Inorganic-framework molecularly imprinted TiO2/WO3 nanocomposites with molecular recognitive photocatalytic activity were first prepared successfully by a facile one-step sol-gel method using ...2-nitrophenol and 4-nitrophenol as template molecules, and tetrabutyl orthotitanate as titanium source as well as the precursor of functional monomer which could complex with template molecules. The template molecules could be completely removed by means of high-temperature calcination, avoiding the traditional extraction procedures that are time- as well as solvent-consuming. Compared to nonimprinted TiO2/WO3, the molecularly imprinted TiO2/WO3 shows a much higher adsorption capacity and selectivity toward the template molecules. The enhancement in terms of adsorption capacity and selectivity can be attributed to the chemical interaction between target molecules and imprinted cavities, as well as size matching between imprinted cavities and target molecules. The photocatalytic activity of molecularly imprinted TiO2/WO3 toward the target molecules is more than two times that of non-imprinted TiO2/WO3, a result of selective adsorption of target molecules on molecularly imprinted TiO2/WO3. The formation pathway of intermediate products in 2-nitrophenol and 4-nitrophenol degradation process was provided. Moreover, molecularly imprinted TiO2/WO3 exhibits high stability. The results indicate that inorganic-framework molecularly imprinted TiO2/WO3 nanocomposites have a promising prospect in the treatment of wastewater for irrigation.
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► RGO–ZrO(OH)2 was prepared by hydro-thermal co-precipitation method. ► RGO–ZrO(OH)2 had high adsorption capacity for both As(III) and As(V). ► RGO–ZrO(OH)2 showed high adsorption ...capacity in wide pH range. ► RGO–ZrO(OH)2 exhibited good anti-interference ability to co-existing anions. ► Adsorption equilibrium of As(III, V) on RGO–ZrO(OH)2 was obtained within 15min.
Hydrated zirconium oxide (ZrO(OH)2) nanoparticles were modified with graphite oxide (GO) (denoted herein as GO–ZrO(OH)2) by hydro-thermal co-precipitation reaction, and were used for the simultaneous removal of As(III) and As(V) from drinking water. The GO–ZrO(OH)2 nanocomposites were characterized using Fourier transformer infrared spectroscopy, X-ray diffraction analysis, high resolution transmission electron microscopy, Zeta-potential, and specific surface area analysis. The size of ZrO(OH)2 particles in GO–ZrO(OH)2 is below 5nm, and the specific surface area of GO–ZrO(OH)2 is about 4 times that of ZrO(OH)2 nanoparticles. The GO–ZrO(OH)2 nanocomposites showed high adsorption capacity in a wide pH range, and the monolayer adsorption amounts calculated based on the Langmuir adsorption model were 95.15 and 84.89mg/g for As(III) and As(V), respectively, which are 3.54 and 4.64 times that of ZrO(OH)2 nanoparticles. The high adsorption capacity is attributed to good dispersion of ZrO(OH)2 nanoparticles in the GO substrate. The GO–ZrO(OH)2 nanocomposites can simultaneously remove As(III) and As(V) in water. Moreover, GO–ZrO(OH)2 showed good anti-interference ability to co-existing anions, and exhibited excellent recyclability. The experimental results suggest that GO–ZrO(OH)2 is a promising adsorbent for the removal of arsenic from drinking water.
p-Nitrophenol (PNP) is a difficultly decomposed organic pollutant under solar light in the absence of strong oxidants. This study shows that under artificial solar light PNP can be effectively ...degraded by a Cu2O/TiO2 p-n junction network which is fabricated by anodizing Cu0 particles-loaded TiO2 nanotubes (NTs). The network is composed of p-type Cu2O nanowires on the top surface and Cu2O nanoparticles on the inner walls of the n-type TiO2 NT arrays. The Cu2O/TiO2 network shows much higher degradation rate (1.97 μg/min cm2) than the unmodified TiO2 NTs (0.85 μg/min cm2). The enhanced photocatalytic acitivity can be attributed to the extended absorption in the visible resulting from the Cu2O nanowire networks and the effective separation of photogenerated carriers driven by the photoinduced potential difference generated at the Cu2O/TiO2 p-n junction interface.
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•1T MoS2 nanosheets were stabilized by the confinement effect of TiO2 nanotube arrays.•The architecture benefited the fast transmission of electrolyte ions and electrons.•It is the ...first report about 1T-MoS2@TiO2 nanotube arrays used in supercapacitors.•1T-MoS2@TiO2/Ti showed an excellent capacitance performance and cycle stability.
Metallic 1T phase molybdenum disulfide (1T-MoS2) holds great promise in energy storage applications due to its excellent conductivity and hydrophilicity. However, free 1T-MoS2 nanosheets are prone to agglomeration and convert to 2H-MoS2, resulting in a decrease in electrochemical performance. In this study, metallic 1T phase MoS2 nanosheets are confined among TiO2 nanotube arrays (1T-MoS2@TiO2/Ti) via a facile hydrothermal process. The architecture in the glory of ultrathin 1T-MoS2 nanosheets and highly ordered pore tunnel of TiO2 nanotube arrays benefits fast electrolyte diffusion and electron transfer. As a result, the 1T-MoS2@TiO2/Ti composite shows a high specific capacitance of 428.1F g−1 at 0.2 A g−1, high energy density of 48.2 Wh kg−1, high power density of 2481.7 W kg−1 and 97% capacitance retention after 10,000 cycles. This study proves an artful thought for designing electrode materials to enhance their electrochemical performances.
Efficient evolution of hydrogen through electrocatalysis holds tremendous promise for clean energy. The catalytic efficiency for hydrogen evolution reaction (HER) strongly depends on the number and ...activity of active sites. To this end, making vertically aligned, ultrathin, and along with rich metallic phase WS
2
nanosheets is effective to maximally unearth the catalytic performance of WS
2
nanosheets. Metallic 1T polymorph combined with vertically aligned ultrathin WS
2
nanosheets on flat substrate is successfully prepared via one-step simple hydrothermal reaction. The nearly vertical orientation of WS
2
nanosheets enables the active sites of surface edge and basal planes to be maximally exposed. Here, we report vertical 1T-WS
2
nanosheets as efficient catalysts for hydrogen evolution with low overpotential of 118 mV at 10 mA cm
−2
and a Tafel slope of 43 mV dec
−1
. In addition, the prepared WS
2
nanosheets exhibit extremely high stability in acidic solution as the HER catalytic activity and show no degradation after 5000 continuous potential cycles. Our results indicate that vertical 1T-WS
2
nanosheets are attractive alternative to the precious platinum benchmark catalyst and rival MoS
2
materials that have recently been heavily scrutinized for hydrogen evolution.
Graphical Abstract
Vertical 1T-WS2 for hydrogen evolution.
A novel electrochemiluminescence (ECL) sensor based on carbon quantum dots (CQDs) immobilized on graphene (GR) has been first developed for the determination of chlorinated phenols (CPs) in water. ...The detection is based on the ECL signals from the interaction between the analytes and the excited CQDs (C*+) using S2O8 2– as coreactant. GR facilitates both C•– and SO4 •– production, resulting in a high yield of C*+, and the multistage amplification effect leads to a nearly 48-fold ECL amplification. Pentachlorophenol (PCP) is often monitored as an important indicator for CPs in real environmental samples, but its ultratrace and real-time analysis is an intractable issue in environmental monitoring. The resulting ECL sensor enables the real-time detection of PCP with unprecedented sensitivity reaching 1.0 × 10–12 M concentration in a wide linear range from 1.0 × 10–12 to 1.0 × 10–8 M. The ECL sensor showed high selectivity to CPs, especially to PCP. The practicability of the sensing platform in real water samples showed ideal recovery rates. It is envisaged that the eco-friendly and recyclable sensor could be employed in the identification of key CPs in the environment.
Bioaugmentation is a promising method for assisting phytoextraction of heavy metals from contaminated soil, and the development of bioaugmentation-assisted phytoextraction requires the understanding ...of the mechanism involved in the interaction between plants and inocula. In this study, a pot study was conducted to evaluate the effect of bacterial endophyte Pseudomonas sp. Lk9 which can produce biosurfactants, siderophores and organic acids on the growth and metal uptake of Cd-hyperaccumulator Solanum nigrum L. growing in multi-metal-contaminated soil. The results revealed that Lk9 inoculation could improve soil Fe and P mineral nutrition supplies, enhance soil heavy metal availability, and affect host-mediated low-molecular-weight organic acids secretion, thereby significantly increasing S. nigrum shoot dry biomass by 14% and the total of Cd by 46.6%, Zn by 16.4% and Cu by 16.0% accumulated in aerial parts, compared to those of non-inoculated control. The assessment of phytoextraction showed that Lk9 inoculation elevated the bioaccumulation factor of Cd (28.9%) and phytoextraction rates of all metals (17.4%, 48.6% and 104.6% for Cd, Zn and Cu, respectively), while the translocation factors had negligible difference between Lk9 inoculation (3.30, 0.50 and 0.40 for Cd, Zn and Cu, respectively) and non-inoculated control (2.95, 0.53 and 0.42 for Cd, Zn and Cu, respectively). It was also found that the symbiotic association between S. nigrum and Lk9 significantly increased the soil microbial biomass C by 39.2% and acid phosphatase activity by 28.6% compared to those in S. nigrum without Lk9. This study would provide a new insight into the bioaugmentation-assisted phytoextraction of heavy metal-contaminated soils.
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•Functional Pseudomonas sp. Lk9 enhanced Solanum nigrum extraction of Cd, Zn and Cu.•Lk9 inoculation improved soil Fe, P mineral nutrition supplies.•Lk9 inoculation enhanced soil Cd, Zn and Cu bioavailability.•Lk9 inoculation affected host-mediated low-molecular-weight organic acids secretion.•Lk9 is a good candidate for bioaugmentation-assisted metal phytoextraction.
► Catalytic ion was first applied to the bioleaching process of spent lithium-ion batteries. ► The bioleaching efficiency was great improved from 43.1% to 99.9% in the presence of copper ion. ► A new ...reaction model was proposed to explain the catalytic mechanism.
A copper-catalyzed bioleaching process was developed to recycle cobalt from spent lithium-ion batteries (mainly LiCoO
2) in this paper. The influence of copper ions on bioleaching of LiCoO
2 by
Acidithiobacillus ferrooxidans (
A.f) was investigated. It was shown that almost all cobalt (99.9%) went into solution after being bioleached for 6 days in the presence of 0.75
g/L copper ions, while only 43.1% of cobalt dissolution was obtained after 10 days without copper ions. EDX, XRD and SEM analyses additionally confirmed that the cobalt dissolution from spent lithium-ion batteries could be improved in the presence of copper ions. The catalytic mechanism was investigated to explain the enhancement of cobalt dissolution by copper ions, in which LiCoO
2 underwent a cationic interchange reaction with copper ions to form CuCo
2O
4 on the surface of the sample, which could be easily dissolved by Fe
3+.
Oxcarbazepine (OXC) is ubiquitous in the aqueous environment. And due to its ecotoxicological effects and potential risks to human, an effective way to eliminate OXC from aqueous environment has ...aroused public concerns in recent years. Radical-based reactions have been shown to be an efficient way for OXC destruction, but the reactions of OXC with reactive oxygen species (ROS) and carbonate radical (CO3•−) are still unclear. In this study, we focused the degradation of OXC and ROS, CO3•− generation mechanism, and their roles in OXC degradation via UV and UV/H2O2. The triplet state of oxcarbazepine (3OXC∗) was found to play an important role in OXC degradation via UV. And hydroxyl radicals (•OH) and singlet oxygen (1O2) were found to be the dominant ROS in OXC degradation. Superoxide radical (O2•−) did not react with OXC directly, but it may react with intermediate byproducts. Generation of CO3•− played a positive role on OXC degradation for both UV and UV/H2O2. In addition to •OH, 3OXC* also contribute to CO3•− production. The second-order rate constants of OXC with •OH and CO3•− were 1.7 × 1010 M−1 s−1 and 8.6 × 107 M−1 s−1, respectively. Potential OXC degradation mechanisms by •OH were proposed and included hydroxylation, α-ketol rearrangement, and benzylic acid rearrangement. Compared with non-selective •OH, the reactions involving CO3•− are mainly electron transfer and hydrogen abstraction. And the acute toxicity of OXC was lower after UV/H2O2 and UV/H2O2/HCO3− treatments, which was confirmed by luminescent bacterial assay (Vibrio fischeri bacterium).
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•The photodegradation mechanism of OXC involving 3OXC* and ROS was proposed.•The 3OXC* played an important role in OXC degradation via UV.•HCO3− enhanced the OXC degradation, 3OXC* and •OH contributed for CO3•− production.•The reactions involved in CO3•− are electron transfer and hydrogen abstraction.
•No chitosan material has been reported to simultaneously remove both NO3− and PO4−.•A nanocomposite of modified chitosan was firstly reported in this study.•The nanocomposite can remove both nitrate ...and phosphate.•The composite is easy to fabricate at mild condition with low cost.•All the components are biocompatible.
A novel nanocomposite with a BET surface area of 212.9m2/g was synthesized from chitosan and Fe3O4/ZrO2 using an inexpensive protocol at mild condition. The Fe3O4/ZrO2/chitosan composite has the ability to adsorb both nitrate and phosphate. The maximum adsorption amount of nitrate and phosphate is 89.3mg/g and 26.5mgP/g, respectively. The adsorption process fits well to the pseudo-first-order kinetic rate model, and the mechanism involves simultaneous adsorption and intra-particle diffusion. The experimental results suggest that the composite is a promising adsorbent for treating water that is contaminated with nutrients.
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