Characteristics and Properties of Absorption Materials for Mercury Removal at High Temperature

In this study, some metal-M/aluminum carbonate absorption materials with molar ratio of M:Al=3:1 were manufactured. There was Cu–Al, Mn–Al, Fe–Al three kinds of sorbents synthesized by co-precipitate method. The physicochemical structures during mercury removal were analyzed by a surface area and pore structure analyzer (BET), an X-ray diffraction (XRD), a scanning electron microscope coupled with an electron detection scanning (SEM/EDS), and X-ray fluorescence (XRF). The results showed that surface areas for metal-M/aluminum carbonate sorbents were only about 11~12 m2/g and the metal ratio loaded was more than 80%. Lab-scale tests mercury removal efficiency in the temperature range of 200–300 oC indicated that there was an improvement in the performance of mercury removal by increasing reaction temperature. Cu–Al, Fe–Al and Mn–Al all three sorbents reached their absorption equivalent of 256.6, 253.3 and 247.0 μg/g under 300 oC operating temperature and 19736 h-1 gas hourly space velocity. Additionally, the presence of transition metals can significantly improve the efficiency of mercury removal of the absorption materials.

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CO2 Methanation of Biogas over 20 wt% Ni-Mg-Al Catalyst: on the Effect of N2, CH4, and O2 on CO2 Conversion Rate

Catalysts ◽

10.3390/catal10101201 ◽

2020 ◽

Vol 10 (10) ◽

pp. 1201

Author(s):

Danbee Han ◽

Yunji Kim ◽

Hyunseung Byun ◽

Wonjun Cho ◽

Youngsoon Baek

Keyword(s):

Reaction Temperature ◽

Photoelectron Spectroscopy ◽

Conversion Rate ◽

Space Velocity ◽

Molar Ratio ◽

Co2 Conversion ◽

X Ray Diffraction ◽

Co2 Methanation ◽

X Ray ◽

Ch4 Production

Biogas contains more than 40% CO2 that can be removed to produce high quality CH4. Recently, CH4 production from CO2 methanation has been reported in several studies. In this study, CO2 methanation of biogas was performed over a 20 wt% Ni-Mg-Al catalyst, and the effects of CO2 conversion rate and CH4 selectivity were investigated as a function of CH4, O2, H2O, and N2 compositions of the biogas. At a gas hourly space velocity (GHSV) of 30,000 h−1, the CO2 conversion rate was ~79.3% with a CH4 selectivity of 95%. In addition, the effects of the reaction temperature (200–450 °C), GHSV (21,000–50,000 h−1), and H2/CO2 molar ratio (3–5) on the CO2 conversion rate and CH4 selectivity over the 20 wt% Ni-Mg-Al catalyst were evaluated. The characteristics of the catalyst were analyzed using Brunauer–Emmett–Teller surface area analysis, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The catalyst was stable for approximately 200 h at a GHSV of 30,000 h−1 and a reaction temperature of 350 °C. CO2 conversion and CH4 selectivity were maintained at 75% and 93%, respectively, and the catalyst was therefore concluded to exhibit stable activity.

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Total Oxidation of Toluene and Propane over Co3O4 Catalysts: Influence of Precipitating pH and Washing

Catalysts ◽

10.3390/catal10080900 ◽

2020 ◽

Vol 10 (8) ◽

pp. 900

Author(s):

Imane Driouch ◽

Weidong Zhang ◽

Michèle Heitz ◽

Jose Luis Valverde ◽

Anne Giroir-Fendler

Keyword(s):

Spinel Phase ◽

Space Velocity ◽

Catalytic Performance ◽

Precipitation Method ◽

Molar Ratio ◽

X Ray Diffraction ◽

Total Oxidation ◽

Ph Values ◽

Surface Areas ◽

Weight Hourly Space Velocity

A series of Co3O4 catalysts were synthesized by an ammonia precipitation method at various precipitating pH values (8.0, 8.5, 9.0, 9.5, and 10.0) and with different numbers of washings. Their performance in the total oxidation of two selected hydrocarbons, toluene and propane, was evaluated at a reactant/oxygen molar ratio of 1/210 and a Weight Hourly Space Velocity (WHSV) of 40,000 mL g−1 h−1. The physicochemical properties of the catalysts were characterized by thermogravimetric and differential thermal analysis (TG/DTA), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and N2 absorption–desorption. The results show that the catalysts are in the cubic spinel phase (Fd-3m (227), a = 8.0840 Å) with average crystalline sizes of 29−40 nm and specific surface areas of 12–20 m2 g−1. All catalysts allowed 100% conversion of both toluene and propane at temperatures below 350 °C. The precipitating pH and the number of washings were observed to significantly affect the catalytic performance. The optimal synthesis condition was established to be pH 8.5 with two washings. The best catalyst gave 100% conversion of toluene and propane at 306 °C and 268 °C, respectively.

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Effect of Hydrated Metal Salts on the Coordination Product of Cobalt(II) halide and PNP Type Ligand, 2,6-bis(di-tertbutylphosphinomethyl) pyridine

10.26434/chemrxiv.5851701 ◽

2018 ◽

Author(s):

Tasneem Siddiquee ◽

Abdul Goni

Keyword(s):

Metal Salts ◽

Molar Ratio ◽

Pincer Complexes ◽

Asymmetric Unit ◽

X Ray Diffraction ◽

Pincer Ligand ◽

Tetrahedral Geometry ◽

X Ray ◽

Distorted Tetrahedral Geometry ◽

Cobalt Center

Chemical treatment of CoX2. 6H2O (X = Cl, Br, I) with the potentially tridentate PNP pincer ligand 2,6-bis(di-tert-butylphosphinomethyl)pyridine in 1:1 molar ratio results in cobalt(II) halide-PNP pincer complexes. The effect of the hydrated metal source on molecular structure and geometry of the complexes was studied by single crystal X-ray diffraction analysis. The complexes are neutral and the cobalt center adopts a penta-coordinate system with potential atropisomerization. Within the unit cell there are two distinct molecules per asymmetric unit. One of the two phosphorus atoms in the PNP ligand was observed to be partially oxidized to phosphinoxide. Disorder in the structure reflects a mixture of square pyramidal and distorted tetrahedral geometry.

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Photocatalytic Reduction of CO2 to Methanol Using a Copper-Zirconia Imidazolate Framework

Catalysts ◽

10.3390/catal11030346 ◽

2021 ◽

Vol 11 (3) ◽

pp. 346

Author(s):

Sonam Goyal ◽

Maizatul Shima Shaharun ◽

Ganaga Suriya Jayabal ◽

Chong Fai Kait ◽

Bawadi Abdullah ◽

...

Keyword(s):

Photoelectron Spectroscopy ◽

Catalyst Support ◽

Oxidation Potential ◽

Molar Ratio ◽

X Ray Diffraction ◽

X Ray ◽

Molar Ratios ◽

Optimum Parameters ◽

Reduction Of Co2 ◽

Enhanced Yield

A set of novel photocatalysts, i.e., copper-zirconia imidazolate (CuZrIm) frameworks, were synthesized using different zirconia molar ratios (i.e., 0.5, 1, and 1.5 mmol). The photoreduction process of CO2 to methanol in a continuous-flow stirred photoreactor at pressure and temperature of 1 atm and 25 °C, respectively, was studied. The physicochemical properties of the synthesized catalysts were studied using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL) spectroscopy. The highest methanol activity of 818.59 µmol/L.g was recorded when the CuZrIm1 catalyst with Cu/Zr/Im/NH4OH molar ratio of 2:1:4:2 (mmol/mmol/mmol/M) was employed. The enhanced yield is attributed to the presence of Cu2+ oxidation state and the uniformly dispersed active metals. The response surface methodology (RSM) was used to optimize the reaction parameters. The predicted results agreed well with the experimental ones with the correlation coefficient (R2) of 0.99. The optimization results showed that the highest methanol activity of 1054 µmol/L.g was recorded when the optimum parameters were employed, i.e., stirring rate (540 rpm), intensity of light (275 W/m2) and photocatalyst loading (1.3 g/L). The redox potential value for the CuZrIm1 shows that the reduction potential is −1.70 V and the oxidation potential is +1.28 V for the photoreduction of CO2 to methanol. The current work has established the potential utilization of the imidazolate framework as catalyst support for the photoreduction of CO2 to methanol.

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Application of vermiculite and limestone to desulphurization and to the removal of dust during briquette combustion

Mineralogical Magazine ◽

10.1180/0026461036760162 ◽

2003 ◽

Vol 67 (6) ◽

pp. 1243-1251 ◽

Cited By ~ 4

Author(s):

A. Lu ◽

D. Zhao ◽

J. Li ◽

C. Wang ◽

S. Qin

Keyword(s):

Electron Microscopy ◽

Coal Combustion ◽

Combustion Temperature ◽

Molar Ratio ◽

X Ray Diffraction ◽

Retention Ratio ◽

X Ray ◽

Major Factors ◽

Chemical Reactant ◽

Scanning Electron

AbstractSmall domestic cooking furnaces are widely used in China. These cooking furnaces release SO2 gas and dust into the atmosphere and cause serious air pollution. Experiments were conducted to investigate the effects of vermiculite, limestone or CaCO3, and combustion temperature and time on desulphurization and dust removal during briquette combustion in small domestic cooking furnaces. Additives used in the coal are vermiculite, CaCO3 and bentonite. Vermiculite is used for its expansion property to improve the contact between CaCO3 and SO2 and to convey O2 into the interior of briquette; CaCO3 is used as a chemical reactant to react with SO2 to form CaSO4; and bentonite is used to develop briquette strength. Expansion of vermiculite develops loose interior structures, such as pores or cracks, inside the briquette, and thus brings enough oxygen for combustion and sulphation reaction. Effective combustion of the original carbon reduces amounts of dust in the fly ash. X-ray diffraction, optical microscopy, and scanning electron microscopy with energy dispersive X-ray analysis show that S exists in the ash only as anhydrite CaSO4, a product of SO2 reacting with CaCO3 and O2. The formation of CaSO4 effectively reduces or eliminates SO2 emission from coal combustion. The major factors controlling S retention are vermiculite, CaCO3 and combustion temperature. The S retention ratio increases with increasing vermiculite amount at 950°C. The S retention ratio also increases with increasing Ca/S molar ratio, and the best Ca/S ratio is 2-3 for most combustion. With 12 g of the original coal, 1 to 2 g of vermiculite, a molar Ca/S ratio of 2.55 by adding CaCO3, and some bentonite, a S retention ratio >65% can be readily achieved. The highest S retention ratio of 97.9% is achieved at 950°C with addition of 2 g of vermiculite, a Ca/S ratio of 2.55 and bentonite.

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Microporous Materials Based on Norbornadiene-Based Cross-Linked Polymers

Polymers ◽

10.3390/polym10121382 ◽

2018 ◽

Vol 10 (12) ◽

pp. 1382 ◽

Cited By ~ 8

Author(s):

Dmitry Alentiev ◽

Dariya Dzhaparidze ◽

Natalia Gavrilova ◽

Victor Shantarovich ◽

Elena Kiseleva ◽

...

Keyword(s):

Pore Volume ◽

Total Pore Volume ◽

Amorphous Polymers ◽

Co2 Uptake ◽

Wide Angle ◽

X Ray Diffraction ◽

Pd Catalysts ◽

X Ray ◽

Positron Annihilation Lifetime ◽

Surface Areas

New microporous homopolymers were readily prepared from norbornadiene-2,5, its dimer and trimer by addition (vinyl) polymerization of the corresponding monomers with 60–98% yields. As a catalyst Pd-N-heterocyclic carbene complex or Ni(II) 2-ethylhexanoate activated with Na+[B(3,5-(CF3)2C6H3)4]− or methylaluminoxane was used. The synthesized polynorbornenes are cross-linked and insoluble. They are glassy and amorphous polymers. Depending on the nature of the catalyst applied, BET surface areas were in the range of 420–970 m2/g. The polymers with the highest surface area were obtained in the presence of Pd-catalysts from the trimer of norbornadiene-2,5. The total pore volume of the polymers varies from 0.39 to 0.79 cm3/g, while the true volume of micropores was 0.14–0.16 cm3/g according to t-plot. These polymers gave CO2 uptake from 1.2 to 1.9 mmol/g at 273 K and 1 atm. The porous structure of new polymers was also studied by means of wide-angle X-ray diffraction and positron annihilation lifetime spectroscopy.

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Synthese und Kristallstrukturen einiger Tetramethylstibonium-Hydrogendicarboxylate / Synthesis and Crystal Structures of Some Tetramethylstibonium Hydrogendicarboxylates

Zeitschrift für Naturforschung B ◽

10.1515/znb-1982-1106 ◽

1982 ◽

Vol 37 (11) ◽

pp. 1393-1401 ◽

Cited By ~ 12

Author(s):

Beatrix Milewski-Mahrla ◽

Hubert Schmidbaur

Keyword(s):

Hydrogen Bonds ◽

Crystal Structures ◽

Spectroscopic Data ◽

Molar Ratio ◽

Ionic Structure ◽

X Ray Diffraction ◽

X Ray ◽

Carboxylate Oxygen ◽

Donor Acceptor ◽

New Compounds

Reactions of pentamethylantimony (CH3)5Sb with carboxylic acids in the molar ratio 1:2 afford one equivalent of methane and essentially quantitative yields of crystalline tetramothylstibonium hydrogendicarboxylates. Six new compounds of this series have been synthesized using benzoic, o-phthalic, salicylic, 4-ethoxy-salicylic, oxalic, and malic acid, and characterized by analytical and spectroscopic data. An ionic structure with strong hydrogen bonds in the anionic components is proposed.The crystal structures of the hydrogen-dibenzoato (1), hydrogen-ortho-plithalato (2) and 4-ethoxy-hydrogen-salicylate (3) were determined by single crystal X-ray diffraction. The compounds can be described as having ionic lattices with some donor-acceptor interactions between the stibonium centers and the carboxylate oxygen atoms. The anions are characterized by strong hydrogen bonds O...H...O. Thus, the (CH3)4Sb-tetrahedron in 1 is distorted by two benzoate oxygon atoms (at 304(2) and 340(2) pin). The cation in 2 is largely undistorted and the anion has a hydrogenphthalate hydrogen bond of d(O...H...O) = 232 pm. The cation-anion contact in 3 is as short as d(Sb-O) = 289 pm rendering the Sb atom pentacoordinate.

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Controlled Synthesis of Different Morphologies of SrWO4 Crystals via a Surfactant-Assisted Hydrothermal Precipitation Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.785-786.449 ◽

2013 ◽

Vol 785-786 ◽

pp. 449-454

Author(s):

Yan Zhao ◽

Chun Yan Wu ◽

Dan Qin ◽

Xin Lai ◽

Si Wu ◽

...

Keyword(s):

Ph Value ◽

Precipitation Method ◽

Molar Ratio ◽

X Ray Diffraction ◽

X Ray ◽

Experimental Parameters ◽

Infrared Spectrometer ◽

Luminescent Spectra ◽

Hydrothermal Precipitation ◽

Surfactant Assisted

SrWO4 octahedrons, flowers, bundles, ellipsoids and dendrites had been successfully synthesized via surfactant-assisted method. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photo-luminescent spectra techniques (PL) and fourier transrform infrared spectrometer (FTIR). By through various comparison experiments, it can be found that some related experimental parameters including the reagent concentration, [Sr2+]/[WO42-] molar ratio (R), aging temperature and the pH value had great influences on morphology of the products.

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Pengaruh Suhu dan Konsentrasi terhadap Proses Pemisahan Nikel dari Logam Pengotor Menggunakan Metode Leaching

FLUIDA ◽

10.35313/fluida.v13i2.2388 ◽

2020 ◽

Vol 13 (2) ◽

pp. 81-92

Author(s):

Ade Yanti Nurfaidah ◽

Dheana Putri Lestari ◽

Rheisya Talitha Azzahra ◽

Dian Ratna Suminar

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Sulfuric Acid ◽

Atmospheric Pressure ◽

Operating Temperature ◽

Acid Leaching ◽

X Ray Diffraction ◽

X Ray ◽

Pressure Acid Leaching ◽

Scanning Electron

Abstrak Nikel merupakan unsur logam yang penggunaannya sudah dikenal dalam industri, terutama pada pelapisan logam dan paduan. Pengolahan nikel dari bijih nikel laterit (jenis Limonit) menggunakan proses hidrometalurgi Atmospheric Pressure Acid Leaching (APAL) yang dinilai lebih ekonomis karena pemakaian energi dan biaya operasional cukup rendah. Media pelarut yang digunakan berupa larutan asam sulfat (H2SO4). Sebelum dilakukan pengolahan, karakterisasi bijih dilakukan menggunakan X-Ray Diffraction (XRD), X-Ray Flourscence (XRF), dan Scanning Electron Microscopy (SEM). Metode penelitian yang dilakukan yaitu literature review. Hasil review dari beberapa artikel jurnal menunjukkan bahwa kadar nikel yang terkandung pada suatu bijih sekitar 1,42%, 2,94 dan 0,95% serta sisanya adalah pengotor. Kondisi operasi yang tepat akan menghasilkan pemurnian nikel yang cukup tinggi. Parameter kondisi operasi yang dapat memengaruhi proses pemisahan nikel diantaranya suhu operasi yang ditunjukan dengan semakin meningkatnya % ekstraksi nikel seiring dengan kenaikan suhu. Selain suhu operasi, konsentrasi pelarut juga salah satu parameter yang mempengaruhi % ekstraksi karena semakin tinggi ion H+ akan memudahkan proses pelarutan sehingga akan mengikat Nikel Oksida yang terdapat pada bijih. Suhu paling optimal untuk menghasilkan nikel dengan kemurnian tinggi dalam operasi pelindian atmosferik adalah 90°C dan konsentrasi asam sulfat 5 M. Kata Kunci: Nikel, pelindian, suhu, konsentrasi Abstract Nickel is a metal element whose use is well known in industry, especially in metal and alloy plating. The processing of nickel from laterite nickel ore (Limonite type) uses a hydrometallurgical process of Atmospheric Pressure Acid Leaching (APAL) which is considered more economical because energy consumption and operational costs are quite low. The solvent medium used is a solution of sulfuric acid (H2SO4). Prior to processing, ore characterization was carried out using X-Ray Diffraction (XRD), X-Ray Flourscence (XRF), and Scanning Electron Microscopy (SEM). The research method literature review article. The results of reviews from several journal articles show that the nickel content contained in an ore is around 1.42%, 2.94% and 0.95% and the rest is impurity. The right operating conditions will result in relatively high nickel refining. The operating condition parameters that can affect the nickel separation process include the operating temperature which is indicated by the increasing % nickel extraction along with the increase in temperature. In addition to operating temperature, solvent concentration is also one of the parameters that affects the% extraction because the higher the H+ ion will facilitate the dissolving process so that it will bind to the Nickel Oxide contained in the ore. The optimal temperature to produce high-purity nickel in atmospheric leaching operations is 90°C and a sulfuric acid concentration of 5 M. Keywords: Nickel, leaching, temperature, concentration

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Effect of Mg/Al molar ratio on the basicity of Mg-Al mixed oxide derived from Mg-Al hydrotalcite

Mediterranean Journal of Chemistry ◽

10.13171/mjc10602007021464sa ◽

2020 ◽

Vol 10 (6) ◽

pp. 625

Author(s):

Said Arhzaf ◽

Mohammed Naciri Bennani ◽

Sadik Abouarnadasse ◽

Hamid Ziyat ◽

Omar Qabaqous

Keyword(s):

Thermal Analysis ◽

Mixed Oxide ◽

Mixed Oxides ◽

Molar Ratio ◽

Acid Molecule ◽

X Ray Diffraction ◽

Phenol Adsorption ◽

X Ray ◽

Maximum Quantity ◽

Uv Visible

The fundamental character of the Mg-Al mixed oxide (Mgn(Al)O), derived from the Mg-Al hydrotalcite (MgnAl-CO3-HT), where n corresponds to the Mg/Al molar ratio (n: 2, 2.5, 3, 3.5 and 4), was studied by using the adsorption of phenol as a probe acid molecule. The hydrotalcite precursors were prepared by the coprecipitation method. Their derived mixed oxides were obtained by thermal treatment at 450°C in a flow of air. The resulting solids were characterized by X-ray fluorescence spectroscopy (XRF), X-ray diffraction (XRD), infrared spectroscopy (FTIR), thermogravimetric and differential thermal analysis (TG-DTA), nitrogen physisorption (BET) and phenol chemisorption. The phenol adsorption followed by UV-Visible spectrophotometry shows that the basicity increases with the Mg/Al molar ratio, such that maximum quantity of phenol adsorbed (Qads = 0.54 mmol/g cat) was obtained with the mixed oxide derived from the Mg-Al hydrotalcite of Mg/Al molar ratio equal to 3.5.

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