Optimization of cation-doped nano-hydroxyapatite in combination with amorphous aluminum hydroxide for defluoridation

2019 ◽  
Vol 19 (6) ◽  
pp. 1686-1694 ◽  
Author(s):  
Agman Gupta ◽  
Chelli Sai Manohar ◽  
Belliraj Siva Kumar
Keyword(s):  
Aluminum Hydroxide ◽  
Room Temperature ◽  
Optimal Conditions ◽  
Total Removal ◽  
Fluoride Solution ◽  
Kinetics And Thermodynamics ◽  
Adsorption Capacities ◽  
Heavily Doped ◽  
Nano Rods ◽  
Ph Range

Abstract Given widespread fluoride in the ground water, there is a need for effective defluoridation in several geographical areas. In this regard, we explored heavily doped cationic nano-composites of hydroxyapatite (HA) given its surface chemistry for adsorption of the specific anion. We synthesized and extensively characterized HA nano-rods (HA-NR), Al/Mg-HA nanocomposites and amorphous aluminum hydroxide, and optimized their efficient defluoridation. The kinetics and thermodynamics of adsorption were further evaluated to establish the mechanistic rationale and its spontaneity. We report the optimized ideal adsorbents for the near-total removal of fluoride that demonstrated 99.99% and 99.98% efficiency with adsorption capacities of 83.3 and 81.3mg/g respectively. The adsorbent composites were (Mg-HA)-Al(OH)3 and (HA-NR)-Al(OH)3 in 1:1 ratio. The optimal conditions for defluoridation were 25mg of adsorbent in 25ml (10mg/L) fluoride solution at room temperature agitated for 10h in the pH range of 4.88–7.20.

Effects of Aging on the Solubility of Palladium

1995 ◽  
Vol 412 ◽  
Author(s):  
C. Oda ◽  
H. Yoshikawa ◽  
M. Yui
Keyword(s):  
Aqueous Solution ◽  
Aging Time ◽  
Room Temperature ◽  
High Level Waste ◽  
Anaerobic Conditions ◽  
Dilute Aqueous Solution ◽  
Waste Repository ◽  
Ph Range ◽  
Effects Of Aging ◽  
High Level

AbstractPalladium solubility was measured in a dilute aqueous solution at room temperature in the pH range from 3 to 13 under anaerobic conditions. Crystalline Pd metal was clearly visible and the concentration of palladium in solution decreased gradually with aging time. The palladium concentrations in solution were less than 9.4×10-10M in the pH range from 4 to 10 and increased to 10-7M in the pH range greater than 10. This study suggests that palladium concentrations in certain high-level waste repository environments may be limited by Pd metal and may be less than 10-9M.

Growth mechanism and characterization of ZnO nano-tubes synthesized using the hydrothermal-etching method

2009 ◽  
Vol 63 (6) ◽  
Author(s):  
Yan Li ◽  
Chuan-Sheng Liu ◽  
Yun-Ling Zou
Keyword(s):  
Room Temperature ◽  
Morphological Analysis ◽  
Diffraction Field ◽  
X Ray Diffraction ◽  
X Ray ◽  
Room Temperature Photoluminescence ◽  
Etching Method ◽  
Nano Rods ◽  
Two Stages

AbstractZnO nano-tubes (ZNTs) have been successfully synthesized via a simple hydrothermal-etching method, and characterized by X-ray diffraction, field emission scanning electron microscopy and room temperature photoluminescence measurement. The as-synthesized ZNTs have a diameter of 500 nm, wall thickness of 20–30 nm, and length of 5 µm. Intensity of the plane (0002) diffraction peak, compared with that of plane (10$$ \bar 1 $$0) of ZNTs, is obviously lower than that of ZnO nano-rods. This phenomenon can be caused by the smaller cross section of plane (0002) of the nano-tubes compared with that of other morphologies. On basis of the morphological analysis, the formation process of nano-tubes can be proposed in two stages: hydrothermal growth and reaction etching process.

scholarly journals TEMPO-Functionalized Nanoporous Au Nanocomposite for the Electrochemical Detection of H2O2

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Dongxiao Wen ◽  
Qianrui Liu ◽  
Ying Cui ◽  
Huaixia Yang ◽  
Jinming Kong
Keyword(s):  
Electrochemical Detection ◽  
Nanoporous Gold ◽  
Carboxyl Groups ◽  
Time Interval ◽  
Optimal Conditions ◽  
Sem Images ◽  
One Step ◽  
Ph Range ◽  
Synthesis Approach ◽  
Higher Sensitivity

A novel nanocomposite of nanoporous gold nanoparticles (np-AuNPs) functionalized with 2,2,6,6-tetramethyl-1-piperidinyloxy radical (TEMPO) was prepared; assembled carboxyl groups on gold nanoporous nanoparticles surface were combined with TEMPO by the “bridge” of carboxylate-zirconium-carboxylate chemistry. SEM images and UV-Vis spectroscopies of np-AuNPs indicated that a safe, sustainable, and simplified one-step dealloying synthesis approach is successful. The TEMPO-np-AuNPs exhibited a good performance for the electrochemical detection of H2O2 due to its higher number of electrochemical activity sites and surface area of 7.49 m2g-1 for load bigger amount of TEMPO radicals. The TEMPO-functionalized np-AuNPs have a broad pH range and shorter response time for H2O2 catalysis verified by the response of amperometric signal under different pH and time interval. A wide linear range with a detection limit of 7.8 × 10-7 M and a higher sensitivity of 110.403 μA mM-1cm-2 were obtained for detecting H2O2 at optimal conditions.

Optimal conditions for induction of competence in nitrogen-fixing Azotobacter vinelandii

1982 ◽  
Vol 28 (4) ◽  
pp. 389-397 ◽  
Author(s):  
William J. Page
Keyword(s):  
Dissolved Oxygen ◽  
Sodium Acetate ◽  
Azotobacter Vinelandii ◽  
Nitrogenase Activity ◽  
Cell Mass ◽  
Apparent Competition ◽  
Competence Development ◽  
Optimal Conditions ◽  
Nitrogen Fixing ◽  
Ph Range

Competence development in nitrogen-fixing Azotobacter vinelandii cells was optimal at pH 7.2–7.4 which necessitated additional buffering of the iron-limited nitrogen-free competence medium or the addition of a suitable organic acid salt, e.g., sodium acetate. An autolysin was active in this pH range and competent cells were more susceptible to autolysis than the general cell population. Competence development also required restricted aeration of the culture, and only those cultures that attained zero dissolved oxygen became competent. Restricted aeration served to protect the iron-limited cell nitrogenase from oxygen inactivation thus allowing the culture to reach zero dissolved oxygen. The inclusion of additional sources of reductant, e.g., malate, in buffered competence medium resulted in increased respiration and protection of nitrogenase, increased cell mass, and poly-β-hydroxybutyrate synthesis, but decreased competence. A possible explanation for the apparent competition between competence development and nitrogenase activity is discussed.

scholarly journals Influence of hydrotalcite preparation conditions on its physico-chemical properties

2019 ◽  
Vol 12 (1) ◽  
pp. 119-126
Author(s):  
Miroslava Mališová ◽  
Michal Horňáček ◽  
Pavol Hudec ◽  
Jozef Mikulec ◽  
Vladimír Jorík ◽  
...  
Keyword(s):  
Catalytic Properties ◽  
Chemical Properties ◽  
Synthesis Temperature ◽  
Optimal Synthesis ◽  
Preparation Process ◽  
Optimal Conditions ◽  
Temperature Range ◽  
Preparation Conditions ◽  
Physico Chemical ◽  
Ph Range

Abstract The aim of the research was to prepare and characterize hydrotalcite synthesized under different preparation conditions. The most common hydrotalcite preparation is the co-precipiaton method. The preparation process strongly influences the catalytic properties of hydrotalcite; therefore, optimal conditions have to be determined. During the study, seven samples of the catalyst were prepared in the pH range from 8 to 12 and the synthesis temperature range from 25 to 55 °C. Based on several catalyst properties, optimal synthesis pH 10 was found. Ideal temperature of the preparation was determined to be 35 °C, but the temperature does not have a significant effect on the catalyst properties.

Wide pH Range Electroless Copper Deposition at Room Temperature EQCM and CV Study of Autocatalytic Copper(II) Reduction by Cobalt(II)-Pentaethylenehexamine Complexes

2014 ◽  
Vol 58 (43) ◽  
pp. 11-28
Author(s):  
E. Norkus ◽  
I. Stankevi iene ◽  
L. Tamaauskaite-Tamai naite ◽  
G. Stalnionis ◽  
K. Pruinskas ◽  
...  
Keyword(s):  
Room Temperature ◽  
Copper Deposition ◽  
Electroless Copper ◽  
Wide Ph Range ◽  
Ph Range

NANOEMULSIONS BASED ON LIPOIC ACID DERIVATIVES WITH VARIOUS ALCOHOLS: PRODUCTION AND INFLUENCE ON FUNCTIONAL ACTIVITY OF PLATELETS

2020 ◽  
pp. 461-464
Author(s):  
A. Sinebryukhova ◽  
A. Shipelova ◽  
E. Darnotuk ◽  
A. Chekanov ◽  
O. Baranova ◽  
...  
Keyword(s):  
Particle Size ◽  
Arachidonic Acid ◽  
Lipoic Acid ◽  
Encapsulation Efficiency ◽  
Room Temperature ◽  
Optimal Conditions ◽  
Pluronic F68 ◽  
Long Term Storage ◽  
Term Storage

The optimal conditions were selected for obtaining homogeneous nanoemulsions (NE) of lipoic acid conjugates (LA-conjugates) based on Pluronic F68 (1,8%) with a particle size not exceeding 400 nm, characterized by 97±2% encapsulation efficiency of substances in nanoparticles (NP). A heterogeneous NE (polydispersity index, PDI>0,3) with the derivative of LA and myo-inositol based on phosphatidylcholine (PC, C = 3 mg/ml) was also obtained consisting of 2 particle fractions: 20–70 nm (27%) and 122–212 nm (73%). The obtained NEs with LA-conjugates based on Pluronic F68 and PC were stable during long-term storage (more than 12 months) at room temperature. The effect of the obtained NEs of LA-conjugates on platelet aggregation (Pt) caused by arachidonic acid (AA) was determined, and a mechanism of their action was proposed.

scholarly journals EUPHORBIA CADUCIFOLIA HAINES, EUPHORBIA NIVULIA BUCH. HAM AND EUPHORBIA TIRUCALLI LINN. LATEX SHELF-LIFE ASSESSMENT OF EUPHORBIA ANTIQUORUM LINN.

2020 ◽  
pp. 119-123
Author(s):  
SUDIPTA ROY ◽  
RABINARAYAN ACHARYA ◽  
ANAGHA RANADE ◽  
M. S. CHOLERA
Keyword(s):  
Shelf Life ◽  
Room Temperature ◽  
Microbial Growth ◽  
Life Assessment ◽  
Fungal Culture ◽  
Standard Protocol ◽  
Euphorbia Tirucalli ◽  
Physical Attributes ◽  
Ph Range

Objective: In the present study, an attempt was made to assess the shelf life of the Snuhi latex which is frequently used in fresh condition for the preparation of Ksharasutra, a medicated thread, used in Ayurveda. Methods: The latex of E. antiquorum, E. caducifolia, E. nivulia and E. tirucalli were collected individually and stored in air tight glass vials during the month of May, 2018. Physical attributes like Colour, odour, appearances, pH and microbial load of all four samples were assessed as per standard protocol. Assessment was made every day, 9 AM, for 7 d in room temperature and for 10 d in refrigerated samples. Results: Result shows that, pH range (start-end day) was 4.25-5.18, 4.79-5.12, 4.48-4.76 and 4.40-5.42 in case of E. antiquorum, E. caducifolia, E. nivulia and E. tirucalli at room temperature. It was found that, Aspergillus niger was found in Euphorbia antiquorum, Euphorbia caducifolia whereas Candida albicans was found in Euphorbia tirucalli latex in fungal culture on the 7th day after collection, when the samples were stored at room temperature. All the samples were free from microbial growth up to 10thday when stored at 4-5 °C in a refrigerator. Conclusion: Temperature, and moisture affects the quality of fresh snuhi latex. The latex remains free from microbial growth up to six days in room temperature and up to 10 d under at refrigerated temperature (4-5 °C).

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