Efficient and selective electro-reduction of nitrobenzene by the nano-structured Cu catalyst prepared by an electrodeposited method via tuning applied voltage

Pollution caused by toxic nitrobenzene has been a widespread environmental concern. Selective reduction of nitrobenzene to aniline is beneficial to further efficient and cost-effective biologic treatment. Electrochemical reduction is a promising method and Cu-based catalysts have been found to be an efficient cathode material for this purpose. In this work, Cu catalysts with different morphologies were fabricated on Ti plate using a facile electrodepositon method via tuning the applied voltage. The dendritic nano-structured Cu catalysts obtained at high applied voltages exhibited an excellent efficiency and selectivity toward the reduction of nitrobenzene to aniline. Effects of the working potential and initial nitrobenzene concentration on the selective reduction of nitrobenzene to aniline using the Cu/Ti electrode were investigated. A high rate constant of 0.0251 min⁻¹ and 97.1% aniline selectivity were achieved. The fabricated nano-structured Cu catalysts also exhibited good stability. This work provides a facile way to prepare highly efficient, cost-effective, and stable nano-structured electrocatalysts for pollutant reduction.     

国有企业安全生产中发挥党组织作用的思考

剖析了国企安全生产中发挥党组织作用的现实差距,提出了安全生产中发挥党组织作用的路径措施:深化政治建设提升引领力,抓好有效覆盖提升组织力,促进深度融合提升推动力,加强群团作用提升凝聚力,强化监督考评提升驱动力。充分发挥党组织作用,使"根"从基层扎牢、"魂"从堡垒筑强,就能本固基稳,扛起安全生产"泰山之重"的责任,引领保障企业高质量发展和建设世界一流企业行稳致远。     

Reduced cadmium accumulation in tobacco by sodium chloride priming

Environmental Science and Pollution Research - Cadmium (Cd) pollution threatens agricultural security worldwide. This study tested the efficacy of priming chemicals to decrease Cd uptake by tobacco...     

Seasonal variation of net ecosystem CO2 exchange and its influencing factors in an apple orchard in the Loess Plateau

Environmental Science and Pollution Research - The Loess Plateau is the largest apple cultivation region in the world. However, the role of rain-fed apple orchards as carbon sinks or sources,...     

Household costs and benefits of biodiversity conservation: case study of Sichuan giant panda reserves in China

Households in communities in and around nature reserves are important stakeholders in biodiversity conservation; they are the focus of the conflict between ecological protection and community development. This study surveyed 927 households in 16 giant panda reserves in Sichuan Province, China, to calculate the costs and benefits to households of biodiversity conservation, and the differences for those inside and outside reserves. A multilevel regression model was used to measure the factors influencing the costs and benefits. There are three main findings. First, the direct economic cost for average biodiversity conservation for households inside reserves (1166.83 yuan/year) is significantly higher at the 1% level than for those outside (578.27 yuan/year), while the direct economic benefit for average biodiversity conservation to households living inside reserves (3881.94 yuan/year) is not statistically different than those outside (3653.47 yuan/year). Second, the influence of biodiversity conservation on households is significantly different depending on whether they live inside or outside the reserve, regarding employment opportunities, ties with the outside world, infrastructure, and the community environment. There is also a significant difference between those inside and those outside in perceptions with regard to restrictions in the collection of wild plants and destruction of traditional culture by biodiversity conservation. Third, the factors that affect the costs for and benefits to households of biodiversity conservation include, at the household level, the head of household’s education level, village cadres, number of migrant workers, distance from the town market, reserve-based employment, development projects, and ecotourism management participation, and, at the reserve level, establishment time, level of reserve, protective effect, and location.     

Simulation of the migration and transformation of petroleum pollutants in the soils of the Loess plateau: a case study in the Maling oil field of northwestern China

We developed a coupled water–oil simulation model to simulate the migration and transformation of petroleum-derived contaminants in the soil of the Xifeng oil field. To do so, we used the HYDRUS-2D model, which simulates the diffusion, adsorption or desorption, and microbial degradation of petroleum-derived hydrocarbons in the soil–water system. The saturated soil hydraulic conductivity of petroleum-derived pollutants was 0.05 cm?day^?1, which is about 1 to 2 % of the soil moisture permeability coefficient. Our numerical simulation results show that spilled crude oil was mainly concentrated in the surface horizons of the soil. The organic pollutant concentration tended to be highest nearest to the pollution source. The pollutant migration was generally concentrated within the top 20 to 30 cm of the soil, with the maximum concentration in the top 5 cm of the soil. With passing time, the pollutant accumulation increased and the adsorption and degradation functions reached a dynamic balance with the input rate at depths greater than 30 cm below the soil surface. The oil-derived pollutants totaled 50 to 100 mg?kg^?1 under the dynamic balance condition, which occurred after 20 to 30 years. The petroleum-derived pollutant concentration in the loess soil was inversely correlated with the horizontal distance from the oil well, and the concentration decreased greatly at a distance greater than 40 m from the well.     

Specific absorption and backscattering coefficients of the main water constituents in Poyang Lake, China

Obtaining and analyzing the specific inherent optical properties (SIOPs) of water bodies is necessary for bio-optical model development and remote sensing-based water quality retrievals and, further, for related ecological studies of aquatic ecosystems. This study aimed to measure and analyze the specific absorption and backscattering coefficients of the main water constituents in Poyang Lake, China. The specific absorption and/or backscattering coefficients of the main water constituents at 85 sampling sites (47 in 2010 and 38 in 2011) were measured and analyzed as follows: (1) the concentrations of chlorophyll a (C _CHL), suspended particulate matter (C _SPM) (including suspended particulate inorganic matter (C _SPIM) and suspended particulate organic matter (C _SPOM)), and the absorption coefficients of total particulate (a _p), phytoplankton (a _ph), and non-pigment particulate (a _d) were measured in the laboratory; (2) the total backscattering coefficients at six wavelengths of 420, 442, 470, 510, 590, and 700 nm, including the contribution of pure water, were measured in the field with a HydroScat-6 backscattering sensor, and the backscattering coefficients without the contribution of pure water (b _b) were then derived by subtracting the backscattering coefficients of pure water from the total backscattering coefficients; (3) the specific absorption coefficients of total particulate ( $ a_{\mathrm{p}}^{ * } $ ), phytoplankton ( $ {a_{{\mathrm{ph}}}}^{ * } $ ), and non-pigment particulate ( $ a_{\mathrm{d}}^{ * } $ ) were calculated by dividing a _p, a _ph, and a _d by C _SPM, C _CHL, and C _SPIM, respectively, while the specific backscattering coefficients of total suspended particulate matter ( $ b_{\mathrm{b}}^{ * } $ ) were calculated by dividing b _b by C _SPM; and (4) the $ {a_{{\mathrm{ph}}}}^{ * } $ , $ a_{\mathrm{d}}^{ * } $ , $ a_{\mathrm{p}}^{ * } $ and $ b_{\mathrm{b}}^{ * } $ of the remaining samples (46 in 2010 and 36 in 2011) were visualized and analyzed, and their relations to C _CHL, C _SPIM or C _SPM were studied, respectively. The main results are summarized as follows: (1) the $ {a_{{\mathrm{ph}}}}^{ * } $ values at 440 nm were 0.0367–0.7203 m²?mg^?1 with a mean of 0.1623?±?0.1426 m²?mg^?1 in 2010 and 0.0319–0.7735 m²?mg^?1 with a mean of 0.3145?±?0.1961 m²?mg^?1 in 2011; there existed significant, negative, and moderate correlations between $ {a_{{\mathrm{ph}}}}^{ * } $ and C _CHL at 400–700 nm in 2010 and 2011 (p?<?0.05); (2) The $ a_{\mathrm{d}}^{ * } $ values at 440 nm were 0.0672–0.2043 m²?g^?1 with a mean of 0.1022?±?0.0326 m²?g^?1 in 2010 and 0.0559–0.1347 m²?g^?1 with a mean of 0.0953?±?0.0196 m²?g^?1 in 2011; there existed negative correlations between $ a_{\mathrm{d}}^{ * } $ and C _SPIM, while the correlations showed overall decreasing and increasing trends before and after around 575 nm with increasing wavelengths, respectively; (3) The $ a_{\mathrm{p}}^{ * } $ values at 440 nm were 0.0690–0.1929 m²?g^?1 with a mean of 0.1036?±?0.0298 m²?g^?1 in 2010 and 0.0571–0.1321 m²?g^?1 with a mean of 0.1014?±?0.0191 m²?g^?1 in 2011, and the negative correlations between $ a_{\mathrm{p}}^{ * } $ and C _SPM were found in both years; (4) The $ b_{\mathrm{b}}^{ * } $ at the six wavelengths generally decreased with increasing wavelengths, while the $ b_{\mathrm{b}}^{ * } $ values at 420 nm were lower than those at 442 nm for some samples; the correlation between $ b_{\mathrm{b}}^{ * } $ and C _SPM increased with increasing wavelength. Such results can only represent the SIOPs during the sampling time periods, and more measurements and analyses considering different seasons need to be carried out in the future to comprehensively understand the SIOPs of Poyang Lake.     

Occurrence, distribution and bioaccumulation of antibiotics in the Haihe River in China

The occurrence, distribution and bioaccumulation of 22 antibiotics, including eight fluoroquinolones (FQs), nine sulfonamides (SAs) and five macrolides (MLs), in the Haihe River were investigated. Surface water, sediment and fish samples were analyzed by HPLC-MS/MS. Ofloxacin, sulfamethoxazole, sulfadiazine, erythromycin and roxithromycin were found in all surface water samples. SAs were the predominant antibiotics in surface water samples in the mainstream of Haihe River, with the maximum concentration of 201 ng L(-1) for sulfamethoxazole. Compared with Haihe River, higher concentrations of antibiotics were found in the surface water samples in the Dagu and Chentaizi Drainage Rivers. The antibiotics pollution in the mainstream of Haihe River may derive from its tributaries, whereas the wastewater from fish ponds was not the main source of FQs, SAs and MLs in the river water. In sediment samples, FQs were the most frequently detected antibiotics and their concentrations were much higher than SAs and MLs. The high concentrations and detection frequencies of FQs in sediments indicate that sediments are an important reservoir for FQs as they are strongly adsorbed onto sediments. Ciprofloxacin and erythromycin exhibited potential bioaccumulation in crucian carp, with mean bioaccumulation factors of 3262 L kg(-1) and 4492 L kg(-1), respectively.     

Dissolved inorganic tin sources and its coupling with eco-environments in Bohai Bay

Dissolved inorganic tin (DISn) and its spatial variation were examined in Bohai Bay seawaters to understand the DISn behavior and pollution in this area. DISn concentration gradually increased with the distance from the coast and showed a slight decrease with the increasing depth from surface water, suggesting the scavenged behavior of tin with an atmospheric input to surface water. Besides, the higher DISn values also were found near the Haihe Estuary inferring that the riverine input was a source of DISn. Based on the data in this study, a preliminary estimate of the tin budget via riverine input and atmospheric deposition has been established. According to our estimate, about 2 × 10⁶ and 8.47 × 10⁵ g/year of tin reach Bohai Bay via rivers and atmosphere. Environmental factors such as suspended particulate material, salinity, total organic matter, pH, nutrients, and phytoplankton had the important influences on DISn distribution. Among them, the negative correlation between DISn and phytoplankton at most stations might indicate the biological uptake of tin.     

Measurement of HONO flux using the aerodynamic gradient method over an agricultural field in the Huaihe River Basin, China

To investigate nitrous acid(HONO) levels and potential HONO sources above crop rotation fields. The HONO fluxes were measured by the aerodynamic gradient(AG) method from 14 December 2019 to 2 January 2020 over an agricultural field in the Huaihe River Basin. The ambient HONO levels were measured at two different heights(0.15 and 1.5 m), showing a typical diurnal cycle with low daytime levels and high nighttime levels. The upward HONO fluxes were mostly observed during the day, whereas deposition...