Nitrate removal from water using complex of activated carbon with Fe3+

Pollution of surface and ground waters with nitrate is a serious issue in many regions of the world. Therefore, this study attempts to investigate the extent of nitrate removal from aqueous solutions using a new complex of activated carbon. The effects of operating parameters such as pH of solution (3 to 9), adsorbent dosage (0.4 to 5 g in 50 mL), contact time (5 to 300 min) and initial concentration of nitrate (50 to 300 mg L−1) were studied. The highest efficiency of nitrate removal (95.4%) was related to application of modified activated carbon to a solution with pH of 7 and 100 mg L−1 nitrate concentration. Increasing the amount of modified activated carbon from 0.5 to 1 g in 50 mL promoted removal of nitrate from 82.6% to 94.1%. Furthermore, increasing contact time from 5 to 30 min improved removal efficiency from 76.6% to 92.3%. The obtained experimental data were compatible with the Langmuir isotherm model. In general, the results demonstrated that employing Fe3+-modified activated carbon can be considered as a new method of nitrate removal from aqueous solutions due its convenience, safety and high efficiency.