Surface reactivity of A horizons towards polar compounds estimated from water adsorption and water content

Soil Research ◽  
2001 ◽  
Vol 39 (5) ◽  
pp. 1105 ◽  
Author(s):  
R. L. Parfitt ◽  
J. S. Whitton ◽  
B. K. G. Theng
Keyword(s):  
Water Content ◽  
Surface Area ◽  
Water Adsorption ◽  
Polar Compounds ◽  
Water Area ◽  
Surface Reactivity ◽  
Bet Surface Area ◽  
Quick Method ◽  
Dry Water ◽  
Water Contents

The measurement of the specific surface area of soils may be useful for ranking soils in their ability to sorb polar compounds such as some pesticides and pollutants. For A horizons with varied mineralogy, particularly those containing large amounts of soil organic matter, this is problematic. We have estimated the surface area of a range of topsoils from water adsorption using the BET equation. The values obtained were greater than those measured from the adsorption of para-nitrophenol. There was a good relationship between the BET water area and the CEC of the samples (r2 = 0.83). There was a better relationship between the BET surface area and the water content of air-dry topsoils (r 2 = 0.98). We suggest that the air-dry water contents of topsoils could be used as a quick method to rank soils in order of their surface reactivity towards polar molecules, and this is preferable to more complicated methods.

scholarly journals Oxidized BPL Carbons

1993 ◽  
Vol 10 (1-4) ◽  
pp. 75-84 ◽  
Author(s):  
S.S. Barton ◽  
M.J.B. Evans ◽  
J.A.F. Macdonald
Keyword(s):  
Nitric Acid ◽  
Surface Area ◽  
Water Adsorption ◽  
Adsorption Properties ◽  
Bet Surface Area ◽  
Adsorption Sites ◽  
A Value ◽  
Nitrogen Desorption ◽  
Oxidized Carbon ◽  
Increasing Temperature

A series of oxidized carbons has been prepared by treatment of the carbon with concentrated nitric acid at various temperatures, and the surface and adsorption properties of the prepared carbons studied. Water adsorption was modelled using a recently derived equation capable of predicting a value for the primary adsorption sites on the surface of a microporous carbon while fitting the experimentally determined isotherm at high relative pressures. The concentration of primary sites was seen to increase with increasing temperature of oxidation. The very highly oxidized carbon samples were found to have a significantly lower BET surface area determined from nitrogen desorption at 77 K and higher apparent density measured from mercury displacement.

scholarly journals Characterization of Mn-Doped Vanadium Phosphorus Oxide (VPO) Catalyst: Effect of Ball Milling

2016 ◽  
Vol 7 (1) ◽  
pp. 73 ◽  
Author(s):  
Y.H. Taufiq-Yap ◽  
C.K. Goh
Keyword(s):  
Ball Milling ◽  
Surface Area ◽  
Surface Acidity ◽  
Milling Process ◽  
Surface Reactivity ◽  
Bet Surface Area ◽  
Phosphorus Oxide ◽  
Vanadium Phosphorus Oxide ◽  
Milled Material ◽  
Mn Doped

<p>The effect of ball milling on the structure and surface reactivity of the Mn-doped vanadium phosphorus oxide (V–P–O) catalyst is discussed. Mn-doped VOHPO<sub>4</sub>·½H<sub>2</sub>O precursor was prepared via organic method. The precursor was ball milled in isopropyl alcohol using agate balls for 60 min at 800 rpm. XRD, BET surface area measurements, SEM, O<sub>2</sub>-TPD, H<sub>2</sub>-TPR and TPD of NH<sub>3</sub> were used to characterize properties of the final catalysts. The results revealed that mechanical treatment of Mn-doped V–P–O catalyst increased surface area as well as reduced particle size of the material. Furthermore, process also increased exposure of (001) crystallographic plane of VOHPO4·½H<sub>2</sub>O precursor. The secondary structure of the milled material is also lost. The total amount of oxygen desorbed (from O<sub>2</sub>-TPD) and removed (by H<sub>2</sub>-TPR) from milled material is higher compared to the unmilled one. The surface acidity of the catalyst was also increased after milling process, as evidenced by lower desorption temperature and higher total amount of the ammonia desorbed.</p>

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.

scholarly journals Preparation, Characterization, and Evaluation of Macrocrystalline and Nanocrystalline Cellulose as Potential Corrosion Inhibitors for SS316 Alloy during Acid Pickling Process: Experimental and Computational Methods

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2275
Author(s):  
Arafat Toghan ◽  
Mohamed Gouda ◽  
Kamal Shalabi ◽  
Hany M. Abd El-Lateef
Keyword(s):  
Surface Area ◽  
Density Functional ◽  
Protective Efficacy ◽  
Protective Layer ◽  
Nanocrystalline Cellulose ◽  
Bet Surface Area ◽  
Natural Polymers ◽  
Active Centers ◽  
Acid Pickling ◽  
Pickling Process

Converting low-cost bio-plant residuals into high-value reusable nanomaterials such as microcrystalline cellulose is an important technological and environmental challenge. In this report, nanocrystalline cellulose (NCC) was prepared by acid hydrolysis of macrocrystalline cellulose (CEL). The newly synthesized nanomaterials were fully characterized using spectroscopic and microscopic techniques including FE-SEM, FT-IR, TEM, Raman spectroscopy, and BET surface area. Morphological portrayal showed the rod-shaped structure for NCC with an average diameter of 10–25 nm in thickness as well as length 100–200 nm. The BET surface area of pure CEL and NCC was found to be 10.41 and 27 m2/g, respectively. The comparative protection capacity of natural polymers CEL and NCC towards improving the SS316 alloy corrosion resistance has been assessed during the acid pickling process by electrochemical (OCP, PDP, and EIS), and weight loss (WL) measurements. The outcomes attained from the various empirical methods were matched and exhibited that the protective efficacy of these polymers augmented with the upsurge in dose in this order CEL (93.1%) < NCC (96.3%). The examined polymers display mixed-corrosion inhibition type features by hindering the active centers on the metal interface, and their adsorption followed the Langmuir isotherm model. Surface morphology analyses by SEM reinforced the adsorption of polymers on the metal substrate. The Density Functional Theory (DFT) parameters were intended and exhibited the anti-corrosive characteristics of CEL and NCC polymers. A Monte Carlo (MC) simulation study revealed that CEL and NCC polymers are resolutely adsorbed on the SS316 alloy surface and forming a powerful adsorbed protective layer.

scholarly journals Silica and Silica–Titania Xerogels Doped with Iron(III) for Total Antioxidant Capacity Determination

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2019
Author(s):  
Maria A. Morosanova ◽  
Ksenia V. Chaikun ◽  
Elena I. Morosanova
Keyword(s):  
Antioxidant Capacity ◽  
Surface Area ◽  
Total Antioxidant Capacity ◽  
Solid Phase ◽  
Bet Surface Area ◽  
Sensor Material ◽  
Total Antioxidant ◽  
Sensor Materials ◽  
Ascorbic Acids ◽  
Capacity Determination

In order to design a sensor material for total antioxidant capacity determination we have prepared silica and silica–titania xerogels doped with iron(III) and modified with 1,10-phenanthroline. Titanium(IV) tetraethoxyde content in the precursors (titanium(IV) tetraethoxyde and tetraethyl orthosilicate) mixtures has been varied from 0 to 12.5% vol. Iron(III) concentrations in sol has been varied from 1 to 100 mM. The increase of titanium(IV) content has led to a decrease in BET surface area and average pore diameter and an increase of micropore surface area and volume, which has resulted in better iron(III) retention in the xerogels. Iron(III), immobilized in the xerogel matrix, retains its ability to form complexes with 1,10-phenanthroline and to be reduced to iron(II). Static capacities for 1,10-phenanthroline have been determined for all the iron(III) doped xerogels (0.207 mmol/g–0.239 mmol/g) and they are not dependent on the iron(III) content. Sensor materials—xerogels doped with iron(III) and modified with 1,10-phenanthroline—have been used for antioxidants (catechol, gallic and ascorbic acids, and sulphite) solid phase spectrophotometric determination. Limits of detection for catechol, gallic and ascorbic acids, and sulphite equal 7.8 × 10−6 M, 5.4 × 10−6 M, 1.2 × 10−5 M, and 3.1 × 10−4 M, respectively. The increase of titanium(IV) content in sensor material has led to an increase of the reaction rate and the sensitivity of determination. Proposed sensor materials have been applied for total antioxidant capacity (in gallic acid equivalents) determination in soft beverages, have demonstrated high stability, and can be stored up to 6 months at room temperature.

Probing the performance of imide linked micro-porous polymers for enhanced CO2 gas adsorption applications

2021 ◽  
Author(s):  
Narendran Rajendran ◽  
Ali A. Husain ◽  
Saad Makhseed
Keyword(s):  
Surface Area ◽  
Gas Adsorption ◽  
Oxidative Polymerization ◽  
Porous Polymers ◽  
Bet Surface Area ◽  
Co2 Gas

Three new carbazole containing cross-linked polymers namely AH-Poly, TM-PDA-Poly and TMB-PDA-Poly were designed and successfully synthesized by an oxidative polymerization protocol. The prepared AH-Poly showed a specific BET surface area...

Preferential adsorption of ethane over ethylene on a Zr-based metal-organic framework: impacts of C-H···N hydrogen bonding

2021 ◽  
Author(s):  
Yaping Zhang ◽  
Daofei Lv ◽  
Jiayu Chen ◽  
Zewei Liu ◽  
Chongxiong Duan ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Surface Area ◽  
Energy Efficient ◽  
Metal Organic Framework ◽  
Bet Surface Area ◽  
Preferential Adsorption ◽  
Metal Organic ◽  
Organic Framework

The separation of ethylene/ethane mixture using energy-efficient technologies is important but challenging. Here, we prepared a Zr-based metal-organic framework (MOF-545) possessing high Brunauer-Emmett-Teller (BET) surface area of 2265.4 m2/g, and...

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