scholarly journals Specific Adsorption of Aspartic Acid on Iron (III) and Nickel (II) Oxides

2012 ◽  
Vol 14 (4) ◽  
pp. 299
Author(s):  
I.B. Dmitrieva ◽  
A.S. Chukhno ◽  
E.Y. Rodionova ◽  
R.V. Novichkov
Keyword(s):  
Zeta Potential ◽  
Aspartic Acid ◽  
Potentiometric Titration ◽  
Acid Concentration ◽  
Specific Adsorption ◽  
Bulk Solution ◽  
Oxide Surface ◽  
Acid Anion ◽  
Adsorption Time ◽  
Complexation Process

<p>The dependences of zeta – potential and adsorption of aspartic acid on NiO and Fe<sub>2</sub>O<sub>3</sub> oxideswere investigated as a function of aspartic acid concentration, pH and adsorption time using microelectrophoresis and potentiometric titration methods. Shifting of pHIEP (the isoelectric point or IEP) towards the acid zone for Fe<sub>2</sub>O<sub>3</sub> and towards the base zone for NiO in the solutions of aspartic acid in comparison with HCl shows the presence of specific adsorption of aspartic acid anion and cation forms on the surfaces of Fe<sub>2</sub>O<sub>3</sub> and NiO oxides, respectively. The complexation process of Fe(III) ions with aspartic acid in the bulk solution and on the oxide surface was examined by spectrophotometer. It was determined that Fe(III) ions form complexes with aspartic acid in the bulk solution.</p>

Bulk Solution Assay Test Procedure Development and validation for Esomeprazole Sodium Injection 40mg as a CPP

2021 ◽  
pp. 177-192
Author(s):  
Santoshkumar R. Mulik ◽  
Rishikesh S. Bachhav
Keyword(s):  
Potentiometric Titration ◽  
Method Development ◽  
Uv Spectroscopy ◽  
Test Procedure ◽  
Processing Parameters ◽  
Test Method ◽  
Bulk Solution ◽  
Uv Spectrometry ◽  
Delayed Release ◽  
It Impact

Assay analytical test procedure at the Bulk-Solution stage for Esomeprazole Sodium Injection 40mgas a Critical Processing Parameters during manufacturing developed and validated. As per current available literature and the references, Esomeprazole active substance is available in market in the five forms, i.e. Esomeprazole as Plain [Tablet]; Esomeprazole Magnesium Trihydrate [Tablet, Capsule Delayed Release]; Esomeprazole Potassium [Tablet and Capsule]; Esomeprazole Strontium [Capsule Delayed Release] and Esomeprazole Sodium [Injectable].Assay test procedure for Active and other dosage forms [Tablet, Capsule] were available based on either Potentiometric Titration or HPLC basis. Product Esomeprazole Sodium Injection 40mg is not available in official pharmacopeia. As per available reference and literature assay test method for intermediate testing and finished product is based on HPLC. Intermediate testing [In-Process Testing] required as Critical Process Parameters [CPP] to ensure the quality i.e. appropriate bulk-solution purity, before to proceed for filtration and filling of Bulk-solution in unit dosage form [Vials]. To test the bulk solution purity approximate 5-6 hours required by HPLC. Which leads to hold the Bulk solution, further it impact and may risk to Bio-Burden of bulk solution. Also it impact and reduce the productivity of line by 5-6 hours. HPLC testing required special skilled manpower and cost. Considering all above concerns Study carried for test method development based on UV-Spectroscopy, HPLC and potentiometric titration. Based on method validation performed for UV-Spectrometry, HPLC and potentiometric titration; Test procedure developed and validated based on UV-Spectrometry is found Simple, Accurate, Precise, Economical and Rapid to save time and cost with increase in productivity as a Critical Processing Parameters for Esomeprazole Sodium Injection 40mgat the Bulk-Solution stage during manufacturing.

scholarly journals Studies of Some Properties and the Structure of Polyethylene Glycol (PEG) Macromolecules Adsorbed on a TiO2 Surface

2001 ◽  
Vol 19 (5) ◽  
pp. 397-407 ◽  
Author(s):  
S. Chibowski ◽  
M. Paszkiewicz
Keyword(s):  
Molecular Weight ◽  
Polyethylene Glycol ◽  
Zeta Potential ◽  
Surface Charge ◽  
Adsorption Layer ◽  
Bulk Solution ◽  
Ionic Structure ◽  
Solution Interface ◽  
Main Factors ◽  
Presence And Absence

In the studies presented, the influence of the molecular weight of polyethylene glycol (PEG) on the adsorption and electrical properties at the metal oxide/polymer solution interface has been determined. The main factors responsible for the observed changes in the zeta potential and surface charge of titania were determined on the basis of the data obtained. It was demonstrated that changes in the ionic structure of the Stern layer depend on the molecular weight of PEG and its conformation. A possible mechanism for the changes in zeta potential both with pH and molecular weight was proposed on the basis of values of the surface charge difference (Δσ0) and the diffuse layer charge difference (Δσd) as determined in the presence and absence of the polymer. The thickness of the adsorption layer (δ) on the surface of titania was calculated from the zeta potential changes, both in the presence and absence of the polymer. A distinct influence of the PEG molecular weight was noted on the values of the adsorption layer thickness (δ) determined. The structures of the macromolecules in solution and at the solid/solution interface were compared and from the dependencies obtained some changes in the shape and dimensions of the polymer coils on passing from the bulk solution to the interface were proposed.

Searching for a high efficiency and environmental benign reagent to leach ion-adsorption rare earths based on the zeta potential of clay particles

2018 ◽  
Vol 20 (19) ◽  
pp. 4528-4536 ◽  
Author(s):  
Lifen Yang ◽  
Dashan Wang ◽  
Cuicui Li ◽  
Yuanyuan Sun ◽  
Xuezhen Zhou ◽  
...  
Keyword(s):  
Zeta Potential ◽  
Rare Earths ◽  
Aluminum Sulfate ◽  
High Efficiency ◽  
Specific Adsorption ◽  
Environmentally Benign ◽  
Ion Adsorption ◽  
Clay Particles ◽  
Highly Efficient

Aluminum sulfate is the best reagent for highly efficient and environmentally benign leaching of IAREs because of its specific adsorption towards CPs.

scholarly journals Effect of Magnesium on the Hydrophobicity of Sphalerite

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1359
Author(s):  
Gloria I. Dávila-Pulido ◽  
Adrián A. González-Ibarra ◽  
Mitzué Garza-García ◽  
Danay A. Charles
Keyword(s):  
Contact Angle ◽  
Zeta Potential ◽  
Zinc Sulfide ◽  
Sodium Carbonate ◽  
Thermodynamic Simulation ◽  
Bulk Solution ◽  
Sulfide Ores ◽  
Recycled Water ◽  
Negative Effects ◽  
Dissolved Species

The use of untreated recycled water has negative effects in the flotation of zinc sulfide ores due to the presence of dissolved species, such as magnesium and calcium. Although it has been found that magnesium is a more potent depressant than calcium, it has not been investigated in this role or for the effect of adding sodium carbonate. The results of an investigation to evaluate the effect of magnesium on the hydrophobicity of Cu-activated sphalerite conditioned with Sodium Isopropyl Xanthate (SIPX) are presented. Zeta potential of natural and Cu-activated sphalerite as a function of the conditioning pH and Cu(II) concentration, respectively, was first evaluated. Later, the effect of pH and presence of magnesium on the contact angle of Cu-activated sphalerite conditioned with SIPX was studied; it was also evaluated the effect of sodium carbonate to counteract the effect of magnesium. Cu-activation enhances the zeta potential of sphalerite up to a concentration of 5 mg/L. Contact angle tests, thermodynamic simulation, and surface analysis showed that magnesium hydroxide precipitates on the sphalerite surface at pH 9.6, decreasing its hydrophobicity. Addition of sodium carbonate as alkalinizing agent precipitates the magnesium in the form of a species that remained dispersed in the bulk solution, favoring the contact angle of Cu-activated sphalerite and, consequently, its hydrophobicity. It is concluded that the use of sodium carbonate as alkalinizing agent favors the precipitation of magnesium as hydromagnesite (Mg5(OH)2(CO3)4∙4H2O) instead of hydroxide allowing the recovery of sphalerite.

scholarly journals PEMBUATAN BIOSORBEN DARI BIJI PEPAYA (Carica papaya L) UNTUK PENYERAPAN ZAT WARNA

2017 ◽  
Vol 6 (2) ◽  
pp. 7-13
Author(s):  
Siswarni MZ ◽  
Lara Indra Ranita ◽  
Dandri Safitri
Keyword(s):  
Sulfuric Acid ◽  
Methyl Orange ◽  
Surface Area ◽  
Acid Concentration ◽  
Sulfuric Acid Concentration ◽  
Methyl Violet ◽  
Methyl Red ◽  
Drying Time ◽  
Adsorption Time ◽  
Papaya Seeds

Biosorbent is a material that has a pore - pore lot, where the adsorption process can take place on the pore walls or occur in certain regions of the particles. Preparation from papaya seeds biosorbent using H2SO4 as an activator, and then used as a textile dye absorption, namely methyl orange, methyl violet and methyl red. This study aims to determine the optimum conditions in the manufacturing biosorbent from papaya seeds. Analysis is iodine number, surface area, and test the ability of sarap to dyes (methyl orange, methyl violet and methyl red). In the manufacture biosorbent of this papaya seeds, the method used is chemical activation process. This study uses papaya seeds as raw material and sulfuric acid as an activator. The concentration of sulfuric acid used 5%, 7%, 10% and the drying time of 30 minutes, 60 minutes, 90 minutes, and 120 minutes. Biosorbent mass of 0.5 g (2.5% of 20 ml), 1.0 g (5% of 20 ml) and 1.5 g (7.5% of 20 ml) with adsorption time of 20 minutes, 30 minutes, and 40 minutes for the absorption of the dye. The results showed the highest iodine gained 482.22 mg / g on the drying time of 120 minutes and a sulfuric acid concentration of 10% and the highest surface area was obtained 33.43556 m2 / g on the drying time of 120 minutes and a sulfuric acid concentration of 10%. The analysis results of the adsorption capacity for methyl violet dye that is 9.547 mg / g on biosorbent mass of 1.0 g and the adsorption time of 40 minutes..

Complexation of Alkali Metal Ions by the Cryptand 4,7,13,16-Tetraoxa-1,10-diazabicyclo[8.8.5]tricosane in Several Solvents

1994 ◽  
Vol 47 (1) ◽  
pp. 123 ◽  
Author(s):  
R Dhillon ◽  
SF Lincoln
Keyword(s):  
Stability Constant ◽  
Alkali Metal ◽  
Metal Ions ◽  
Potentiometric Titration ◽  
Propylene Carbonate ◽  
Alkali Metal Ions ◽  
Factors Affecting ◽  
The Stability ◽  
Titration Study ◽  
Complexation Process

A potentiometric titration study of the complexation of metal ions (M+) by 4,7,13,16- tetraoxa-1,10-diazabicyclo[8.8.5] tricosane (C22C5) at 298.2 K and I = 0.05 (NEt4ClO4) yields log(K/dm3 mol-1) =6.07 and 5.36, 7.55 and 5.95, 6.26 and 7.56, 5.5 and 6.66, 4.57 and 5.16, and 8.14 and 14.51 when M+ = Li+, Na+, K+, Rb +, Cs+ and Ag+, respectively, where the first and second magnitudes of each pair refer to the stability constant (K) for [M(C22C5)]+ in acetonitrile and ropylene carbonate solvent, respectively. A 7Li n.m.r. tudy yields kd (298.2 K) = 428 s-1, ∆ Hd ‡ = 24.7 kJ mol-1 and ∆ Sd ‡ = -111 J K-1 mol-1 for the monomolecular decomplexation of Li+ from [Li(C22C5)]+, and kc(298.2 K) = 9.83×107 dm3 mol-1 s-1 for the complexation process in propylene carbonate. These data are compared with those for related systems and are discussed in terms of the factors affecting cryptate stability and lability.

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