Khan, Abdul Farhan (2008) STUDY ON EFFECT OF HEAVY METALS AND THE STABILIZATION OF HYDROGEN PEROXIDE BLEACH BATH BY POLYCARBOXYLIC ACID, AMINO POLYCARNOXYLIC ACID, POLY AMINOPHOSPHONIC ACID, AND THEIR SALTS. PhD thesis, University of Karachi, Karachi.
This study gives a comparative view on the performance of sodium silicate and organic or non-silicate stabilizers. The role of stabilizers is to reduce the rate of hydrogen peroxide decomposition by forming complex with hydrogen peroxide, i.e. an intermediary compound, and with metal ions in the solution. Sodium silicate was the first stabilizer used for hydrogen peroxide bleaching. But the problem of silicaceous deposits on fabric and equipment led to the search for better stabilizers. Six new organic compounds (stabilizers) were investigated under same conditions named, 2.5-Dimethvl-2,4-hexadiene-1,6-dioic acid, molecular formula (C8H10O4), I 12 Dodecanedicarboxvlic acid, molecular formula (C12H2204 ), N-2-Hvdroxyethvl-N.N diacetic acid amine molecular formula (C6HIINO5), 2-Amino-ethvl phosphonic acid, molecular formula (C2H5N03P), 3-Amino-1.1.3-Propanetricarboxvlic acid, molecular formula (C6H9N06) and 1.8-Decanedicarboxvlic acid, molecular formula (CIOH1804).The criteria chosen for assessing stabilizers performance was to carry out hydrogen peroxide bleaching along with and without substrate and with metal ions. Also residual hydrogen peroxide over a period of time in the presence of different stabilizer was measured. To understand more about stabilizers effect, other parameters such as whiteness index, tensile strength, absorbency and fluidity were studied. The CIE whiteness index value of fabrics was measured by a spectrophotometer using appropriate computer software. Universal Strength Tester (Titan) was used to measure tensile strength. Ostwald - Fenske Cuen viscosimeter was used to determine chemical degradation of cotton fabric by measurement of its fluidity and embroidery hoop was used to determine absorbency. The general introduction shows complete and up-to-date analysis and literature survey. The experimental part shows all the equipments, chemicals and substrates used. The results on this investigation have been discussed in details. As a result of this research, highly active organic stabilizers for hydrogen peroxide bleaching were found.
|Item Type:||Thesis (PhD)|
|Uncontrolled Keywords:||heavy metals, hydrogen peroxide bleach bath, polycarboxylic acid, amino polycarnoxylic acid, poly aminophosphonic acid, sodium silicate, non-silicate stabilizers, silicaceous deposits, rope bleaching, open width bleaching|
|Subjects:||Physical Sciences (f) > Chemistry(f2)|
|Deposited By:||Mr. Javed Memon|
|Deposited On:||03 Aug 2009 09:44|
|Last Modified:||10 Oct 2009 18:22|
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