scholarly journals Titanium Silicates Precipitated on the Rice Husk Biochar as Adsorbents for the Extraction of Cesium and Strontium Radioisotope Ions

2019 ◽  
Vol 3 (1) ◽  
pp. 36 ◽  
Author(s):  
Igor Zhuravlev
Keyword(s):  
Hydrothermal Treatment ◽  
Rice Husk ◽  
Aqueous Media ◽  
Distribution Coefficients ◽  
Water Soluble ◽  
Titanium Sulfate ◽  
Titanium Silicates ◽  
Different Temperatures ◽  
Thermochemical Processing ◽  
Strontium Ions

The aim of the work was the development of cheap and effective adsorbents based on titanium silicates deposited on the products of thermochemical processing of rice husk to extract cesium and strontium radioisotopes from aqueous media. Synthesis of adsorbents was carried out using the cheapest and widely used titanium water-soluble reagent, titanium sulfate (an intermediate product of white rutile pigment production), as feedstock. After treatment with titanium sulfate and neutralization, hydrothermal treatment was carried out in various ways. The traditional method of processing in an autoclave was used, as well as the blowing at different temperatures by steam. The distribution coefficients and the adsorption capacity for cesium and strontium ions on these sorbents were studied. Along with the chemical composition of adsorbents obtained by those ways, the type and the temperature of hydrothermal treatment also affected the adsorption properties. It was found that the adsorbent obtained by hydrothermal treatment in an autoclave has the highest degree of cesium ions extraction (Kd = 27,500). The highest degree of strontium ions extraction (Kd = 2,095,000) has an adsorbent obtained by hydrothermal treatment with water vapor blowing.

scholarly journals Self-Healing Polymer-Clay Hybrids by Facile Complexation of a Waterborne Polymer with a Clay

2021 ◽  
Author(s):  
Aranee Pleng Teepakakorn ◽  
Makoto Ogawa
Keyword(s):  
Vinyl Alcohol ◽  
Aqueous Media ◽  
Water Soluble ◽  
Poly Vinyl Alcohol ◽  
Self Healing ◽  
Soluble Polymer ◽  
Water Soluble Polymer ◽  
Smectite Clay

Water-induced self-healing materials were prepared by the hybridization of a water-soluble polymer, poly(vinyl alcohol), with a smectite clay by mixing in an aqueous media and subsequent casting. Without using chemical...

Dissociation of imino proton(s) of a highly water-soluble metal-free phthalocyanine and determination of its pKa value in water

2013 ◽  
Vol 17 (06n07) ◽  
pp. 447-453 ◽  
Author(s):  
Hiroaki Isago ◽  
Harumi Fujita
Keyword(s):  
Aqueous Media ◽  
Thermal Reaction ◽  
Water Soluble ◽  
Acid Dissociation ◽  
Acid Dissociation Constant ◽  
Metal Free ◽  
Imino Proton ◽  
Pka Value ◽  
Triton X

Dissociation of imino proton(s) in the cavity of the macrocycle of a highly water-soluble, metal-free phthalocyanine ( H 2( H 4 tsppc ); where H 4 tsppc denotes tetrakis{(2′,6′-dimethyl-4′-sulfonic acid)phenoxy}phthalocyaninate) in ethanolic and aqueous solutions has spectrophotometrically been investigated. The spectral changes associated with reaction with NaOH have been found to involve one-proton transfer process in aqueous media while two-protons process in ethanolic media. The acid-dissociation constant of the first imino proton in water (in the presence of Triton X-100) has been determined to be 12.5 ± 0.2 (as pKa) at 25 °C. The doubly deprotonated species in EtOH has been easily converted to its corresponding cobalt(II) derivative by thermal reaction with anhydrous CoCl 2.

scholarly journals Poly(N-isopropylacrylamide-co-methacrylic acid) microgel stabilized copper nanoparticles for catalytic reduction of nitrobenzene

2015 ◽  
Vol 33 (3) ◽  
pp. 627-634 ◽  
Author(s):  
Zahoor H. Farooqi ◽  
Zonarah Butt ◽  
Robina Begum ◽  
Shanza Rhauf Khan ◽  
Ahsan Sharif ◽  
...  
Keyword(s):  
Copper Nanoparticles ◽  
Methacrylic Acid ◽  
Catalytic Reduction ◽  
Aqueous Media ◽  
Activation Parameters ◽  
Reducing Agent ◽  
Different Temperatures ◽  
Entropy Of Activation ◽  
Micro Reactors

Abstract Poly(N-isopropylacrylamide-co-methacrylic acid) microgels [p(NIPAM-co-MAAc)] were synthesized by precipitation polymerization of N-isopropylacrylamide and methacrylic acid in aqueous medium. These microgels were characterized by dynamic light scattering and Fourier transform infrared spectroscopy. These microgels were used as micro-reactors for in situ synthesis of copper nanoparticles using sodium borohydride (NaBH4) as reducing agent. The hybrid microgels were used as catalysts for the reduction of nitrobenzene in aqueous media. The reaction was performed with different concentrations of cat­alyst and reducing agent. A linear relationship was found between apparent rate constant (kapp) and amount of catalyst. When the amount of catalyst was increased from 0.13 to 0.76 mg/mL then kapp was increased from 0.03 to 0.14 min-1. Activation parameters were also determined by performing reaction at two different temperatures. The catalytic process has been discussed in terms of energy of activation, enthalpy of activation and entropy of activation. The synthesized particles were found to be stable even after 14 weeks and showed catalytic activity for the reduction of nitrobenzene.

One-Pot Synthesis of Water Soluble, Extremely Small-Sized Superparamagnetic Magnetite Nanoparticles

2012 ◽  
Vol 531 ◽  
pp. 219-222
Author(s):  
Li Hua Shen ◽  
Ting Shang ◽  
Jun Zhou ◽  
Dong Wang ◽  
Yu Han ◽  
...  
Keyword(s):  
Magnetite Nanoparticles ◽  
Room Temperature ◽  
Colloidal Stability ◽  
Aqueous Media ◽  
Mri Contrast Agents ◽  
Water Soluble ◽  
Potential Candidate ◽  
One Pot ◽  
Mri Contrast

Extremely small-sized superparamagnetic magnetite nanoparticles of 3Cit). The resulting Cit-coated magnetite nanoparticles exhibited long-term colloidal stability in aqueous media without any surface modification. Regarding the magnetic properties, the nanoparticles were superparamagnetic at room temperature, and might be the potential candidate for MRI contrast agents.

Solubilization of poorly water‐soluble bioactive molecules in neutral aqueous media by complexation with renatured β‐1,3‐1,6‐glucan nanoparticles

Biopolymers ◽  
2020 ◽  
Vol 111 (4) ◽  
Author(s):  
Ayumu Kodama ◽  
Akifumi Nakagawa ◽  
Yuki Nonoguchi ◽  
Haruka Sakurai ◽  
Chieko Yano ◽  
...  
Keyword(s):  
Aqueous Media ◽  
Water Soluble ◽  
Bioactive Molecules ◽  
Poorly Water Soluble

scholarly journals Sequential extraction and thermal desorption of mercury from contaminated soil and tailings from Mongolia

2012 ◽  
Vol 10 (5) ◽  
pp. 1565-1573 ◽  
Author(s):  
Pavel Coufalík ◽  
Pavel Krásenský ◽  
Marek Dosbaba ◽  
Josef Komárek
Keyword(s):  
Sequential Extraction ◽  
Thermal Desorption ◽  
Solid Phase ◽  
Extraction Procedure ◽  
Speciation Analysis ◽  
Water Soluble ◽  
Mercury Species ◽  
Different Temperatures ◽  
Acidic Conditions ◽  
Desorption Method

AbstractMercury forms in contaminated environmental samples were studied by means of sequential extraction and thermal desorption from the solid phase. The sequential extraction procedure involved the following fractions: water soluble mercury, mercury extracted in acidic conditions, mercury bound to humic substances, elemental Hg and mercury bound to complexes, HgS, and residual mercury. In addition to sequential extraction, the distribution of mercury species as a function of soil particles size was studied. The thermal desorption method is based on the thermal decomposition or desorption of Hg compounds at different temperatures. The following four species were observed: Hg0, HgCl2, HgS and Hg(II) bound to humic acids. The Hg release curves from artificial soils and real samples were obtained and their applicability to the speciation analysis was considered.

scholarly journals Adsorption Studies of Cyanide (CN)- on Rice Husk Ash (RHA)

2011 ◽  
Vol 46 (1) ◽  
pp. 101-104 ◽  
Author(s):  
S Naeem ◽  
U Zafar ◽  
T Amann
Keyword(s):  
Rice Husk ◽  
Contact Time ◽  
Rice Husk Ash ◽  
Cyanide Solution ◽  
Adsorption System ◽  
Solution System ◽  
Adsorbate Concentration ◽  
Adsorption Data ◽  
Batch Technique ◽  
Different Temperatures

In this investigation, adsorption of cyanide has been studied by means of batch-technique. Percentage adsorption was determined for Rice Husk Ash (RHA)-Cyanide solution system as a function of i) contact time, ii) pH, iii) adsorbate concentration and iv) temperature. Adsorption data has been interpreted in terms of Freundlich and Langmuir equations. Thermodynamics parameters for the adsorption system have been determined at three different temperatures. The value of ΔH°=38.326KJ/mole and ΔG°=-6.117KJ/mole at 283°K suggest that the adsorption of cyanide on RHA is an endothermic and a spontaneous process.Key words: Cyanide; Rice husk ash (RHA); Adsorption Isotherms DOI: http://dx.doi.org/10.3329/bjsir.v46i1.3524 Bangladesh J. Sci. Ind. Res. 46(1), 101-104, 2011

scholarly journals TWO-STEP CROSSLINKING OF PVP/GEL NANOFIBERS

2021 ◽  
Vol 2021 ◽  
pp. 164-170
Author(s):  
H.K. Güler ◽  
F.C. Çallıoğlu
Keyword(s):  
Fiber Diameter ◽  
Experimental Studies ◽  
Water Soluble ◽  
Diameter Distribution ◽  
Sem Images ◽  
Crosslinking Process ◽  
Different Temperatures ◽  
Ft Ir ◽  
Ir Analysis ◽  
Gel Polymers

In this study, it was achieved that crosslinking of PVP/GEL nanofibers with two-steps. Crosslinking is a process highly important for water-soluble polymers in terms of application areas and mechanical properties. Firstly, crosslinking of PVP polymers experimental studies were carried out via heat treatment at different temperatures and times. Then, GEL polymers were crosslinked with GTA vapour at different times. Morphological analysis was carried out via SEM images and chemical characteristics were determined via FT-IR analysis. Moreover, after the crosslinking process, SD and WL values were calculated. All results showed that before crosslinking of SEM images, nanofibers were smooth, fine and without beads. The average fiber diameter is 196 nm and the fiber diameter distribution is quite uniform. After crosslinking of SEM images, it is expected that all nanowebs will turn from fibrous surfaces to membranous. Generally, SD and WL values decrease with crosslinking time increase. According to all of the SEM images, SD and WL values, optimum conditions were determined for PVP as 4 hours at 180oC and for GEL as 24 hours. Lastly, the presence of PVP and GEL polymers in the nanofiber structure was verified chemically with FT-IR analysis.

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