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Although a facile route to prepare AgCu nanoalloys (NAs) with enhanced antibacterial efficacy using Ag NP catalysis of Cu ions at elevated temperatures was previously developed, its detailed reaction process is still unclear due to the fast reaction process at higher temperatures. This work found that AgCu NAs can also be synthesized by the same process but at room temperature. AgCu NAs formation kinetics have been studied using UV–Visible spectra and Transmission Electron Microscopy (TEM), where formation includes Cu2+ deposition onto the Ag NP surface and Ag+ release, reduction, and agglomeration to form new Ag NPs; this is followed by a redistribution of the NA components and coalescence to form larger AgCu NPs. It is found that SPR absorption is linear with time early in the reaction, as expected for both pseudo-first-order (PFO) and pseudo-second-order (PSO) kinetics; neither model is followed subsequently due to contributions from newly formed Ag NPs and AgCu NAs. The antibacterial efficacy of the AgCu NAs thus formed was estimated, with a continuous increase over the whole alloying process, demonstrating the correlation of antibacterial efficacy with the extent of AgCu NA formation and Ag+ release.

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Although Ag nanoparticles (NPs) have been widely applied in daily life and in biomedical and industrial fields, there is a demand for Ag-based bimetallic nanoalloys (NAs), such as AgCu and AgFe, due to their enhanced antibacterial efficacy and reduced Ag consumption. In this work, we present a comparison study on the antibacterial efficacy and cytotoxicity rates of Ag NPs and AgCu and AgFe NAs to L929 mouse fibroblast cells using the CCK-8 technique based on the relative cell viability. The concept of the minimum death concentration (MDC) is introduced to estimate the cytotoxicity to the cells. It is found that the minimum inhibitory concentrations (MICs) of the NPs against E. coli and S. aureus decrease with the addition of both Cu and Fe. There is a strong correlation between the MDC and MIC, implying that the mechanisms of both antibacterial efficacy and cytotoxicity are similar. The enhanced antibacterial efficacy to bacteria and cytotoxicity toward the cell are attributed to Ag+ release. The following order is found for both the MIC and MDC: AgFe < AgCu < Ag NPs. However, there is no cytotoxicity to the L929 cells for AgFe and AgCu NAs at their MIC Ag concentrations against S. aureus.

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A new kind of silica-based (Crea + TODGA)/SiO2-P adsorbent with high selectivity adsorption for palladium (Pd) was synthesized to examined the applicability for partitioning process of high level liquid waste (HLLW). Adsorption behavior of Pd(II) towards (Crea + TODGA)/SiO2-P adsorbent and stability of adsorbent against HNO3 solution were investigated by batch method. The degradation parts of (Crea + TODGA)/SiO2-P dissolved in liquid phase were estimated by total organic carbon (TOC) analyzer. (Crea + TODGA)/SiO2-P adsorbent showed good selectivity adsorption for Pd(II) and reached equilibrium within 24 hr. The adsorption ability of (Crea + TODGA)/SiO2-P for Pd(II) and the content of TOC leaked decreased with the increasing of HNO3 concentration. In 3 M HNO3, the average of K d values were 85.03 cm3/g and 26.10 cm3/g after contact time one to 28 days at 298 K and 323 K, respectively. While the content of TOC leaked from the adsorbent after 28 days were 1095 ppm (298 K) and 2989 ppm (323 K), respectively. Therefore, the adsorbent showed good stability at 298 K after contact with nitric acid for a long time. All results indicated (Crea + TODGA)/SiO2-P can be proposed as an applicable and efficient absorbent for separation of Pd(II) in 3 M HNO3 at 298 K.

a b s t r a c tChitosan-graft-benzo-15-crown-5 ether (CTS-g-B15C5) for metal ion separation was prepared and optimized by Box-Behnken design (BBD). Results showed that the maximum immobilization amount (I A ) of crown ether grafting on chitosan (CTS) polymer was 4.93 mmol·g -1 under the optimal conditions, which is in good agreement with the result predicted by BBD (4.97 mmol·g -1 ). Moreover, the CTS-g-B15C5 film exhibited an excellent adsorption ability and selectivity to different metal ions. The adsorption rates obtained by CTS-g-B15C5 film were 96.9% for Ag + and 94.3% for Pd 2+, which were higher than those obtained by CTS at the similar conditions. The order of adsorption ability on CTS-g-B15C5 . Furthermore, the CTS-g-B15C5 film could be reused after regeneration, and the adsorption rates for Ag + and Pd 2+ kept up to 90% after being regenerated for five times, which suggests a good stability and potential application in heavy metal recycling field.