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Antibiotic-resistant bacterial infections are a global health problem. A commonly-used antibiotic Penicillin G was incorporated into ZnAl-layered double hydroxides (PNG/LDH) with a varied amount of PNG. PNG/LDH nanocomposites were well characterized in structure and composition using elemental analysis, X-ray diffraction pattern, Fourier transform infrared spectroscopy and TEM images, revealing that PNG were mostly adsorbed on the LDH surfaces at a lower PNG loading but some were intercalated into LDH interlayers at a higher PNG loading. The typical release profile of PNG and Zn 2+ from PNG/LDH was a quick release, followed by a sustainable slow release. The antibacterial tests against Escherichia coli demonstrated that PNG/LDH with a suitable composition synergistically improved bacterial inhibition compared with free PNG and pristine LDHs. In specific, PNG/LDH with much higher cost-effectiveness showed a potent antimicrobial activity and maintained the activity for up to 10 days, significantly elongating the antibacterial effect compared with just 1 day for free PNG in the same conditions. Our results suggest suitable composition of nanoparticle carriers and antibiotics could significantly enhance antibacterial activity of antibiotics for a long period via the synergistic effect between carrier and antibiotics, a potential approach to overcome the bacterial resistance to antibiotics., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Aqueous batteries with high safety and cost efficiency usually employ metallic cations as charge carriers. Recently, ammonium (NH4+) ion batteries using the nonmetal NH4+ as a charge carrier exhibit distinct electrochemical features from conventional aqueous batteries. Herein, the electrochemical performances of a bimetallic hydroxide material are systematically studied with different charge carriers in the electrolytes, including NH4+, as well as the conventional monovalent metallic cations K+ and Na+, respectively. Electrochemical results indicate that the charge storage process using NH4+ as the working ions exhibits a higher discharge plateau, smaller electrochemical polarization, and larger discharge capacity than that using conventional metallic charge carriers. Experimental characterizations and theoretical calculations suggest that the strong interaction between NH4+ and the electrode material, as well as the low NH4+‐ion diffusion barrier lead to these superior electrochemical features. The assembled NH4+‐ion battery exhibits a good energy density of 123 Wh kg(cathode+anode)−1 at the power density of 480 W kg(cathode+anode)−1. These fundamental findings are important for developing good safety, low‐cost, and high‐energy aqueous batteries with sustainable NH4+ charge carriers. [ABSTRACT FROM AUTHOR]

• ZnO-dotted nanohybrids using LDHs as precursor (ZnO/LDHs) were synthesized via facile hydrothermal method. • Transformation of LDHs to ZnO and ZnAl 2 O 4 crystallites on zinc hydroxide nitrate layers was found. • ZnO/LDHs showed a potent and 4 days' antimicrobial activity toward E. coli and S. aureus at 100–300 μg/mL. The search for effective alternatives to traditional antibiotics to avoid antibiotic resistant bacteria is growing worldwide. ZnO nanoparticles are found to effectively inhibit growth and proliferation of bacteria, and ZnO-based layered double hydroxides (ZnO-based LDHs) have been intensively investigated for this purpose. However, the nanocomposites are made in a multi-step preparation process with severe agglomeration and limited bactericidal ability. In this research, ZnO-dotted nanohybrids using Zn 3 Al-LDHs as precursors (ZnO-dotted LDHs or ZnO/LDHs) were synthesized under facile hydrothermal conditions. An understanding of the transformation of the LDH precursors to the ZnO/LDHs was conducted with TEM/HRTEM/XRD/FTIR. ZnO/LDHs can be transformed from ZnAl-LDHs, with more ZnO nanodots generated upon heating at 150 and 200 °C for 2 h (Zn 3 Al-150, Zn 3 Al-200). Zn 3 Al-200 nanohybrids showed potent antibacterial activity towards Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) at 100–300 μg/mL for 4 days. Antibacterial activity of Zn 3 Al-200 may be attributed to the synergistic effects (ROS, leached Zn2+ and physical interaction). This research thus suggests a potential economic approach to prepare ZnO/LDH nanocomposites for avoiding the antibiotic resistant bacteria in environmental engineering or clinic fields. [ABSTRACT FROM AUTHOR]

Phosphorus removal from wastewater is important for eutrophication control of water bodies. Metal oxides and metal hydroxides have always been developed and investigated for phosphorus removal, because of their abundance, low cost, environmental friendliness, and chemically stability. This paper presents a comparative review of the literature on the preparation methods, adsorption behaviors, adsorption mechanisms, and the regeneration of metal (hydr)oxides (e.g., Fe, Zn, Al, etc.) with regard to phosphate removal. The contrasting results showed that metal hydroxides could offer an effective and economic alternative to metal oxides, because of their cost-benefit synthesis methods, higher adsorption capacities, and shorter adsorption equilibrium times. However, the specific surface area of metal oxides is larger than that of metal hydroxides because of the calcination process. Metal oxides with a higher pH at the zero point of charge have wider optimal adsorption pH ranges than metal hydroxides because of their surface precipitation in alkaline solutions. The regeneration of metal oxides using acids, bases, and salts and that of metal hydroxides using acids and bases has been critically examined. Further research on uniform metal (hydr)oxides with small particle size, high stabilities, low cost, and that are easily regenerated with promising desorbents are proposed. In addition, quantitative mechanism study and application in continuous-mode column trials are also suggested. [ABSTRACT FROM AUTHOR]

• Nanocomposite ZnO/ZnFe-LDH loaded on BC was prepared via a facile hydrothermal method. • BC improved visible-light adsorption and enhanced charge separation. • ZnO/ZnFe-LDH@BC exhibited synergistic effect towords visible light-activated degradation of TC. • The degradation pathway of TC and the underlining mechanisms were analyzed. To explore effective treatment of antibiotics-contaminated water using visible light-responsive photocatalyst, a series of ZnO decorated ZnFe-layered double hydroxide @ biochar (ZnO/ZnFe-LDH@BC) nanocomposites were obtained via a facile hydrothermal method. The fabricated nanocomposites exhibited uniform distribution of ZnO/ZnFe-LDH on BC matrix, allowing more active sites of ZnO/ZnFe-LDH to be utilized. The BC matrix brought widened visible-light absorbance, narrowed bandgap, and improved charge separation and transfer. During photocatalytic degradation of tetracycline (TC) under visible LED light, the nanocomposites showed significant enhancement of degradation efficiency, compared to ZnO/ZnFe-LDH or BC alone, indicating a strong synergy between ZnO/ZnFe-LDH and BC. The nanocomposite containing 23.0 wt% of BC (ZnO/ZnFe-LDH@BC 0.2) showed optimal performance (achieving 87.7% of degradation within 4 h) in comparison to the reported LDHs@carbon photocatalysts. Alkaline condition and co-existing CO 3 2– ions could enhance the stability and recyclability of the nanocomposites. Additionally, the possible degradation pathway of TC was analyzed via LC-MS and the reduction in toxicity resulting from photocatalytic degradation was confirmed by the culture of mung bean sprouts. This study provides a rational design strategy and performance assessment of LDH-based nanocomposites for the treatment of antibiotics-contaminated water. [ABSTRACT FROM AUTHOR]