Study on adsorption of ammonia nitrogen by iron-loaded activated carbon from low temperature wastewater.

In order to improve the adsorption efficiency of ammonia nitrogen in low temperature wastewater, the modified activated carbon (Fe-AC) was prepared by impregnation-calcination modification of Fe(NO). The characterization results indicated that the total pore volume, specific surface area and the point of zero charge of activated carbon increased after modification. A better adsorption effect was achieved under neutral condition than under alkaline or acidic condition. The effect of Ca on competitive adsorption of NH was greater than that of Na when both cations were present. Pseudo-first-order kinetic model was confirmed to be consistent with Fe-AC adsorption kinetic data, and Langmuir model was consistent with adsorption isotherm data. The adsorption thermodynamics demonstrated that the ammonia nitrogen adsorption process by Fe-AC was spontaneous and low-temperature was helpful to improve the adsorption capacity. The mechanism of adsorption of ammonia nitrogen by Fe-AC was the comprehensive effect of physical adsorption and chemical adsorption, which was the essential reason for improving the adsorption efficiency of ammonia nitrogen by Fe-AC at a low temperature. This research offered a new way for the modification of activated carbon and a new method for the removal of ammonia nitrogen at a low temperature.