Study Of Physiochemical Properties Research Articles

Surfactant Modified Bentonite Characterization: Effects and Comparative Analysis

Extensive soils can be found all over the world. The clay mineral montmorillonite is predominantly responsible for soil expansion. Because of their ability to shrink and swell with seasonal changes in moisture content, these expansive soils can cause significant damage to engineering construction. To stabilize the effects of swelling soil various ground improvement techniques, incorporate mineralogical modification of clays. The application of nanotechnology increased in past few years to deal with clay minerals as it possesses the same dimensional properties. To understand the behaviour of Nano modified clay, bentonite was selected as it represents the montmorillonite clay mineral. The characterization of surface-treated bentonite by nanomaterial was carried out. The study of physio-chemical properties and textural properties of surface-modified bentonite clay was carried out. Swelling pressure was evaluated by a consolidometer test. With the advanced nanotechnology instrumentation technique, particle size analysis, zeta potential, wettability, contact angle, infra-red spectroscopy, rheological properties, BET surface area, pH values, XRD, TGA, etc was carried out for treated and untreated soil, to understand the comparative behaviour of surface modification. It was found that by using Nano surfactant, liquid limit and shrinkage limit were reduced considerably. The increase in the quantity of surfactant increases the d-spacing. Thermal stability and particle size increase after surface treatment of bentonite clay. Soil reaches a visco-elastic state and BET surface area decreased after surface modification.

Nanofluorapatite Hydrogels in the Treatment of Dentin Hypersensitivity: A Study of Physiochemical Properties and Fluoride Release.

The aim of this work was to prepare a new hydrogel based on nanohydroxyapatite (nFAP, 10% w/w) and fluorides (4% w/w), both of which are used as sources of fluoride ions in the treatment of dentin hypersensitivity, and to characterize its physicochemical properties. The release of fluoride ions from 3 gels (G-F, G-F-nFAP, and G-nFAP gel) was controlled in Fusayama-Meyer artificial saliva at pH 4.5, 6.6, and 8.0. The properties of the formulations were determined by an analysis of viscosity, a shear rate test, a swelling study, and gel aging. Various methods, i.e., FT-IR spectroscopy, UV-VIS spectroscopy, and thermogravimetric, electrochemical, and rheological analysis, were used for the experiment. The profiles of fluoride release indicate that the amount of fluoride ions released increases with a decrease in the pH value. The low pH value facilitated water absorption by the hydrogel, which was also confirmed by the swelling test, and it promoted the exchange of ions with the surrounding environment. Under conditions similar to physiological conditions (at pH 6.6), the amounts of fluorides released into artificial saliva were approximately 250 µg/cm2 and 300 µg/cm2 for the G-F-nFAP hydrogel and G-F hydrogel, respectively. The aging study and properties of the gels showed a loosening of the gel network structure. The Casson rheological model was used to assess the rheological properties of the non-Newtonian fluids. Hydrogels consisting of nanohydroxyapatite and sodium fluoride are promising biomaterials in the prevention and management of the dentin hypersensitivity.

Biodiesel Production from Waste Animal Fat by Transesterification Using H2SO4 and KOH Catalysts: A Study of Physiochemical Properties

Biodiesel is marketed as a long-term renewable fuel that may partially replace fossil fuels in transportation while also helping to reduce global warming. The current study is focused on using waste animal fat as a feedstock for biodiesel production. Sulfuric acid (H2SO4) and potassium hydroxide (KOH) are used as catalysts, with methanol as an alcohol. Temperature at 60°C, reaction time 2 hrs for acid catalyst, and 55°C, reaction time 90 min for base catalyst with a methanol to oil ratio of 5 : 1 are the experimental and optimized process conditions. With the H2SO4 catalyst, the biodiesel yield was 65.7%, while with the KOH catalyst, it was 48.8%. The ASTM standards are used to compare and study the physicochemical characteristics. This study offers an environmentally friendly solution to a global problem of atmospheric pollution, and at the same time, it shows a commercial alternative to reduce the ecological impact caused by waste animal fat.

Role of nickel on vanadium poisoned FCC catalyst: A study of physiochemical properties

Active sites of Fluid catalytic cracking (FCC) catalyst are poisoned during operation in the FCC reactor due to causes including feedstock contaminant metals deposition. This leads to activity, selectivity and increasing coking problems, thereby raising concern to the refiner. This work investigated effect of nickel coexisting with vanadium in the FCC feedstock on the standard FCC catalyst during cracking process, in which destruction of active sites occurs as a result of the metals deposition. Laboratory simulated equilibrium catalysts (E-cats) were studied by XRD, FTIR spectroscopy, N2 adsorption, solid state MAS-NMR, SEM and H2-TPR. Results revealed that vanadium, above a certain concentration in the catalyst, under hydrothermal conditions, is highly detrimental to the catalyst's structure and activity. Conversely, nickel hardly affects the catalyst structure, but its co-presence in the catalyst reduces destructive effects of vanadium. The mechanism of nickel inhibition of vanadium poisoning of the catalyst is discussed.

Assimilating Mixes for a Tundish During Steel Casting Intended for Cold Rolling

The question is considered of assimilating non-metallic inclusions from metal by slag in a tundish during steel casting intended for cold rolling. The authors study changes in slag composition in a tundish and develop new assimilating mix compositions. Proceeding from results of laboratory study of physiochemical properties of the mixes developed, the authors recommend an assimilating mix for industrial tests. It is established that the rate of non-metallic Al2O3 inclusion absorption by in the given mix is several times higher than for the standard mix used.