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Silver nanoparticles (AgNPs) have been globally applied in consumer products because of their antimicrobial properties. Broad applications inevitably release AgNPs into the natural environment. Moreover, AgNPs are produced naturally in soils. Plant uptake of AgNPs is the first step of their transfer along the food chains, which ultimately raises concerns about human health. This review systematically summarizes the current knowledge on the uptake process of AgNPs in plants which is regulated by the physical properties of nanoparticles (e.g., size, surface coating, and morphology), environmental conditions (e.g., soil redox condition, soil components, co-contaminants, and symbiotic microorganisms), and plant species (e.g., monocotyledon and dicotyledon). After internalization, AgNPs are translocated within plants and undergo biotransformation, including aggregation, oxidative dissolution, sulfidation, chlorination, and complexation with organic matter such as thiolates. Little is known about whether the internalized AgNPs and the transformed products will be accumulated in edible tissues of plants, which can raise possibility of Ag to enter the food chains. Knowledge gaps about detailed mechanisms of transformation and translocation of AgNPs in planta still limit our understanding of Ag fate in plant-soil systems. This review intends to give a comprehensive assessment of the interaction between AgNPs and plants, highlighting that an integrated investigation of the full life cycle of AgNPs in plant-soil systems is needed to ensure safe application of nanoparticles.

Silver is an antimicrobial agent that is used extensively in consumer products, such as fabrics and humidifiers. Silver ion (Ag

Many studies have examined the redox behavior of ferrous ions (Fe(II)) sorbed to mineral surfaces. However, the associated hydroxyl radical (

Scandium is a critical raw material with a technological potential to reduce transportation costs and CO2 emissions. However, global supply and market adoption are crucially impaired by the lack of high-grade Sc ores and recovery strategies. A tandem nanofiltration solvent extraction route is demonstrated to enable effective Sc recovery from real-world acid waste from the chloride TiO2 production route. The process involving several filtration stages, solvent extraction, and precipitation was optimized, ultimately producing >97% pure (NH4)(3)ScF6.

With the widespread emphasis on sustainability in transportation, dockless bike-sharing (DBS) is gaining popularity. This research proposed an extended norms activation model (NAM) to study the eff...

With the development of mobile communication technology and the wide application of intelligent devices, mobile payments with great commercial potential have been born. However, the penetration rate of mobile payment is not satisfactory. In order to explore user acceptance of mobile payments, this study proposes a new research model based on the technology acceptance model, which integrates the characteristics of mobile payments (i.e., mobility) and inhibiting factors (i.e., risk and cost). Partial least squares was performed to analyse measurement and structural models on the data collected from 245 survey samples. The results indicated that perceived mobility has a positive and direct impact on perceived ease of use and perceived usefulness, as well as an indirect impact on adoption intention; however, perceived risk and perceived cost negatively affect a user’s intention to use mobile payments. Finally, the research provides empirical evidence for practitioners to enhance the adoption of mobile payments.

Benzophenones (BPs), which are widely used UV filters, have aroused considerable public concern owing to their potential endocrine-disrupting activities. Herein, we systematically investigated their photochemical behavior and fate, which is mediated by nitrate in aquatic environments. The results showed that 10 μM of 3 BPs can be completely degraded within 4 h of simulated sunlight irradiation in a 10 mM nitrate solution at pH 8.0, and 2,4-dihydroxybenzophenone (BP-1) has a 31.6% mineralization rate after 12 h irradiation. Their photolytic rates (kobs) presented a significant linear correlation with the logarithmic values of the nitrate concentration for 0.1–10 mM (R2 > 0.98), and in three actual waters, the rates of BP-1 were also positively related to the intrinsic nitrate concentration. Furthermore, higher transformation rates under alkaline condition were observed, especially for BP-1, with its kobs at pH 10 being 8.3-fold higher than that at pH 6.0. Moreover, dissolved oxygen (DO) also has an impact on the reaction kinetics to some degree. According to the quenching experiments, we found that three reactive oxygen species (ROS), namely, •OH, •NO, and •NO2, participated in this photolysis of BPs, and the contribution of •OH accounted for 32.1%. Furthermore, we selected BP-1 as the model molecule to study the transformation pathways and toxicity changes in this system. Four main transformation pathways including hydroxylation, nitrosylation, nitration, and dimerization were proposed, based on liquid chromatography quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS) analysis and density functional theory (DFT). According to the toxicity test, the formed intermediates were more toxic to Photobacterium phosphoreum than the parent BP-1. Therefore, these results can help reveal primary phototransformation mechanisms and evaluate the potential ecological risks of BPs in aquatic environments.

In this work, two spirobifluorene-based probes, namely SPF-1 and SPF-2, were designed and synthesized. They exhibited high selectivity and sensitivity toward Zn2+ with enhanced emissions, which could be attributed to the formation of an L–Zn complex. The detection limit of SPF-2 is 63 nM for Zn2+ and this is significantly lower than most previous reports. SPF-1 was successfully used for intracellular Zn2+ imaging. In addition, SPF-2 possesses two-photon absorption properties and has been applied in two-photon fluorescence cell imaging. This study is the first time that a spirobifluorene-based probe with aggregation-induced emission enhancement (AIEE) properties has been reported. We hope that this molecular design triggers further interest in using spiro-configured compounds in AIEE-based bioprobes for further applications.

A two-photon fluorescent probe derived from spirobifluorene has been developed. The probe exhibits large two-photon cross-section value. It displayed fast response toward ClO− / Hg2+ with high sensitivity and selectivity, exhibiting fluorescence enhancement. In the case of TPA, the detection limit of SPF-S is 11nM for ClO− and 24nM for Hg2+, which is lower than that obtained with one-photon fluorescence. Moreover, the present probe was successfully applied to the two-photon fluorescence imaging of ClO− and Hg2+ in living cells. This work indicated that the compound is an excellent fluorescence probe for the detection of Hg2+ and ClO− and provides a two-photon fluorescence probe for ClO−, which is rarely reported till now.

The frequently occurring redox fluctuations in paddy soil are critical to the cycling of redox-sensitive elements (e.g., iron (Fe) and carbon) due to the driving of microbial processes. However, the associated abiotic process, such as hydroxyl radical (•OH) formation, was rarely investigated. Hence, we examined the under-appreciated role of •OH formation in driving polycyclic aromatic hydrocarbons (PAHs) degradation upon oxygenation of anoxic paddy slurries. Results showed that •OH production largely differed in different paddy slurries, in the range of 271.5-581.2 μmol kg-1 soil after 12 h reaction. The •OH production was highly hinged on the contents of active Fe species, i.e., exchangeable, surface-bound Fe and Fe in low-crystalline phases rather than Fe in high-crystalline minerals or silicates. Besides, •OH production significantly decreased with increasing soil depth due to the declined active Fe species and abundance of functional microbes. Oxygenation also induced the transformation of these active Fe species into the low- and high-crystalline phases, which might affect the following redox process. The produced •OH can efficiently degrade PAHs with degradation extents depending on their physiochemical properties. Our findings highlight the key roles of active Fe species in driving •OH formation and organic contaminants degradation during redox fluctuations of paddy soils.

Sulfide is one of the most abundant reductants in the subsurface environment, while pyrogenic carbon is a redox medium that widely exists in sulfide environment. Previous studies have found pyrogenic carbon can mediate the reductive degradation of organic pollutants under anoxic sulfide conditions; however, the scenario under oxic sulfide conditions has rarely been reported. In this study, we found that pyrogenic carbon can mediate hydroxyl radicals (•OH) generation from sulfide oxidation under dark oxic conditions. The accumulated •OH ranged from 2.07 to 101.90 μM in the presence of 5 mM Na2S and 100 mg L-1 pyrogenic carbon at pH 7.0 within 240 min. The Raman spectra and electrochemical cell experiments revealed that the carbon defects were the possible chemisorption sites for oxygen, while the graphite crystallites were responsible for the electron transfer from sulfide to O2 to generate H2O2 and •OH. Quenching experiments and degradation product identification showed that As(III) and sulfanilamide can be oxidized by the generated •OH. This research provides a new insight into the important role of pyrogenic carbon in redox reactions and dark •OH production.

The widely occurring silver sulfide nanoparticles (Ag2S-NPs) are regarded as stable Ag species in subsurface environments, where are often disturbed by human activities, such as the application of advanced oxidation technologies (e.g. persulfate based in situ chemical oxidation (PS-ISCO)) in the remediation of contaminated soil and groundwater. However, stability of Ag2S-NPs was rarely investigated referring to these processes. Here, we systematically investigated the dissolution process of Ag2S-NPs in thermal activation of PS system. Results showed that dissolution of Ag2S-NPs fitted the pseudo-first-order kinetics and the kobs increased from 0.017 h−1 to 0.249 h−1 with increasing PS concentration from 2 mM to 10 mM (36 h, 40 °C). Quenching experiments and EPR results showed that sulfate radical (SO4•–) and hydroxyl radical (•OH) were the dominant oxidants in inducing the oxidative dissolution of Ag2S-NPs. XPS analysis showed that surface-bound S2− in Ag2S-NPs was oxidized and transformed into aqueous sulfur species. The released Ag+ may also act as effective catalysts to activate PS and therefore promote the oxidation process. These findings suggest that stability of Ag2S-NPs should be reevaluated to better understand its risk to the ecological system in the subsurface environment where ISCO was widely applied.

Purpose – The purpose of this research is to investigate which factors influence users’ loyalty to smart dockless bike-sharing systems (DBSS). Design/methodology/approach – A sample of 374 subjects who had previously experienced smart DBSS was obtained and the partial least squares (PLS) method was performed to analyze the measurement and structural models. Findings – The results indicated that customer loyalty was the final construct produced by perceived green value, customer satisfaction, and perceived pleasure, which were found to be partial mediators between service quality and customer loyalty. Originality/value – This study (1) provides a new perspective from which to examine consumer loyalty behavior in a smart DBSS context, (2) it identifies the role of service quality as an important stimulus, (3) it confirms that perceived pleasure not only has an effect on customer loyalty, but also acts as an excellent mediator, and (4) it provides empirical evidence for smart DBSS providers to enhance the adoption of green transport and to strengthen customer loyalty to smart DBSS. Objetivo – O objetivo desta pesquisa é investigar quais fatores influenciam na lealdade dos usuários de sistemas inteligentes de compartilhamento de bicicletas sem estações. Metodologia – Um total de 374 indivíduos que tiveram experiência anterior com o uso de sistemas inteligentes de compartilhamento de bicicletas sem estações foi reunido e o método parcial de mínimos quadrados (PLS) foi utilizado para analisar os modelos de medição e estrutural. Resultados – Os resultados indicaram que a lealdade do cliente era o construto final produzido pelo valor ecológico percebido, pela satisfação do cliente e pelo prazer percebido, que são avaliados como mediadores parciais entre a qualidade do serviço e a lealdade do cliente. Contribuições – Este estudo: 1) oferece uma nova perspectiva para se examinar o comportamento de lealdade do consumidor em um contexto de sistemas inteligentes de compartilhamento de bicicletas sem estações inteligentes; 2) identifica o papel da qualidade do serviço como um estímulo importante; 3) confirma o prazer percebido não apenas como um efeito sobre a lealdade do cliente, mas também como atuando como um excelente mediador; e 4) oferece evidência empírica para os prestadores do sistema inteligente de compartilhamento de bicicletas sem estações aprimorarem a adoção do transporte ecológico e fortalecerem a lealdade do cliente ao sistema inteligente. Objetivo – O objetivo desta pesquisa é investigar quais fatores influenciam na lealdade dos usuários de sistemas inteligentes de compartilhamento de bicicletas sem estações. Metodologia – Um total de 374 indivíduos que tiveram experiência anterior com o uso de sistemas inteligentes de compartilhamento de bicicletas sem estações foi reunido e o método parcial de mínimos quadrados (PLS) foi utilizado para analisar os modelos de medição e estrutural. Resultados – Os resultados indicaram que a lealdade do cliente era o construto final produzido pelo valor ecológico percebido, pela satisfação do cliente e pelo prazer percebido, que são avaliados como mediadores parciais entre a qualidade do serviço e a lealdade do cliente. Contribuições – Este estudo: 1) oferece uma nova perspectiva para se examinar o comportamento de lealdade do consumidor em um contexto de sistemas inteligentes de compartilhamento de bicicletas sem estações inteligentes; 2) identifica o papel da qualidade do serviço como um estímulo importante; 3) confirma o prazer percebido não apenas como um efeito sobre a lealdade do cliente, mas também como atuando como um excelente mediador; e 4) oferece evidência empírica para os prestadores do sistema inteligente de compartilhamento de bicicletas sem estações aprimorarem a adoção do transporte ecológico e fortalecerem a lealdade do cliente ao sistema inteligente.

Hydroxyl radical (•OH) plays a critical role in driving organic pollutants degradation during redox fluctuations. Such processes have been frequently investigated in sedimentary environments, but rarely referred to the agricultural fields, such as paddy soils with frequent occurrence of redox fluctuations. Our findings demonstrated that extensive •OH (40.3–1061.4 μmol kg−1) was produced during oxygenation of anoxic paddy slurries under circumstance conditions. Wet chemical sequential extractions, Mossbauer spectra, and X-ray photoelectron spectroscopy characterizations collectively corroborated that 0.5 M HCl-extracted Fe(II) (i.e., surface-bound Fe and Fe in low-crystalline minerals) contributed to more •OH production than aqueous Fe2+. The produced •OH can efficiently induce the oxidative transformation of organic carbon and the degradation of imidacloprid (IMP), which in turn produced the by-products, such as IMP-urea, IMP-olefin, and 6-chloronicontinic acid, via •OH-attacking mechanisms. Quenching experiments showed that hydrogen peroxide (H2O2) was the important intermediate for •OH formation via Haber-Weiss mechanisms during oxygenation processes. These findings indicate that abundant •OH can be produced during the redox fluctuations of paddy soil, which might be of great significance to predict the removal of organic contaminants and the mineralization of organic carbon in paddy fields.

This study integrated the theoretical perspective of social capital into community-based ecotourism (CBET). Two destinations were selected to test the conceptual model to see whether social capital improves cooperation between community residents and the coordination of CBET development, and whether its role is persuasive and encourages residents' pro-environmental behaviors. The sample consisted of 420 residents living in two typical ecotourism destinations in China. Findings from a two-stage structural equation model analysis show that economic benefits have a direct impact on residents' pro-environmental behaviors; and the cognitive, rather than structural social capital has a partially mediating effects on this relationship. These findings indicate that a high level of social capital, particularly the cognitive variant, is instrumental in encouraging residents' pro-environmental behaviors.

The theoretical perspective of this study is to integrate Visitor Environmental Learning (VEL) into the Theory of Planed Behavior (TPB). The Xiangjiang Safari Park, which is one of the largest theme parks in Asia, was selected to test the conceptual model to examine whether Post-Visit Action Resources (PVAR), Ease of Behavior (EB), and Sunk Cost (SC) have the mediate/moderate effect on the relationship between short-term pro-environment intentions and long-term behaviors. The sample consisted of 269 tourists who have travel experience with the Xiangjiang Safari Park. Findings from a Structural Equation Model analysis show that post-visit action resources partially mediate the relationship between tourists’ short-term proenvironmental intentions and behaviors, and that ease of behavior and sunk cost both have moderating effects on this relationship. These findings indicate that a high level of post-visit action resources, ease of behavior and sunk cost are instrumental in encouraging visitors’ pro-...