Chemical Modification of HZSM-5 for Selective Methylation

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Sonali Sengupta ◽  
Debarpita Ghosal ◽  
Jayanta Kumar Basu ◽  
Prashant Kamble
Keyword(s):  
Phosphoric Acid ◽  
Chemical Modification ◽  
Boric Acid ◽  
Surface Area ◽  
Bet Surface Area

Commercial HZSM-5 was modified by treating with phosphoric acid and boric acid for the selective methylation of benzene. The study of the performance with respect to the selectivity of the major products, toluene and xylene is the interest of the work. Catalysts were characterized based on BET surface area and XRD, SEM and NH3-TPD analysis to observe the change in properties due to their modification. Although benzene conversion is the highest with HZSM-5 catalyst, but in terms of selectivity, BZSM-5 and PZSM-5 are found to be the suitable catalyst for toluene and xylenes respectively. Xylene selectivity declines for HZSM-5 with the increase in temperature where as the PZSM-5 and BZSM-5 show slightly increasing tendency.

Physicochemical Properties of Carbons Prepared from Physic Nut Waste by Phosphoric Acid and Potassium Hydroxide Activations

2007 ◽  
Vol 561-565 ◽  
pp. 1719-1722 ◽  
Author(s):  
Chiravoot Pechyen ◽  
Duangdao Aht-Ong ◽  
Duangduen Atong ◽  
Viboon Sricharoenchaikul
Keyword(s):  
Activated Carbon ◽  
Phosphoric Acid ◽  
Physicochemical Properties ◽  
Adsorption Capacity ◽  
Surface Area ◽  
Potassium Hydroxide ◽  
Bet Surface Area ◽  
Physic Nut ◽  
Monolayer Adsorption ◽  
Adsorption Data

Char derived from pyrolysis of physic nut waste at 400-800°C was used for the preparation of activated carbon by chemical impregnation of phosphoric acid and potassium hydroxide. The original char exhibited the BET surface area in the range of 120-250 m2·g-1. The surface area increased to 480 and 532 m2·g-1 when activated with H3PO4 and KOH, respectively. Equilibrium adsorption data was found to be best represented by the Langmuir isotherm with maximum monolayer adsorption capacity of 560.13 mg·g-1 at 30°C. The adsorption capacity of the physic nut residue activated carbon was comparable to commercial activated carbon.

Physical and Chemical Activation Effect on Activated Carbon Prepared from Local Pineapple Waste

2014 ◽  
Vol 699 ◽  
pp. 87-92 ◽  
Author(s):  
Abdul Rahim Yacob ◽  
Adlina Azmi ◽  
Mohd Khairul Asyraf Amat Mustajab
Keyword(s):  
Activated Carbon ◽  
Phosphoric Acid ◽  
Surface Area ◽  
Activated Carbons ◽  
Chemical Activation ◽  
Bet Surface Area ◽  
Activation Effect ◽  
Pineapple Waste ◽  
Pineapple Peel ◽  
Physical And Chemical

The characteristics and quality of activated carbons prepared depending on the chemical and physical properties of the starting materials and the activation method used. In this study, activated carbon prepared using pineapple waste. Three parts of pineapple waste which comprises of peel, crown and leaf were studied. For comparison activated carbon were prepared by both physical and chemical activation respectively. Three types of chemicals were used, phosphoric acid (H3PO4), sulphuric acid (H2SO4), and potassium hydroxide (KOH). The preparation includes carbonization at 200°C and activation at the 400°C using muffle furnace. The chemical characterization of the activated carbon was carried out using Thermogravimetric analysis (TGA), Nitrogen gas adsorption analysis and Fourier transform infrared (FTIR). The highest BET surface area was achieved when the pineapple peel soaked in 20% phosphoric acid with a surface area of 1115 m2g-1. FTIR analysis indicates that the reacted pineapple waste successfully converted into activated carbons.

Activated carbon from potassium hydroxide spent liquor lignin using phosphoric acid

TAPPI Journal ◽  
2018 ◽  
Vol 17 (02) ◽  
pp. 63-69 ◽  
Author(s):  
Mamon Sarkar ◽  
Chao Tian ◽  
M. Sarwar Jahan
Keyword(s):  
Activated Carbon ◽  
Phosphoric Acid ◽  
Iodine Number ◽  
Surface Area ◽  
Potassium Hydroxide ◽  
Bet Surface Area ◽  
Koh Activation ◽  
Activation Temperature ◽  
Impregnation Ratio ◽  
Spent Liquor

Activated carbon was prepared by phosphoric acid (H3PO4) activation of potassium hydroxide (KOH) pulping spent liquor lignin from rice straw and compared with KOH hydroxide activation. The process parameters, such as impregnation ratio, activation temperature, and activation time were varied and their effects on the yield of activated carbon and iodine number were studied. The activated carbon prepared by H3PO4 at 800°C for 60 min at an impregnation ratio of 2.5 reached a Brunauer-Emmett-Teller (BET) surface area of 1063 m2/g, including pore diameter of 14.4 nm, iodine number of 525 mg/g, and yield of 49.2%. Yield and BET surface area in KOH activation was much lower than that of H3PO4.

Morphology and BET surface area of phosphoric acid stabilized tropical soils

2013 ◽  
Vol 154 ◽  
pp. 36-41 ◽  
Author(s):  
Amin Eisazadeh ◽  
Khairul Anuar Kassim ◽  
Hadi Nur
Keyword(s):  
Phosphoric Acid ◽  
Surface Area ◽  
Tropical Soils ◽  
Bet Surface Area

Chemically Modified Sago Fly Ash for Pb(II) Removal from Water

2021 ◽  
Vol 411 ◽  
pp. 93-105
Author(s):  
Rafeah Wahi ◽  
Showkat Ahmad Bhawani ◽  
Zainab Ngaini ◽  
Nur Farhana Yusop ◽  
Nur Hanani Hasana
Keyword(s):  
Fly Ash ◽  
Chemical Modification ◽  
Surface Area ◽  
Contact Time ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Bet Surface Area ◽  
Aqueous Environment ◽  
Initial Concentration ◽  
Chemically Modified

The use of agricultural by-products has been widely studied to develop effective and inexpensive adsorbent for heavy metal removal. In this study, sago (M.sagu) fly ash (FA) was chemically modified to afford an operational adsorbent for Pb (II) elimination from water. Chemical modification was carried out via acid-base treatment using NaOH and HCl. The chemically modified fly ash (MFA) was characterized via proximate, surface morphology, and functional groups' surface area analyses. The effects of adsorption parameters, namely, Pb (II) initial concentration, sorbent dosage and contact time on the eradication of Pb (II) by MFA was analyzed in batch experiments with Langmuir and Freundlich isotherms. Optimization of Pb (II) removal by MFA was studied via response surface methodology (RSM) approach. Results revealed that chemical modification has successfully enhanced the adsorptive properties of MFA (BET surface area: 231.4 m2/g, fixed carbon: 55.83%). MFA exhibits better Pb (II) removal efficiency (90.8%) compared to FA (63.6%) at the following adsorption condition: Pb (II) initial concentration (5 ppm), contact time (30 min) and agitation speed (150 rpm). The adsorption of Pb (II) by FA and MFA fitted well with Freundlich isotherm (R2>0.9). RSM study suggested that the optimum Pb (II) removal was 99.4% at the following conditions: Pb (II) initial concentration (20 ppm), contact time (2 h) and sorbent dosage (0.6 g/50 mL). The results concluded the potential optimum operational condition for Pb (II) removal from aqueous environment by MFA as a low cost adsorbent, at larger scale.

scholarly journals Comparative study for adsorption of acidic and basic dyes on activated carbon prepared from date stone by different activation agent

2020 ◽  
Vol 13 (1) ◽  
pp. 12-20
Author(s):  
Azhaar Radhi Jabbar
Keyword(s):  
Activated Carbon ◽  
Phosphoric Acid ◽  
Surface Area ◽  
Zinc Chloride ◽  
Potassium Hydroxide ◽  
Adsorption Process ◽  
Activated Carbons ◽  
Second Order ◽  
Bet Surface Area ◽  
Pseudo Second Order

This research includes a lab scale work to investigate the feasibility of treating waste water which polluted with dyes exhausted from textile factory by using adsorption process. Three type of activated carbon were prepared using locally available waste material (date stone). Chemical activation method  with (zinc chloride, potassium hydroxide, or phosphoric acid) was used  as activators  to  prepared carbon. Firstly, the materials were carbonized at 275 oC for 90 min and then the carbonized materials were treated with (4 molar) solution of acid, base or salt for 24 hour. Finally, these materials were activated at 600 oC for two hours in the presence of nitrogen gas flow. The resulted activated carbons were checked by its (BET) surface area analysis and surface morphology by SEM. The surface area values were (815, 950,600) m2/g for carbon produced from the activation of date  stone by phosphoric acid, potassium hydroxide or zinc chloride respectively. SEM characterizations show that activated carbons that prepared from potassium hydroxide have higher surface area and good adsorption characteristics than that prepared from activation with phosphoric acid or zinc chloride. The  adsorption process was studied using two types of dyes. The first one is acidic (methyl orange) and the other is basic (bismark brown). The adsorption isotherms and kinetics where investigated for both dyes at temperatures (30,40,50,60)oC for concentration  range  equal to (6-16)mg/l.  The  adsorption data of equilibrium were presented by using two common adsorption isotherm equations. The data was fitted fairly well with Langmuir isotherm for both dyes on all types of prepared activated carbons. The kinetic of adsorption was study by using two kinetic equations, pseudo first order and pseudo second order. The result showed the rapid increase in the rate of adsorption at the initial until equilibrium achieved. Pseudo second order model were represent the data very well with confidence level 0.99.

scholarly journals Chemical Activation of a South African Coal using Phosphoric Acid

1993 ◽  
Vol 10 (1-4) ◽  
pp. 181-192 ◽  
Author(s):  
François D. Botha ◽  
Brian Mcenaney
Keyword(s):  
Activated Carbon ◽  
Phosphoric Acid ◽  
Surface Area ◽  
South African ◽  
Froth Flotation ◽  
Mercury Porosimetry ◽  
Chemical Activation ◽  
Ash Content ◽  
Bet Surface Area ◽  
Adsorption Of Nitrogen

The potential of a South African coal, Bosjesspruit, as a precursor for a phosphoric acid-activated carbon has been assessed using the adsorption of nitrogen at 77 K and mercury porosimetry. Column cleaning of the coal by froth flotation reduced the ash content from 22 to 12 wt.% and caused maceral separtion, resulting in an intertinite-rich product. Reaction of the column-cleaned coal with phosphoric acid in the range 450–550°C produced an activated carbon which was dominantly microporous. The notional BET surface area of the coal reached a maximum of 600 m2/g at a reaction temperature of 550°C.

Synthesis and Characterization of Florfenicol-silver Nanocomposite and its Antibacterial Activity against some Gram Positive and Gram-negative Bacteria

2020 ◽  
Keyword(s):  
Silver Nanoparticles ◽  
Electron Microscope ◽  
Zeta Potential ◽  
Surface Area ◽  
Spherical Shape ◽  
Bet Surface Area ◽  
Sonochemical Method ◽  
Raman Spectrometry ◽  
Silver Nanocomposite ◽  
Morphology Characterization

In this paper, easy, rapid and cheap synthetic method was described for florfenicol-silver nanocomposite by sonochemical method. Florfenicol-silver nanocomposite was characterized based on three classes namely index, identification and morphology class. Index characterization was carried out by zeta sizing, BET surface area and zeta potential. Identification characterization was performed using X-ray diffraction (XRD) and Raman spectrometry. Morphology characterization was done utilizing transmission electron microscope (TEM), scanning electron microscope (SEM) and atomic force microscope (AFM). Characterization results showed zeta sizing of florfenicol was 30.44nm, while florfenicol-silver nanocomposite was 33.5 nm with zeta potential -14.1 and -18, respectively. BET surface area was found to be 13.3, 73.2 and 103.69 m2/g for florfenicol, silver nanoparticles and florfenicol-silver nanocomposite respectively. XRD and Raman charts confirmed the formation of florfenicol-silver nanocomposite without any contamination. TEM, SEM and AFM spectral data illustrated spherical to sub spherical shape of silver nanoparticles on cubic to sheet shape of florfenicol with size less than 50 nm. Antimicrobial activity was screened where the average zone of inhibitions caused by the prepared nanocomposite were 28.3 mm, 24 mm, 27.3 mm and 24 mm compared to 17.7 mm, 16 mm, 18.7 mm and 13.3 mm of the native drug and 13 mm, 10 mm, 14.3 mm and 15 mm of the used positive reference standards against E. coli, Salmonella typhymurium, Staphylococcus aureus and Staph.aureus MRSA respectively.

Life Time Improvement of Hierarchically Structured SAPO-34 Nanocatalyst in MTO Reaction via Applying Clinoptilolite, Investigating of Composite Design via RSM

2020 ◽  
Vol 23 ◽  
Author(s):  
Reza Yazdanpanah ◽  
Eshagh Moradiyan ◽  
Rouein Halladj ◽  
Sima Askari
Keyword(s):  
Surface Area ◽  
Natural Zeolite ◽  
Coke Formation ◽  
Life Time ◽  
Weight Percent ◽  
Light Olefins ◽  
Bet Surface Area ◽  
Relative Crystallinity ◽  
Mto Reaction ◽  
The Common

Aim and Objective: The research focuses on recent progress in the production of light olefins. Hence, the common catalyst of the reaction (SAPO-34) deactivates quickly because of coke formation, we reorganized the mechanism combining SAPO-34 with a natural zeolite in order to delay the deactivation time. Materials and Methods: The synthesis of nanocomposite catalyst was conducted hydrothermally using experimental design. Firstly, Clinoptilolite was modified using nitric acid in order to achieve nano scaled material. Then, the initial gel of the SAPO-34 was prepared using DEA, aluminum isopropoxide, phosphoric acid and TEOS as the organic template, sources of Aluminum, Phosphor, and Silicate, respectively. Finally, the modified zeolite was combined with SAPO-34's gel. Results: 20 different catalysts due to D-Optimal design were synthesized and the nanocomposite with 50 weight percent of SAPO-34, 4 hours Crystallization and early Clinoptilolite precipitation showed the highest relative crystallinity, partly high BET surface area and hierarchical structure. Conclusion: Different analysis illustrated the existence of both components. The most important property alteration of nanocomposite was the increment of pore mean diameters and reduction in pore volumes in comparison with free SAPO-34. Due to low price of Clinoptilolite, the new catalyst develops the economy of the process. Using this composite, according to formation of multi-sized pores located hierarchically on the surface of the catalyst and increased surface area, significant amounts of Ethylene and Propylene, in comparison with free SAPO-34, were produced, as well as deactivation time that was improved.

scholarly journals Hydrochloric Acid Modification and Lead Removal Studies on Naturally Occurring Zeolites from Nevada, New Mexico, and Arizona

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1238
Author(s):  
Garven M. Huntley ◽  
Rudy L. Luck ◽  
Michael E. Mullins ◽  
Nick K. Newberry
Keyword(s):  
New Mexico ◽  
Surface Area ◽  
Bet Surface Area ◽  
Lead Removal ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Naturally Occurring ◽  
27Al Mas Nmr ◽  
Modified Zeolites

Four naturally occurring zeolites were examined to verify their assignments as chabazites AZLB-Ca and AZLB-Na (Bowie, Arizona) and clinoptilolites NM-Ca (Winston, New Mexico) and NV-Na (Ash Meadows, Nevada). Based on powder X-ray diffraction, NM-Ca was discovered to be mostly quartz with some clinoptilolite residues. Treatment with concentrated HCl (12.1 M) acid resulted in AZLB-Ca and AZLB-Na, the chabazite-like species, becoming amorphous, as confirmed by powder X-ray diffraction. In contrast, NM-Ca and NV-Na, which are clinoptilolite-like species, withstood boiling in concentrated HCl acid. This treatment removes calcium, magnesium, sodium, potassium, aluminum, and iron atoms or ions from the framework while leaving the silicon framework intact as confirmed via X-ray fluorescence and diffraction. SEM images on calcined and HCl treated NV-Na were obtained. BET surface area analysis confirmed an increase in surface area for the two zeolites after treatment, NM-Ca 20.0(1) to 111(4) m2/g and NV-Na 19.0(4) to 158(7) m2/g. 29Si and 27Al MAS NMR were performed on the natural and treated NV-Na zeolite, and the data for the natural NV-Na zeolite suggested a Si:Al ratio of 4.33 similar to that determined by X-Ray fluorescence of 4.55. Removal of lead ions from solution decreased from the native NM-Ca, 0.27(14), NV-Na, 1.50(17) meq/g compared to the modified zeolites, 30 min HCl treated NM-Ca 0.06(9) and NV-Na, 0.41(23) meq/g, and also decreased upon K+ ion pretreatment in the HCl modified zeolites.

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