Sharif Digital Repository

Pectin from two different plant sources: apple and sugar beet was studied. Apple pectin was modified by chemical treatments such as: acid, alkali and ammonia, so as to obtain an ester level equal to or less than 50 %, which is described as low methoxyl (LM) pectin. LM pectin form gels with significant characteristic. In this study, de-esterification of apple pectin with acid treatment resulted in gel specification with higher molecular weight and viscosity. Acid treatment resulted in pectin with average molecular weight of 32000 Dalton. Pectin was extracted from sugar beet pulp by acid and alkali treatments. The quality of gel formation and water uptake was improved using sugar source... 

The aim of the work reported was to investigate the effect of bases and neutralization steps on hydrogel microstructures. A series of porous hydrogels with various pore sizes were prepared by neutralizing a conventional hydrogel after gel formation. Scanning electron microscopy was used to characterize the microstructure of the porous hydrogels. The morphology of the samples showed the pores were induced into the hydrogels by water evaporation and gas release resulting from the neutralization process. Experimental results indicated that the hydrogels had an absorbency of 200-220 and 48-50 g g-1 for distilled water and sodium chloride solutions, respectively. A simple method was used to... 

The effects of different parameters including membrane type (regenerated cellulose and polysulphone), transmembrane pressure (TMP), the content of oil in the feed, the flow velocity of the feed and pH on the ultrafiltration of an emulsion of kerosene in water were studied. It was found that the important factors affecting ultrafiltration were, in order, membrane type, pressure and oil concentration. The greatest flux at the optimum conditions here of 3 bar, an oil content of 3% (v/v) and with membrane type C30F was predicted as 108 L/(m2 h) that was within the range of the confidence limit of the measured value of 106 L/(m2 h). The normalised FTIR results of the virgin cellulosic membranes...