Heavy metal contamination of urban topsoil in a petrochemical industrial city in Xinjiang, China

Heavy metal pollution is a widespread phenomenon in many countries of the world.In this study,we conducted a field investigation to assess the status of heavy metal pollution in urban soils of Dushanzi,a district of Karamay city in Xinjiang,China.A total of 56 soil samples in the topsoil layer of 0–15 cm were collected within the urban area and seven elements(Cu,Zn,Cd,Pb,Cr,As and Ni) were analyzed.The mean concentrations of these metals were all higher than their corresponding background values of soils in Xinjiang.We used the pollution index and ecological risk index to assess the degree of heavy metal pollution and the potential ecological risk of urban soils.The pollution index values of Cu,Zn,Cd,Pb,Cr,As and Ni were 1.81,1.35,4.64,1.27,1.80,1.39 and 1.22,respectively;and the potential ecological risk index values for them were 12.03,1.79,185.05,8.39,4.78,18.44 and 1.79,respectively.These results indicated that urban soils in Dushanzi were polluted by heavy metals to some extent and demonstrated a high ecological risk,as influenced by industrial activities.Cd was the key element for the metal pollution of urban soils in the study area.Correlation analyses,principal component analysis coupled with the spatial distribution maps of element concentrations further revealed that heavy metal pollution of urban soils can be mainly attributed to petrochemical industry,coal chemical industry,traffic and commercial activities.

Incorporating the magnetic alignment of GO composites into Pebax matrix for gas separation

The mixed matrix membranes(MMMs) were developed by incorporating graphite oxide(GO) flakes functionalized with iron oxide(Fe_3O_4) into Pebax matrix. The Pebax/Fe_3O_4–GO MMMs were used to separate CO_2/CH_4 and CO_2/N_2 gas mixture. The results showed that the MMMs with magnetic alignment presented the better gas separation performance than that of random arrangement of Pebax/Fe_3O_4–GO mixed matrix membranes. The reason was that the Fe_3O_4–GO flakes arranged magnetically in the membrane played a multiple role in improving the performance of MMMs. Firstly, under the action of the magnetic field,the magnetic alignment of Fe_3O_4–GO flakes in Pebax matrix constructed the shorter transfer path for gas molecule, increasing the CO_2 permeability. Secondly, the hydroxyl groups in GO flakes and the presence of Fe_3O_4 have stronger binding force for water, improving the CO_2 solubility selectivity. Thirdly, the better interaction between the magnetic alignment of GO composites and polymer matrix, reduced the interface defects. Especially, the optimum gas separation performance was obtained at the Fe_3O_4–GO flakes content of 3 wt% in Pebax matrix at vertical arrangement with selectivity of 47 and 75 for CO_2/CH_4 and CO_2/N_2, respectively, and CO_2 permeability of 538 Barrer at 0.2 MPa and room temperature.

Preparation and adsorption performance of multi-morphology H_(1.6)Mn_(1.6)O_(4) for lithium extraction

In this paper,a lithium-ion sieve(LIS)with different morphologies,such as rod-like(LIS-R),spherical(LIS-S),flower-like(LIS-F),and three-dimensional macroporous-mesoporous(LIS-3D),was prepared by hydrothermal synthesis,solid reaction,and hard-template synthesis.The results showed that the LIS with different morphologies presented great differences in specific surface area,pore volume,adsorption selectivity,and structure stability.LIS-3D with highest specific surface area and pore volume displayed the maximum adsorption capacity and adsorption rate,but the stability of LIS-3D was poor because of the manganese dissolution.By comparison,LIS-S has the best structural stability while maintaining a satisfactory adsorption capacity(35.02 mg·g^(-1))and adsorption rate.The LIS-S remained about 90%of the original adsorption capacity after five cycles of adsorption-desorption process.In addition,in the simulated brine system(the magnesium to lithium ratio of 400),the LIS-S exhibited the highest selectivity(α_(Mg)^(Li))of 425.14.In sum,the LIS-S with good morphology is a potential adsorbent for lithium extraction from brine.

Robust photo-assisted removal of NO at room temperature:Experimental and density functional theory calculation with optical carrier

Photo-assisted SCR(PSCR) offers a potential solution for removal of NO at room temperature. MnTiO_(x)as PSCR catalyst exhibits superior performance with NO removal of 100% at the room temperature. Electron paramagnetic resonance(EPR) analysis revealed the presence of numerous oxygen vacancies on MnTiO_(x). Optical carrier density functional theory(DFT) calculations showed that the threedimensional orbital hybridization of Mn and Ti is significantly enhanced under light irradiation. The MnTiO_(x)catalyst exhibited excellent electron–hole separation ability, which can adsorbe NH_(3)and dissociate to form NH_(2)fragments and H atoms. In-situ diffuse reflectance infrared fourier-transform spectroscopy(DRIFTS) indicated that the optical carrier enhanced NH_(3)adsorption on MnTiO_(x), which makes it possess excellent PSCR activity. This work provided an additional strategy to NO removal with PSCR catalysts and showed potential for use in photocatalysis.

High efficient oxygen reduction performance of Fe/Fe3C nanoparticles in situ encapsulated in nitrogen-doped carbon via a novel microwave-assisted carbon bath method

Fe-based carbon materials are widely considered promising to replace Pt/C as next-generation electrocatalysts towards oxygen reduction reaction (ORR). However, the preparation of Fe-based carbon materials is still carried out by conventional heating method (CHM). Herein, a novel microwave-assisted carbon bath method (MW-CBM) was proposed, which only took 35 min to synthesize Fe/Fe3C nanoparticles encapsulated in N-doped carbon layers derived from Prussian blue (PB). The catalyst contained large specific surface area and mesoporous structure, abundant Fe-Nx and C–N active sites, unique core-shell structure. Due to the synergistic effects of these features, the as-prepared Fe/Fe3C@NC-2 displayed outstanding ORR activity with onset potential of 0.98 VRHE and halfwave potential of 0.87 VRHE, which were more positive than 20 wt.% Pt/C (0.93 VRHE and 0.82 VRHE). Besides, Fe/Fe3C@NC-2 gave a better stability and methanol tolerance than Pt/C towards ORR in alkaline media, too.

Process monitoring of the Au-S bond conversion in acetylene hydrochlorination

The continuous expansion of vinyl chloride production increases environmental pollution caused by mercury catalysts,which is an issue that urgently needs to be solved.Green and stable catalysts should be researched to alleviate this issue.In this research,Thiolactic acid acts as a ligand where sulfhydryl groups form a stable complex with Au on the surface of a spherical activated carbon(SAC).An Au-thiolactic acid/SAC catalyst was designed with a Au theoretical loading of 0.5%(mass)to overcome the disadvantages of traditional Au-based catalysts,such as a low conversion rate and poor life cycle.The ratio of Au to ligand was screened,and the activity was best when Au/S=1:8.The formation of the Au-S bond was proven by FT-IR and UV-vis.The longevity test of the Au1 S8/SAC catalyst was carried out at 1200 h^(-1) for 50 h.Samples with reaction times of 0 h,5 h,10 h,20 h,and 50 h were taken to monitor the catalyst status.The XPS and TPR tests proved that the Au-S bond broke as the acetylene hydrochlorination reaction proceeded,The DFT calculation proved that the Au-S bond is the active site,and the sulfur atom promotes the adsorption of C_(2)H_(2) by the catalyst.

Biocontrol Efficiency of Bacillus subtilis SL-13 and Characterization of an Antifungal Chitinase

种子萌芽和西红柿幼苗测试证明杆菌 subtilis SL-13 能支持发芽和西红柿的幼苗生长。西红柿幼苗的新鲜、干燥的重量分别地增加了 42.86% 和 18.75% 。到西红柿 Rhizoctonia 的 SL-13 的控制功效腐烂分别地在温室和域是 20.65% 和 35.23% 。植物病原的真菌 Rhizoctonia solani 的生长更加面对紧张 SL-13 文化上层清液被禁止。主要抗真菌的蛋白质被检测是通过 vitro 试金的 chitinase。chitinase 为进一步的描述与 DEAE-Sepharose 快流动离子交换列层析和 Sephadex G-75 胶化过滤被净化。为 chitinase 活动的最佳的 pH 和温度是 7.0 和 50 (C 分别地。酶在 pH 5-9 和 40-60 是稳定的，这被表明(C。当在 121 点孵化了时， 70% 酶活动被保留(为 20 min 的 C 和 0.11 MPa，和酶不对朊酶 K 和紫外放射敏感。因此它对在相对不稳定的环境的有效生物控制合适。

Adsorption Kinetics of β-Carotene and Chlorophyll onto Acid-activated Bentonite in Model Oil

组织上，激活酸的火山灰成胶状黏土(AAB ) 的性质，用硫酸的四不同集中被准备，被氮使用的吸附解吸附作用等温线分析一个自动化比表面积和孔分析器。全部的毛孔体积，比表面积和这些四种 AAB 的平均孔径显示出一个常规变化趋势，增加第一然后减少其最佳能在 25% 的硫酸集中(样品 A25 ) 被完成。在模型油答案的β - 叶红素和叶绿素的吸附的动力学分析，也就是二甲苯和食用油答案，被使用 AAB 调查了。试验性的结果显示吸附数据适合 pseudo-second-order 模型很好。AAB 上的二颜料的整个吸附过程基本上被划分成二部分：颜料的起始的吸附在开始的 10 min 是快速的，由一个更慢的吸附过程列在后面直到平衡在 60 min 被达到。另外， A25 上的数量和吸附速率与起始的颜料集中和温度同时地增加。结果证明关于颜料的 AAB 的吸附动力学行为不是由二甲苯和食用油答案的影响。

Enhanced selective catalytic reduction of NO with NH3 via porous micro-spherical aggregates of Mn–Ce–Fe–Ti mixed oxide nanoparticles

We rationally designed a high performance denitration(De-NOx) catalyst based on a micrometer-sized spherical Mn–Ce–Fe–Ti(CP-SD)catalyst for selective catalytic reduction(SCR). This was prepared by a co-precipitation and spray drying(CP-SD) method. The catalyst was systematically characterized, and its morphological structure and surface properties were identified. Compare with conventional Mn–Ce–Fe–Ti(CP) catalysts, the Mn–Ce–Fe–Ti(CP-SD) catalyst had superior surface-adsorbed oxygen leading to enhanced 'fast NH3-SCR' reaction. The asobtained Mn–Ce–Fe–Ti(CP-SD) catalyst offered excellent NO conversion and N2 selectivity of 100.0% and 84.8% at 250℃, respectively, with a gas hourly space velocity(GHSV) of 40,000 h-1. The porous micro-spherical structure provides a larger surface area and more active sites to adsorb and activate the reaction gases. In addition, the uniform distribution and strong interaction of manganese, iron, cerium, and titanium oxide species improved H2O and SO2 resistance. The results showed that the Mn–Ce–Fe–Ti(CP-SD) catalyst could be used prospectively as a denitration(De-NOx) catalyst.

Deep Desulfurization of Diesel Fuels with Plasma/Air as Oxidizing Medium,Diperiodatocuprate(Ⅲ)as Catalyzer and Ionic Liquid as Extraction Solvent

In this paper,the oxidative desulfurization(ODS)system is directly applied to deal with the catalytic oxidation of sulfur compounds of sulfur-containing model oil by dielectric barrier discharge(DBD)plasma in the presence of air plus an extraction step with the oxidation-treated fuel put over ionic liquid[BMIM]FeCl_4(1-butyl-3-methylimidazolium tetrachloroferrate).This new system exhibited an excellent desulfurization effect.The sulfur content of DBT in diesel oil decreased from 200 ppm to 4.92 ppm(S removal rate up to 97.5%)under the following optimal reaction conditions:air flow rate(v)of 60 mL/min,amplitude of applied voltage(U)on DBD of 16 kV,input frequency(f)of 79 kHz,catalyst amount(ω)of 1.25 wt%,reaction time(t)of10 min.Moreover,a high desulfurization rate was obtained during oxidation of benzothiophene(BT)or 4,6-DMDBT(4,6-dimethyl-dibenzothiophene)under the aforementioned conditions.The oxidation reactivity of different S compounds was decreased in the order of DBT,4,6-DMDBT and BT.The remarkable advantage of the novel ODS system is that the desulfurization condition applies in the presence of air at ambient conditions without peroxides,aqueous solvent or biphasic oil-aqueous solution system.

Melamine Modification of Spherical Activated Carbon and Its Effects on Acetylene Hydrochlorination

Commercial spherical activated carbon(SAC) was modified by impregnation to enhance the catalytic properties of SAC in acetylene hydrochlorination through melamine modification. Different modification conditions for SAC with nitrogen were compared by changing the SAC-Melamine ratios. The effect of carbonization temperature on the modification was also investigated. Surface chemistry and adsorption properties of the modified and unmodified SACs were studied by scanning electron microscope(SEM), X-ray photoelectron spectroscopy(XPS), elementary analysis, BET, and temperature-programmed desorption(TPD). Moreover, the catalytic properties of SAC in acetylene hydrochlorination under differently modified conditions were also investigated. Elemental analysis showed that the nitrogen content of the modified SAC was greatly improved. XPS revealed that nitrogen mainly exists in Pyrrole nitrogen and Pyridine nitrogen. TPD showed that desorption of C2H2 was changed by modification. The conversion rate of acetylene was up to 70% under the following reaction conditions: temperature, 150 ℃; C2H2 hourly space velocity(GHSV), 36 h-1; feed volume ratio V(HCl)/V(C2H2) = 1.15. The catalytic properties of SAC were improved significantly via melamine modification.

Oxygen vacancies enriched nickel cobalt based nanoflower cathodes: Mechanism and application of the enhanced energy storage

The rational design of oxygen vacancies and electronic microstructures of electrode materials for energy storage devices still remains a challenge. Herein, we synthesize nickel cobalt-based oxides nanoflower arrays assembled with nanowires grown on Ni foam via the hydrothermal process followed annealing process in air and argon atmospheres respectively. It is found that the annealing atmosphere has a vital influence on the oxygen vacancies and electronic microstructures of resulting NiCo_(2)O_(4) (NCO-Air) and CoNiO_(2) (NCO-Ar) products, which NCO-Ar has more oxygen vacancies and larger specific surface area of 163.48 m^(2)/g. The density functional theory calculation reveals that more oxygen vacancies can provide more electrons to adsorb –OH free anions resulting in superior electrochemical energy storage performance. Therefore, the assembled asymmetric supercapacitor of NCO-Ar//active carbon delivers an excellent energy density of 112.52 Wh/kg at a power density of 558.73 W/kg and the fabricated NCO-Ar//Zn battery presents the specific capacity of 180.20 mAh/g and energy density of 308.14 Wh/kg. The experimental measurement and theoretical calculation not only provide a facile strategy to construct flower-like mesoporous architectures with massive oxygen vacancies, but also demonstrate that NCO-Ar is an ideal electrode material for the next generation of energy storage devices.

High-efficiency removal of NO_x using dielectric barrier discharge nonthermal plasma with water as an outer electrode

With the rapid increase in the number of cars and the development of industry, nitrogen oxide(NO_x)emissions have become a serious and pressing problem. This work reports on the development of a water-cooled dielectric barrier discharge reactor for gaseous NOxremoval at low temperature. The characteristics of the reactor are evaluated with and without packing of the reaction tube with 2 mm diameter dielectric beads composed of glass, ZnO, MnO_2, ZrO_2, or Fe_2O_3. It is found that the use of a water-cooled tube reduces the temperature, which stabilizes the reaction, and provides a much greater NO conversion efficiency(28.8%) than that obtained using quartz tube(14.1%) at a frequency of 8 k Hz with an input voltage of 6.8 k V. Furthermore,under equivalent conditions, packing the reactor tube with glass beads greatly increases the NO conversion efficiency to 95.85%. This is because the dielectric beads alter the distribution of the electric field due to the influence of polarization at the glass bead surfaces, which ultimately enhances the plasma discharge intensity. The presence of the dielectric beads increases the gas residence time within the reactor. Experimental verification and a theoretical basis are provided for the industrial application of the proposed plasma NO removal process employing dielectric bead packing.

Salen-Cu(II) Complex Catalyzed <i>N</i>-Arylation of Imidazoles under Mild Conditions

Three inexpensive and air-/moisture-stable Salen-Cu complexes 1-3 were evaluated to be a novel class of catalysts for the N-arylation of imidazoles with aryl halides. A variety of aryl iodides, bromides underwent the coupling with imida-zoles, promoted by the complex 3, in moderate to excellent yields without the protection by an inert gas.

Synthesis, Characterization and Application of ZS/HMS Catalyst in the Esterification of Gossypol

A solid acid catalyst of zirconium sulfate (ZS) on a pure hexagonal mesoporous silica (HMS) sieve was prepared and characterized by small angle X-ray diffraction, NH3-temperature programmed desorption, and thermogravimetric analysis. The obtained ZS/HMS catalyst displayed a typical mesoporous structure, ZS was well dispersed on the HMS support, and the acidity increased with the amount of ZS loading. Gossypol was extracted from cottonseed cake with acetone as solvent, and then the gossypol solution was esterified with ZS/HMS as catalyst to yield products of acetic acid gossypol. Under the optimal conditions, the conversion efficiency of gossypol was as high as 96.7%.

Engineering of a NIR-activable hydrogel-coated mesoporous bioactive glass scaffold with dual-mode parathyroid hormone derivative release property for angiogenesis and bone regeneration

Osteogenesis,osteoclastogenesis,and angiogenesis play crucial roles in bone regeneration.Parathyroid hormone(PTH),an FDA-approved drug with pro-osteogenic,pro-osteoclastogenic and proangiogenic capabilities,has been employed for clinical osteoporosis treatment through systemic intermittent administration.However,the successful application of PTH for local bone defect repair generally requires the incorporation and delivery by appropriate carriers.Though several scaffolds have been developed to deliver PTH,they suffer from the weaknesses such as uncontrollable PTH release,insufficient porous structure and low mechanical strength.Herein,a novel kind of NIR-activable scaffold(CBP/MBGS/PTHrP-2)with dual-mode PTHrP-2(a PTH derivative)release capability is developed to synergistically promote osteogenesis and angiogenesis for high-efficacy bone regeneration,which is fabricated by integrating the PTHrP-2-loaded hierarchically mesoporous bioactive glass(MBG)into the N-hydroxymethylacrylamide-modified,photothermal agent-doped,poly(N-isopropylacrylamide)-based thermosensitive hydrogels through assembly process.Upon on/off NIR irradiation,the thermoresponsive hydrogel gating undergoes a reversible phase transition to allow the precise control of on-demand pulsatile and long-term slow release of PTHrP-2 from MBG mesopores.Such NIR-activated dual-mode delivery of PTHrP-2 by this scaffold enables a well-maintained PTHrP-2 concentration at the bone defect sites to continually stimulate vascularization and promote osteoblasts to facilitate and accelerate bone remodeling.In vivo experiments confirm the significant improvement of bone reparative effect on critical-size femoral defects of rats.This work paves an avenue for the development of novel dual-mode delivery systems for effective bone regeneration.

Hydrochlorination of acetylene over the Ru-based catalysts treated by plasma under different atmospheres

Ru-based catalysts modified in different atmospheres by plasma technology were prepared to catalyze the acetylene hydrochlorination reaction.The(Ru/AC)-N2(AC = activated carbon)catalyst yielded by the plasma modification of Ru/AC catalyst in N2 atmosphere exhibits the best catalytic performance with a stable C2H2 conversion of 87.2%;a relative increase of 27.1%in C2H2 conversion was achieved compared with that of the untreated Ru/AC catalyst.The results of the analysis revealed that the modification produced a mutual effect between the generated function groups on carrier AC and the active components, which can disperse and yield more active species in the fresh catalysts.These are benefits of enhancing the activity of the catalysts.Moreover, the modification can restrain coke formation and inhibit the loss of active species in the reaction, as well as strengthen the adsorption ability of reactants on the catalysts.These are benefits of improving the catalysts’ performance.

Dechlorination of Crude Oil by Phase Transfer Catalyst via Nucleophilic Substitution Reaction

Dechlorination of crude oil is an effective way to alleviate corrosion in refinery units,and the critical process is the removal of organochlorine which can be efficiently removed through nucleophilic substitution reaction catalyzed by phase transfer.Herein,seven typical chlorinated alkanes were selected as model compounds to study the mechanism of dechlorination of crude oil by phase transfer catalyst in the nucleophilic substitution method,and a new dechlorination reagent using hexamethyl quaternary ammonium hydroxide(HMQAH)with two quaternary ammonium groups as phase transfer catalyst,ethylenediamine as nucleophile and ethanol as solvent was developed.The results show that the dechlorinating performance of the dechlorination reagent on the model compounds decreases in the following order:epichlorohydrin>1,2-dichlorobutane>1,2-dichloroethane>1,3-dichloropropane>2-chloropropane>1-chlorobutane>chloroisobutane.Meanwhile the results of the reaction kinetics show that epichlorohydrin with epoxy structure has the lowest activation energy in the process of nucleophilic substitution reaction by the phase transfer catalyst which makes it easier to be removed by the dechlorination reagent.The removal rate of epichlorohydrin can reach up to 99.4%.The optimal dechlorination reagent used ethylenediamine as nucleophile,ethanol as solvent and HMQAH as phase transfer catalyst.The dechlorinating rate of the Iranian crude oil reached 71.6%under conditions covering a reaction temperature of 95℃,a reaction time of 90 minutes,a dechlorination reagent dosage of 1000μg/g,and a phase transfer reagent/nucleophile molar ratio of 6:1.In addition,the mechanism of phase transfer in nucleophilic substitution reaction of chloroalkanes was investigated in the paper.

Recent advances of versatile reagents as controllable building blocks in organic synthesis

Diversity-oriented synthesis is a powerful and interesting synthetic tool for the rapid construction of structurally complex and privileged scaffolds from readily accessible starting materials.To date,diversity-oriented synthesis mostly relies on the employment of versatile reagents.Versatile reagents can be regulated as controllable and flexible building blocks for multipurpose utilizations.Over the past decade,a variety of multifunctional reagents have been developed.However,most versatile reagents usually need multi-step synthesis,thus restricting their wide application to a large extent.In terms of the practicalities and universalities,we prefer to pay more attention to the utilization of simple and practical versatile reagents with multiple reactivities,mainly including atropaldehyde acetals,aryl methyl ketones,vinylene carbonate,vinyl azides,aryldiazonium salts,rongalite,halodifluoromethyl compounds.Most importantly,these versatile reagents can also play different roles simultaneously in the same reaction,in which their different reactivities are converged into the final target products.Such strategy can not only offer more possibilities for the synthesis of several active pharmaceutical ingredients,but also minimize the occurrence of some side reactions by lessening the varieties of materials.Also,a perspective is given at the end of this review.

Enhanced oxygen reduction reaction performance of Co@N–C derived from metal-organic frameworks ZIF-67 via a continuous microchannel reactor

Traditional methods of preparing metal-organic frameworks(MOFs)compounds have the disadvantages such as poor dispersion,inefficient and discontinuous process.In this work,microchannel reactor is used to prepare MOFs-derived zeolite-imidazole material via flash nanoprecipitation to form ZIF-67+PEI(FNP),which reduces the MOF synthesis time down to millisecond time interval while keeping the synthesized ZIF-67+PEI(FNP)highly dispersed.The Co@N–C(FNP)catalyst obtained by flash nanoprecipitation and carbonization has a higher Co content and thus more active sites for oxygen reduction reaction than the Co@N–C(DM)catalyst prepared by direct mixing method.Electrochemical tests show that the Co@N–C(FNP)catalyst prepared by this method has excellent oxygen reduction performance,good methanol resistance and high stability.The onset potential and half-wave potential of Co@N–C(FNP)are 0.92 VRHE and 0.83 VRHE,respectively,which are higher than that of Co@N–C(DM)(Eonset=0.90 VRHEand E1/2=0.83VRHE).Moreover,the Zn-air battery assembled with Co@N–C(FNP)as the cathode catalyst has high open circuit voltage,high power density and large specific capacity.The performance of these batteries has been comparable to that of Pt/C assembled batteries.Density functional theory(DFT)calculations confirm that the Co(220)crystal plane present in Co@N–C(FNP)have stronger adsorption energy than that of Co(111)crystal plane in Co@N–C(DM),leading to better electrocatalytic performance of the former.