Change in electrosurface properties of Methylomonas rubra cells at contact interaction with particles of silicon dioxide

1993 ◽  
Vol 39 (9) ◽  
pp. 902-905 ◽  
Author(s):  
A. S. Gordienko ◽  
I. V. Zbanatskaya ◽  
I. K. Kurdish
Keyword(s):  
Silicon Dioxide ◽  
Contact Interaction ◽  
Negative Charge ◽  
Highly Dispersed ◽  
Adsorption Processes

The addition of highly dispersed silicon dioxide to a suspension of Methylomonas rubra cells under defined conditions resulted in an increasing negative charge in the cells. This phenomenon is not explained in terms of the known conceptions of adsorption processes, in spite of the fact that it is probably a consequence of the contact interaction between cells and silicon dioxide particles.Key words: contact interaction, electrosurface property, silicon dioxide, Methylomonas rubra.

scholarly journals MECHANOCHEMICAL AND ULTRASONIC TREATMENT – A CONTROLLED METHOD FOR FORMING THE STRUCTURE AND PROPERTIES OF NANOCOMPOSITE GEL SYSTEMS

2021 ◽  
Vol 2 (446) ◽  
pp. 36-44
Author(s):  
А.О. Zhapekova ◽  
N.N. Mofa ◽  
B. Elouadi ◽  
R.S. Iminova ◽  
А.Е. Bakkara ◽  
...  
Keyword(s):  
Silicon Dioxide ◽  
Microcrystalline Cellulose ◽  
Ultrasonic Treatment ◽  
Homogeneous System ◽  
The State ◽  
Gelling Agent ◽  
Structure And Properties ◽  
Colloidal Systems ◽  
Silica Powder ◽  
Highly Dispersed

In this work, the preparation of colloidal systems with microcrystalline cellulose as a gelling agent and silica powder as a filler was considered. By mechanochemical and ultrasonic treatment of a filler made of silicon dioxide and a colloidal base, varying the constituent ingredients, one can purposefully influence the structure of the system and regulate the properties of the resulting compositions. It is shown that the introduction of a filler made of highly dispersed silicon dioxide into a gel system based on cellulose, modified by ultrasonic treatment (UST) with acid additives, provides both acceleration of the gelation process and stabilization of the state of the obtained colloidal composition. As a result of UST, a nanostructured colloidal homogeneous system is formed.

A Simple Nanocasting Route for Preparation of Mesoporous Titanium Dioxide/GCM Microsphere

2014 ◽  
Vol 521 ◽  
pp. 576-580
Author(s):  
Hai Bin Yang ◽  
Wei Rao
Keyword(s):  
Titanium Dioxide ◽  
Theoretical Analysis ◽  
Silicon Dioxide ◽  
Titanium Dioxide Nanoparticles ◽  
Graphitic Carbon ◽  
Carbon Microspheres ◽  
Highly Dispersed ◽  
Nanocasting Route ◽  
Mesoporous Titanium Dioxide ◽  
Battery Material

Mesoporous titanium dioxide/graphitic carbon microspheres were synthesized by a simple nanocasting route using monodisperse silicon dioxide microspheres as the template. The characterize and the morphology of the titanium dioxide/graphitic carbon microspheres have been analyzed by means of XRD, N2-sorption, SEM, TEM, TG-DTA and EDAX. Indicated by the experimental results and the theoretical analysis, the anatase titanium dioxide nanoparticles of 8-14 nm in diameter were highly dispersed in the graphitic carbon microspheres. The obtained material can be used as catalyst or battery material. Key words: titanium dioxide/graphitic carbon; Microspheres; Nanocasting route;Mesoporous

Effect of ageing on surface charge characteristics and adsorption behaviour of cadmium and arsenate in two contrasting soils amended with biochar

Soil Research ◽  
2014 ◽  
Vol 52 (2) ◽  
pp. 155 ◽  
Author(s):  
Chamali Laksala Nagodavithane ◽  
Balwant Singh ◽  
Yunying Fang
Keyword(s):  
Surface Charge ◽  
Contaminated Soils ◽  
Negative Charge ◽  
Exchange Capacity ◽  
Batch Adsorption ◽  
Adsorption Behaviour ◽  
Solution Ph ◽  
Adsorption Method ◽  
Adsorption Processes ◽  
Anionic Species

Biochar has been recognised as an effective amendment for the remediation of contaminated soils; however, there is limited knowledge on the effects of biochar ageing in soil on its adsorption behaviour for cationic and anionic species. Biochars are considered to develop negative charge from oxidation with ageing, which may create additional interaction mechanisms for adsorption processes. In the present study, surface charge characteristics and cadmium (Cd) and arsenate (AsO43–) adsorption behaviour of aged biochar were investigated in two soils with variable charge, an Oxisol and an Inceptisol, by comparing (i) unamended soils, and soils amended with (ii) fresh biochar (450°C) and (iii) biochar (450°C) aged for 12 months, applied at a rate of 2% w/w. Surface charge characteristics were assessed using the ‘index’ ion adsorption method, with a LiCl electrolyte. Batch adsorption studies were conducted using fresh and aged soil–biochar mixtures. In contrast to previous studies, the results provided no evidence of an increase in cation exchange capacity as a consequence of biochar ageing. There was an increase in Cd adsorption in the presence of aged biochar in both soil types compared with unamended soils and soils amended with fresh biochar. Results also indicated an increase in AsO43– adsorption in the Inceptisol amended with aged biochar, whereas a decrease in AsO43– adsorption was observed in the Oxisol amended with aged biochar. Overall, the study has highlighted that adsorption behaviour of aged biochar varies depending on the ion it interacts with, soil properties and solution pH.

Confirmation of Aluminum-Induced Negative Charge in Native Silicon Dioxide

1991 ◽  
Vol 30 (Part 1, No. 10) ◽  
pp. 2466-2467 ◽  
Author(s):  
Hirofumi Shimizu ◽  
Chusuke Munakata
Keyword(s):  
Silicon Dioxide ◽  
Negative Charge

scholarly journals Enhanced Removal of Metal Ions from Water by Novel Composite Magnesia-Amended Silica Granules

2009 ◽  
Vol 27 (4) ◽  
pp. 383-394
Author(s):  
P. Y. Zhu ◽  
H.Z. Wang ◽  
X. Li ◽  
X.F. Tang
Keyword(s):  
Silicon Dioxide ◽  
Metal Ions ◽  
Contact Time ◽  
Ph Value ◽  
Weak Acid ◽  
Adsorption Processes ◽  
Infrared Spectral ◽  
Removal Of Metal ◽  
Removal Of Metal Ions ◽  
Best Fit

The potential of a novel sorbent, magnesia-amended silica granules (MAS), for the removal of metal ions from aqueous solution has been examined. MAS, prepared by calcining magnesium chloride-impregnated silicon dioxide at 773 K, exhibited an adsorption capacity towards metal ions that was 15- to 30-times larger than that of silicon dioxide. Batch sorption studies were performed as a function of contact time and pH. X-Ray powder diffraction (XRD), infrared spectral analysis (FT-IR), porosity and surface area measurements were used to characterize the physicochemical properties of MAS. At an initial concentration of 50 mg/ℓ, more than 90% removal of metal ions was achieved within 8 h contact time at a weak acid pH value. Of the kinetic models tested, the pseudo-second-order model gave the best fit to the kinetic data, while the Langmuir isotherm model provided the best fit to the equilibrium adsorption data for metal ions onto MAS. The adsorption processes were endothermic.

scholarly journals Research of the adsorption of aliphatic carboxylic acids on the surface of polysorb

2020 ◽  
Vol 64 (10) ◽  
pp. 63-67
Author(s):  
Alexander A. Kimyashov ◽  
◽  
Alexander V. Syromolotov ◽  
Maksim O. Pavlov ◽  
◽  
...  
Keyword(s):  
Silicon Dioxide ◽  
Carboxylic Acids ◽  
Targeted Delivery ◽  
Overweight People ◽  
Saturation Region ◽  
Highly Dispersed ◽  
Medicinal Substances ◽  
Pseudo Second Order ◽  
Aliphatic Carboxylic Acids ◽  
Kinetics Of

The enterosorbent "Polysorb" is a highly dispersed powder of silicon dioxide. In medicine, it is used as a detoxifier for poisoning with organic substances and heavy metals. Recently, the direction in pharmaceuticals related to targeted delivery of medicines has begun to develop. One of the carriers of medicinal substances is highly dispersed silicon dioxide. There are explorations that show that with simultaneous oral administration of highly dispersed silicon dioxide and the antibiotic amphotericin, the concentration of the latter in the blood increases significantly. Recently, there have been studies showing that delivering propionic acid to the gut reduces fat accumulation in overweight people. The goal of this work is study the adsorption of aliphatic carboxylic acids, namely: formic, acetic, propionic on the surface of polysorb. Using electron microscopy, it was shown that polysorb powder consists of particles of different sizes and shapes. Their size varies from units to tens of micrometers. Adsorption isotherms of formic, acetic, and propionic acids were constructed at a temperature of 295 K. It is shown that they have an S-shaped character, therefore, adsorption is due to the formation of hydrogen bonds between the silanol groups of the hydrated POLYSORB and the carboxyl groups of acids. It is established that these isotherms are adequately described by the Freundlich model up to the saturation region. With an increase in the hydrocarbon radical, the adsorption capacity of acids decreases. The kinetics of acid adsorption on the polysorb surface was described using pseudo-first and pseudo-second order models. It was found that the adsorption kinetics of carboxylic acids is adequately described by the pseudo-first-order model. The time of onset of adsorption equilibrium is 30 seconds at a temperature of 295 K.

The Fine Structure of Glycocalyx in Human Spermatozoa. A High Resolution Cytochemical Study

1973 ◽  
Vol 31 ◽  
pp. 640-641
Author(s):  
P. Hernández-Jáuregui ◽  
A. Sosa ◽  
A. González Angulo
Keyword(s):  
Negative Charge ◽  
Iron Hydroxide ◽  
Human Spermatozoa ◽  
Surface Coat ◽  
Cell Surfaces ◽  
Colloidal Iron ◽  
Cytochemical Study ◽  
Specific Permeability ◽  
Extracellular Glycoprotein ◽  
Mammalian Spermatozoa

Glycocalyx is the name given by Bennett to the extracellular glycoprotein coat present in some cell surfaces. It appears to play an important role in cell properties such as antigenicity, cell adhesivity, specific permeability, and ATP ase activity. In the sperm this coat can be directly related to such important phenomena as capacitation and fertilization. The presence of glycocalyx in invertebrate spermatozoa has already been demonstrated. Recently Yanagimachi et al. has determined the negative charges on sperm surfaces of mammalian spermatozoa including man, using colloidal iron hydroxide. No mention was made however of the outer surface coat as composed of substances other than those confering a negative charge. The purpose of this work was therefore to determine the presence of a glycocalyx in human spermatozoa using alcian blue and lanthanum staining.

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