Iranian Natural Red Soil and Its Modified Form with EDTA for Removal of Phosphorous from Aqueous Solution

In water, removing excessive amounts of phosphorus is necessary to prevent eutrophication. Phosphorus can be seen usually in the form of organic phosphate and inorganic phosphate in surface waters and wastewater. Phosphates are one of the main materials of many factories and industries and it is a major factor in the development and control of water resources eutrophication. The purpose of this study is the survey of potential use of red Pumice Stone of western Azerbaijan region and its Modified form by EDTA for remove phosphate from aqueous solutions. In this study, we used the red soil of western Azerbaijan region to remove phosphorus from simulated solutions. All experiments were performed in a batch system. The effect of various parameters such as reaction time, initial concentration of phosphorus, pH and dissolved amount of adsorbent on the removal efficiency of the process was studied. The results showed that the removal efficiency increased with increasing contact time, adsorbent dose and initial concentration of phosphate ions. The highest efficiency occurred in 150 minutes of reaction time with 10 g/L adsorbent and 50 mg/ L dissolved phosphate concentration at the pH 5. In optimal conditions, using of raw sorbent removed about 65 percent of the phosphate ion and with the modified inorganic Pumice removed about 78 percent of phosphorus ions. In general, results showed that raw red soil was able to remove phosphate ions in the acceptable range due to high calcium levels in soil context. And its removing ability will increase significantly if modified by EDTA.