Removal of nitrate, ammonium and phosphate from water using activated carbon

Abstract

Background and ObjectivesSeveral physical, chemical, and biological methods are used to extract nitrate from water, which may be expensive and lead to the production of additional materials and toxic wastes, and are widely used.Materials and MethodsIn this study, the ability of activated carbon as adsorbent for the removal of nitrate, ammonium and phosphate from the water were evaluated. For this purpose, the effect of contact time, initial concentration and pH on the absorption of nitrate, ammonium and phosphate on activated carbon were investigated. Absorbent surface characteristics studied by FTIR and SEM and their surface area were determined by methylene blue. Kinetics models to describe the psuedo-first-order and pseudo-second-order kinetics data and models to describe Langmuir and Freundlich isotherm adsorption data were used. ResultsThe results showed that the absorption of nitrate, ammonium and phosphate, over time, increased respectively after 60 and 120 minutes, reached its maximum. Ammonium and nitrate in activated carbon absorption maximum at pH=2 and the maximum adsorption at pH=8. By increasing the initial concentration of nitrate removal efficiency resulted in increased nitrate removal at a concentration of 100 mg/l of 86/88 percent and the highest removal efficiency of ammonia at a concentration of 5 mg/l of 92% and maximum removal of phosphate at a concentration of 7 mg/l 77 percent. According to the obtained results, the studied activated carbon had a high ability to remove nitrate, ammonium and phosphate pollutants.

Keywords

• activated carbon
• absorbent
• absorption kinetics
• isotherm adsorption