Determination of Breakthrough Curves for the Uptake of Fe3 Using Magmatic Rock Material in Fixed Bed Column

Abstract

Abstract-The breakthrough curves of the particles of magmatic rock to uptake Fe 3+ ions from aqueous solution were investigated using a fixed-bed sorption column. The effect of inlet Fe 3+ concentration, feed flow rate, bed height, initial solution pH and particle size on the breakthrough characteristics of the sorption system were investigated. 1.IntroductionExcessive concentrations of Fe +3 in public water supplies causes turbidity, unpleasant taste and odor. It imparts a brownish color to laundered cloths and stains plumbing fixtures. It also causes difficulties in distribution systems by supporting the growth of iron bacteria, resulting in the clogging of pipes (1). Therefore, the presence of Fe +3 is objectionable in certain industries such as food, textile and paper (2). Up to now, various traditional treatment technologies including chemical precipitation, filtration, ion exchange and activated carbon adsorption on a solid heterogeneous surface are widely applied (3-5). These methods, however, display one or more limitations, such as ineffective, expensive, generation of secondary pollution and narrow appliance range (6-8).Magmatic rock is an economical rock, and is included to light concrete category (9). These rocks are widely used as building stone in low storeyed buildings and especially in historical building in the past (10). One of the main advantages of Fe +3 removal using magmatic rock over the other chemical treatment methods is that any chemical sludge does not produce after sorption. The purpose of this study is to investigate the performance of magmatic rock particles in the removal of Fe +3 from aqueous solutions in a fixed-bed coloumn. The effect of influent Fe +3 concentration, pH, particle size, bed height, and flow rate on the column performance and shape of the breakthrough curves was evaluated. Kinetic column model (Bed depth service time (BDST)) was applied to describe the dynamic performance of the sorption process. 2.Material and Methods Sorbent preparationThe magmatic rock particles were grounded in a blender and sieved to obtain the particle sizes such as 0.25<x<0.5, 0.5<x< 1 and 1<x< 2 mm. Magmatic rock samples were washed with distilled water and then dried at 298 K during two weeks. The samples of 7 g were taken for sorption studies Fe +3 solutions were prepared by diluting 483 mg/L of FeCl 3 ·6H 2 O (Merck) stock solution with deionized water to a desired concentration range between 20 and 75 ppm. Fe +3 AnalysisA sample of 5 ml that has a concentration less than 20 mg Fe 3+ /100 mL was added 10 ml of 1% sulfosalicylic acid and a few drops of 25% aqueous ammonia solution to keep the value of pH between 2.1 and 3.3, and then diluted to 50 ml with distilled water. The content of Fe +3 was determined by titration with 0.05 M EDTA solution. 1 ml, 0.05 M EDTA solution is equivalent to 2.792 mg Fe +3 (11). Column experimentsContinuous flow sorption experiments were conducted in teflon columns of 1 cm i.d. and 5, 10, 15 and 20 cm heights. Fe +3 solution having an initial concentratio...