| الملخص | This study included different experiments to prepare modified montmorillonite samples (Fe-pillared clay, Al- pillared clays and organoclay) and investigate the removal efficiency and adsorption capacity of unmodified montmorillonite clay and these prepared samples for phosphor pollutants in water.
Fe-pillared clay was prepared by mixing ferric chloride (0.2M) with sodium hydroxide (0.2M). The molar ratio for Fe+3: OH- was 1:2. Montmorillonite clay was suspended in distilled water with ratio 1g clay: 5ml water, then added to Fe pillaring solution at 60°C for three- hours, aged for 6 days, after filtration and drying, prepared samples calcined at 350°C for 2 hours. Al-pillared clay was prepared by mixing (0.2M) aluminum chloride with sodium hydroxide (0.2M). Al+3: OH- ratio was 1:2.5. Montmorillonite clay was suspended in distilled water with ratio 1g clay: 5ml water, then added to Al pillaring solution at 60°C for three- hours, aged for 6 days, after filtration and drying, prepared samples calcined at 350°C for 2 hours. Organoclay was prepared by mixing montmorillonite clay with water, then hexadecyl trimethyl amine solution was added, for 10 g clay about 10 ml of amine solution was used. The solid: total liquid ratio was 10 g: 200 ml. The mixture was mixed for 3 hours at 60°C, filtered, washed and dried.
Removing of phosphor from water by using the prepared modified and unmodified clays was studied by batch experiments. Different initial concentrations (25, 50, 100 and 200 mg phosphor per liter (mg P/L) were tested at pH value 6 and contact time three hours. According to the experimental results, Fe- pillared clay had the best activity with initial concentration 100 mg P/L, phosphor final concentration was < 0.4 mg P/L with removal efficiency 98.33% and adsorption capacity 4.97 mg P/g. While using Al-pillared clay, organoclay and unmodified montmorillonite with initial concentration 25 mg P/L gave removal efficiency 98.33%, 91.43%, 61.89%, and adsorption capacities 1.18, 1.09, 0.74 mg/g clay respectively.
Different pH of phosphor solutions (4, 6, and 9) were studied for three hours with the preferred initial concentrations for each sample (100 mg P/L for Fe-pillared, 25 mg P/L for Al-pillared, organoclay and unmodified montmorillonite). The results show that changing pH has a little effect on the adsorption process. The best results were at pH 6 for modified montmorillonite (removal efficiency 98.3%, 98.3%, 91.4% and adsorption capacities 4.97, 1.18, 1.09 mg P/g clay for Fe-pillared, Al- pillared clay and organoclay respectively), and at pH 9 for unmodified montmorillonite the removal efficiency was 78.7% and adsorption capacity 0.94 mg P/g clay.
Effect of contact time was studied for 5, 10, 15, 30, 60, 90, 120 and 180 minutes. Most of the phosphate removal done in the first 60 minutes, then increased slightly. | |
