تحضير ودراسة حركية بولمرات الامتصاص العالي للماء من مصادر زراعية وتطبيقاتها لاطلاق الاسمدة == Preparation and Kinetic Study of Super absorbent Polymers Based on Agriculture Resources and their Applications as Fertilizer Release
Author name:
صلاح محمود عبد الله مسربت
Supervisor name:
طارق سهيل نجم
General topic:
Chemistry
Specific topic:
Chemistry
Degree:
Doctorate
University:
Mustansiriyah University - College Of Science
Language:
English
University location:
Baghdad
First pages:
25T1806 - p.pdf
Abstract:
The present work deals with the extraction of cellulose from Reeds and Rushes, which are wild plants, grow in most parts of Iraq near the bank of rivers but especially at the southern part of Iraq in the marshes. The cellulose from these plants were extracted by alkali cooking via two methods, in the first one, which is a well known method, high temperature with pressure were used, while the second one which is developed by our laboratory to avoid the high temperature and pressure as well as, the cellulose extracted from reeds and rushes used as it is without purification, the development was carried out in order to be feasible in industrial application. The effect of pH on swelling capacity was also studied and revealed that the maximum swelling capacity was obtained at neutral and near neutral environment. Moreover, the swelling of these polymers, studied in different types of water, Tap water, Saline water 0.9% NaCl beside the distilled water, showed that the swelling capacity in these media was lower than that in distilled water, which is in agreement with that found in the literature. In order to increase the swelling capacity of the super absorbent polymers, a composite with the Iraqi bentonite was attempted, a simple increase in the swellingcapacity was achieved at 15% bentonite but, unfortunately soft material was obtained.The swelling kinetics for both polymers SAP - AA and SAP - AAm were studied, the results reveal that both polymers follow the second - order kinetic model, and the second order rate constants were 1.3 x 10 - 5 and 1.9 x 10 - 5 min - 1. g - 1 for SAP - AAm and SAP - AA respectively. Krosmeyer - Peppas equation was applied to the experimental data, which reveal that the swelling follow Fickian diffusion mechanism. Heat of swelling was evaluated through the effect of temperature on swelling capacity at different temperature and found to be 4.05 and 27.78 KJ/mole for SAP - AA and SAP - AAm respectively. The ability to use the super absorbent polymers in agriculture was also studied through, first : the ability of those polymers to retain water or its evaporation percentage (EP), in this aspect unfortunately the surface crosslinking was not done for the polymers so, the evaporation percentage was somewhat high, and second : The use of polymers to release fertilizers, both polymers were loaded with dipotassium hydrogen phosphate (DPHP) and the release was studied in distilled water and in soil using distilled water for irrigation every four days, it was found that the release data follow second order kinetic, the release of fertilizer in soil reveals that the fertilizer can last for about four months in case the irrigation is done every four days.
