Cs-P Oxide Catalysts for Aldol Condensation to Produce Methyl Acrylate

2015 ◽  
Vol 1104 ◽  
pp. 51-56 ◽  
Author(s):  
Shi Feng Jiang ◽  
Zhen Qiu Li ◽  
Hong Nan Chen ◽  
Er Qiang Wang
Keyword(s):  
Methyl Acrylate ◽  
Circulating Fluidized Bed ◽  
Aldol Condensation ◽  
Theoretical Calculations ◽  
High Surface ◽  
High Surface Area ◽  
Fixed Bed ◽  
Catalyst Particle ◽  
Raw Material ◽  
Cold Model

In this research, methyl acrylate has been synthesized from industrial raw material methyl acetate through highly efficient and eco-friendly method, One-step aldol condensation, using acid-base bifunctional catalyst Cs, P and K as catalysts. Carbon deposits and other issues led to the catalysts deactivation in the process of fixed bed, which led to the production interruption. While, the process of circulating fluidized bed can overcome this defect and the catalyst can maintain good catalytic activity in the whole process. Cs (8%), P (5%), K (2%)/γ-Al2O3/ catalyst showed better performance due to its high surface area and more weak basicity and acidity. In addition, theoretical calculations and cold model experiments were also conducted in this work to determine the catalyst particle size，operation gas velocity and gas distributor plate.

scholarly journals Design Considerations for Borehole Thermal Energy Storage (BTES): A Review with Emphasis on Convective Heat Transfer

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-26 ◽  
Author(s):  
Helge Skarphagen ◽  
David Banks ◽  
Bjørn S. Frengstad ◽  
Harald Gether
Keyword(s):  
Energy Storage ◽  
Thermal Energy ◽  
Thermal Energy Storage ◽  
Theoretical Calculations ◽  
High Surface ◽  
High Surface Area ◽  
Volume Ratio ◽  
Thermal Recovery ◽  
Conductive Heat ◽  
Geological Environment

Borehole thermal energy storage (BTES) exploits the high volumetric heat capacity of rock-forming minerals and pore water to store large quantities of heat (or cold) on a seasonal basis in the geological environment. The BTES is a volume of rock or sediment accessed via an array of borehole heat exchangers (BHE). Even well-designed BTES arrays will lose a significant quantity of heat to the adjacent and subjacent rocks/sediments and to the surface; both theoretical calculations and empirical observations suggest that seasonal thermal recovery factors in excess of 50% are difficult to obtain. Storage efficiency may be dramatically reduced in cases where (i) natural groundwater advection through the BTES removes stored heat, (ii) extensive free convection cells (thermosiphons) are allowed to form, and (iii) poor BTES design results in a high surface area/volume ratio of the array shape, allowing high conductive heat losses. The most efficient array shape will typically be a cylinder with similar dimensions of diameter and depth, preferably with an insulated top surface. Despite the potential for moderate thermal recovery, the sheer volume of thermal storage that the natural geological environment offers can still make BTES a very attractive strategy for seasonal thermal energy storage within a “smart” district heat network, especially when coupled with more efficient surficial engineered dynamic thermal energy stores (DTES).

scholarly journals Diatoms - nature materials with great potential for bioapplications

2016 ◽  
Vol 70 (6) ◽  
pp. 613-627 ◽  
Author(s):  
Djordje Medarevic ◽  
Dusan Losic ◽  
Svetlana Ibric
Keyword(s):  
Drug Delivery ◽  
Gas Sensing ◽  
High Surface ◽  
High Surface Area ◽  
Raw Material ◽  
Nanoporous Structure ◽  
Mechanical Resistance ◽  
Diatom Frustule ◽  
Wide Availability ◽  
Made In

Diatoms are widespread unicellular photosynthetic algae that produce unique highly ordered siliceous cell wall, called frustule. Micro- to nanoporous structure with high surface area that can be easily modified, high mechanical resistance, unique optical features (light focusing and luminescence) and biocompatibility make diatom frustule as a suitable raw material for the development of devices such as bio- and gas sensors, microfluidic particle sorting devices, supercapacitors, batteries, solar cells, electroluminescent devices and drug delivery systems. Their wide availability in the form of fossil remains (diatomite or diatomaceous earth) as well as easy cultivation in the artificial conditions further supports use of diatoms in many different fields of application. This review focused on the recent achievements in the diatom bioapplications such as drug delivery, biomolecules immobilization, bio- and gas sensing, since great progress was made in this field over the last several years.

Synthesis and Characterization of Supercapacitor Electrode from Fiber of Borassus flabelifer L by Activation Method

2019 ◽  
Vol 966 ◽  
pp. 444-450 ◽  
Author(s):  
Fandi Angga Prasetya ◽  
Ufafa Anggarini ◽  
Yudha Zakaria ◽  
Rosa Dwi Sasqia Putri
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Raw Material ◽  
High Porosity ◽  
Supercapacitor Electrode ◽  
Nitrogen Gas ◽  
Reduced Graphene ◽  
Higher Temperature ◽  
Constant Heating

Supercapacitor require electrode which has high surface area so that it able to store large amounts of charge. In this study, electrode was synthesized from carbon of Borassus Flabellifer L fiber which was carried out through activation and carbonization processes. Raw material was calcined at 400°C for 4 hours followed by activation with NaOH 1 M. The carbonization was then conducted in Nitrogen gas flowing by temperature variations; 650°C, 750°C, and 850°C with a constant heating rate of 20 °C/min. Based on XRD data, it was shown that the material has formed Reduced graphene Oxide (RGO) which has main peaks at (2θ) 240 and 440 with higher purity in higher temperature. SEM results clarified more pores formation at higher temperature which is mesoporous. Cyclic Voltammetry (CV) test was done to determine the capacitance value. By RGO forming with high porosity, it is suitable for supercapacitor electrode application and CV test has examined that heating of Borassus Flabelifer L fiber at 850°C with 5 mV/s scan rate has the highest specific capacitance by 8.25 F/gram with Energy density is 4.125 watt/gram.

scholarly journals Effect of Microwave Heating Conditions on the Preparation of High Surface Area Activated Carbon from Waste Bamboo

2015 ◽  
Vol 34 (7) ◽  
pp. 667-674
Author(s):  
Jian Wu ◽  
Hongying Xia ◽  
Libo Zhang ◽  
Yi Xia ◽  
Jinhui Peng ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Microwave Heating ◽  
Surface Area ◽  
Microwave Power ◽  
High Surface ◽  
High Surface Area ◽  
Significant Proportion ◽  
Heating Time ◽  
Raw Material ◽  
Carbon Surface

Abstract The present study reports the effect of microwave power and microwave heating time on activated carbon adsorption ability. The waste bamboo was used to preparing high surface area activated carbon via microwave heating. The bamboo was carbonized for 2 h at 600°C to be used as the raw material. According to the results, microwave power and microwave heating time had a significant impact on the activating effect. The optimal KOH/C ratio of 4 was identified when microwave power and microwave heating time were 700 W and 15 min, respectively. Under the optimal conditions, surface area was estimated to be 3441 m2/g with pore volume of 2.093 ml/g and the significant proportion of activated carbon was microporous (62.3%). The results of Fourier transform infrared spectroscopy (FTIR) were illustrated that activated carbon surface had abundant functional groups. Additionally the pore structure is characterized using Scanning Electron Microscope (SEM).

scholarly journals Synthesis of activated carbon from biowaste of fir bark for methylene blue removal

2019 ◽  
Vol 6 (9) ◽  
pp. 190523 ◽  
Author(s):  
Lu Luo ◽  
Xi Wu ◽  
Zeliang Li ◽  
Yalan Zhou ◽  
Tingting Chen ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Activated Carbon ◽  
Nonlinear Models ◽  
Low Cost ◽  
High Surface ◽  
High Surface Area ◽  
Raw Material ◽  
Maximum Adsorption Capacity ◽  
Koh Activation ◽  
Mb Adsorption

Activated carbon (AC) was successfully prepared from low-cost forestry fir bark (FB) waste using KOH activation method. Morphology and texture properties of ACFB were studied by scanning and high-resolution transmission electron microscopies (SEM and HRTEM), respectively. The resulting fir bark-based activated carbon (ACFB) demonstrated high surface area (1552 m 2 g −1 ) and pore volume (0.84 cm 3 g −1 ), both of which reflect excellent potential adsorption properties of ACFB towards methylene blue (MB). The effect of various factors, such as pH, initial concentration, adsorbent content as well as adsorption duration, was studied individually. Adsorption isotherms of MB were fitted using all three nonlinear models (Freundlich, Langmuir and Tempkin). The best fitting of MB adsorption results was obtained using Freundlich and Temkin. Experimental results showed that kinetics of MB adsorption by our ACFB adsorbent followed pseudo-second-order model. The maximum adsorption capacity obtained was 330 mg g −1 , which indicated that FB is an excellent raw material for low-cost production of AC suitable for cationic dye removal.

Intrinsic kinetics for fixed bed bioreactor in hospital wastewater treatment

2016 ◽  
Vol 74 (8) ◽  
pp. 1992-1998 ◽  
Author(s):  
Mehrdad Farrokhi ◽  
Mostafa Mahdavianpour ◽  
Mehdi Shirzad-Siboni ◽  
Mohammad Naimi-Joubani ◽  
Hamzeh Ali Jamali
Keyword(s):  
Municipal Wastewater ◽  
High Surface ◽  
High Surface Area ◽  
Fixed Bed ◽  
Oxygen Demand ◽  
Hospital Wastewater ◽  
Rice Husks ◽  
Kinetics Parameters ◽  
Fixed Media ◽  
Fixed Bed Bioreactor

Variation in hospital wastewater (HWW) pollutants and differences with municipal wastewater (MWW), make the use of biokinetic coefficients obtained from activated sludge in the MWW treatment unprofitable for designing, modeling and evaluation of biological processes for HWW treatment. Since this study was conducted to evaluate the performance and biokinetic coefficients of a fixed bed bioreactor (FBBR) using rice husks as fixed media in HWW treatment, a new modified method was also proposed for biokinetic estimation in FBBR processes. For these purposes, five hydraulic retention times along with five sludge retention times were introduced to a pilot setup and the required data were attained. The performance process for chemical oxygen demand (COD) removal was significant (87.8–97.5%) in different conditions. The values of biokinetic coefficients k, Ks, Y and Kd were obtained as 2.42 (day−1), 55.5 (mgCOD/L), 0.2929 (mgBiomass/mgCOD) and 0.0164 (day−1), respectively. The rice husks with high surface area and high affinity for biomass accumulation on its surface are promising media for a green and environmentally friendly FBBR process. The kinetics parameters values are utilizable for modeling of FBBR using rice husks as fixed media in HWW treatment.

COx Free Hydrogen Production From Ammonia Decomposition Over Platinum Based Siliceous Materials

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Dilek Varisli ◽  
Tugba Rona
Keyword(s):  
Flow Reactor ◽  
High Surface ◽  
High Surface Area ◽  
Fixed Bed ◽  
Space Velocity ◽  
Decomposition Reaction ◽  
Ammonia Decomposition ◽  
One Pot ◽  
Free Hydrogen ◽  
Synthesis Procedure

Abstract Ammonia has become an important source for hydrogen especially for fuel cell applications that require COx free hydrogen. In this study, high surface area Pt incorporated mesoporous siliceous materials were prepared for ammonia decomposition reaction to produce clean hydrogen. The results of a fixed bed flow reactor tests, conducted using pure ammonia showed that Pt-SiO2 type catalysts which were prepared by a one-pot hydrothermal synthesis procedure were very active in ammonia decomposition, such as 72% conversion was reached at 500°C at a gas hourly space velocity of 5,100 ml/h.gcat over the catalyst prepared at Pt/Si mol ratio of 0.03. Activity of the synthesized catalysts increased with an increase in Pt loading. Platinum incorporated siliceous materials prepared by impregnation procedures were also tested in ammonia decomposition and highly promising results were obtained.

scholarly journals Effective Elimination of Contaminant Antibiotics Using High-Surface-Area Magnetic-Functionalized Graphene Nanocomposites Developed from Plastic Waste

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1517 ◽  
Author(s):  
Noha A. Elessawy ◽  
M. H. Gouda ◽  
Safaa M. Ali ◽  
M. Salerno ◽  
M. S. Mohy Eldin
Keyword(s):  
Adsorption Process ◽  
High Surface ◽  
High Surface Area ◽  
Functional Materials ◽  
Raw Material ◽  
Resistant Bacteria ◽  
Antibiotic Resistant ◽  
Graphene Nanocomposites ◽  
Sulfonated Graphene ◽  
Living Organisms

The presence of pharmaceutical residues in aquatic environments represents a risk for the equilibrium of the ecosystem and may seriously affect human safety itself in the long term. To address this issue, we have synthesized functional materials based on highly-reduced graphene oxide (HRGO), sulfonated graphene (SG), and magnetic sulfonated graphene (MSG). The method of synthesis adopted is simple and inexpensive and makes use of plastic bottle waste as the raw material. We have tested the fabricated materials for their adsorption efficiency against two model antibiotics in aqueous solutions, namely Garamycin and Ampicillin. Our tests involved the optimization of different experimental parameters of the adsorption process, such as starting antibiotic concentration, amount of adsorbent, and time. Finally, we characterized the effect of the antibiotic adsorption process on common living organisms, namely Escherichia coli DH5α (E. coli DH5α) bacteria. The results obtained demonstrate the efficiency of the method in addressing the issue of the emergence of antibiotic-resistant bacteria, which will help in preventing changes in the ecosystem.

An overview of the obtaining of biomass-derived gamma-valerolactone from levulinic acid or esters without H2 supply

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 8417-8444
Author(s):  
Giselle González ◽  
María C. Area
Keyword(s):  
Levulinic Acid ◽  
High Pressures ◽  
High Surface ◽  
High Surface Area ◽  
Transfer Hydrogenation ◽  
Raw Material ◽  
Secondary Alcohols ◽  
Hydrogen Donors ◽  
Subsequent Cyclization ◽  
Catalytic Transfer

Gamma-valerolactone (GVL) is a highly reactive keto-lactone and a promising platform biomolecule, used as an additive for food and fuels, green solvent, and fuels precursor, among others. Its production from biomass usually involves hydrogenation and subsequent cyclization of levulinic acid or its esters. The process of conventional hydrogenation requires high pressures and temperatures, an external hydrogen source, and scarce noble/precious materials as catalysts. However, it could be produced under mild conditions, using bifunctional metal-acid catalysts with high metal dispersion and meso or microporosity, high surface area, temperatures lower than 200 °C, pressures ≤ 1MPa, and secondary alcohols (such as isopropanol) as hydrogen donors. The catalytic transfer hydrogenation followed by cyclization (CTHC) of levulinic acid (LA) and its esters (LE) to produce GVL using secondary alcohols as H donor is a great alternative. Variables involved in CTHC such as raw material, time, temperature, and type of catalyst, mainly transition metals and their combinations, are reviewed in this work.

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