Preparation of nanoporous activated carbon and its application as nano adsorbent for CO2 storage

Alimorad Rashidi,Davood Kazemi,Nosrat Izadi,Mahnaz Pourkhalil,Abbas Jorsaraei,Enseyeh Ganji,Roghayeh Lotfi 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.2

Nanoporous activated carbons, as adsorbent for CO2 storage, were prepared from walnut shells via two chemical processes including phosphoric acid treatment and KOH activation at high temperature. Specific surface area and porosities were controlled by KOH concentration and activation temperature. The obtained adsorbents were characterized by N2 adsorption at 77.3 K. Their carbon dioxide adsorption capacities were measured at different pressures at 290 K by using volumetric adsorption equipment. The KOH-treated nanoporous carbons typically led to the production of high specific surface areas and high micropore volumes and showed better performance for CO2 adsorptions. The maximum experimental value for adsorption capacity happened when pressure increased from 5 to 10 bar (1.861- 2.873mmol·g−1). It was found that in order to improve the highest capacity of CO2 adsorption for KOH-modified carbon (9.830-18.208mmol·g−1), a KOH: C weight ratio of 3.5 and activation temperature of 973 K were more suitable for pore development and micro-mesopore volume enhancement.

N-doped reduced graphene oxide aerogel for the selective adsorption of oil pollutants from water: Isotherm and kinetic study

Zahra Rahmani,Alimorad Rashidi,Abbass kazemi,Mohhammad Taghi Samadi,Ali Reza Rahmani 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.61 No.-

N-doped graphene aerogel with a 3D inter-connected network was synthesized using graphene oxide and pyrrole in an aqueous medium with ammonia. Hydrothermal and thermal annealing methods were employed to do it so. The structure and surface properties of the synthesized aerogel were characterized using Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffraction (XRD), Raman spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM), XPS, and nitrogen adsorption/desorption measurements. The prepared n-doped aerogel exhibited elevated specific surface area (340 m2/g), hydrophobic nature, and excellent adsorption capacity (210 g/g for crude oil removal). Adsorbent recyclability was also investigated; it is worth noting that after ten subsequent cycles, only just a negligible decrement in adsorption capacity was observed. Furthermore, the effect of salts and temperature on adsorption capacity was studied. Isotherm and kinetic studies were last examined. The conformity of various adsorption models, including Freundlich, Langmuir, Temkin, and Dubinin–Radushkevich (D–R) to the equilibrium data was evaluated among which Langmuir isotherm model gave the best fitting result. The sorption kinetics data were well described by the pseudo-second-order kinetic model. As a consequence, oil spills adsorption using n-doped graphene aerogel is a relatively cost-effective method which can be scaled up, and it could be a promising material for removal of organic contaminants from water.

Particle size control effect on activity and selectivity of functionalized CNT-supported cobalt catalyst in Fischer-Tropsch synthesis

Ali Karimi,Bahram Nasernejad,Alimorad Rashidi 한국화학공학회 2012 Korean Journal of Chemical Engineering Vol.29 No.11

The influence of cobalt particle size on catalyst performance in Fischer-Tropsch synthesis (FTS) has been investigated using functionalized carbon nanotube (CNT)-supported nano catalyst. The catalysts were synthesized by wet impregnation and special sol-gel technique. The catalysts were characterized by BET, XRD, H2 chemisorption,TPR, and TEM. According to TEM analysis, small Co particles (3-8 nm) synthesized by sol-gel technique have very narrow particle size distributions and are mostly confined inside the CNT. The deposition of cobalt nanoparticles synthesized by sol-gel technique on the functionalized CNT shifted the reduction peaks to a low temperature, indicating higher reducibility for uniform cobalt particles. The proposed sol-gel technique increased the FTS rate from 0.62 to 0.71 g HC/gcat./h, C5+ selectivity increased 7% and CH4 selectivity decreased 4%, compared to that prepared by incipient wetness impregnation. This new catalyst preparation method may offer an attractive alternative for nanoparticles synthesis with uniform, and various size distributions.

A highly efficient MIL-101(Cr)-Graphene-molybdenum oxide nano composite for selective oxidation of hydrogen sulfide into elemental sulfur

Alimohammad Pourreza,Saeed Askari,Alimorad Rashidi,Saeed Fakhraie,Mohammad Kooti,Marzieh Shafiei-Alavijeh 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.71 No.-

Hybrid composites of MIL-101(Cr) and Nanoporous Graphene with ratios in the range of 10-50% wereprepared via hydrothermal synthesis method. This study deals with an experimental investigation onselective oxidation of H2S into elemental sulfur in the range of 200-270 C, the catalyst activity andselectivity toward sulfur was studied. High-temperature reactor tests indicated that the MIL-101(Cr)-NPG50-Mo could be a promising candidate with conversion and selectivity of 100% and 99.5% at 200 C. The MIL-101(Cr)-NPG50-Mo stability showed there were not any significant changes in physicalproperties, the activity was evaluated after 20 h which was completely stable without any changes.

Nanoclays as nano adsorbent for oxidation of H_2S into elemental sulfur

Ali Mohamadalizadeh,Jafar Towfighi,Alimorad Rashidi,Mehrdad Manteghian,Ali Mohajeri,Rohollah Arasteh 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.5

Modified bentonites were used for the oxidation of H_2S into elemental sulfur. Active phases such as iron and cobalt sulfide were added to supports Cloisite 30B and 15A. The produced nano adsorbents were characterized by X-Ray diffraction, ICP, BET surface area and SEM. Selective oxidation of H_2S was carried out over the nano adsorbent in the experimental setup. The tests were performed at 70 and 180℃, under atmospheric pressure and in the presence of 5,000 ppm of H_2S in the inlet gas stream. The results confirmed the increase in the distribution of active metals and activity of Cloisite 30B, in comparison with Cloisite 15A. Cobalt-containing support showed significant improvement in the capacity of H_2S removal, and in the outlet stream less than 50 ppm of H_2S was detected.

Fabrication of nanoporous graphene by chemical vapor deposition (CVD) and its application in oil spill removal as a recyclable nanosorbent

Sanaz Pourmand,Majid Abdouss,Alimorad Rashidi 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.22 No.-

In this research, nanoporous graphene which is used as nanosorbent was synthesized by CVD method and the product was characterized by SEM, TEM, BET, TGA, XRD. FT-IR and Raman spectroscopy. The sorption of two samples of crude oil and also hydrocarbons which cause severe environmental pollution especially in water, on to nanoporous graphene was studied. Due to the high pore volume (1.17 cm3/g), large specific surface area (410m2/g) and small pore size, high sorption capacitywas achieved. Maximum sorption capacity of this nanoporous graphene for two samples of crude oil (A) and (B) was 102.17 and 105.39 g crude oil/g nanosorbent, respectively. The maximum sorption capacity of this nanosorbent for hydrocarbons was obtained at 155.46 g hydrocarbon per gram nanosorbent. Crude oils and hydrocarbons sorbed into nanoporous graphene could be recovered by three methods of heat treatment, extraction with solvent and filtration under mild suction with the proper recovery ratio. The recovery capacity by three methods was obtained, 99.01, 98.50, 98.05%, respectively. By means of these recycling methods, crude oil can be separated from nanosorbent and reused after the recovery. According to proper performance and good shaping ability of this nanosorbent, it can be used as a good candidate in the removal of oil spills.

Preparation of Co–Mo supported multi-wall carbon nanotube for hydrocracking of extra heavy oil

Mohsen Rahimi Rad,Alimorad Rashidi,Leila Vafajoo,Maryam Rashtchi 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.6

In this study, multi-wall carbon nanotube (MWCNT) supported Co–Mo nanocatalysts with changes insynthesis steps, one and two-step, were prepared through impregnation to be used in extra heavy oilhydrocracking process. In both of the synthesized nanocatalysts, the Co/Mo weight ratio was 1/3. Thenanocatalysts were characterized by scanning electron microscopy (SEM), transmission electronmicroscopy (TEM), X-ray diffraction (XRD), and accelerated surface area and porosimetry (ASAP)methods. The results showed that the nanocatalysts prepared through a two-step impregnation methodhad higher surface area and pore volume than the other synthesized nanocatalysts. The nanocatalysts were used in hydrocracking process under mild operating conditions, 260–300 ℃and at H2 initial pressure of 5 MPa. Hydrocracking of extra heavy oil was conducted in an autoclavereactor. The results indicated that both nanocatalysts were capable of hydrocracking heavy oil at mildoperating conditions. However, the nanocatalysts synthesized through the two-step impregnationexhibited higher performance, better heavy oil to light oil conversion, and better sulfur removal than theother methods. This superiority is due to the nanocatalyst’s structure and better distribution of metalclusters on the support.

Surface modification of silica-graphene nanohybrid as a novel stabilizer for oil-water emulsion

Sanaz Tajik,Bahram Nasernejad,Alimorad Rashidi 한국화학공학회 2017 Korean Journal of Chemical Engineering Vol.34 No.9

The surface modification of silica-graphene nanohybrid through treatment with a mixture of nitric and sulfuric acid vapors to prepare a novel stabilizer for decalin-water emulsion was investigated. The nanohybrid was prepared through chemical vapor deposition using silica aerogel and acetylene as catalyst and carbon precursor at atmospheric pressure and 600 oC. The physicochemical properties of the modified nanohybrid were characterized by FT-IR, XPS, Raman spectroscopy, and TEM. The surface modification of nanohybrid was at various duration times (24, 48, and 72 hours) to optimize the surface modification conditions. Zeta potential of −39.9 mV revealed that the surface modification of nanohybrid after 72 hours had an excellent stability in aqueous phase due to the presence of exceptional functional groups. The emulsion average droplet size decreased by increasing the nanohybrid concentration. The negative value of the zeta potential showed the proposed nanohybrid can be applied as an appropriate stabilizer for emulsion.

Kinetic modeling of oxidative dehydrogenation of propane (ODHP) over a vanadium–graphene catalyst: Application of the DOE and ANN methodologies

Moslem Fattahi,Mohammad Kazemeini,Farhad Khorasheh,Alimorad Rashidi 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4

In this research the application of design of experiment (DOE) coupled with the artificial neural networks (ANN) in kinetic study of oxidative dehydrogenation of propane (ODHP) over a vanadium–graphene catalyst at 400–500 ℃ and a method of data collection/fitting for the experiments were presented. The proposed reaction network composed of consecutive and simultaneous reactions with kinetics expressed by simple power law equations involving a total of 20 unknown parameters (10 reaction orders and 5 rate constants each expressed in terms of a pre-exponential factors and activation energies) determined through non-linear regression analysis. Because of the complex nature of the system, neural networks were employed as an efficient and accurate tool to model the behavior of the system. Response surface methodology (RSM) and ANN methods were constructed based upon the DOE’s points and were then utilized for generating extra-simulated data. The three data sets including the original experimental data, those simulated by the ANN and RSM methods were subsequently used to fit power law kinetic rate expressions for the main ODHP and side reactions. The results of kinetic modeling with simulated data sets from the ANN and RSM models compared with collected experimental data. Both methods were able to satisfactorily fit the experimental data for which the ANN data set showed the best fitting amongst them all.

Oil-in-water Pickering emulsions stabilized with functionalized multi-walled carbon nanotube/silica nanohybrids in the presence of high concentrations of cations in water

Amir Hossein Bornaee,Mehrdad Manteghian,Alimorad Rashidi,Mahshad Alaei,Mahshid Ershadi 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.4

Functionalized multi-walled carbon nanotube (MWCNT)/silica nanohybrid was synthesized and proposed as a stabilizer for oil-in-water Pickering emulsion. Carbon nanotube-to-silica weight ratio was a decisive factor influencing the performance of the synthesized nanohybrid. The results showed an appropriate value of such a ratio for a sol–gel synthesized nanohybrid structure was 28–33%. The emulsion formation time was dictated by the adopted mixing strategy such that without any mixing or ultrasonication it took 12 days for stabilization to be established. Conversely, the use of ultrasonication accompanied by mechanical mixing reduced this time to less than 4 h. Another key factor pertained to the type of the cation contained in water. Bivalent cations, such as magnesium and calcium, changed the hydrophilic–lipophilic balance more intensely than the sodium univalent cation. The nanohybrid holds a great promise to be adopted in enhanced oil recovery (EOR) processes as it does not require any emulsifier and mechanical treatment.