LOCAL PRODUCTION OF ALGINATE AND ITS APPLICATION IN CONTROL OF CRYSTALLIZATION OF EPSOM SALT PRODUCED FROM SEA WATER

Abstract

Alginate (an extract from seaweed e.g. Sargassum fluitans) that finds applications largely in nanotechnology, industrial/pharmaceutical processes have not been produced locally. Sargassum fluitans harvested from Agbama Sea, in Andoni, Rivers State was dried, ground and reacted with CaCl2 (3.02g) in 300 ml of deionized water. The mixture was allowed to stand for 24 h before filtration and the residue reacted with 1 % HCl in 100 ml of distilled water for 1 h. The recovered residue was washed thrice with 300 ml of distilled water and reacted further with Na2CO3 (containing 9.66 g in 300 ml of distilled water) for 24 h before the addition of 250 ml of distilled water. This was allowed to stand for 1 h before filtration. The filtrate was then mixed with 1:1 (vol/vol) Ethanol/water and allowed to stand. The mixture separated into two layers and the denser bottom layer was collected with a separatory funnel and allowed to dry for 72 h to form a light brownish sodium alginate powder. Similarly, MgSO4.7H2O was extracted from brackish water, by reacting the evaporated salt with CaO to precipitate Mg(OH)2 which was further reacted with 0.1 M HCl and the mixture evaporated to yield MgCl2. The recovered MgCl2 was stoichiometrically reacted with (NH4)2SO4 to crystallize MgSO4.7H2O upon heating. It was tailored to nanoscale by adding 10 ml of alginate solution (0.1 g in 100 ml of water) to several volumes (10, 20, 30 and 40 ml) of 0.1 M MgSO4.7H2O mixed thoroughly, dried and ashed at 750 ˚C to eliminate the alginate residue. The resultant porous aggregate polycrystallites are shown on the Scanning Electron Microcopy (SEM) micrographs. Antimicrobial activity with Agar well diffusion method showed that the nanoparticles and the bulk sample both were non susceptible to pseudomonas aeruginosa being a known macronutrient. SEM, UV-Vis and FTIR analysis confirmed tailored differences with varied alginate gel volume used.