis of the chemical and photophysical properties suggests that the nickel ions dissolve in the molten molecules, leading to the homogeneous distribution of nickel atoms within the carbon nitride layers. We found that the nickel atoms can alter the growth mechanism of carbon nitride layers, resulting in extended light absorption, charge transfer properties, and the total photoelectrochemical performance. For the most photoactive electrode, the Ni ions have an oxidation state of 2.8, as confirmed by soft X-ray absorption spectroscopy. Furthermore, important parameters such as absorption coefficient, exciton lifetime, and diffusion length were studied in depth, providing substantial progress in our understanding of the photoelectrochemical properties of carbon nitride films. This work opens new opportunities for the growth of carbon nitride layers and similar materials on different surfaces and provides important progress in our understanding of the photophysical and photoelectrochemical properties of carbon nitride layers toward their implantation in photoelectronic and other devices., We thank the use Katz Institute for Nanoscale Science & Technology Ben Gurion University for HR-TEM measurements. M.S. thanks Dr. Laurent Chabanne for fruitful discussion. K.M.L. is grateful for the support by the Helmholtz Association (VH-NG-1140).

Microfabrication technology provides a highly versatile platform for engineering hydrogels used in biomedical applications with high-resolution control and injectability. Herein, we present a strategy of microfluidics-assisted fabrication photo-cross-linkable gelatin microgels, coupled with providing protective silica hydrogel layer on the microgel surface to ultimately generate gelatin-silica core-shell microgels for applications as in vitro cell culture platform and injectable tissue constructs. A microfluidic device having flow-focusing channel geometry was utilized to generate droplets containing methacrylated gelatin (GelMA), followed by a photo-cross-linking step to synthesize GelMA microgels. The size of the microgels could easily be controlled by varying the ratio of flow rates of aqueous and oil phases. Then, the GelMA microgels were used as in vitro cell culture platform to grow cardiac side population cells on the microgel surface. The cells readily adhered on the microgel surface and proliferated over time while maintaining high viability (∼90%). The cells on the microgels were also able to migrate to their surrounding area. In addition, the microgels eventually degraded over time. These results demonstrate that cell-seeded GelMA microgels have a great potential as injectable tissue constructs. Furthermore, we demonstrated that coating the cells on GelMA microgels with biocompatible and biodegradable silica hydrogels via sol-gel method provided significant protection against oxidative stress which is often encountered during and after injection into host tissues, and detrimental to the cells. Overall, the microfluidic approach to generate cell-adhesive microgel core, coupled with silica hydrogels as a protective shell, will be highly useful as a cell culture platform to generate a wide range of injectable tissue constructs.

The influence of the supramolecular interaction type—hydrogen bonding, proton transfer, and pure ionic bonding—on photoresponsive behavior, particularly surface relief grating (SRG) inscription, has been investigated using a homopolymer with an ambient temperature glass transition (Tg). To this end, poly(dimethylaminoethyl methacrylate) (PDMAEMA or PDM) of relatively high molecular weight (42K) was complexed at various azo/DM molar ratios with dimethylaminoazobenzene derivatives functionalized by hydroxyl (azoOH) or carboxylic acid (p-methyl red or azoCOOH) groups, and quaternized PDM (PDMQ) was complexed at equimolar ratio with a sulfonated analogue (methyl orange or azoSO3), and the structural and thermal properties of these complexes were determined. SRG inscription on spin-coated films was found to be possible because complexation increases the Tg above ambient. The efficiency of SRG inscription on spin-coated films, which increases with azo content, is highest for the purely ionic azoSO3/PDMQ complex despite its very high Tg, while the proton transfer azoCOOH/PDM complexes, involving ionic and H-bonding with acid-salt structures, show somewhat more efficient SRG inscription than do the purely hydrogen-bonded azoOH/PDM complexes, and this despite some azoCOOH crystallization at the highest molar ratios. These findings clarify the comparative effectiveness of different supramolecular bond types on SRG inscription and provide a useful guide for the design of supramolecular photoresponsive polymers for SRG applications.