Browsing AURA by Author "Christy, Alfred A."
Now showing items 1-19 of 19
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Catalytic oxidation and reduction of polycyclic aromatic hydrocarbons (PAHs) present as mixtures in hydrothermal media
Nkansah, Marian Asantewah; Christy, Alfred A.; Barth, Tanja (Journal article; Peer reviewed, 2012)The reactivity of fluorene, anthracene, and fluoranthene under oxidation and reduction conditions were investigated in this study. This project looks at catalytic and green approaches of converting PAHs to less toxic and/or ... -
Chemistry of desiccant properties of carbohydrate polymers as studied by near-infrared spectroscopy
Christy, Alfred A. (Journal article; Peer reviewed, 2013)The combination frequency of water molecule in near-infrared spectroscopy is very useful for studying water molecular adsorption on solid surfaces. The absorption is purely from water molecules, and the variation in the ... -
Effect of heat on the adsorption properties of silica gel
Christy, Alfred A. (Journal article; Peer reviewed, 2012)Adsorption properties of silica gel have been attributed to the surface hydroxyl groups of silica gel. Some hydroxyl groups are free standing and called free silanol groups. Some are hydrogen bonded to neighbouring silanol ... -
Evidence in the formation of conjugated linoleic acids from thermally induced 9t12t linoleic acid: a study by gas chromatography and infrared spectroscopy
Christy, Alfred A. (Journal article; Peer reviewed, 2009)Thermally induced isomerisation leading to the formation of conjugated linoleic acids (CLAs) has been observed for the first time during the thermal treatment of 9t12t fatty acid triacylglycerol, and methyl ester. Fifteen ... -
The Fate of Phthalates in Surface Waters During Humus Removal by Precipitation
Christy, Alfred A. (Journal article; Peer reviewed, 2010)Phthalates are esters of aromatic 1,2 di-carboxylic acids and are widely found in surface waters and their removal is necessary because of their effects on human health. Humic material in water can adsorb phthalates and ... -
Isomerization of 9c11t/10t12c CLA in Triacylglycerols
Christy, Alfred A. (Journal article; Peer reviewed, 2010)Isomers of conjugated linoleic acid from 7t9c through 12t14t can be induced by thermal treatment of triacylglycerol samples of 9c11t or 10t12c fatty acids in glass tubes. The formation of conjugated linoleic acids (CLAs) ... -
Near infrared spectroscopic characterisation of surface hydroxyl groups on hydrothermally treated silica gel
Christy, Alfred A. (Journal article; Peer reviewed, 2011)Surface hydroxyl groups on hydrothermally treated silica gel have been under discussion several decades back with contradictory conclusions. Some authors meant that the hydrothermally treated sila gel increases the ... -
Near infrared spectroscopic study on the adsorption of methanol on silica gel
Christy, Alfred A. (Journal article; Peer reviewed, 2013)The silanol groups on Silica gel surface are sites for adsorption of polar molecules. Alcohols and other polar molecules are easily adsorbed by forming hydrogen bondings with OH groups on silica gel surface. A study on the ... -
New insights into the surface functionalities and adsorption evolution of water molecules on silica gel surface: A study by second derivative near infrared spectroscopy
Christy, Alfred A. (Journal article; Peer reviewed, 2010)Surface functionalities and adsorption evolution of water molecules on silica gel samples were studied by second derivative near infrared spectroscopy. Four different silica gel samples with varying surface area were used ... -
Pyrolytic formation of polyaromatic hydrocarbons from steroid hormones
Christy, Alfred A.; Lian, Monica I.; Francis, George W. (Journal article; Peer reviewed, 2011)Four steroid hormones, namely androsterone, cholesterol, estrone and estradiol, have been pyrolysed at 300, 400 and 500 °C and the pyrolysates from these have been analysed by GC-MS. The results indicate that these formed ... -
Pyrolytic formation of polycyclic aromatic hydrocarbons from sesquiterpenes
Francis, George W.; Christy, Alfred A.; Øygarden, Jostein (Journal article; Peer reviewed, 2012)The products of the pyrolysis of four sesquiterpenes, β-caryophyllene, α-cedrene, longifolene and valencene, have been examined. Pyrolysis was carried out at 300, 400 and 500 °C, the products determined by GC–MS and then ... -
The nature of rest silanol groups on the surfaces of silica based solid phase extraction materials
Christy, Alfred A. (Journal article; Peer reviewed, 2013)Chemically bonded solid phase materials are very important in separation chemistry. The chemically modified silica gel contains rest silanol groups that can affect the retention properties when they are used for separation ... -
The use of lightweight expanded clay aggregate (LECA) as sorbent for PAHs removal from water
Nkansah, Marian Asantewah; Christy, Alfred A.; Barth, Tanja; Francis, George William (Journal article; Peer reviewed, 2012)Lightweight expanded clay aggregate (LECA) has been explored as a sorbent for the removal of PAHs (phenanthrene, fluoranthene and pyrene) from water. The efficacy of LECA as a sorbent for PAHs was assessed using contact ... -
Thermal degradation and isomerisation kinetics of triolein studied by infrared spectrometry and GC-MS combined with chemometrics
Christy, Alfred A.; Xu, Zhanfeng; Harrington, Peter de B (Journal article; Peer reviewed, 2009)Triolein, a triglyceride containing oleic acid as the only acid moiety in the glyceride molecules has been isothermally treated at 280,300,and 325 degrees C in glass vials under nitrogen atmosphere. The products formed ... -
Thermal induction of 9t12t linoleic acid: A new pathway for the formation of Conjugated Linoleic Acids
Christy, Alfred A. (Journal article; Peer reviewed, 2009)Thermal induction of 9t12t fatty acid leading to the formation of Conjugated Linoleic Acids (CLA) has been demonstrated by subjecting glyceride, and methyl ester of the acid to heat treatment. Fifteen micro liter portions ... -
Thermally Induced Isomerisation Kinetics of the 9c11t and 10t12c Conjugated Linoleic Acids in Triacylglycerols as Studied by FT-IR Spectrometry Aided by Gas Chromatography
Christy, Alfred A. (Journal article; Peer reviewed, 2010)Isomerisation kinetics of the 9c11t and 10t12c Conjugated Linoleic Acids (CLA) in triaclglycerols at isothermal conditions (250, 280 and 325oC) has been studied by infrared spectroscopy. Fifteen micro liter portions of ... -
Thermally Induced Isomerization of Trilinolein and Trilinoelaidin at 250 A degrees C: Analysis of Products by Gas Chromatography and Infrared Spectroscopy
Christy, Alfred A. (Journal article; Peer reviewed, 2009)The products formed by thermally induced isomerization of trilinolein and trilinoelaidin at 250 A degrees C were studied by infrared spectroscopy and gas chromatography. The triglycerides of the 9c12c and 9t12t fatty acids, ... -
The use of anthracene as a model compound in a comparative study of hydrous pyrolysis methods for industrial waste remediation
Nkansah, Marian Asantewah; Christy, Alfred A.; Barth, Tanja (Journal article; Peer reviewed, 2011)Polycyclic aromatic hydrocarbons are very stable compounds and tend to bioaccumulate in the environment due to their high degree of conjugation and aromaticity. Hydrous pyrolysis is explored as a technique for the treatment ... -
Water Chemistry in the Confluence Zone Downstream a Limestone Treated Lake and an Acid Tributary: Principal Component Analyses Including Warm and Cold Winters and an Episode High in Sea-Salts
Andersen, Dag Olav; Christy, Alfred A. (Journal article; Peer reviewed, 2010)Extensive limestone treatment of lakes and watercourses has been carried out especially in Norway and Sweden to counteract effects of acidification. Lakes have been the most commonly treated part of the water systems. ...