scholarly journals Colloidal stability and aggregation of lignocellulosic materials in aqueous suspension: A review

BioResources ◽  
2008 ◽  
Vol 3 (4) ◽  
pp. 1419-1491 ◽  
Keyword(s):  
Colloidal Stability ◽  
Aqueous Suspension ◽  
Supporting Electrolyte ◽  
Double Layers ◽  
Lignocellulosic Materials ◽  
Wood Extractive ◽  
Charged Surfaces ◽  
Salt Ions ◽  
Aqueous Conditions ◽  
Supporting Electrolyte Solution

Aqueous dispersions of lignocellulosic materials are used in such fields as papermaking, pharmaceuticals, and preparation of cellulose-based composites. The present review article considers published literature dealing with the ability of cellulosic particle dispersions (fiber, fines, nanorods, etc.) to either remain well dispersed or to agglomerate in response to changes in the composition of the supporting electrolyte solution. In many respects, the colloidal stability and coagulation of lignocellulosics can be understood in terms of well-known concepts, including effects due to osmotic pressure arising from overlapping electrostatic double layers at the charged surfaces. Details of the morphology and surface properties of lignocellulosic materials give rise to a variety of colloidal behaviors that make them unique. Adjustments in aqueous conditions, including the pH, salt ions (type and valence), polymers (charged or uncharged), and surfactants can be used to control the dispersion stability of cellulose, lignin, or wood-extractive materials to serve a variety of applications.

Tb2(bpdc)3 and Eu2(bpdc)3 Nanoparticles (bpdc: 2,2ʹ-Bipyridine-4,4ʹ- dicarboxylate) and Their Luminescence

2014 ◽  
Vol 69 (2) ◽  
pp. 248-254 ◽  
Author(s):  
Ana Kuzmanoski ◽  
Claus Feldmann
Keyword(s):  
Colloidal Stability ◽  
Aqueous Suspension ◽  
Earth Metal ◽  
Quantum Yields ◽  
X Ray Diffraction ◽  
Antenna Effect ◽  
Metal Centers ◽  
X Ray ◽  
Suspension Particle ◽  
Absolute Quantum

Tb2(bpdc)3 and Eu2(bpdc)3 nanoparticles (bpdc: 2,2ʹ-bipyridine-4,4ʹ-dicarboxylate) have been prepared via straightforward precipitation from aqueous solution. The nanoparticles exhibit mean diameters of 41(5) nm (Tb2(bpdc)3) and 56(4) nm (Eu2(bpdc)3) and show a very good colloidal stability in aqueous suspension. Particle size and chemical composition have been characterized based on electron microscopy, X-ray diffraction, infrared spectroscopy and thermogravimetry. Photoluminescence validates an efficient excitation of Tb3+/Eu3+ via the bpdc ligand as an antenna that leads to intense characteristic green and red emissions. The absolute quantum yields of Tb2(bpdc)3 and Eu2(bpdc)3 have been determined at 28 and 12%, respectively. Although rare-earth metal-based photoluminescence is typically quenched in water due to vibronic loss processes (v(O-H)), here, the antenna effect and the shielding of the metal centers via the bpdc ligand are very efficient, allowing for an intense green and red emission of the Tb2(bpdc)3 and Eu2(bpdc)3 nanoparticles even in aqueous suspension.

scholarly journals Evaluation of filtration efficiency for single layer and double layers alumina filter using aqueous suspension

2010 ◽  
Vol 60 (10) ◽  
pp. 505-510
Author(s):  
Osamu Yamakawa ◽  
Hiroshi Shirakawa ◽  
Osamu Sakurada ◽  
Minoru Hashiba
Keyword(s):  
Aqueous Suspension ◽  
Single Layer ◽  
Filtration Efficiency ◽  
Double Layers

scholarly journals Electrochemical fluoromethylation triggered lactonizations of alkenes under semi-aqueous conditions

2019 ◽  
Vol 10 (11) ◽  
pp. 3181-3185 ◽  
Author(s):  
Sheng Zhang ◽  
Lijun Li ◽  
Jinjin Zhang ◽  
Junqi Zhang ◽  
Mengyu Xue ◽  
...  
Keyword(s):  
Supporting Electrolyte ◽  
Aqueous Conditions

Electrochemical fluoromethylation triggered lactonizations of alkenes were achieved under chemical oxidant-, catalyst- and additional supporting electrolyte-free conditions.

Adsorption and Oxidation of Thiosulfate on a Platinum Electrode in Acid Solution

1998 ◽  
Vol 63 (1) ◽  
pp. 20-30 ◽  
Author(s):  
Tomáš Loučka
Keyword(s):  
Open Circuit Potential ◽  
Platinum Electrode ◽  
Supporting Electrolyte ◽  
Open Circuit ◽  
Adsorbed Layers ◽  
Adsorbed Substance ◽  
Adsorbed Sulfur ◽  
Adsorption Desorption ◽  
Supporting Electrolyte Solution ◽  
Thiosulfate Concentration

The adsorption of thiosulfate on a platinum electrode was measured at the open circuit potential. A monolayer of the adsorption products covers the electrode at lower thiosulfate concentrations. The charge used up during the reduction of the monolayer roughly corresponds to 0.5 electron per surface site (e.p.s.), the charge used up during the oxidation of the monolayer after reduction corresponds approximately to 4 e.p.s. Multiple adsorbed layers, which are presumably constituted mainly by adsorbed sulfur, build up at higher thiosulfate concentrations. The amount of the adsorbed substance increases with increasing thiosulfate concentration and time of adsorption. Desorption from the surface coated by multiple layers can take place in supporting electrolyte solution. The build-up of multiple adsorbed sulfur layers also takes place during adsorption from solutions of colloidal sulfur.

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