This research aimed to explore the potential and mechanism of heat modified sawdust combined with Festuca arundinacea for the remediation of Pb-contaminated soil. We determined Pb concentration and ...biochemical indices in plants and soils, analyzed microbial communities in soil, and studied Pb distribution in subcellular and tissues. Under co-remediation of 5% material addition and Festuca arundinacea, the concentration of Pb in soil decreased. Pb toxicity of Festuca arundinacea was alleviated by 2% material addition through the promotion of plant growth and reduction of oxidative stress. In addition, soil enzyme activities and microbial community in contaminated soil were promoted by the application of co-remediation. Festuca arundinacea cell wall accumulated a large amount of Pb, and the addition of material promoted the accumulation of Pb in Festuca arundinacea root. The concentration of Pb in the shoot of the plant treated with 2% material was higher than that of the plant treated with 5% material, and the damage of Festuca arundinacea leaves was lower under 2% treatment. The combination of heat modified sawdust and Festuca arundinacea promoted the adsorption of Pb by plants, and protected the growth of plants.
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•Perovskite-related photocatalysts for organic contaminants removal are reviewed.•Design strategies of perovskite-related photocatalysts are highlighted.•Future perspectives of ...perovskite-related photocatalysts are proposed.
The development of new generation photocatalytic materials for the organic contaminants removal has been a research focus. Perovskite and perovskite-related structures offer a broad scope in designing novel photocatalysts for this process. The present review summarizes and highlights the state-of-the-art progress of third-generation photocatalysts perovskite and perovskite-related semiconductors, and their application for the photocatalytic decomposition of both waterborne and airborne organic contaminants. Special attention is paid to the design strategies for promoting the photocatalytic performance of perovskite and perovskite-related materials, including ion doping/substitution, noble metal decoration, heterojunctions formation and morphology regulation. Future perspectives of perovskite-related photocatalysts are also included in this review.
Beijing experienced a period of severe atmospheric particulate pollution from 2015 to 2016. In order to acquire the characteristics of polycyclic aromatic hydrocarbons (PAHs) under heavy polluting ...status, one year sampling campaign was carried out. We selected PM2.5 samples which had the highest concentrations or suffered serious haze-fog weathers in each month. Through the analysis of data from heavily polluting phase, the mean concentrations of PM2.5 and PAHs in winter (369.63 μg m−3 and 223.60 ng m−3) were obviously higher than that in other seasons. The concentration of Σ16PAHs ranged from 3.22 to 297.01 ng m−3, with a mean value of 77.48 ng m−3. In winter, 4-ring PAH congeners (52.33%) contributed the most in PM2.5, followed by 5-rings (27.05%), 6-rings (11.55%) and 2∼3-rings (9.06%). Summertime measurements showed the highest decline in PAHs concentrations for 3∼5-ring congeners. The diagnostic ratios and PCA analysis manifest that vehicle and combustion emission were major sources and totally occupied 88.57% under heavy polluting stage. Moreover, exponential relationship between LWM/HWM (light/high weight molecule-PAHs) and combustion-derived PAHs, as well as linear relationship between BghiP and ∑PAHs verified that the pollution sources mentioned above affected local atmosphere environment as major sources. The highest total BaP equivalent concentration suggested that toxicity potency under heavy polluting phase was mainly attributed to 5-ring PAHs. Through analysis of carcinogenic-PAHs, potency risk to adults was significantly higher than that to children. BaP, BbF and DahA, which belong to 5-ring congeners, contributed the highest potency carcinogenic risk. BbF in winter, BaP in spring and winter may cause potential risk to local residents.
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•Characteristics of PAHs under heavy polluting phase were studied in urban Beijing.•4-ring PAH congeners (52.33%) contributed the most in PM2.5 in winter.•Diesel-fuelled vehicle emission and coal combustion were major sources under heavy polluting stage.•Toxicity potency was mainly influenced by 5-ring PAH congeners, such as BaP, BbF and DahA.•BbF in winter, BaP in spring and winter may cause potential risk to citizen.
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•Vo-BiVO4/FeOOH photoanode was prepared by hydrothermal and photodeposition treatment.•Oxygen vacancy and FeOOH cocatlayst enhance the charge transfer and separation ...efficiency.•Vo-BiVO4/FeOOH photoanode demonstrated excellent PEC performance than prsitine BiVO4.
Herein, a new approach of inducing oxygen vacancy in BiVO4/FeOOH nanostructures is designed, where metal trichalcogenide is introduced. The strategy involves integration of Bi2S3 quantum dots (QDs) in BiVO4/FeOOH to construct defect-rich BiVO4/FeOOH (denoted Vo-BiVO4/FeOOH) as high-performance photoanode for photoelectrochemical water oxidation. Both experimental and theoretical analysis confirm that the excellent PEC performance is due to the introduction of oxygen vacancies and FeOOH cocatalyst, which significantly improves the charge separation. As a result, the obtained Vo-BiVO4/FeOOH photoanode not only demonstrates an optimized Photoelectrochemical (PEC) performance for water oxidation, with photocurrent density of 4.71 mA cm−2 at 1.23 V versus RHE under AM 1.5 G illumination but the interaction of BiVO4 with FeOOH cocatlayst also significantly enhance the stability for Vo-BiVO4/FeOOH without any decrease after 11 h. The oxygen vacancy and FeOOH can effectively enhance the light conversion efficiency, charge transfer efficiencies and charge separation efficiency. This work highlights an effective strategy towards achieving efficient and stable BiVO4 photoanode for sustainable solar energy conversion.
Hydrogen, a clean energy carrier with high energy capacity, is a very promising candidate as a primary energy source for the future. Photoelectrochemical (PEC) hydrogen production from renewable ...biomass derivatives and water is one of the most promising approaches to producing green chemical fuel. Compared to water splitting, hydrogen production from renewable biomass derivatives and water through a PEC process is more efficient from the viewpoint of thermodynamics. Additionally, the carbon dioxide formed can be re-transformed into carbohydrates via photosynthesis in plants. In this review, we focus on the development of photoanodes and systems for PEC hydrogen production from water and renewable biomass derivatives, such as methanol, ethanol, glycerol and sugars. We also discuss the future challenges and opportunities for the design of the state-of-the-art photoanodes and PEC systems for hydrogen production from biomass derivatives and water.
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There are wide interests in developing high-performance electrode materials for electrochemical energy storage and conversion devices. Among them, transition metal nitrides (TMNs) are ...suitable for a wide range of devices because they have better electrical conductivity than the oxides and excellent catalytic properties. In particular, properly designed nanostructured TMNs offer additional advantages for performance enhancement. However, reviews of the rapid utilization of metal nitrides as electrode materials are still not much. In this mini-review, we present a recent (mostly since 2015) update on nanostructured TMNs as high-performance electrode materials for energy storage devices and water splitting; we discussed how a judicious nanostructure design will lead to improving performance in lithium ion battery, supercapacitor and Li-ion capacitor, as well as in electrochemical water splitting (oxygen and hydrogen evolution reactions). Knowledge about this review on metal nitrides is aimed at sharing a wide view in recent TMNs synthetic development, applications, prospects and challenges.
We herein demonstrate the unusual effectiveness of two strategies in combination to enhance photoelectrochemical water splitting. First, the work function adjustment via molybdenum (Mo) doping ...significantly reduces the interfacial energy loss and increases the open-circuit photovoltage of bismuth vanadate (BiVO
) photoelectrochemical cells. Second, the creation and optimization of the heterojunction of boron (B) doping carbon nitride (C
N
) and Mo doping BiVO
to enforce directional charge transfer, accomplished by work function adjustment via B doping for C
N
, substantially boost the charge separation of photo-generated electron-hole pairs at the B-C
N
and Mo-BiVO
interface. The synergy between the above efforts have significantly reduced the onset potential, and enhanced charge separation and optical properties of the BiVO
-based photoanode, culminating in achieving a record applied bias photon-to-current efficiency of 2.67% at 0.54 V vs. the reversible hydrogen electrode. This work sheds light on designing and fabricating the semiconductor structures for the next-generation photoelectrodes.
Preparation of single atom catalysts (SACs) is of broad interest to materials scientists and chemists but remains a formidable challenge. Herein, we develop an efficient approach to synthesize SACs ...via a precursor-dilution strategy, in which metalloporphyrin (MTPP) with target metals are co-polymerized with diluents (tetraphenylporphyrin, TPP), followed by pyrolysis to N-doped porous carbon supported SACs (M
/N-C). Twenty-four different SACs, including noble metals and non-noble metals, are successfully prepared. In addition, the synthesis of a series of catalysts with different surface atom densities, bi-metallic sites, and metal aggregation states are achieved. This approach shows remarkable adjustability and generality, providing sufficient freedom to design catalysts at atomic-scale and explore the unique catalytic properties of SACs. As an example, we show that the prepared Pt
/N-C exhibits superior chemoselectivity and regioselectivity in hydrogenation. It only converts terminal alkynes to alkenes while keeping other reducible functional groups such as alkenyl, nitro group, and even internal alkyne intact.
Sawdust wastes were used as precursors to prepare adsorbents by combustion and pyrolysis for experimental and mechanism studies and determine the potential of biomass extracted from agro-industrial ...residues for Pb-polluted soil remediation. Pot experiments were conducted on contaminated soils near Pb–Zn mining with sawdust ash (SA) and sawdust biochar (SB) in different proportions and dosage ratios. Studies have indicated that the application of biomass materials can enhance the adsorption, complexation and precipitation of Pb cations in soil and reduce the mobility of Pb. The concentrations of SPLP-Pb and DTPA-extractable Pb in amended soils were the lowest under 1% 1:2 and 5% 1:1 treatment, respectively. Results of fraction extraction and XANES analysis showed that the materials change the main forms of Pb in soil. Moreover, the binding behavior of Pb with organic matter increases the proportion of Pb (Ac)2, leading to the transformation of high toxicity Pb-compounds into precipitates and complexes. The remediation methods of 2% 1:2 and 5% 1:2 were better than those of other methods in stabilizing Pb in soil. This study indicated that heat-treated sawdust can be used for Pb-polluted soil remediation, which is a type of environmental remediation measure with considerable ecological potential.
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•Mixed material with high biochar content had better stability of Pb in soil.•Bioavailability fraction of Pb was transformed to residual fraction.•Addition of ash and biochar with 1:2 ratio increased the proportion of Pb(Ac)2.•PbSO4, PbO and Pb(Ac)2 are important components of Pb in soil.
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•Photothermocatalytic synergistic oxidation overcomes the negative effect of H2O.•Photothermocatalytic synergistic oxidation enhances VOCs oxidation efficiency.•Relative dominance of ...photocatalysis and thermocatalysis is identified.
Thermocatalytic oxidation over supported noble metal catalysts shows a promising application prospect in eliminating VOCs. However, the high consumption of the expensive noble metals and input energy as well as catalyst deactivation from H2O poisoning limit its practical application. Herein, we report that photothermocatalytic synergistic oxidation over bifunctional supported noble metal catalysts can attenuate the negative effect of H2O vapour and achieve efficient mineralization of aromatic VOCs with high concentration at a low Pt loading and a mild temperature. Photothermocatalytic synergistic oxidation of aromatic VOCs was performed over bifunctional Pt/SrTiO3-x with a low 0.1 wt% Pt loading in the co-presence of visible-light illumination and mild thermal energy input (≤150 °C), achieving much more effective mineralization of toluene in high concentrations than the pristine thermocatalytic or photocatalytic oxidation. The introduction of photocatalysis lowers the activation energy and attenuates the negative H2O effect in the conventional thermocatalytic process through activating oxygen and consuming H2O for oxidative species O2− and OH production with photogenerated charges. Such a finding may provide some new insight into the construction of robust photothermocatalytic process and catalysts for efficient and economic VOCs elimination.
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