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Organic and inorganic mixtures can be developed as immobilizing agents that could reduce heavy metal accumulation in crops and contribute to food safety. Here, inorganic materials (lime, L; zeolite, Z; and sepiolite, S) and organic materials (biochar, B, and compost, C) were selectively mixed to produce six composite soil amendments (LZBC, LSBC, LZC, LZB, LSC, and LSB). Given the fact that LZBC showed the best performance in decreasing soil Cd availability in the incubation experiment, it was further applied in the field condition with 14 vegetables as the test crops to investigate its effects on crop safety production in polluted greenhouse. The results showed that LZBC addition elevated rhizosphere soil pH by 0.1-2.0 units and reduced soil Cd availability by 1.85-37.99%. Both the biomass and the yields of edible parts of all vegetables were improved by LZBC addition. However, LZBC addition differently affected Cd accumulation in edible parts of the experimental vegetables, with the observation that Cd contents were significantly reduced in Allium fistulosum L., Amaranthus tricolor L., and Coriandrum sativum Linn., but increased in the three species of Lactuca sativa. Further health risk assessment showed that LZBC application significantly decreased daily intake of metal (DIM), health risk index (HRI), and target hazard quotient (THQ) for Cd in Allium fistulosum L., Amaranthus tricolor L., and Coriandrum sativum Linn., whereas increased all the indexes in Lactuca sativa. Our results showed that the effect of a composite amendment on Cd accumulation in different vegetables could be divergent and species-dependent, which suggested that it is essential to conduct a pre-experiment to verify applicable species for a specific soil amendment designed for heavy metal immobilization.

The combination of intercropping and phytoremediation in the remediation of cadmium contaminated soil is an emerging model in recent years, but the results of previous studies are inconsistent. In the field experiment, eggplant was intercropped with hyperaccumulator Sedum alfredii Hance (inoculated or not inoculated with endophytic bacteria) to study the effects of intercropping on vegetable safety production, phytoremediation efficiency of hyperaccumulator and variation of soil available nutrients. The results showed that the intercropping treatment had a negative effect on the growth of eggplant and Sedum, but endophyte SaMR12 alleviated the inhibition of intercropping on plant growth. Intercropping treatment increases the Cd concentration in edible part of eggplant to 1.34 mg/kg compared with eggplant monoculture (1.19 mg/kg). While the application of SaMR12 reduces the Cd concentration of eggplant fruit to 0.95 mg/kg and significantly promotes the Cd uptake by Sedum. What's more surprising is that compared with eggplant monocropping, the content of soil available nitrogen, phosphorus and potassium in the treatment of intercropping with inoculated Sedum increased significantly. And according to the correlation analysis of various indexes of plants and soil, the Cd content of eggplant is negatively correlated with the available phosphorus and potassium in the soil, while the Cd content of Sedum is positively correlated with it, which suggested that the application of phosphorus and potassium fertilizers in this experimental site was beneficial to reduce Cd content in eggplant and improve Cd phytoextraction of Sedum. Therefore, in the daily production of moderately Cd-contaminated soil, intercropping eggplant with Sedum inoculated with endophytic bacteria is an excellent Phytoextraction Coupled with Agro-safe-production (PCA) pattern.

Oxygen vacancy-rich CeO2/BiOBr was prepared via solvothermal method combined with rGO to design a Z-scheme heterojunction, which was used for photocatalytic oxidation of gaseous elemental mercury. The Z-scheme heterojunction constructed by interface engineering significantly promotes charge carriers transfer at the interface. Moreover, the surface oxygen vacancies and Ce3+/Ce4+ redox centers tend to capture electrons to accelerate the Z-scheme path of charge transfer to maintain efficient redox performance and facilitate molecular oxygen activation to boost photocatalytic removal of Hg0. The collaboration of oxygen vacancies, Ce3+/Ce4+ and heterojunction enhances the photocatalytic oxidation activity, which achieves a removal efficiency of 76.53%, which is 1.29 times that of BiOBr and 1.91 times that of CeO2. The effect of actual flue gas components (SO2, NO and HCl) on the performance of photocatalytic Hg0 removal was further investigated. Combined with DFT theoretical calculations, the photocatalytic reaction mechanism of Z-scheme heterojunction with oxygen vacancies-rich was proposed. It provides a feasible strategy for the development of high-efficiency Z-scheme heterojunction photocatalytic system for environmental purification.

A Z-scheme heterojunction polyhedral-shaped BiOIO3/MIL-53(Fe) photocatalyst is prepared by a solvothermal method. The samples are characterized by XRD, XPS, SEM, TEM, FT-IR, UV–vis, PL, and other m...

Constructing a heterojunction and designing a band gap are effective methods to promote the efficiency of a photocatalyst and solar energy utilization. In this work, g-C3N4/Yb3+-Bi5O7I nanostructur...

Aims: For a metal hyperaccumulator plant Sedum alfredii, the recruitment of unique rhizospheric bacterial communities from bulk soils has been well studied. However, in the root-soil interface, the knowledge on the establishment of endospheric microbiomes from rhizospheric soil is still scarce. Methods: In this study, we combined culture-independent that was 16S rRNA gene amplicon sequencing, and culture-dependent methods that included bacterial isolation, heavy metal tolerance and plant growth-promoting traits. Results: The Cd/Zn concentrations in endosphere were significantly higher than in soil, while Pb concentration in endosphere was significantly lower than in soil. The α-diversity in rhizosphere soils was higher than in root endosphere, and the compartments as a major determinant revealed 85.9% of the taxa variations. The relative abundance of Proteobacteria increased in endosphere compared to rhizosphere. The difference of Cd/Zn tolerance between endospheric and rhizospheric isolates was not obvious, while the Pb tolerance of endospheric isolates significantly decreased compared to rhizosphere. Conclusions: The results suggest that S. alfredii recruits Cd/Zn-tolerant but not Pb-tolerant endospheric bacterial communities from its rhizospheric soil. The difference in the microbial structure and function in the root-soil interface might be related to the selective absorption of metals in S. alfredii.

The influences of the physical features and chemical properties of activated carbon on Hg0 adsorption were investigated. The textural characteristics of the samples were studied by Brunauer–Emmett–...

A novel gaseous elemental mercury (Hg0) removal agent was successfully synthesized via impregnation method, by using molybdenum trioxide (MoO3) as the active component and carbon aerogel (CA) as the carrier. The as-prepared samples maintained a large specific surface area and excellent pore structure of the pure carbon aerogel, so that MoO3 was better dispersed to obtain enhanced Hg0 removal performance. The maximum efficiency of elemental mercury removal was about 74%, achieved by Mo/C500 sample at 300 °C, while it still had good ability (nearly 60%) in the range of 500–700 °C. The mechanism of mercury oxidation removal was also verified by DFT calculation. This work should help in developing suitable materials for thermocatalytic oxidation of elemental mercury, and also provide some theoretical basis and data support for full-scale application of heavy metal mercury pollution control in coalfired power plants.

A new ternary composite BiOIO3/MoS2/C500 was prepared via sol-gel and hydrothermal method. The energy bands, surface structures and optical properties of the as-prepared samples were characterized by XRD, SEM, TEM, UV–vis DRS, BET, XPS, PL, ESR and electrochemical measurement. The density functional theory (DFT) was adopted to explore the capability as well. It is discovered that BiOIO3/MoS2/C500 possesses excellent Z-scheme heterostructure for separating photogenerated electron-hole pairs mainly provided by BiOIO3/MoS2, and large specific surface area as charge carriers transfer channel mainly provided by C500, which can accelerate charges to transfer to the surface reaction area for photocatalytic oxidation. Then, the ternary catalyst was utilized to remove gas-phase Hg0 including its oxidation product, and possessed the highest removal efficiency of 78.32%, which is much higher than that of its pure component. Meanwhile, the photocatalytic activity of ternary catalyst are of high stability, and the product after the reaction is HgO and can be adsorbed on BiOIO3/MoS2/C500, which is detected by high resolution XPS. The loading manner provides a new vision for both photocatalysis and adsorption.

The total particulate matter (TPM) is a crucial indicator when evaluating flue gas emissions from coal-fired units. TPM contains solid and liquid contaminants and condensable particulate matter (CPM), which is mainly composed of sulfate and various anions, cations, and metal ions. This study selected three typical large-capacity coal-fired power plants in Shanghai retrofitted with ultra-low emission technology and monitored their emissions of PM2.5, SO3, and CPM during power generation. The results showed that the plants achieved comprehensive removal rates of 99.689–99.878% and 86.99–92.92% for PM2.5 and SO3, resulting in emitted concentrations of approximately 0.99–1.79 and 1.91–2.50 mg m–3, respectively, which are considerably lower than those associated with the traditional flue gas process. Additionally, a significant decrease in the emitted filterable particulate matter (FPM) caused a simultaneous decrease in CPM. After being equipped with the ultra-low emission technology, the units displayed a 76% reduction in the emitted FPM concentration and a smaller FPM/CPM ratio (1:2 vs. 1:1). The emitted TPM (the sum of CPM and FPM) was reduced by 82%, with an average measured concentration of 7.36 ± 3.56 mg m–3. The values we obtained are representative and provide basic data for environmental assessment and local environmental policy formulation.

Developing of effective photocatalysts is of great significance for realizing photocatalytic environment purification. Herein, an interfacial bent bands and internal electric field modulated CeO

Electric vehicles (EVs) have been promoted acceleratively to reduce greenhouse gas (GHG) emissions, however, the GHG emission reduction potential of different powertrain EVs has not been investigated thoroughly. In this study, we firstly quantified and compared the GHG emissions of different powertrain vehicles in a life cycle perspective with particular focus on energy and climate consequences, for current and future integrated scenarios, to facilitate carbon reduction assessment for Shanghai. Four major types of EVs were considered. The results show that life cycle total energy consumption and GHG emissions of all EVs are lower than that of gasoline internal combustion engine vehicles (GICEVs), among which battery-powered electric vehicles (BEVs) is the lowest. Compared with GICEVs, the total energy use and GHG emissions of BEVs decrease by 34.2% and 41.7% respectively. As the electrification of vehicle powertrain system innovates, the life cycle emissions of GHG are gradually concentrated to the upstream stage. The sensitivity analysis demonstrates that life cycle GHG emissions of vehicles are most sensitive to the proportion of thermal power than other three parameters (utilization rate of recycled steel, vehicle lifetime and curb weight). The scenario analysis indicates that BEVs present the more favorable carbon emission decline performance over other EVs from a long-term perspective. It is estimated that up to 12.5 million tons of GHG emissions could be reduced under the optimistic scenario in 2050 in Shanghai. In the process of energy conversion from oil to electricity in transport in Shanghai, BEVs should be constantly promoted.

The emission of air pollutants from the municipal solid waste (MSW) incineration is one of the major concerns in air pollution. The up-to-date emission situation for Chinese MSW incineration is largely unknown. The emission factors (EFs) are the key parameters to estimate the emissions from MSW incineration. The localized EFs from MSW incineration in Shanghai, China were established using continuous emission monitoring system data from 2017 to 2019. Our results showed that the EFs were 9.80 g t

Bi5O7I nanosheets and Bi5O7I nanorods photocatalysts were successfully fabricated by calcination and hydrothermal methods respectively. The different morphologies of Bi5O7I were characterized by XRD, SEM, HRTEM, UV–vis DRS and PL. The as-prepared samples were used to photocatalytic removal of Hg0 under visible-light irradiation. The results indicated that the photocatalytic activity of Bi5O7I nanorods is better than that of Bi5O7I nanosheets. It can be attributed to the synergistic and internal electric field effects of the (0 0 1) and (1 0 0) facets of Bi5O7I nanorods, which improves the photogenerated charge transfer and separation efficiency.

With the implementation of the ultra-low emission policy in China, emission factors (EFs) of power plant pollutants are constantly changing. Emission inventories developed using the recommended EFs contain high levels of uncertainty and it is difficult to achieve a high temporal resolution. Detailed sulfur dioxide (SO 2 ), nitrogen oxides (NOx), and particulate matter (PM) emission data based on a continuous emission monitoring system (CEMS) were obtained from 33 units at 13 power plants in Shanghai in 2017. The data were used to develop an hourly unit-based emission inventory and to devise updated EFs for coal-fired power plants. Emissions of SO 2 , NOx, and PM typically met the ultra-low emission limit, with total emissions of SO 2 , NOx, and PM of 2895.0, 5348.3, and 503.8 tons, respectively. Emission proportions of SO 2 and NOx for 300–600, 600–1000, and above 1000 MW units were similar, while the emission proportion of PM decreased with an increase in unit capacity. Emissions of SO 2 , NOx, and PM displayed similar monthly variations, peaking in winter and summer. Diurnal hourly variations of SO 2 , NOx, and PM emissions displayed a bimodal trend, with higher emissions at night on weekends than on weekdays. EFs based on CEMS (EF C ) of SO 2 , NOx, and PM were 0.10, 0.36, and 0.04 g kg −1 of coal, respectively, which were one or two orders of magnitude lower than the widely-used EFs and 4–30 times lower than EFs based on the mass balance approach. After replacing the recommended fixed decontamination efficiencies with individually fitted values, the calculated EFs were consistent with the corresponding EF C and discrepancies were further reduced. The new inventory and updated EFs will enable a better understanding of the temporal variations of power plant emissions and reduce the uncertainty caused by the overestimation of EFs after the implementation of ultra-low emissions technology.

The flower-like BiOI/Bi5O7I heterojunction photocatalysts were prepared by a pH adjustment method, and the photocatalytic oxidation activity of the as-prepared samples was investigated by gas-phase Hg0 removal. XRD, SEM, TEM, UV-vis, and PL characterization analysis method were adopted to evaluate the physicochemical property of samples. It was found that the sample showed an excellent photocatalytic performance for mercury removal when the pH of the sample fabrication arrived at 10.0. It can be attributed to the formation of an interfacial heterojunction between BiOI and Bi5O7I, which inhibits the recombination of electrons and holes. A possible photocatalytic reaction mechanism for the oxidation of Hg0 has also been proposed.

The ternary complex photocatalysts of BiOIO3/g-C3N4/MoS2 by solvent-exfoliation method was synthesized for the first time. In the typical procedure, the BiOIO3/g-C3N4 was obtained via hydrothermal synthesis technique, and then the BiOIO3/g-C3N4/MoS2 photocatalysts were prepared via ultrasonic solvent-exfoliation method from bulk commercial MoS2 in the alcohol solution. The samples of BiOIO3/g-C3N4/MoS2 were analyzed by PL, XRD and other characterization analysis methods. The photocatalytic activity of the as-prepared samples was investigated by removing gas phase mercury irradiation under visible light. The as-prepared BCM-0.3 exhibits excellent photocatalytic performance, being with the highest efficiency of 70.58%. Owing to the electronic channels of field-effect, an internal electric field was formed through the corresponding band-gap engineering, improving photocatalytic reaction. Besides, the excellent activity of the ternary photocatalysts BiOIO3/g-C3N4/MoS2 is attributed to heterostructure between BiOIO3/g-C3N4 and MoS2, which enlarges spectral response and improved separation efficiency of charge carriers, and MoS2-composing, which provides more active sites for catalytic oxidation. In addition, the as-prepared samples with excellent photocatalytic performance also offer a perspective insight into the hydrogen evolution, CO2 conversion and degradation of organic pollutants.

A series of colored TiO2/Bi5O7I composites were successfully fabricated. The physicochemical properties of the as-prepared TiO2/Bi5O7I heterostructures were investigated by XRD, SEM, TEM, HRTEM, FT-IR, BET, UV–vis DRS, XPS and PL characterization. The characterization indicates that colored TiO2 nanoparticles are tightly anchored to the Bi5O7I nanorods to form heterojunctions. The photocatalytic activity of the sample was examined by photocatalytic oxidation of gas-phase Hg0 under visible-light irradiation. The results show that TiO2/Bi5O7I composites exhibits highly enhanced visible light photocatalytic activity compared to pure Bi5O7I. Hg0 removal rate of TiO2/Bi5O7I composite is up to 89%. Compared with the pure Bi5O7I, the as-prepared composite photocatalyst enhanced the visible light absorption and increased the specific surface area. More importantly, the heterostructure formed in the composite effectively promotes the charge transfer, ultimately improves the photocatalytic activity. Meanwhile, the cyclic experiments were performed to confirm the stability of TiO2/Bi5O7I composites. The influence of various flue gas components (O2, NO and SO2) on the performance of photocatalytic removal of Hg0 was studied. Based on characterization and experiments, the reasonable charge transfer and photocatalytic reaction mechanism were proposed.

Cadmium (Cd) exposure is related to a multitude of adverse health outcomes because food crops grown on Cd-polluted soil are widely consumed by the public. The present study investigates the different application techniques of a combined amendment (lime + zeolite + biochar + compost, LZBC) for soil Cd immobilization effect on growth performance, Cd uptake by the second season crops, and soil quality in greenhouse vegetable production (GVP) under a rotation system. Five fruit vegetables were cultivated as the second season crop in the same plots which have been used for pakchoi as the first season crop (with or without LZBC application). The results indicated that LZBC with the consecutive application (T3) promoted crops biomass and fruit yield the most, followed by LZBC with the second crop application (T2) and LZBC with the first crop application (T1). LZBC application showed increasing rhizosphere soil pH and improvement in soil fertility of all crops including available nitrogen, available phosphorus, available potassium, organic matter, and cation exchange capacity. LZBC had positive influences on soluble sugar, soluble protein, and vitamin C in edible parts of 5 vegetables. Cd contents in fruit, shoot, and root of eggplant, pimento, cowpea, and tomato except cucumber were reduced by adding LZBC. As for the economic performance, T3 had the highest output/input ratio in general. Overall, these results demonstrated that T3 was dramatically more effective for minimizing health risk, increasing production, and facilitating sustainable utilization of soil under the Cd-contaminated GVP system.

For purifying pollutants in photocatalytic reactions, promoting electron migration and preserving photogenerated charge-carrier with high redox ability are of significance. Here, flower-like nanosphere of CeO2/Bi7O9I3 with Z-scheme heterojunction and oxygen vacancy was designed and synthesized to apply to photocatalytic oxidation of heavy metal pollutant Hg0. The experimental results manifested that CB-20 (moral ratio Ce/Bi = 2:10) exhibited more excellent photocatalytic performance for Hg0 removal than that of pure CeO2 and Bi7O9I3, and Hg0 removal efficiency of CB-20 can reach up to 97.63% in simulated flue gas. Moreover, the characterization results proved presence of abundant oxygen vacancies on CB-20, which can act as electron traps to accelerate electron transfer. And combining with results of DFT calculation, ESR analysis and reactive active species trapping experiments, a built-in electric field between CeO2 and Bi7O9I3 was confirmed, and photogenerated electrons transfer along Z-scheme path, which indicated Z-scheme heterojunction was formed between CeO2 and Bi7O9I3. Finally, we proposed the dual effect of Z-scheme heterojunction and oxygen vacancy can promote electron transport and retain generated charge-carrier with high redox ability, and analyzed the photocatalytic reaction mechanism.

Developing of effective photocatalysts is of great significance for realizing photocatalytic environment purification. Herein, an interfacial bent bands and internal electric field modulated CeO2/ZnIn2S4 Z-scheme heterojunction for photocatalytic Hg0 oxidation. It is found that the charge transfer mechanism of Z-scheme was driven by the interfacial bent bands and internal electric field, which was confirmed by electrochemical measurements, electron spin paramagnetic resonance spectroscopy and density functional theory calculations. Moreover, the (110) dominant CeO2 nanorods partially converted Ce4+ to Ce3+ and formed oxygen vacancies, and as an electron mediator in Z-scheme systems to further facilitate charge transfer process and molecular oxygen activation. Under the strong synergistic effect between the large specific surface area, Z-scheme heterojunction and oxygen vacancies, the optimized photocatalyst exhibits 86.7% of photocatalytic removal efficiency. This work provides Z-scheme heterojunction photocatalyst design perspective for photocatalytic air purification.

Oxygen vacancy-rich CeO

Plant growth-promoting bacteria (PGPB) can promote root uptake and shoot accumulation of cadmium (Cd) in hyperaccumulator plants, but the mechanisms by which PGPB accelerate root-to-shoot transport of Cd is still unknown. A better understanding of these mechanisms is necessary to develop the strategies that can promote the practical phytoextraction of Cd-polluted soils. In this study, we found that Pseudomonas fluorescens accelerates a reversed and a long-distance transport of Cd and sucrose in Sedum alfredii, by examining the xylem and phloem sap and by quantifying the concentrations of Cd and sucrose in shoot and root. The transcriptome sequencing has revealed the up-regulated expressions of starch metabolism and sucrose biosynthesis related genes in the shoots of Cd hyperaccumulator plant S. alfredii that was inoculated with PGPB P. fluorescens. In addition, the genes of sugar, cation and anion transporters were also up-regulated by bacterial treatment, showing a complicated co-expression network with sucrose biosynthesis related genes. The expression levels of Cd transporter genes, such as ZIP1, ZIP2, HMA2, HMA3 and CAX2, were elevated after PGPB inoculation. As a result, the PGPB successfully colonized the root, and promoted the sucrose shoot-to-root transport and Cd root-to-shoot transport in S. alfredii. Since non-photosynthetic root-associated bacteria usually obtain sugars from photosynthetic plants, our results highlight the importance of PGPB-induced changes in hyperaccumlator plants for both the host and the PGPB.

To control the spread of COVID-19, China has imposed national lockdown policies to restrict the movement of its population since the Chinese New Year of January 2020. In this study, we quantitatively analyzed the changes of pollution sources in Shanghai during the COVID-19 lockdown; a high-resolution emission inventory of typical pollution sources including stationary source, mobile source, and oil and gas storage and transportation source was established based on pollution source data from January to February 2020. The results show that the total emissions of sulfur dioxide (SO2), nitrogen oxides (NOx), particulate matter (PM), and volatile organic compounds (VOCs) were 9520.2, 37,978.6, 2796.7, and 7236.9 tons, respectively, during the study period. Affected by the COVID-19 lockdown, the mobile source experienced the largest decline. The car mileage and oil sales decreased by about 80% during the COVID-19 lockdown (P3) when compared with those during the pre-Spring Festival (P1). The number of aircraft activity decreased by approximately 50%. The impact of the COVID-19 epidemic on industries such as iron and steel and petrochemicals was less significant, while the greater impact was on coatings, chemicals, rubber, and plastic. The emissions of SO2, NOx, PM2.5, and VOCs decreased by 11%, 39%, 37%, and 47%, respectively, during P3 when compared with those during P1. The results show that the measures to control the spread of the COVID-19 epidemic made a significant contribution to emission reductions. This study may provide a reference for other countries to assess the impact of the COVID-19 epidemic on emissions and help establish regulatory actions to improve air quality. Supplementary Information The online version contains supplementary material available at 10.1007/s11356-020-11858-x.

Cadmium (Cd) pollution in soil is a serious problem affecting environmental safety and human health, and the majority of Cd in human body comes from edible vegetables, especially leafy vegetables. Therefore, it is necessary to understand the absorption and transport of Cd soil by leafy vegetables. In this study, the meta-analysis method was firstly employed to study the relationship of Cd in leafy vegetables and soil systems. The results showed that different kinds of leafy vegetables have different abilities of Cd accumulation (measured by bioconcentration factor (BCF)) and transportation (measured by translocation factor (TF)): Brassica juncea (BCF = 5.10) and Brassica pekinensis (BCF = 1.90) had significantly higher ability to absorb cadmium in soil among the 19 studied species, Brassica pekinensis (TF = 2.52), Coriandrum sativum (TF = 2.18) had significantly higher cadmium transport capacity than other 11 species. To further clarify the influence of the three main factors of soil pH, Cd content and leafy vegetable species on the Cd enrichment ability of leafy vegetables, the regression equation was obtained by meta-regression analysis. BCF is affected by species, soil pH, soil cadmium content in the order from high to low. It was found that the estimated range of SOM for safe production of leafy vegetables is 20–30 g/kg. It could also be observed that soil cation exchange capacity (CEC) had a negative correlation with BCF, while soil salinity had a strong positive correlation with BCF. This study can provide a reliable reference for leafy vegetable security production in the Cd polluted field and aids in selecting species suitable for avoiding the absorption of heavy metals from polluted soil.

Mercury emission from coal-fired power plants has posed a great threat to the environment and human, and reducing and controlling mercury emissions has become a global environmental issue. In this work, the In2S3/g-C3N4 adsorbent was prepared by simple hydrothermal method to achieve efficient removal of Hg0 from coal-fired flue gas. When the loading value of In2S3 was 40 %, the effect of removing Hg0 by as-synthesized IC-40 was the best. IC-40 showed excellent Hg0 adsorption performance in a temperature range of 80–240 °C. Under the condition of 120 °C and N2 atmosphere, the Hg0 adsorption capacity of the synthesized IC-40 reached 14.78 mg/g. The study on the impacts of flue gas components demonstrate that IC-40 has good resistance to nitric oxide, and has a slight inhibitory effect by SO2 and water vapor. According to the results of XPS and Hg-TPD, the formed main mercury compound is extremely stable HgS. In addition, DFT was conducted to calculate the adsorption energy of Hg0 on In2S3 (1 1 0) surface, which further illustrated the sulfur site served as stable adsorption site to convert Hg0 into HgS. From the above analysis, IC-40 as an efficient and scientific adsorbent to remove Hg0 from coal-fired power plants is a promising technical method.

Plant growth regulators (PGRs) assisted phytoextraction was investigated as a viable phytoremediation technology to increase the phytoextraction efficiency in contaminated soils. This study aimed to evaluate the cadimum (Cd)/lead (Pb)/zinc (Zn) phytoextraction efficiency by a hyperaccumulator Sedum alfredii Hance (S. alfredii) treated with 9 PGRs, including indole-3-acetic acid (IAA), gibberellin (GA3), cytokinin (CKs), abscisic acid (ABA), ethylene (ETH), brassinosteroid (BR), salicylic acid (SA), strigolactones (SL) and jasmonic acid (JA), in slightly or heavily contaminated (SC and HC, respectively) soil. Results demonstrated that PGRs were able to improve S. alfredii biomass, the most significant increases were observed in GA3 and SL for HC soil, while for SC soil, IAA and BR exhibited positive effects. The levels of Cd, Pb and Zn in the shoots of S. alfredii treated with ABA and SL were noticeably greater than in the CK treatment in HC soil, while the uptake of metals were increased by IAA and CKs in SC soil. Combined with the results of biomass and metal contents in shoots, we found that ABA showed the highest Cd removal efficiency and the maximum Pb and Zn removal efficiency was observed with GA3, which was 62.99%, 269.23%, and 41.18%, respectively higher than the control in HC soil. Meanwhile, compared to control, the maximum removal efficiency of Cd by IAA treatment (52.80%), Pb by JA treatment (165.1%), and Zn by BR treatment (44.97%) in the SC soil. Overall, our results suggested that these PGRs, especially, ABA, SL, IAA, BR and GA3 had great potential in improving phytoremediation efficiency of S. alfredii grown in contaminated soils.

Selectively exposing different facets of the photocatalysts to enhance the photocatalytic activity is a promising method. However, the role of exposed specific facets in a photocatalytic process is not fully understood. In order to clarify this mechanism, we have systemically explored the relationships between selectively exposed facets and photocatalytic activity of the nanoplate bismuth oxyiodide (BiOI). The BiOI was synthesized by pH-induced transformation method, and the photocatalytic activity was evaluated by photocatalytic oxidation of gas-phase mercury. The exposed specific facet ratios can be adjusted, and depend on the pH of the precursors. Our results showed that the BiOI with exposed (1 1 0) facets possesses an excellent photocatalytic oxidation activity on gas-phase mercury than the BiOI with exposed (0 0 1) facets. Characterization analysis indicated that the BiOI with exposed (1 1 0) facets can generate more superoxide radical ( · O 2 - ) than the BiOI with exposed (0 0 1) facets. Furthermore, both the BiOI with exposed (1 1 0) and (0 0 1) facets can not produce free hydroxyl groups ( · OH ) directly, but can generate it by transformation of the surface absorbance oxygen process. The BiOI with exposed (1 1 0) facets can generate more · O 2 - , which accumulate on the conduction band of the BiOI and transform to · OH by process of O2 → · O 2 - → H2O2 → · OH . Thus, the BiOI with exposed (1 1 0) facets can produce more · OH than the BiOI with exposed (0 0 1) facets as well. This finding may enhance the comprehension of the mechanism between the selectively exposed facets and the photocatalytic activity of the as-prepared samples.

Bismuth oxide iodate (BiOIO3) has recently been discovered to apply to the research on photocatalytic territory in environmental pollutants solution. However, its weak response to the visible light and high recombination rate of electron–hole pairs have been the stumbling block on the road to application. In this work, to remit the drawbacks, carbon modified BiOI/BiOIO3 heterostructures are prepared by a facile hydrothermal method and a simple calcination method. The prepared structure can effectively promote the separation of charge and suppress recombination of electron–hole pairs. When the ternary photocatalyst is applied to remove gas phase elemental mercury (Hg0) in the condition with visible light irradiating, it exhibits excellent photocatalytic properties. Compared with pure BiOIO3, the removal efficiency of ameliorated samples has been drastically increased. On the basis of the results of experiments, the possible charge migration and recombination mechanism are put forward. As a novel and promising method to enhance photocatalytic performance, this method presents a strategy, which yields tremendous benefits in designing efficient photocatalyst and environmental remediation applications.

In-situ reduction method was successfully taken out to control the highly reactive (010) facets and decline band gaps in interlining-I/BiOIO3. It gave a fairly easy way to coordinate the control of bandgap engineering and structural engineering. The interlining-I provided an impurity level served as a plate for photo-generated electron to hop, which expanded the light reaction intensity and displayed excellent photocatalytic performance as well. The as-prepared samples were characterized and estimated for removing gas-phase Hg°. It demonstrated that there existed an optimization of I− to construct a suitable impurity level for effectively separating and transferring electron-hole pairs. The corresponding structural engineering made the internal electric field(IEF) intensify, which was attributed to its increasing exposed surface in favor of obstructing their recombination in the bulk, generating a large number of essential species related to the larger exposed (010) facets to oxidize Hg° into Hg2+ under visible light. BI-1 showed the highest efficiency of 92.15%. However, because of the existence of light corrosion, a small part of the iodine ions may be oxidized to elemental iodine to volatilize, fortunately it could be regenerated to the original efficiency in the same preparation method. In addition, the samples with super photocatalytic properties and excellent electron transport properties also gave out a capacious prospect in CO2 conversion, hydrogen evolution, NO removal, degradation of organic pollutants, also the super capacitors and batteries.