Influencing Factors On Ammonia Removal By Electrochemical Oxidation Treatment

Ammonia nitrogen is one of the serious pollutants in the water bodies. More andmore ammonia nitrogen discharged into water bodies as the development of theeconomy and population. Because of high ammonia nitrogen content of water bodiesharm on the ecological, biological and the human body, the discharging standard forammonia nitrogen is stricter by the state. A more effective ammonia nitrogen removaltechnology is needed base on the reasons above. The study focus on the staticexperiments of synthetic wastewater by the electrochemical oxidation, respectivelyanalysis of its process conditions, the two-dimensional and three-dimensionalelectrochemical oxidation factors, as well as the anode material and particle electrodematerials.The anode materials, cathode materials, current density, chloride concentration,electrode gap, zeolite added and initial ammonia concentration of seven influencingfactors were examined by orthogonal experiments. There are good performances onboth two-dimensional electrode and three-dimensional electrode in the orthogonalexperiment. The ammonia nitrogen removal rate of two-dimensional electrodeexperiments is13%~100%in the orthogonal experiment, and the ammonia removalefficiency of the three-dimensional electrode with the Siallite-carbonate zeolite ormodified zeolite particle electrode is respectively22%~93%and28%~97%. It can bedescribed that the ammonia nitrogen can be treated effectively by the electrochemicaloxidation in a short period of time as long as having an appropriate reaction condition.The three-dimensional electrode with modified zeolite has the best performance. Theoptimum operating factors educed by orthogonal experiments in this study is thethree-dimensional system dealing with20mg/L initial ammonia concentration in5mA/cm2current density, with RuO2-IrO2-SnO2/Ti as anode, titanium mesh cathode,200mg/L chloride concentration,1cm electrode gap and modified zeolite as particleelectrode.The modified zeolite was dealed before examining electrochemical oxidationaffecting factors in three-dimensional reaction because of the strong adsorption of themodified zeolite. The impact of the ammonia initial concentration, current density and chloride concentration were examined respectively both in the two-dimensionaland the three-dimensional electrochemical reactor. The removal of the ammonianitrogen and total nitrogen comply with the quasi-zero-order reaction kinetics intwo-dimensional conditions were known form this study. And it is pseudo-first-orderreaction kinetics in three-dimensional conditions.The electrode materials have the good stability that were know from analysis thephysics and chemistry of the anode material and the particle electrode. They aresuitable for the electrochemical reactor.