scholarly journals Adsorption modification of the zeolite surface with chitosan

2019 ◽  
pp. 20-26
Author(s):  
Zhadra Tattibayeva ◽  
Mirzhan Tursynbetov ◽  
Sagdat Tazhibayeva ◽  
Wojciech Kujawski ◽  
Kuanyshbek Musabekov
Keyword(s):  
High Temperature ◽  
Solid Phase ◽  
Acid Activation ◽  
Zeolite A ◽  
Amino Groups ◽  
Oh Groups ◽  
Zeolite Surface ◽  
Modified Zeolite ◽  
Chitosan Concentration ◽  
Langmuir And Freundlich Models

In order to modify the surface, thermal acid activation of the zeolite of the Chankanai deposit was conducted. It was found that the treatment of the mineral with acid at high temperature leads to a decrease in the content of Ca, Al and Sr in its composition. Adsorption of chitosan on the surface of thermoacid-activated zeolite was also studied. Processing of the adsorption isotherms according to Langmuir and Freundlich models showed that the maximum adsorption of chitosan on the zeolite surface is 30.1 mg/g and the Freundlich constant 1/n is 0.75. On the IR-spectra of chitosan-modified zeolite, a certain shift to the higher frequencies of the peak was found at the oscillation frequency of 1638 cm-1, which can be explained by the contribution of amino groups adsorbed on the surface of the mineral. The shift to the left of the peak at 581 cm-1, typical for aluminosilicate groups, is also an evidence of their interactions with chitosan. When studying the effect of chitosan concentration on the wetting of the modified zeolite powder, it was found that at concentration of 2.10-3 base mol/L, an increase in the wetting angle from 10° to 47° occurs due to surface overcharging. According to the data of adsorption, IR spectroscopy and wetting of the surface, the main mechanism for binding chitosan to the zeolite surface was due to the electrostatic interaction of polymer amino groups with silicate and aluminosilicate groups of the mineral, stabilized by hydrogen bonds between the OH-groups of the polymer and ≡Si-O-groups of the solid phase.

Vortex-Assisted Dispersive Micro-Solid Phase Extraction Using CTAB-Modified Zeolite NaY Sorbent Coupled with HPLC for the Determination of Carbamate Insecticides

2016 ◽  
Vol 64 (10) ◽  
pp. 2145-2152 ◽  
Author(s):  
Pawina Salisaeng ◽  
Prapha Arnnok ◽  
Nopbhasinthu Patdhanagul ◽  
Rodjana Burakham
Keyword(s):  
Solid Phase Extraction ◽  
Solid Phase ◽  
Phase Extraction ◽  
Modified Zeolite ◽  
Zeolite Nay ◽  
Carbamate Insecticides

In Situ High-Temperature Transmission Electron Microscopy Observations of the Formation of Nanocrystalline TiC from Nanocrystalline Anatase (TiO2)

1998 ◽  
Vol 4 (3) ◽  
pp. 269-277 ◽  
Author(s):  
A. Agrawal ◽  
J. Cizeron ◽  
V.L. Colvin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Temperature ◽  
Solid Phase ◽  
Anatase Phase ◽  
High Resolution Electron Microscopy ◽  
Rutile Phase ◽  
Transmission Electron ◽  
New Phase

In this work, the high-temperature behavior of nanocrystalline TiO2 is studied using in situ transmission electron microscopy (TEM). These nanoparticles are made using wet chemical techniques that generate the anatase phase of TiO2 with average grain sizes of 6 nm. X-ray diffraction studies of nanophase TiO2 indicate the material undergoes a solid-solid phase transformation to the stable rutile phase between 600° and 900°C. This phase transition is not observed in the TEM samples, which remain anatase up to temperatures as high as 1000°C. Above 1000°C, nanoparticles become mobile on the amorphous carbon grid and by 1300°C, all anatase diffraction is lost and larger (50 nm) single crystals of a new phase are present. This new phase is identified as TiC both from high-resolution electron microscopy after heat treatment and electron diffraction collected during in situ heating experiments. Video images of the particle motion in situ show the nanoparticles diffusing and interacting with the underlying grid material as the reaction from TiO2 to TiC proceeds.

Stimulation of Wells Damaged by Barite Present in Filter Cake or Scale

SPE Journal ◽  
2021 ◽  
pp. 1-11
Author(s):  
Igor Ivanishin ◽  
Hisham A. Nasr-El-Din ◽  
Dmitriy Solnyshkin ◽  
Artem Klyubin
Keyword(s):  
High Temperature ◽  
Filter Cake ◽  
Ethylenediaminetetraacetic Acid ◽  
Solid Phase ◽  
Barium Carbonate ◽  
Process Analysis ◽  
Drilling Fluid ◽  
Field Application ◽  
X Ray ◽  
Dissolution Efficiency

Summary High-temperature (HT) deep carbonate reservoirs are typically drilled using barite (BaSO4) as a weighting material. Primary production in these tight reservoirs comes from the network of natural fractures, which are damaged by the invasion of mud filtrate during drilling operations. For this study, weighting material and drilling fluid were sampled at the same drillsite. X-ray diffraction (XRD) and X-ray fluorescence analyses confirmed the complex composition of the weighting material: 43.2 ± 3.8 wt% of BaSO4 and 47.8 ± 3.3 wt% of calcite (CaCO3); quartz and illite comprised the rest. The drilling fluid was used to form the filter cake in a high-pressure/high-temperature (HP/HT) filter-press apparatus at a temperature of 300°F and differential pressure of 500 psig. Compared with the weighting material, the filter cake contained less CaCO3, but more nondissolvable minerals, including quartz, illite, and kaolinite. This difference in mineral composition makes the filter cake more difficult to remove. Dissolution of laboratory-grade BaSO4, the field sample of the weighting material, and drilling-fluid filter cake were studied at 300°F and 1,000 to 1,050 psig using an autoclave equipped with a magnetic stirrer drive. Two independent techniques were used to investigate the dissolution process: analysis of the withdrawn-fluid samples using inductively coupled plasma-optical emission spectroscopy, and XRD analysis of the solid material left after the tests. The dissolution efficiency of commercial K5-diethylenetriaminepentaacetic acid (DTPA), two K4-ethylenediaminetetraacetic acid (EDTA), Na4-EDTA solutions, and two “barite dissolvers” of unknown composition was compared. K5-DTPA and K4-EDTA have similar efficiency in dissolving BaSO4 as a laboratory-grade chemical and a component of the calcite-containing weighting material. No pronounced dissolution-selectivity effect (i.e., preferential dissolution of CaCO3) was noted during the 6-hour dissolution tests with both solutions. Reported for the first time is the precipitation of barium carbonate (BaCO3) when a mixture of BaSO4 and CaCO3 is dissolved in DTPA or EDTA solutions. BaCO3 composes up to 30 wt% of the solid phase at the end of the 6-hour reaction, and can be dissolved during the field operations by 5 wt% hydrochloric acid. Being cheaper, K4-EDTA is the preferable stimulation fluid. Dilution of this chelate increases its dissolution efficiency. Compared with commonly recommended solutions of 0.5 to 0.6 M, a more dilute solution is suggested here for field application. The polymer breaker and K4-EDTA solution are incompatible; therefore, the damage should be removed in two stages if the polymer breaker is used.

scholarly journals Difference in the Dissolution Behaviors of Tablets Containing Polyvinylpolypyrrolidone (PVPP) Depending on Pharmaceutical Formulation After Storage Under High Temperature and Humid Conditions

2016 ◽  
Vol 19 (4) ◽  
pp. 511 ◽  
Author(s):  
Yoh Takekuma ◽  
Haruka Ishizaka ◽  
Masato Sumi ◽  
Yuki Sato ◽  
Mitsuru Sugawara
Keyword(s):  
High Temperature ◽  
Benzoic Acid ◽  
Dissolution Rate ◽  
Simple Structure ◽  
Pharmaceutical Formulations ◽  
Magnesium Stearate ◽  
Principal Agent ◽  
Amino Groups ◽  
Dissolution Tests ◽  
Rosuvastatin Calcium

PURPOSE. Storage under high temperature and humid conditions has been reported to decrease the dissolution rate for some kinds of tablets containing polyvinylpolypyrrolidone (PVPP) as a disintegrant. The aim of this study was to elucidate the properties of pharmaceutical formulations with PVPP that cause a decrease in the dissolution rate after storage under high temperature and humid conditions by using model tablets with a simple composition. METHODS. Model tablets, which consisted of rosuvastatin calcium or 5 simple structure compounds, salicylic acid, 2-aminodiphenylmethane, 2-aminobiphenyl, 2-(p-tolyl)benzoic acid or 4.4’-biphenol as principal agents, cellulose, lactose hydrate, PVPP and magnesium stearate as additives, were made by direct compression. The model tables were wrapped in paraffin papers and stored for 2 weeks at 40°C/75% relative humidity (RH). Dissolution tests were carried out by the paddle method in the Japanese Pharmacopoeia 16th edition. RESULTS. Model tablets with a simple composition were able to reproduce a decreased dissolution rate after storage at 40°C/75% RH. These tablets showed significantly decreased water absorption activities after storage. In the case of tablets without lactose hydrate by replacing with cellulose, a decreased dissolution rate was not observed. Carboxyl and amino groups in the structure of the principal agent were not directly involved in the decreased dissolution. 2-Benzylaniline tablets showed a remarkably decreased dissolution rate and 2-aminobiphenyl and 2-(p-tolyl)benzoic acid tablets showed slightly decreased dissolution rates, though 4,4’-biphenol tablets did not show a decrease dissolution rate. CONCLUSIONS. We demonstrated that additives and structure of the principal agent were involved in the decreased in dissolution rate for tablets with PVPP. The results suggested that one of the reasons for a decreased dissolution rate was the inclusion of lactose hydrate in tablets. The results also indicated that compounds as principal agents with low affinity for PVPP may be easily affected by airborne water under high temperature and humid conditions. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

A spectrophotometric assay for solid phase primary amino groups

1992 ◽  
Vol 36 (2) ◽  
pp. 81-85 ◽  
Author(s):  
Violeta G. Janolino ◽  
Harold E. Swaisgood
Keyword(s):  
Solid Phase ◽  
Spectrophotometric Assay ◽  
Amino Groups ◽  
Primary Amino

scholarly journals Removal of direct blue 129 from aqueous medium using surfactant-modified zeolite: a neural network modeling

2018 ◽  
Vol 5 (2) ◽  
pp. 101-113 ◽  
Author(s):  
Mahmoud Zarei ◽  
Nader Djafarzadeh ◽  
Leila Khadir
Keyword(s):  
Neural Network ◽  
Aqueous Medium ◽  
Network Modeling ◽  
Neural Network Modeling ◽  
Zeolite A ◽  
Modified Zeolite ◽  
Direct Blue

scholarly journals STUDY ON DYES ADSORPTION FROM AQUEOUS SOLUTION USING RED MUD ACTIVATED BY SULFURIC ACID

2019 ◽  
Vol 62 (11) ◽  
pp. 143-149
Author(s):  
Vu Xuan Minh ◽  
Nguyen Tuan Dung ◽  
Hương T. M. Le
Keyword(s):  
Red Mud ◽  
Textile Industry ◽  
Solid Phase ◽  
Second Order ◽  
Iron Sulfate ◽  
Activation Process ◽  
Acid Activation ◽  
Order Kinetic ◽  
Adsorption Capacities ◽  
Reactive Red 195

The textile industry wastewater contains the majority of different dyes which are quite toxic and should be removed before disposal. They are often highly resistant for biodegradation and hence are difficult to be treated. The application of adsorbents of natural origin, especially industrial waste, is one of the most attractive solutions for wastewater treatments due to its high socio-economic advantages. In this study, the adsorption capacity of acid activiated red mud for some conventional dyes such as Reactive Red 195 and Direct Yellow 132 was investigated. In this acid activation process part of aluminum oxide, iron oxide on red mud will be dissolved into solution, thereby increasing the specific surface area of the remaining solid phase (from 55 m2/g to 92 m2/g). The amount of red mud dissolved in the solution is about 30% weight. Solid residue is used in this adsorption study. The solution obtained after activation which includes iron sulfate salts, aluminum sulfate used as a coagulant for wastewater treatment. The results showed that, for both dyes, pH 5 is most suitable for the adsorption processes. The adsorption kinetic was based on the pseudo second-order kinetic equation. The rate constants of the second-order model for adsorption of DY132, RR195 on RMA in a solution with a concentration of 100 mg·l-1, pH = 5 are 1.48 and 1.95·10-2 g/(mg·min), respectively, and the equilibrium adsorption capacities are 42.74 and 54.95 mg·g-1, respectively. The adsorption data were well matched to Langmuir isotherm model. The maximum adsorption capacities were found to be 48.54 and 84.31 (mg·g-1) for Reactive Red 195 and Direct Yellow 132, respectively.

scholarly journals Role of capping in peptide synthesis

2020 ◽  
Vol 11 (4) ◽  
pp. 5225-5228
Author(s):  
Deepshikha Verma ◽  
Pillai V N R ◽  
Giriraj Tailor
Keyword(s):  
Peptide Synthesis ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Protecting Groups ◽  
Amino Groups ◽  
Peptide Chemistry ◽  
Fmoc Spps ◽  
Reliable Methods ◽  
Important Test

Protecting groups like Fmoc and coupling both steps are essential to monitoring the Fmoc SPPS (Solid Phase Peptide Synthesis) reaction completion. Reliable methods are used to detect the unreacted number of amino groups for monitoring these two essential reaction steps of coupling and cleavage. The ability to detect the complete coupling, incomplete coupling or failure of coupling we use many colour tests in the laboratory and based on this the Fmoc peptide chemistry allows the control of the completion of the Fmoc cleavage. The most important test used is the Kaiser test and highly recommended to monitor the coupling and cleavage steps. If the result of colour tests is positive after coupling, then the second coupling should be performed. Then again use the colour test to detect the level of coupling. If the result is still slightly positive, repeat coupling with the smaller modification of reagents such as used PyBOP instead of HOBT AND HOAT. These colour tests help in revealing the presence of unreacted amino-functional groups. Thus, we need to block these free N-terminal of amino- acids which help in avoiding the making of deletion of sequence.

scholarly journals Inorganic Nanostructured Anion-Exchange Materials Based on Aluminum Hydroxide

2020 ◽  
Vol 4 (3) ◽  
Keyword(s):  
Anion Exchange ◽  
Aluminum Hydroxide ◽  
Solid Phase ◽  
Structural Motif ◽  
Dynamic Mode ◽  
Isomorphic Substitution ◽  
Ion Exchangers ◽  
Oh Groups ◽  
Wide Range ◽  
Exchange Properties

Inorganic sorbents, in comparison with ordinary organic ion exchangers, have higher selectivity, radiation, thermal, and chemical stability. Inorganic ion exchangers are universal materials exhibiting both cation exchange and anion exchange properties. In this work, using aluminum hydroxide (AHO) as an example, we study the possibility of expanding the range of metal oxyhydrates that can serve as the basis to produce inorganic anion-exchange materials. The properties of aluminum hydroxide largely depend on the method of its production. This phenomenon is associated with a different state of Al3+ ions in aqueous solutions during hydrolysis. Estimation of the size of the primary particles of hydrated alumina gives a value of 19 nm. The most potent effect on the structure and ion-exchange properties of aluminum hydroxide is exerted by the introduction of alloying elements into its composition. Isomorphic substitution of a part of Al(III) ions in the structure of aluminum hydroxide with ions with a higher charge (Ti(IV), Zr(IV), or W(VI)) leads to an increase in the content of exchangeable OH-groups in the resulting material. The synthesized materials are amorphous substances, to study their structure; the method of diffuse X-ray scattering was used. The Gibbsite structural motif is determined, and structural changes occurring under the influence of various factors, and synthesis conditions are analyzed. By optimizing the composition of the material, it is possible to improve its sorption characteristics significantly. AAW-0, AAZ-0, and AAT-0 anion exchangers synthesized based on hydrated aluminum oxide can be used to purify weakly acidic electrolyte solutions from anionic impurities in the dynamic mode of repeated sorptiondesorption cycles. Materials based on mixed hydrated oxides of various elements can also be used as catalyst supports. Their anion exchange properties allow a wide range to vary the number of different anions introduced into the solid phase and, accordingly, to regulate the number and state of active catalytic sites.

scholarly journals The solid-phase joints of high-temperature nickel alloy with ultrafine-grained structure for disks and Ni3Al based single-crystal blade alloy

2015 ◽  
Vol 5 (2) ◽  
pp. 142-146 ◽  
Author(s):  
A. A. Drozdov ◽  
V. A. Valitov ◽  
K. B. Povarova ◽  
O. A. Bazyleva ◽  
E. V. Galieva ◽  
...  
Keyword(s):  
High Temperature ◽  
Single Crystal ◽  
Nickel Alloy ◽  
Solid Phase ◽  
Ultrafine Grained Structure ◽  
Ultrafine Grained ◽  
Blade Alloy ◽  
High Temperature Nickel Alloy
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