NH_4与Pt改性的HZSM-5催化剂上2-甲基萘与甲醇的择形甲基化反应(英文)

Shape-selective methylation of 2-methylnaphthalene (2-MN) was carried out over NH4F and Pt modified HZSM-5 (SiO2/Al2O3 83) catalysts in a fixed-bed down-flow reactor using methanol as methylating agent and 1,3,5-trimethylbenzene (1,3,5-TMB) as a solvent. Pt promoted HZSM-5 catalysts showed low concentration of coke-like polycondensed aromatics, NH4F modification decreased non-shape-selective acid sites. After Pt and NH4F co-modification, both conversion of 2-MN and selectivity to 2,6-DMN were improved. 6%NH4F/0.5%Pt/HZSM-5 catalyst exhibited 13.8% of 2-MN conversion with 6.2% of 2,6-DMN yield after 7 h time on stream (TOS), and 2,6-/2,7-DMN ratio of 1.7 after 10 h of TOS.     

Effects of steam and TEOS modification on HZSM-5 zeolite for 2,6-dimethylnaphthalene synthesis by methylation of 2-methylnaphthalene with methanol

Shape-selective methylation of 2-methylnaphthalene (2-MN) over HZSM-5 catalysts modified by steam and tetraethoxysilane (TEOS) treatments was carried out in a fixed-bed reactor. Catalysts were characterized by XRD, NH₃-TPD, BET, FT-IR spectra of pyridine adsorbed, and by adsorption of hexane and cyclohexane. The results show that the TEOS treatment can effectively passivate external active site and narrow pore mouth of catalyst, but it has less effect on the internal surface than steam modification. Hydrothermal treatment can effectively reduce both external and internal acid sites, and adjust channel of catalyst. Steam treatment can effectively increase the ratio of 2,6/2,7-DMN, but the ratio has no increasing trend on TEOS modified catalyst. So adjusting acidity property is more useful to increase the selectivity to 2,6-DMN and the ratio of 2,6/2,7-DMN than narrowing catalyst pore mouth. Tailoring acidic characteristics is more important than spatial control for distinguishing between 2,6-DMN and 2,7-DMN.     

Effect of hydrothermal treatment temperature on FCC gasoline upgrading properties of the modified nanoscale ZSM-5 catalyst

Nanoscale HZSM-5 zeolite was hydrothermally treated with ammonia water at different temperatures and then loaded with La₂O₃ and ZnO. The parent and the modified nanoscale HZSM-5 catalysts were characterized by SEM, NH₃-TPD, IR and XRF. The performance of the modified HZSM-5 catalysts for FCC gasoline upgrading was evaluated in a fixed bed reactor in the presence of hydrogen. The results indicated that the modified catalyst which was hydrothermally treated at 400 °C exhibited excellent aromatization activity, isomerization activity and higher ability of reducing olefin content in FCC gasoline. Under the given reaction conditions, the olefin content in FCC gasoline could be decreased from 49.6 to 8.1 vol.%. The catalytic performance of the modified nanoscale ZSM-5 catalyst hardly changed within 300 h time on stream, and the research octane number (RON) of gasoline was preserved.     

Characterization of Modified Nanoscale ZSM-5 Zeolite and Its Application in the Olefins Reduction in FCC Gasoline

Nanoscale HZSM-5 zeolite was hydrothermally treated with steam containing 0.8 wt% NH₃ at 773 K and then loaded with La₂O₃ and NiO. Both the parent nanoscale HZSM-5 and the modified nanoscale HZSM-5 zeolites catalysts were characterized by TEM, XRD, IR, NH₃-TPD and XRF, and then the performance of olefins reduction in fluidized catalytic cracking (FCC) gasoline over the modified nanoscale HZSM-5 zeolite catalyst was investigated. The IR and NH₃-TPD results showed that the amount of acids of the parent nanoscale HZSM-5 zeolite decreased after the combined modification, so did the strong acid sites deactivating catalysts. The stability of the catalyst was still satisfactory, though the initial activity decreased a little after the combined modification. The modification reduced the ability of aromatization of nanoscale HZSM-5 zeolite catalyst and increased its isomerization ability. After 300 h onstream, the average olefins content in the gasoline was reduced from 56.3 vol% to about 20 vol%, the aromatics (C₇–C₉ aromatics mainly) and paraffins contents in the product were increased from 11.6 vol% and 32.1 vol% to about 20 vol% and 60 vol% respectively. The ratio of i-paraffins/n-paraffins also increased from 3.2 to 6.6. The yield of gasoline was obtained at 97 wt%, while the Research Octane Number (RON) remained about 90.     

Surface characteristics of titanium anodized in the four different types of electrolyte

This study evaluated the surface characteristics of titanium modified by anodic spark oxidation and a subsequent hydrothermal treatment. The electrolytic compositions of the experimental groups are as follows: GA: 0.015 M dl-α-glycerophosphate disodium salt hydrate (dl-α-GP) and 0.2 M calcium acetate (CA), GB: anodized in 0.015 M β-GP (glycerophosphate disodium salt) and 0.2 M CA, GC: anodized in 0.015 M GP (glycerophosphate disodium salt) and 0.2 M CA, and GD: anodized in 0.015 M GP-Ca (glycerophosphate calcium salt) and 0.2 M CA. Anodic spark oxidation was carried out at 30 mA/cm² to 290 V. In addition, the anodized samples were treated hydrothermally at 300 °C for 2 h in an autoclave system. Regardless of the electrolytic composition, the anodic oxide films on the titanium surface contained pores ∼5 μm in size and the diameter was larger at the protrusion parts than that at the lower parts. The phase of the anodic oxide layer consisted mainly of anatase with a small amount of rutile. HA crystals precipitated on the porous titanium oxide layer after a hydrothermal treatment. Moreover, the morphology of the HA crystals was a dense fine needle shape, which changed according to the electrolytic composition. The mean surface roughness (R_a) was highest in group GB at 0.437 μm. The R_a values of the hydrothermally treated group was approximately 0.14-0.2 μm higher than the anodized groups. Anodic spark oxidation and the hydrothermal treatment resulted in increasing corrosion potential and decreasing corrosion current density, which means an improvement in the corrosion resistance. The surface activity of the specimens in Hanks’ solution was GD > GA > GB > GC.     

Synthesis and characterization of highly soluble 9,10-diphenyl-substituted poly(2,6-anthracenevinylene)

We report the synthesis and optoelectronic properties of highly soluble poly(9,10-bis(3′,4′-di(2″-ethylhexyloxy))phenyl)-2,6-anthracenevinylene) (HSM-PAV). The key intermediate for the synthesis of HSM-PAV is 2,6-dimethyl-9,10-dibromoanthracene, and the high solubility of HSM-PAV is from the incorporation of lateral 3,4-di(2-ethylhexyloxy)phenyl moieties into the 9,10-positions of anthracene units. The increase of side alkyloxy groups endows HSM-PAV with higher molecular weight (M_n = 3.2 × 10⁴) and better electroluminescence performances (L_max = 590 cd/m², LE_max = 0.27 cd/A) compared with the poly(2,6-anthracenevinylene) with lateral monoalkyoxy moieties (M_n = 1.9 × 10⁴, L_max = 340 cd/m², LE_max = 0.17 cd/A). The electrical conductivity of doped HSM-PAV film with iodine is 5 × 10⁻² S cm⁻¹ that is several order higher than that of doped 9,10-anthracene-based polymers, further demonstrating that linkage position has a dramatic effect on the optoelectronic properties of anthracene-based conjugated polymers.     

Hydrothermal mass production of MgBO2(OH) nanowhiskers and subsequent thermal conversion to Mg2B2O5 nanorods for biaxially oriented polypropylene resins reinforcement

Mass production of one-dimensional (1D) nanomaterials has emerged as one of the most significant challenges in powder technology. In this contribution, MgBO₂(OH) nanowhiskers were hydrothermally produced at a kilogram scale in a 150 L stainless steel autoclave at 200 °C for 12.0 h by using MgCl₂·6H₂O, H₃BO₃ and NaOH as the raw materials. The subsequent thermal conversion of the MgBO₂(OH) nanowhiskers at 700 °C for 6 h led to 3.75 kg of high crystallinity monoclinic Mg₂B₂O₅ nanorods, with a length of 0.47-1.3 µm, a diameter of 55-160 nm, and an aspect ratio of 3-15. After the nanorods have been surface modified with the silane coupling agent KH-550, the reinforcing and toughening effects of the Mg₂B₂O₅ nanorods on the biaxially oriented polypropylene resins (BOPP-D1) were evaluated. The filling of the Mg₂B₂O₅ nanorods into the resins resulted in the increase in the tensile strength, the impact strength, and the melt flow index of the BOPP-D1 composites. The appropriate ratio of coupling agent to fillers (Mg₂B₂O₅ nanorods) and the ratio of fillers to resins were determined within the range of 0.6-1.2 wt.% and 8-15 wt.%, respectively. The optimal ratio of fillers to resins was ca. 10 wt.%. The present mass production of MgBO₂(OH) nanowhiskers and Mg₂B₂O₅ nanorods is believed to be helpful for enlarging and propelling the applications of the 1D magnesium borate nanostructures in the near future.     

Textural and pseudocapacitive characteristics of sol-gel derived RuO2·xH2O: Hydrothermal annealing vs. annealing in air

Hydrous ruthenium dioxide (RuO₂·xH₂O) prepared in a modified sol-gel process was subjected to annealing in air and water at various temperatures for supercapacitor applications. The textural and pseudocapacitive characteristics of RuO₂·xH₂O annealed in air and water were systematically compared to show the benefits of annealing in water (denoted as hydrothermal annealing). An important concept that hydrothermal annealing effectively restricts condensation of hydroxyl groups within nanoparticles, inhibits crystal growth, and maintains high water content of RuO₂·xH₂O is demonstrated in this work. The unique textural characteristics of hydrothermally annealed RuO₂·xH₂O are attributable to the high-pressured, water-enriched surroundings which restrain coalescence of RuO₂·xH₂O nanocrystallites. The crystalline, hydrous nature of hydrothermally annealed RuO₂·xH₂O favors the utilization of active species in addition to a merit of minor dependence of specific capacitance on the scan rate of CV for pseudocapacitors. As a result, RuO₂·xH₂O with hydrothermal annealing at 225 °C for 24 h exhibits 16 wt.% water, an average particle size of about 7 nm, and specific capacitance of ca. 390 F g⁻¹.     

Synthesis and characterization of chlorapatite–ZnO composite nanopowders

The influence of zinc oxide content on the formation of chlorapatite-based composite nanopowders in the mechanically alloyed CaO–CaCl₂–P₂O₅–ZnO system was studied. To mechanosynthesize composite nanopowders, different amounts of hydrothermally synthesized zinc oxide nanoparticles (0–10 wt%) were mixed with ingredients and then were mechanically activated for 5 h. Results showed that in the absence of zinc oxide, high crystalline chlorapatite nanopowder was obtained after 5 h of milling. In the presence of 4 and 7 wt% zinc oxide, the main product of milling for 5 h was chlorapatite–zinc oxide composite nanopowder. On increasing the zinc oxide content to 10 wt%, composite nanopowder was not formed due to improper stoichiometric ratio of the reactants. The crystallite size, lattice strain, volume fraction of grain boundary, and crystallinity degree of the samples fluctuated significantly during the milling process. In the presence of 7 wt% zinc oxide, the crystallite size and crystallinity degree reached 51±2 nm and 79±2%, respectively. During annealing at 900 °C for 1 h, the crystallization of composite nanopowder occurred and as a result the crystallinity degree rose sharply to 96±3%. In addition, the crystallite size increased to 77±2 nm after annealing at 900 °C. According to SEM and TEM images, the composite nanopowder was composed of both ellipse-like and polygonal particles with a mean size of about 98 nm.     

A positive type alkaline developable thermally stable and photosensitive polymer based on partially O-methylated poly(2,6-dihydroxy-1,5-naphthylene), an acidolytic de-cross-linker, and a photoacid generator

A positive working and chemically amplified photosensitive polymer based on partially (30%) O-methylated poly(2,6-dihydroxy-1,5-naphthylene) [PMPDHN (30)], 1,3,5-tris[(2-vinyloxy)ethoxy]benzene (TVEB) as an acidolytic de-cross-linker, and a photoacid generator (5-propylsulfonyloxyimino-5H-thiophen-2-ylidene)-(2-methylphenyl)acetonitrile (PTMA) has been developed. Poly(2,6-dihydroxy-1,5-naphthylene) (PDHN) with a number-average molecular weight of 33,000 was prepared by oxidative coupling polymerization of 2,6-dihydroxynaphthalene (2,6-DHN) using di-μ-hydroxo-bis-[(N,N,N′,N′-tetramethylethylenediamine)copper(II)] chloride [CuCl(OH)TMEDA] as the catalyst in 2-methoxyethanol at room temperature. PDHN was converted to PMPDHN by treating with iodomethane. The resist showed a sensitivity of 19.4 mJ cm⁻² and a contrast of 7.5 when it was exposed to 436 nm light, followed by post-baking at 120 °C for 5 min and developing with 2.38 wt% aqueous tetramethylammonium hydroxide (TMAH) solution at 25 °C. A fine positive image featuring 6 μm line and space patterns was obtained on the film exposed to 20 mJ cm⁻² of UV-light at 436 nm by the contact-printed mode. The optically estimated dielectric constants (at 1 MHz) of PMPDHN (30) with and without TVEB and PTMA are 3.03 and 3.01, respectively. The moisture absorption (1.7 wt%) of the resist system based on PMPDHN (30) and TVEB is very low compared to that (4.3%) of the resist system consisting of PDHN and 4,4′-methylenebis[2,6-bis(hydroxymethyl)]phenol (MBHP).     

Environmental durability of slurry based mullite-gadolinium silicate EBCs on silicon carbide

Water vapor oxidation and salt corrosion resistances of mullite-gadolinium silicate (Gd₂SiO₅) environmental barrier coatings (EBCs) dip coated on α-SiC substrates and sintered to 1430 °C/3 h in air were investigated. The EBC exhibited excellent adherence to the substrate during thermal cycling between 1350 °C and room temperature (RT) for 100 h in a simulated lean combustion environment (90% H₂O-balance O₂), ^{[11], [13] and [15]} forming ∼10 μm porous silica layer at coating-substrate interface, compared to ∼17 μm for uncoated α-SiC exposed under same conditions. The EBC did not spall after a 24 h 1200 °C exposure in Na₂SO₄ corrosion environment leading to further coat densification. However, after 48 h salt exposure, the EBC showed severe through-thickness cracks, and cavities and de-lamination at coating-substrate interface. The corrosion gaseous products such as CO₂, CO and SO₂ trapped under a low viscosity glassy (Na₂O·x(SiO₂)) liquid phase were formed due to salt vapor reaction with α-SiC substrate created these cavities.     

Cr(VI) removal by continuous electrodeionization: Study of its basic technologies

The capabilities of continuous electrodeionization process (CEDI) and its basic technologies (electrodialysis (ED) and ion exchange (IX)) were analyzed in order to remove hexavalent chromium from synthetic solutions at pH 5. A cell with two chambers (dilute and concentrate) was used. Two cation exchange membranes (CM-1) and one anion exchange membrane (AFN) (40 cm² effective area) were employed in the experimental setup. IX technology was single evaluated using an IRA-67 anionic resin to know its independent performance from the other technologies, whereas ED was studied in the cell; I_lim determination was done by I vs. U plots and factors of 0.7 I_lim and 0.85 I_lim were applied to ED process. Finally, EDI process was studied at the same conditions that ED in order to know the resin bed role. During IX the removal reached was 50%; ED 98% after 6.25 h operation with an energy consumption of 1.21 kW h/m³; EDI (anionic bed) accomplishing 97.55% chromium removal (energy consumption of 0.91 kW h/m³). Finally EDI with mixed bed removed 99.8% in 1.3 h and of 0.167 kW h/m³ of energy consumption.     

Molybdenum substitution by copper or zinc in H-ZSM-5 zeolite for catalyzing the direct conversion of natural gas to petrochemicals under non-oxidative conditions

This work aims to investigate the influence of substituting half the Mo content in a standard 6%Mo/H-ZSM-5 catalyst with either Cu or Zn in H-ZSM-5 support, on the direct conversion of methane in a flow-type fixed-bed reactor atmospherically at 700 °C at a gas hourly space velocity 1500 cm³ h⁻¹ g⁻¹ and times-on stream (TOS) up to 240 min. The most active was 6%Mo/H-ZSM-5 catalyst while Mo-Zn/H-ZSM-5 was more active than Mo-Cu/H-ZSM-5. The XRD data showed that the crystallite (particle) sizes were found compatible with the catalytic activities. At the initial TOS (5 min), methane splitting selectivity to C and H₂ approached 100%. Higher carbon deposition on Mo-Cu catalyst caused more inhibition of ethylene further conversion to larger hydrocarbons thus leading to ethylene accumulation. TPR showed an almost complete reduction of Cu oxides at relatively lower temperatures such that the Mo-Cu catalyst acquired the highest dehydrogenation activity that enhanced markedly ethylene formation. An outstanding accomplishment is obtaining the highest benzene yield and selectivity using Mo-Zn/H-ZSM-5 catalyst, which is a prosperous challenge against the standard monometallic one. The large size of naphthalene molecule caused significant diffusion restriction on its formation in catalytic pores. The exceptional enhancement of naphthalene yield and selectivity at longer TOS using the Mo-Cu/H-ZSM-5 catalyst can be indicative that naphthalene was mostly formed on external zeolitic surface.     

Effect of carbon nanotubes on sintering behavior of alumina prepared by sol–gel method

Alumina (Al2O3)/carbon nanotube (CNT) (99/1 by weight) composite was prepared by mixing CNT dispersion with AlCl₃-based gel, followed by high temperature sintering at a temperature up to 1150 °C in argon. Composite alumina precursor showed phase transition order from amorphous to γ-Al₂O₃ after sintered at 900 °C for 2 h, partially to θ-Al₂O₃ after sintered at 1000 °C for 2 h, and then partially to α-Al₂O₃ after sintered at 1150 °C for 2 h. By comparison, control alumina precursor directly transformed from amorphous to α-Al₂O₃ after sintered at a relatively low temperature of 600 °C for 2 h. Composite alumina showed porous structure with pore diameter ranging from 100 nm to 2 µm, whereas control alumina was relatively pore-free. The elevated alumina-crystal phase transition temperatures and the formation of porous structure were ascribed to the presence of CNTs in alumina precursor. The composite alumina sintered at 900 °C for 2 h containing only γ-Al₂O₃ had a BET surface area of 138 m²/g, which was significantly higher than that of control alumina sintered at 1150 °C for 2 h containing only α-Al₂O₃, ~15 m²/g.     

Selective formation of light olefin by n-heptane cracking over HZSM-5 at high temperatures

The catalytic cracking of n-heptane has been performed over HZSM-5 catalysts with various Si/Al ratios at 723-923 K to form light olefins selectively. The HZSM-5 zeolites with various acid site densities exhibited almost the same selectivity at the same conversion. The ethylene + propylene selectivity increased, while the propylene/ethylene ratio decreased with an increase in reaction temperatures. It is found that a high temperature is required to obtain a high ethylene + propylene yield. The highest ethylene + propylene yield obtained in this study was 59.7 C-% with a propylene/ethylene ratio of ca. 0.72 at 99.6% conversion over HZSM-5 (Si/Al = 31) at 923 K. Moreover, it is concluded from the selectivities and activation energies that the monomolecular cracking is predominant at a high temperature as 923 K.     

Gasoline-range hydrocarbon synthesis over Co/SiO2/HZSM-5 catalyst with CO2-containing syngas

Selective synthesis of gasoline-range hydrocarbons (C₅-C₁₂) was investigated in a fixed-bed micro reactor using two series of CO₂-containing syngas with various mole CO₂/(CO + CO₂) and H₂/(CO + CO₂) ratios, where Fischer-Tropsch synthesis(FTS) and in situ hydrocracking/hydroisomerization were performed over bifunctional Co/SiO₂/HZSM-5 catalyst. CO₂ was converted at 0.15-0.55 of CO₂/(CO + CO₂) ratio under H₂-rich condition (H₂/(CO + CO₂) = 2.0), highest conversion of 20.3% at 0.42. Further increasing CO₂ content decreased CO₂ conversion and quite amount of CO₂ acted as diluting component. For the syngas with low H₂ content or H₂/(CO + CO₂) ratio(< 1.85, H₂/CO = 2.0), the competitive adsorption of CO, H₂ and CO₂ resulted in low CO, CO₂ and total carbon conversion, which was 57.9%, 12.7% and 31.4% respectively at 0.74 of H₂/(CO + CO₂) ratio(H₂/CO/CO₂/N₂ = 40.8/20.4/34.8/4). FTS results indicated that high H₂ content and proper H₂/(CO + CO₂) ratio were favorable for the conversion of CO₂-containing syngas. More than 45% selectivity to gasoline-range hydrocarbons including isoparaffins was obtained under the two series of syngas. It was also tested that the catalytic activity of Co/SiO₂/HZSM-5 kept stable under CO₂-containing syngas(< 7.5%). And the quick catalytic deactivation under high CO₂ containing syngas(H₂/CO/CO₂/N₂ = 45.3/23.2/27.1/3.06) was due to carbon deposition and pore blockage by heavy hydrocarbon, tested by thermal gravimetry, N₂ physisorption and scanning electron microscopy(SEM).     

XPS study of Li ion intercalation in V2O5 thin films prepared by thermal oxidation of vanadium metal

The intercalation and deintercalation mechanisms of lithium into V₂O₅ thin films prepared by thermal oxidation of vanadium metal have been studied by X-ray photoelectron spectroscopy (XPS) using a direct anaerobic and anhydrous transfer from the glove box (O₂ and H₂O < 1ppm), where the samples were electrochemically treated, to the XPS analysis chamber. Vanadium in the as-prepared oxide films is mostly (from 93 to 96% depending on samples) in a pentavalent state (V⁵⁺) with a stoichiometric O/V concentration ratio fitting that of V₂O₅. Four to seven percent of VO₂ is also observed. After the 1st and the 2nd intercalation steps at E = 3.3 and 2.8 V versus Li/Li⁺, respectively, the V2p core level spectra evidence a partial reduction to V⁴⁺ states with a remaining concentration of 73 and 56% of V⁵⁺, in agreement with the intercalation of about 1/2 mol of Li per V₂O₅ mol at each intercalation step. Intercalated lithium was observed at a binding energy of 56.1 eV for Li1s. Changes of the electronic structure of the V₂O₅ thin film after intercalation are evidenced by the observation, at a binding energy of 1.3 eV, of occupied V3d states (V⁴⁺) originally empty in the pristine film (V⁵⁺). The V2p and Li1s core level spectra show that the process of Li intercalation is partially irreversible. In the first cycle, 34 and 14% of the vanadium ions remain in the V⁴⁺ state after deintercalation at E = 3.4 and 3.8 V versus Li/Li⁺, respectively, indicating a partially irreversible process already after the 1st deintercalation. The analyses of C1s and O1s XP spectra show the formation of a solid-electrolyte interface (SEI). The analyzed surface layer includes lithium carbonate and Li-alkoxides.     

Hydrothermal dewatering of lower rank coals. 3. High-concentration slurries from hydrothermally treated lower rank coals

A novel method of producing a product of low intra-particle porosity (<1 μm pore radius) from highly porous Latrobe Valley raw brown coals uses a combination of hydrothermal and evaporative drying. Low porosity coal was made in three different batch autoclave systems at 320 °C for residence times as low as 10 min. Higher temperatures (up to 350 °C) increased porosity slightly but the water vapour pressure and the loss of organic material were significantly increased. Although the low and high porosity products differed dramatically in appearance and hardness, other chemical and spectroscopic properties were similar with the exception of pyrolysis-gas chromatography-mass spectrometry patterns.The relationship between intra-particle porosity and the maximum wt% dry solids concentration of aqueous slurries (for a viscosity of less than 1000 mPa s), ?_max, established by earlier workers for hydrothermally treated brown coals was found to hold for the new products and was extended to a wider range of porosities and a range of mean particle sizes (mps) (20-100 μm). A range of surfactants (anionic, cationic and neutral), which led to an increase of up to 7% in ?_max for a bituminous, Blair Athol coal, increased ?_max for products of hydrothermal or the new treatment by only 2-4%. This small increase resulted, however, in the formation of slurries of the low porosity products with ?_max's of up to 64%, similar to those obtained with high rank coals, and considered to be of commercial interest.     

Chemical and electrochemical syntheses of a graphite fluoro-tris(pentafluoroethyl)borate intercalation compound

Graphite intercalation compounds (GICs) of composition C_x[FB(C₂F₅)₃] · δF are prepared for the first time by the intercalation of fluoro-tris(pentafluoroethyl)borate anion, [FB(C₂F₅)₃]⁻_, under ambient conditions in 48% hydrofluoric acid containing the oxidant K₂[MnF₆]. Powder XRD data indicate that products are of mixed stages 2 and 3 after reactions for 1-20 h, with a gallery height of 0.87 nm. The intercalate orientation is modeled using an energy-minimized anion structure. Microwave digestion followed by B and F elemental analyses, along with thermogravimetric analyses provide compositional x and δ parameters for the GICs obtained. In addition, C_x[FB(C₂F₅)₃] · δCH₃NO₂ with stage 2 is prepared by electrochemical oxidation of graphite in a nitromethane solution and characterized as above.     

Application of electrochemical technology for removing petroleum hydrocarbons from produced water using a DSA-type anode at different flow rates

The anodic oxidation of organic pollutants from produced water generated by petroleum exploration of the Petrobras plant-Brazil was studied using a RuO₂-TiO₂-SnO₂ electrode. Under galvanostatic conditions (j = 89 mA cm⁻²), it was observed that the performance of the electrode material is influenced by flow rate as it was shown by GC analysis. It was found that the organic pollutants degradation, using different flow rates (0.25, 0.5, 0.8 and 1.3 dm⁻³ h), achieved distinct removal efficiencies (98%, 97%, 95% and 84% were achieved, respectively). Importantly, under the same conditions, RuO₂-TiO₂-SnO₂ showed poor degradation of phenol and ethyl benzene: 20-47% (at 0.25, 0.8 and 1.3 dm⁻³ h) and 17-47% (at 0.25, 0.5, 0.8 dm⁻³ h), respectively. Complete elimination of pollutants was obtained after 0.5-2.5 h of electrolysis. These data were discussed based on the energy and cost requirements for removing organic pollutants from produced water.