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Developing low-cost non-precious metals as efficient catalysts for the reduction of toxic 4-nitrophenol (4-NP) to useful 4-aminophenol (4-AP) have received increasing attention in recent years. Herein, a novel and efficient Cu-based catalyst Cu/CuxO@CN (carbon doped with nitrogen) was prepared via a facile method from pyrolysis of bi-ligand MOFs material Cu-2(BDC)(2)(BPY) (BDC = p-Phthalic acid, BPY = 4,40'-b ipyridyl) in Ar atmosphere. Characterization results revealed that N doping in carbon matrix favors the development of mesoporous structure, the formation of more defect sites in carbon matrix, better dispersion of Cu/CuxO nano particles, and maintenance of Cu species in metallic Cu state (the active site), all of which contribute to a superior catalytic activity for 4-NP reduction with a pseudo-first-order rate constant as high as 0.126 s(-1) (the molar ratio of NaBH4 to 4-NP is 400), nearly 11 times higher than its counterpart Cu/CuxO@C without N doping (0.011 s(-1)). The activation energy for 4-NP reduction to 4-AP catalyzed by Cu/CuxO@CN was determined as 55.6 kJ mol(-1) (the molar ratio of NaBH4 to 4-NP is 100). In addition, Cu/CuxO@CN showed excellent reusability in successive 6 cycles. The facile synthesis and superior catalytic activity make Cu/CuxO@CN a promising catalyst in industrial applications for many other similar reaction systems. (C) 2021 Elsevier Inc. All rights reserved.

A series of Ni/HZSM-5 and Ni/HIM-5 bi-functional catalysts were synthesized and applied to the aqueous-phase hydrodeoxygenation (HDO) of phenol. The Ni dispersibility and particle sizes were shown to be directly related to the porosity and crystal sizes of the parent zeolites, which further influenced the catalytic performances. The large pores and small crystal sizes of the parent zeolites were beneficial for dispersing Ni and forming small Ni particles, and the corresponding Ni/zeolite catalyst exhibited a higher phenol conversion and selectivity towards hydrocarbons. Importantly, the Ni/HIM-5 bi-functional catalyst exhibited a high activity (98.3%) and high selectivity for hydrocarbons (98.8%) when heated at 220°C for 1 h and is thus a new potential catalyst for the HDO of phenolics to form hydrocarbons in the aqueous phase.

Novel Cu-nanoparticles (NPs) embedded in porous carbon materials (Cu@C-x) were prepared by one-pot pyrolysis of metal–organic frameworks (MOF) HKUST-1 at different temperatures. The obtained material Cu@C-x was used as a cost-effective catalyst for the hydrogenation of nitrobenzene using NaBH4 as the reducing agent under mild reaction conditions. By considering the catalyst preparation and the catalytic activity, a pyrolysis temperature of 400 °C was finally chosen to synthesize the optimal catalyst. When the aromatic nitro compounds with reducible groups, such as cyano, halogen, and alkyl groups, were tested in this catalytic hydrogenation, an excellent selectivity approaching 100% was achieved. In the recycling experiment, a significant decrease in nitrobenzene conversion was observed in the third cycle, mainly due to the very small amount of catalyst employed in the reaction. Hence, the easily prepared and cost-effective Cu@C-400 catalyst fabricated in this study demonstrates potential for the applications in selective reduction of aromatic nitro compounds. The catalyst Cu@C-400 exhibited 100 % conversion and high selectivity for the hydrogenation of industrially relevant nitroarenes.

The key to improve the performance of heteroatom catalysts is to ensure the orderliness of catalysts and the good dispersion of heteroatoms. The alkalinity plays the indispensable role in synthetic process of V-MCM-41 catalyst. The excessive alkalinity of synthetic system will make the MCM-41 difficult to crystallize, even to dissolve. It is easy to accumulate for heteroatomic species in the system of low alkalinity. Herein, the highly ordered V-MCM-41 with high vanadic content in framework is synthesized in the condition of excessive NH3·H2O in this paper. A series of characterization results prove the good dispersion of vanadium species, and most of vanadium gets into the framework of MCM-41 with the states of tetravalence and pentavalence. Furthermore, the modified MCM-41 by other transition metals is successful synthesized by the method of V-MCM-41 in this paper. The V-MCM-41 shows well catalytic activity for the selective oxidation of benzyl alcohol, which up to 74.83% for the conversion of benzyl alcohol and 96.20% for selectivity of benzaldehyde when initial V/Si = 0.10. The paper provides the possibility for industrial application of V-MCM-41 in the oxidation of benzyl alcohol for benzaldehyde. Besides, the work provides a significant idea for the synthesis of modified MCM-41 by well-dispersed transition metals.

The adsorption removal of indole and quinoline in octane with and without toluene over zeolites NaY and Yttrium Ion-exchanged Y (YY) using batch adsorption experiments was studied at 25 o C and 1 atm. YY was prepared by treating NaY with Y(NO 3 ) 3 solution twice via liquid ion-exchange method. NaY and YY were both characterized by XRD, SEM, N 2 adsorption, XRF, NH 3 -TPD, and pyridine-FTIR techniques. Adsorption isotherms of indole, quinoline and toluene in octane were conducted at 25.0 o C to explain the influence of toluene on nitrogen removal over NaY and YY. The partial destruct of the crystalline structure of NaY was observed after the introduction of yttrium ion , which led to an evident decline in BET surface area and pore volume of YY. Strong Bronsted acidity and medium Lewis acidity were introduced by yttrium ion-exchange. Though the specific surface area and pore volume of YY were much lower than those of NaY, YY exhibited equivalent adsorption capacities for indole and quinoline as NaY in model fuels without toluene. In the presence of 20 vol.% toluene, however, YY exhibited much higher adsorption capacities for indole and quinoline than NaY, especially in the case of quinoline. The improved toluene-tolerant of YY was ascribed to the strong acid-base interaction between YY and quinoline and the decreased adsorption strength between YY and toluene.

Practical application of metallurgical microbial electrolysis cells (MECs) requires efficient removal of metals and organics in larger reactors. A 40 L cylindrical single-chamber MEC fed acetate was used to achieve high removals of W(VI) and Mo(VI). In the presence of both metals, there were nearly complete removals of W (97 ‒ 98%), Mo (98 ‒ 99%), and acetate (95 ‒ 96%), along with a low level of hydrogen production (0.0037–0.0039 L/L/d) at a hydraulic residence time (HRT) of 2 d (influent ratios of W:Mo:acetate of 0.5:1.0:24 mM). The final concentrations of these conditions were sufficient to meet national wastewater discharge standards. In the controls with individual metals or acetate, lower contaminant removals were obtained (W, 2 ‒ 4%; Mo, 3 ‒ 5%, acetate, 36 ‒ 39%). Metals removal in all cases was primarily due to the biocathodes rather than the bioanodes. The presence of metals decreased microbial diversity on the anodes and increased diversity on the cathodes, based on analysis at the phylum, class and genus levels, as a function of HRT and influent concentration. This study demonstrated the feasibility of larger-scale single-chamber MECs for efficient treatment of W and Mo, moving metallurgical MECs closer to commercialization for wastewater treatment of these two metals.

The simultaneous production of acetate from bicarbonate (from CO2 sequestration) and hydrogen gas, with concomitant removal of Cd(II) heavy metal in water is demonstrated in multifunctional metallurgical microbial electrosynthesis systems (MES) incorporating Cd(II) tolerant electrochemically active bacteria (EAB) (Ochrobactrum sp. X1, Pseudomonas sp. X3, Pseudomonas delhiensis X5, and Ochrobactrum anthropi X7). Strain X5 favored the production of acetate, while X7 preferred the production of hydrogen. The rate of Cd(II) removal by all EAB (1.20–1.32 mg/L/h), and the rates of acetate production by X5 (29.4 mg/L/d) and hydrogen evolution by X7 (0.0187 m3/m3/d) increased in the presence of a circuital current. The production of acetate and hydrogen was regulated by the release of extracellular polymeric substances (EPS), which also exhibited invariable catalytic activity toward the reduction of Cd(II) to Cd(0). The intracellular activities of glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) and dehydrogenase were altered by the circuital current and Cd(II) concentration, and these regulated the products distribution. Such understanding enables the targeted manipulation of the MES operational conditions that favor the production of acetate from CO2 sequestration with simultaneous hydrogen production and removal/recovery of Cd(II) from metal-contaminated and organics-barren waters.

Simultaneous Cu(II) reduction (6.42 ± 0.02 mg/L/h), acetate production (1.13 ± 0.02 mg/L/h) from inorganic carbon (i.e., CO2 sequestration), and hydrogen evolution (0.0315 ± 0.0005 m3/m3/d) were achieved in a Serratia marcescens Q1 catalyzed microbial electrosynthesis system (MES). The biofilms released increasing amounts of extracellular polymeric substances (EPS) with a higher compositional diversity and stronger Cu(II) complexation, compared to the plankton cells, at higher Cu(II) concentrations (up to 80 mg/L) and circuital currents (cathodic potential of −900 mV vs. standard hydrogen electrode (SHE)). Moreover, the biofilms reduced Cu(II) to Cu(0) more effectively than the plankton cells. At Cu(II) concentrations below 80 mg/L, the dehydrogenase activity in the biofilms was higher than in the plankton cells, and increased with circuital current, which was converse to the lower activities of catalase (CAT), superoxide dismutase (SOD) and antioxidative glutathione (GSH) in the biofilms than the plankton cells, although all these physiological activities were positively correlated with the concentration of Cu(II). This is the first study that evaluates the EPS constituents and the physiological activities of the biofilms and the plankton cells in the MESs, that favors the production of acetate from CO2 sequestration and the simultaneous reduction of Cu(II) from organics-barren waters contaminated with heavy metals.

This work presented the synthesis of Ni-based metal-organic framework material with a paddle-wheel structure Ni3(BTC)2 (Ni-BTC) and its application in thiophene (TP) adsorption from gasoline distillate by batch method. Adsorption isotherms of TP, cyclohexene, and toluene in cyclohexane onto Ni-BTC were conducted at 298–308 K to interpret the different effect of cyclohexene and toluene on TP adsorption. The results showed that, compared with cyclohexene, toluene addition in model gasoline led to a more evident decline in sulfur capacity of Ni-BTC, which is opposite to isostructural HKUST-1. The adsorption isotherms of TP, cyclohexene and toluene fit Langmuir model, S-type model and Temkin model well, respectively, indicating that the adsorption mechanisms of TP and the two competitors are different from one another. The adsorption capacities on Ni-BTC followed the order of cyclohexene

BackgroundThe perennial shrub of Calligonum mongolicum is a dominant native plant in all Calligonum species, which has the largest and most widespread geographic distribution in arid deserts of northern China. Understanding the phylogenetic relationship between C. mongolicum and closely related plant species will offer guidance on the classification and identification of inter-species and their varieties. The chloroplast (cp) genome is an optimal model to decipher phylogenetic relationships and genome evolution in related plant families. In the present study, the complete cp genome of C. mongolicum was sequenced, and the characteristics were described, then the genomic structure was compared to other three Polygonaceae species.ResultsThe cp genome of C. mongolicum was 162,124 bp in length with a quadripartite structure. A total of 131 functional genes were annotated, 14 different genes of which harbored introns and exons, 50 long repeat sequences and 244 simple sequences repeats were identified. Synonymous codon usage (SCU) analysis exhibited A/T preference, and 7 codons were identified as the optimal codons. Multivariate statistical analysis of parity rule 2, ENC-plot, and neutrality plot were combined conducted to imply natural selection as the crucial constraint in SCU bias in C. mongolicum cp genome.The phylogenetic tree showed that Rumex acetosa was the most related plant to C. mongolicum. From the comparative analysis of genomic structures, the inverted repeat regions (IRa and IRb) were less divergent than other parts and coding regions was relatively conserved than non-coding regions. Compared to other species in the Polygonaceae, the borders of IRb/SSC and SSC/IRa in C. mongolicum changed greatly. Furthermore, adaptive evolution analysis of 75 orthologous protein-coding genes indicated that only the psbK gene was under positive selection, which might be crucial in the adaptive evolution of C. mongolicum.ConclusionsOur results comprehensively depicts the architecture of C. mongolicum cp genome, and will lay a vigorous foundation for further study on molecular marker selection, phylogenetic analysis, and population researches in Calligonum species.

Background Codon usage bias analysis is a suitable strategy for identifying the principal evolutionary driving forces in different organisms. Delphinium grandiflorum L. is a perennial herb with high economic value and typical biological characteristics. Evolutionary analysis of D. grandiflorum can provide a rich resource of genetic information for developing hybridization resources of the genus Delphinium. Methods Synonymous codon usage (SCU) and related indices of 51 coding sequences from the D. grandiflorum chloroplast (cp) genome were calculated using Codon W, Cups of EMBOSS, SPSS and Microsoft Excel. Multivariate statistical analysis combined by principal component analysis (PCA), correspondence analysis (COA), PR2-plot mapping analysis and ENC plot analysis was then conducted to explore the factors affecting the usage of synonymous codons. Results The SCU bias of D. grandiflorum was weak and codons preferred A/T ending. A SCU imbalance between A/T and G/C at the third base position was revealed by PR2-plot mapping analysis. A total of eight codons were identified as the optimal codons. The PCA and COA results indicated that base composition (GC content, GC3 content) and gene expression were important for SCU bias. A majority of genes were distributed below the expected curve from the ENC plot analysis and up the standard curve by neutrality plot analysis. Our results showed that with the exception of notable mutation pressure effects, the majority of genetic evolution in the D. grandiflorum cp genome might be driven by natural selection. Discussions Our results provide a theoretical foundation for elucidating the genetic architecture and mechanisms of D. grandiflorum, and contribute to enriching D. grandiflorum genetic resources.

A facile and environment-friendly method was developed to prepare porous V2O5 flakes by the crystallization of ammonium metavanadate (NH4VO3) aqueous solution at 8 °C and subsequent calcination in air. The morphologies of the crystallographic NH4VO3 obtained under different vanadium concentrations and crystallization temperatures were characterized by scanning electron microscope (SEM), and a possible growth mechanism was discussed. The impact of the calcination temperatures on the morphologies and electrochemical properties of porous V2O5 flakes was studied. The pores of the obtained V2O5 flakes mainly consist of mesoporous with an average pore size of 28.66 nm. Electrochemical properties of the porous V2O5 flakes as a battery-type electrode were measured. The product exhibited a high capacity of 510 F g−1 at 0.2 A g−1 and remained over 110% of the initial capacitance after 1000 cycles. The outstanding electrochemical performance of the porous V2O5 flakes make them promising candidates as a battery-type electrode material for supercapacitors.

Fe-ZSM-35, as a zeolite with ferrierite-like structure, is an important catalyst in industry, and it is usually very difficult to obtain through conventional methods. Understanding the semi-crystallized structure at the nanoscale is the key to control their properties and design the best materials for their ever increasing uses. Herein, we report a novel and controllable method for the synthesis of Fe-ZSM-35 with pure framework Fe species; the essence of this novel synthetic method is a two-step static hydrothermal process. Initially, semi-crystallized Fe-containing species and a semi-crystallized ZSM-35 structure are prepared, then the two semi-crystallized materials are mixed and crystallized to give Fe-ZSM-35 zeolite. This method can almost eliminate the retarding crystallization effect of hetero Fe and is beneficial for a high content of Fe to be incorporated into the ZSM-35 framework. The formation mechanism of Fe-ZSM-35 zeolite was also investigated by UV Raman spectroscopy in combination with X-ray powder diffraction and UV-vis diffuse reflectance spectroscopy. The studies indicate that the Fe-containing aluminate-silica gel was initially mixed with the semi-crystallized ZSM-35 structure fragments to generate the Fe-ZSM-35 structure, and this method may be extended to the other metal-hetero zeolites.

Layer-by-layer V 2 O 5 structures self-assembly by quadrate sheets like “multilayer cake” were successfully synthesized using NH 4 VO 3 as the vanadium sources by a facile hydrothermal route and combination of the calcination. The structure and composition were characterized by field emission scanning electron microscopy, energy-dispersive X-ray spectrometer, X-ray powder diffraction, Raman and Fourier transform infrared spectroscopy. The optical properties of the as-obtained V 2 O 5 layer-by-layer structures were investigated by the Ultraviolet–visible spectroscopy and photoluminescence spectrum. The electrochemical properties of the as-obtained V 2 O 5 layer-by-layer structures as electrodes in supercapacitor device were measured by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) both in the aqueous and organic electrolyte. The specific capacitance is 347 F g −1 at 1 A g −1 in organic electrolyte, which is improved by 46% compared with 238 F g −1 in aqueous electrolyte. During the cycle performance, the specific capacitances of V 2 O 5 layer-by-layer structures after 100 cycles are 30% and 82% of the initial discharge capacity in the aqueous and organic electrolyte, respectively, indicating the cycle performance is significantly improved in organic electrolyte. Our results turn out that layer-by-layer V 2 O 5 structures are an ideal material for supercapacitor electrode in the present work.

Hierarchical zeolite beta is successfully obtained via treating microporous zeolite beta with urea solution. Desilication takes place in a mild and stable alkaline media provided by the hydrolysis of urea solution. The hierarchy can be easily controlled by adjusting treatment temperature and time, the amount of urea solution and Si/Al ratio of the starting zeolite without loss of crystallinity. The resultant hierarchical zeolite beta can be directly used in acid catalytic reactions without tedious ammonium exchange, and it exhibits improved catalytic performance in nopol synthesis.

Zeolite L has been synthesized by magadiite conversion method. The crystallization behavior and changes of medium-range structure during the crystallization were investigated by X-ray diffraction, scanning electron micrograph, vibrational spectroscopy and 27Al magic angle spinning nuclear magnetic resonance. It is indicated that parts of 6 member-rings in magadiite still exist as secondary building units although the long-range order of magadiite was collapsed in the initial stage. The 4 member-rings and 8 member-rings were formed after the sample was heated for 3 h and 4 h, respectively. The influence of various parameters such as reaction temperature, time and substrate composition was examined. Highly crystallized and pure zeolite L could be prepared from the substrates with molar composition: 0.56M2O–xAl2O3 SiO2 49H2O (M2O = K2O + Na2O, x = 0.0033–0.04) by heating at 140 °C for 18 h, 160 °C for 12 h or 180 °C for 8 h.

VO2(B)/C core–shell composites were successfully prepared using commercial V2O5, glucose and water as the starting materials by a facile one-pot hydrothermal method. The composition of the products was characterized by the techniques including X-ray powder diffraction, infrared spectroscopy, Raman, energy-dispersive X-ray spectrometer and elemental analysis. The morphology of the products was observed by scanning electron microscopy and transmission electron microscopy tests. The results showed the products consisted of the crystal VO2(B) phase and the amorphous carbon phase. The amorphous carbon contained lots of organic groups, such as OH, C H, C O and C C, etc., which suggested that the carbon here was organic carbon. The morphology of the as-obtained VO2(B)/C composites was well-defined nanobelts, and each VO2(B) core was encapsulated into carbon. Furthermore, the electrochemical properties of VO2(B)/C core–shell composites were investigated by cyclic voltammetry and galvanostatic charge–discharge. The results showed the measured capacitance of VO2(B)/C composites was mainly based on the pseudocapacitance. VO2(B)/C composites displayed the specific capacitance of 203, 190, 182, 173, 164, and 147 F g−1 at the current density of 0.2, 0.5, 1, 5, 10 and 20 A g−1, respectively. They also showed an excellent energy density of 198.9 W h kg−1 at a power density of 504.5 W kg−1 and a rapidly reversible redox Faraday response.

LiV 3 O 8 nanosheets were successfully synthesized by a facile hydrothermal approach and subsequent calcination for the first time. The samples were characterized by XRD, FT-IR, SEM and TEM. The results showed that the phase pure LiV 3 O 8 nanosheets with layered structures were formed. Furthermore, the electrochemical properties of LiV 3 O 8 nanosheets were investigated by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD). The results showed that LiV 3 O 8 nanosheets performed a high initial specific capacitance of 288 F g −1 , and the specific capacitance after 10, 40, 100 cycles was 218, 131, 98 F g −1 , respectively. The good electrochemical properties made them a promising candidate as a cathode material for supercapacitors.

It has attracted increasing interest that creating a series of novel supercapacitor electrode materials with promising property. Among many kinds of electrode materials, transition metal silicates and metal oxides have been widely developed as electrode materials for supercapacitors because of their structural stabilization and extremely high theoretical capacity. In our work, manganese dioxide (MnO2) coated on cobalt silicate (Co2SiO4) nanobelts core-shell composites (Co2SiO4 nanobelts@MnO2, abbreviated as CoSi NBs@MnO2) as the improved electrodes for hybrid supercapacitors (HSCs) have been designed and fabricated by a template method. These two electrode materials complement each other and display an excellent synergistic effect. Thanks to the special nanostructures and the capacitance contribution of the two materials, the capacitance value of CoSi NBs@MnO2 can achieve 490.5 F·g−1 at 1 A·g−1 and the capacitance retention with ca. 80% after 5000 cycles. Furthermore, the HSC device fabricated by activated carbon (AC) and CoSi NBs@MnO2 shows the areal capacitance of 328.1 m F·cm−2 at 1 mA·cm−2. Meanwhile, the energy density and power density of the CoSi NBs@MnO2//AC HSC device measure to be 0.89 Wh·m−2 and 42 W·m−2, respectively. The novel and reasonable structural design allows Co2SiO4 and MnO2 to make the contributions in the direction of electrode materials for supercapacitors.

The simultaneous production of acetate from bicarbonate (from CO

It is difficult to synthesize a Silicalite-1 molecular sieve with a high vanadium content in the framework, because heteroatoms significantly affect the formation of V-Silicalite-1. Here, V-Silicalite-1 with a high vanadium content in the framework of the molecular sieve was successfully synthesized by controlling the pH at high levels. In the process of hydrothermal synthesis, OH− ions effectively promoted the entry of vanadium atoms into the framework of the molecular sieve. Samples of V-Silicalite-1 with different vanadium contents were characterized by XRD, FTIR, UV-vis, XPS, EPR, ICP, FE-SEM, elemental mapping, N2 adsorption–desorption, and TPR, which confirmed that vanadium atoms successfully replaced silicon atoms in the framework. V-Silicalite-1 exhibited good catalytic performance in the selective oxidation of styrene at different temperatures, with a styrene conversion of up to 84.89% and a selectivity of 91.04% for styrene oxide at 25 °C and a styrene conversion of 97.47% and a selectivity of 80.97% for benzaldehyde at 85 °C. This study provided a new idea for the synthesis of molecular sieves with high vanadium contents in the framework. Besides, it also enabled the direct application of vanadium-doped molecular sieves for the catalytic oxidation of styrene in industry.

Titanium silicalite (TS-1) zeolites with different titanium species were synthesized and characterized by ultraviolet (UV)-Raman, ultraviolet visible (UV-Vis) diffuse reflectance spectroscopies and by the NH3 temperature programmed desorption (NH3-TPD) method. The roles of different titanium species in TS-1 samples have been investigated by gas chromatography-Raman spectrometry (GC-Raman) during the propylene epoxidation process. For the first time, a positive correlation was found among the concentration of framework Ti species, the amount of active intermediate Ti-OOH (η(2)) and the conversion of propylene by the in situ GC-Raman technique. The results give evidence that the framework titanium species is the active center and Ti-OOH (η(2)) is the active intermediate. The presence of extra-framework Ti species is harmful to propylene epoxidation. Furthermore, the amorphous Ti species has a more negative effect on the yield of propylene oxide (PO) than the anatase TiO2. The NH3-TPD results reveal that the amorphous Ti species are more acidic and thus should be mainly responsible for the further conversion of PO.

Hierarchical titanosilicate composites (HTS) have been synthesized by an aerosol spray method, by which TS-1 nanoparticles were assembled with cetyl trimethyl ammonium bromide and tetraethylorthosilicate/tetra-n-butyl titanate to form a hierarchical porous composites with a core–shell structure. The structure, porosity, morphology and composition of the materials were characterized by X-ray diffraction, nitrogen adsorption isotherm, Raman spectroscopy, electron microscopy and X-ray fluorescence spectroscopy. The hierarchical porous molecular sieve combines the advantages of TS-1 and Ti-KIT-1, and shows high activity and selectivity to epoxide in cyclohexene epoxidation with H2O2. The yield of cyclohexene oxide on HTS is much higher than those on TS-1 and Ti-KIT-1. The selectivities to cyclohexene oxide and 1,2-cyclohexanediol can be adjusted by varying the titanium contents of the HTS samples.

Adsorption desulfurization is one of the most promising ways to reduce the sulfur content of gasoline at deeper level. In this work, thiophene (TP) adsorption capacity in cyclohexane onto [Cu3(BTC)2(H2O)3] (HKUST-1) was measured by batch method, and the effect of cyclohexene and toluene on sulfur capacity was investigated. Adsorption isotherms of TP, cyclohexene, and toluene in cyclohexane onto HKUST-1 were conducted at 298.15–313.15 K to explicate the different extent of influence by cyclohexene or toluene addition. The results showed that, compared with cyclohexene, the addition of toluene in model gasoline led to a moderate decline in sulfur capacity of HKUST-1. The isotherm data of TP adsorption were well-correlated using Langmuir equation, while those of cyclohexene or toluene adsorption fitted Freundlich model, indicating different adsorption mechanisms between TP and competitors. The adsorption capacities followed the order of toluene

Hierarchically structured zeolite Y (meso-Y) was successfully achieved by treating parent NaY (Si/Al = 2.6) by sequential dealumination-desilication. The obtained sample was characterized by X-ray diffraction, N 2 sorption, Transmission electron microscopy, X-ray fluorescence, pyridine-Fourier transform infrared and 29 Si Magic angle spinning nuclear magnetic resonance techniques. The mesopore surface area up to 110 m 2 g − 1 was obtained for meso-Y when the parent zeolite Y was subjected to sequential treatment by ethylenediaminetetraacetic acid and NaOH, with the preserving of the intrinsic crystallinity. The adsorption desulfurization results showed that hierarchically structured CeY (meso-CeY) exhibited much higher desulfurization performance than microporous CeY in the presence of large amount of toluene or cyclohexene, even in fluid catalytic cracking gasoline. FTIR studies and structure characterization indicate that the mesopore of the adsorbent is benefit to the selective adsorption desulfurization, possibly because the enlarged pore size weakens the micropore-filling effect of the microporous adsorbent, and thus depresses the non-selective adsorption of toluene and cyclohexene.

NaY and LaNaY were used as adsorbents to remove thiophene from model gasoline (MG) with and without cyclohexene (CHE) by static adsorption experiments at room temperature (RT). The adsorbents were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), N2 physisorption and pyridine infrared spectrum (IR). The adsorption experiments show that the desulfurization performance of NaY decreases with the rise of CHE concentration in MG, whereas that of LaNaY first increases then declines. FT-IR spectra of thiophene adsorption indicate that thiophene is mainly adsorbed on NaY via π electron interaction, but adsorbed on LaNaY via π electron interaction, La–S direct interaction and protonation of thiophene. The Bronsted acid sites of LaNaY are found to play a crucial role and be responsible for the protonation of either thiophene or CHE molecules, which results in the alkylation reactions between thiophene and CHE in MG. The gas chromatograph–sulfur chemiluminescence detector (GC–SCD) and ultraviolet–visible (Uv–vis) spectra results also confirm the formation of alkylated thiophenes. The improved desulfurization over LaNaY may be attributed to the formation of alkylated thiophenes, owing to the larger molecular sizes and the higher electron densities on sulfur atoms of the alkylated thiophenes.

Small crystal zeolites beta with molar Si/Al ratios of 21, 30 and 40.5 were successfully obtained by treating parent beta (Si/Al = 14.5) with different oxalic acid concentrations. The influence of Si/Al ratio of zeolite beta on effective mesopore formation via NaOH treatment was studied by investigating the changes in crystallinity, morphology, chemical composition, acidity and textural property of zeolite beta before and after alkaline treatment. The catalytic performance was evaluated in terms of α-pinene isomerization and benzoylation of naphthalene with benzoyl chloride. Substantial mesoporosity could be developed for zeolites beta with molar Si/Al ratios of 14.5–30, coupled with better preserved microporosity. Though the largest mesopore surface area (488 m2 g−1) was achieved when Si/Al = 30, the crystallinity of zeolite beta was partly destroyed. The substantially improved catalytic activity of alkaline treated samples in α-pinene isomerization is mainly attributed to the developed mesoporosity, but the volcano curve change in catalytic activities of alkaline treated samples in benzoylation of naphthalene manifested that both mesoporosity and acid property play important role in a medium strong acid catalyzed reaction.

Hierarchical beta zeolites with SiO2/Al2O3 molar ratios of 16 to 25 were obtained by alkaline treatment in NaOH solution. The effects of treatment temperature on crystallinity, textural properties and chemical composites were studied by XRD, N2 sorption, FT-IR and XRF techniques. The desulfurization performance of parent and alkaline-treated beta zeolites was investigated by static absorption in four model fuels, containing four sulfur compounds of different molecular sizes like thiophene (TP), 3-methylthiophene (3-MT), benzothiophene (BT) and dibenzothiophene (DBT), respectively. The crystallinity was observed to be successfully maintained when the treatment temperature was below 50 °C. Mesoporosity of beta zeolite was evidently developed with alkaline treatment. The formation of mesopore remarkably improved the desulfurization performance for TP, 3-MT, BT and DBT, especially for DBT with larger molecular diameter. Though the addition of toluene in the model fuels resulted in a significant drop of the desulfurization performance of mesoporous beta zeolite, the introduction of cerium ions to some extent mitigated the effect of toluene, which means that both the adsorbents porous structure and the adsorption mode are responsible for the desulfurization performance. The adsorbent of cerium ion-exchanged mesoporous beta showed about 80% recovery of desulfurization after the first regeneration.

Small crystal zeolite beta with Si/Al ratio of 12 was subjected to post-synthesis treatment with NaOH solutions. The effect of alkaline concentration on the crystallinity, pore structures, compositions and acidic properties of zeolite beta was studied by XRD, N2 sorption, XRF, and FTIR techniques. The catalytic performance of zeolite beta before and after alkaline treatment was investigated in terms of liquid phase isomerization of α-pinene. No distinct change in the crystallinity was observed after the zeolite was treated by 0.1–0.4 M NaOH solutions. However, mesoporosity was evidently developed; the mesopore surface area up to 349 m2 g−1 was obtained when 0.4 M NaOH solution was employed. The acidic properties of zeolite beta were mostly preserved when it was treated by 0.1–0.2 M NaOH solutions, but the amount of strong Bronsted acid sites was to some extent reduced when 0.4 and 0.7 M NaOH solutions were employed. The catalytic activities of the samples increase with the development of mesoporosity. The best catalytic performance at 70 °C and 30 min reaction time was observed on zeolite beta containing the largest mesopore volume of 0.69 cm3 g−1: 100% conversion of α-pinene with 85.4% selectivity into camphene, terpinolene, α- and γ-terpinene as desired products. At the same conditions only 20.3% conversion was obtained over parent zeolite beta containing only 0.23 cm3 g−1 mesopore volume. This result indicates that the enhanced catalytic activity for α-pinene isomerization is mainly attributed to the mesopore formation resulting from alkaline treatment.

Zeolites NaY and Ce(IV)Y were employed as adsorbents to remove organic sulfur compounds from model gasoline (MG) solutions with and without toluene in static adsorption experiments at room temperature (RT) and atmospheric pressure. The adsorbents were characterized by XRD, XRF and pyridine infrared spectrum (IR). The adsorption experiments show that the desulfurization performance of Ce(IV)Y is much better than that of NaY. The sulfur removal over both NaY and Ce(IV)Y decreases with the increase of toluene concentration in MG, however, the decline tendency on Ce(IV)Y is smooth, and it is steep on NaY. FT-IR spectra of thiophene adsorption indicate that thiophene molecules are mainly adsorbed on NaY via π electron interaction, but on Ce(IV)Y, in addition to the π electron interaction, both Ce 4+ -S direct interaction and protonation of thiophene also play important roles. Toluene molecules are adsorbed on NaY also via π electron interaction. Although the amount of Bronsted acid sites is increased due to the introduction of Ce 4+ ions into NaY zeolite, it is not found to influence the adsorption mode of toluene over Ce(IV)Y. Compared with NaY zeolite, the improved desulfurization performance over Ce(IV)Y for removing organic sulfur compounds from MG solution, especially those containing large amount of aromatics, may be ascribed to the direct Ce(IV)-S interaction, which is much resistant to the influence resulted from toluene adsorption.

Immobilized AlCl3 catalysts supported on γ-Al2O3 and SiO2 were prepared by a two-step vapor method and their catalytic activities were evaluated by the liquid phase isomerization of α-pinene for the first time. The results showed that the immobilized AlCl3 catalyst gave excellent catalytic performance for the isomerization of α-pinene. The AlCl3/SiO2 catalyst gave 98.4% conversion of α-pinene and 93.7% selectivity for the main products such as camphene, limonene, and terpinolene at a reaction temperature of 40 °C. The AlCl3/γ-Al2O3 catalyst gave much higher activity, 95.5% conversion of α-pinene and 94.4% selectivity for the main products even at temperatures as low as 30 °C. The excellent catalytic performance of the immobilized AlCl3 catalysts is due to their strong acidity.

Desert shrubs, a dominant component of desert ecosystems, need to maintain sufficient levels of nutrients in their different organs to ensure operation of various physiological functions for the purpose of survival and reproduction. In the present study, we analyzed 10 elements in leaves, stems and roots of 24 dominant shrub species from 52 sites across a temperate desert ecosystem in northwestern China. We found that concentrations of all 10 elements were higher in leaves than in stems and roots, that non-legumes had higher levels of leaf Na and Mg than did legumes and that Na was more concentrated in C4 leaves than in C3 leaves. Scaling relationships of elements between the photosynthetic organ (leaf) and non-photosynthetic organs (stem and root) were allometric. Results of principal components analysis (PCA) highlighted the important role of the elements responsible for osmoregulation (K and Na) in water utilization of desert shrubs. Soil properties and taxonomy explained most variation of element concentrations in desert shrubs. Desert shrubs may not be particularly susceptible to future change in climate factors, because most elements (including N, P, K, Ca, Mn, Zn and Cu) associated with photosynthesis, osmoregulation, enzyme activity and water use efficiency primarily depend on soil conditions.

Silica-supported binary and ternary phosphides, mop/sio2, ni2p/sio2, and ni-mo-p/sio2 have been prepared and characterized by x-ray diffraction (xrd), bet surface area, co chemisorption, transmission electron microscopy (tem), and infrared spectroscopy (ir). the hydrodesulfurization (hds) activities of dibenzothiophene (dbt) were measured and compared at 593 k and 3.0 mpa for mop/sio2, ni2p/sio2, and ni-mo-p/sio2 catalysts with different mo and ni loadings. the activities of the phosphides follow the order ni2p/sio2 > ni-mo-p/sio2 > mop/sio2. the ni sites in the ni-mo-p/sio2 catalysts play a major role in the conversion of dbt, and the activity of the catalysts increases with increasing ni content. this is different from sulfides, nitrides, and carbides, as no synergetic effect is observed between the phosphided ni and the mo atoms. the surface of these phosphide catalysts is partially sulfided forming a surface phosphosulfide phase, while the bulk structure of the phosphides is maintained in the hds reactions. (c) 2004 elsevier inc. all rights reserved.

Nanostructured tungsten carbides on ultrahigh-surface-area carbon (>3000 m2/g), a kind of novel carbon material with uniform pore distribution, have been prepared by carbothermal reduction, carbothermal hydrogen reduction, and metal-promoted carbothermal hydrogen reduction under mild conditions. The resulting carbides have been characterized by X-ray diffraction, transmission electron microscopy, temperature-programmed reduction−mass spectroscopy, and N2 physico-sorption. The adsorption properties of thiophene on nanostructured tungsten carbides on ultrahigh-surface-area carbon were also investigated in a fixed-bed reactor. The results show that nanostructured W2C particles of about 10 nm on ultrahigh-surface-area carbon material can be synthesized by carbothermal reduction and carbothermal hydrogen reduction at 850 °C. Nanostructured W2C has also been obtained by metal Ni-promoted carbothermal hydrogen reduction even at 650 °C. The results also show that carbothermal hydrogen reduction can form tungsten ...

The surface properties, porosities, and adsorption capacities of activated carbons (AC) are modified by the oxidation treatment using concentrated H2SO4 at temperatures 150−270 °C. The modified AC was characterized by N2 adsorption, base titration, FTIR, and the adsorption of iodine, chlorophenol, methylene blue, and dibenzothiophene. The treatment of AC with concentrated H2SO4 at 250 °C greatly increases the mesoporous volume from 0.243 mL/g to 0.452 mL/g, specific surface areas from 393 m2/g to 745 m2/g, and acidic surface oxygen complexes from 0.071 meq/g to 1.986 meq/g as compared with the unmodified AC. The base titration results indicate that the amount of acidic surface oxygen groups on the modified AC increases with increasing the treatment temperatures and carboxyls and phenols are the most abundant carbon−oxygen functional groups. The carboxyl groups, COO- species, and hydroxyl groups are detected mainly for the sample treated at 250 °C. The mesoporous properties of the AC modified by concentrat...

Correction for ‘High pH promoting the synthesis of V-Silicalite-1 with high vanadium content in the framework and its catalytic performance in selective oxidation of styrene’ by Jing Zhao et al., Dalton Trans., 2018, 47, 11375–11385.

Zeolites NaY and LaNaY (ion-exchanged with aqueous lanthanum nitrate solution) were used as adsorbents for removing organic sulfur compounds from model gasoline solutions (without and with toluene) and fluid catalytic cracked gasoline in fixed-bed adsorption equipment at room temperature and atmosphere pressure. The adsorptive selectivity for organic sulfur compounds was significantly increased when Na(+) ions in zeolite NaY were exchanged with lanthanum ions. IR spectra of thiophene adsorption indicate that thiophene is adsorbed onto La(3+) ions via direct S-La(3+) interaction and Na(+) ions via pi-electronic interaction for La(3+)-exchanged zeolite NaY, but only via pi-electronic interaction with Na(+) ions for NaY. The amount of adsorbed thiophene on La(3+)-exchanged zeolite Y was slightly decreased by coadsorption of benzene, but greatly reduced on NaY. The adsorption of thiophene via interaction with La(3+) on La(3+)-exchanged zeolite Y is hardly replaced by benzene coadsorption. The direct S-La(3+) interaction might be the essential reason for the evidently improved adsorptive selectivity of LaNaY for removing organic sulfur compounds from solutions containing large amount of aromatics.