The Effect Of Different Ion On Catalytic Oxidation Of Ammonium By Iron-manganese Co-oxide

In recent years,due to environmental pollution,the phenomenon of groundwater ammonium exceeded are more and more common.The results show that the catalytic oxidation of iron and manganese oxide in groundwater is more than that of biological method,which can be used to remove ammonium,iron,manganese and other pollutants simultaneously.However,due to the vast territory of China,the groundwater quality varies widely,and iron-manganese co-oxide in this application in other regions may be a new problem.In order to further improve the theory of iron-manganese co-oxide catalyzed oxidation of ammonium,the main research contents of this experiment are the effect of different ion on catalytic oxidation of ammonium by iron-manganese co-oxide.To investigate the effects of different ions on the performance of ammonium removal for catalytic oxidation from groundwater by a co-oxide filter film coating on quartz sands,a pilot-scale filter was used which has been operated for about 2 years,varying influent kinds and concentration of ions.The results showed that high concentration of Na+,K+,Cl-,SO42-,HCO3-had little effect on the performance of catalytic oxidation of ammonium,and the removal rate of effluent ammonium was more than 87%.However,the Ca²⁺ had a great influence.When the influent concentration of CaCl₂ was 1000 mg/L,the removal rate of effluent ammonium dropped by 51%.The performance of catalytic oxidation of ammonium could be recovered with in 8⁹ h after stopping adding CaCl₂.The microstructure characteristic results showed that the concentration of Ca²⁺ increased on the surface of the filter film,leading to the specific surface area and pore volume decrease,which influenced the contact between filter film and ammonium and removal efficiency of ammonium fell significantly.Fe²⁺ and Mn²⁺ have a great effect on the removal efficiency of ammonium.When the concentration of Fe²⁺ in the influent is 10 mg/L,the removal rate is reduced to 65%.With the increase of the concentration of Fe²⁺ in the influent,the concentration of nitrite in the effluent decreased and the nitrite concentration increased.The higher concentration of Mn²⁺ in the influent will affect the removal of ammonium from iron-manganese co-oxide.When the concentration of Mn²⁺ in the influent is more than 4 mg/L,the removal rate of NH₄⁺ in effluent is 81%.The effect of ferrous ions on the removal of ammonium from iron-manganese co-oxide was much more significant than that of manganese ion when the addition of Mn²⁺ and Fe²⁺ was also carried out in the influent.The higher the concentration of Fe²⁺ in the influent,the less obvious the effect of Mn²⁺ on the removal of ammonium from iron-manganese co-oxide.