Study On Continuous Preparation Of Ferrate And Treatment Of Refractory Wastewater

With the development of global agriculture and industry,and the continuous improvement of people’s living standards,the water usage has been increasing year by year.At the same time,with the increase in the types and quantities of chemical agents used in daily life,water pollution has also been worsening.Therefore,effective treatment of wastewater using low-cost and short processes has always been a focus of water pollution researchers.Ammonia nitrogen-containing wastewater is one of the main sources of water pollution,and its effective treatment is an important measure to ensure water environment safety.Currently,most domestic methods for removing ammonia nitrogen use biological methods,which are greatly affected by temperature,reaction time,nutrient ratio,and other factors.Developing a chemical method that can replace biological methods to remove ammonia nitrogen from wastewater is of great significance.This paper explores the principle of generating nitrogen gas by the reaction of ammonium chloride and sodium nitrite,and discusses the effects of p H and medication concentration on the reaction by adding a certain concentration of ammonium chloride or sodium nitrite to the ammonia nitrogen-containing wastewater to achieve the goal of removing ammonia nitrogen.It also uses an adsorbent to adsorb and enrich low-concentration ammonia nitrogen in water to improve the ammonia nitrogen concentration.The adsorption performance of the adsorbent,as well as the removal effect of ammonia nitrogen by the system after adsorption and medication reaction,were analyzed,and the following main conclusions were obtained:(1)The optimal conditions for the reaction of sodium nitrite and ammonium chloride are: p H=4.0,70℃,and a ratio of 1:2 between sodium nitrite and ammonium chloride for 5 hours.Increasing the concentration of sodium nitrite can improve the reaction rate when the total molar concentration of the reaction materials is the same.At this condition,the minimum concentration of ammonium chloride that can cause the reaction to occur is 0.02 mol/L,which is 280mg/L.(2)The adsorption performance of six adsorbent materials,including zeolite,activated carbon,sodium-based bentonite,sodium-based montmorillonite,kaolin,and diatomaceous earth,was studied,and the best adsorption effect was achieved with sodium-based bentonite.The adsorption process of bentonite on ammonia nitrogen is an endothermic process,and the adsorption process is basically stable after 25 minutes.The factors affecting the adsorption process are: amount of bentonite added > p H > temperature > adsorption time > speed.Under the optimal conditions of adding 30g/L of bentonite,a temperature of 30℃,a p H of 7.0,a reaction time of 25 minutes,and a speed of 200r/min,the removal rate of simulated wastewater containing 100mg/L of ammonia nitrogen by sodium-based bentonite was 61.70%,and the adsorption capacity was 2.14mg/g.The adsorption process of bentonite on ammonia nitrogen is consistent with the Langmuir adsorption isotherm,indicating that the process is mainly chemical adsorption,and the theoretical maximum adsorption capacity of bentonite on ammonia nitrogen is 7.35mg/g.(4)With the participation of bentonite,the reaction of ammonium chloride and sodium nitrite can increase the removal rate of ammonia nitrogen and total nitrogen.Bentonite was used to adsorb simulated ammonia nitrogen solutions of 100mg/L and1000mg/L.After saturation,the solutions were reacted with sodium nitrite at a concentration ratio of 1:2 and 1:1,respectively.The removal rates of ammonia nitrogen were 54.10% and 59.02%,respectively,and the removal rates of total nitrogen were 78.22% and 60.67%,respectively.The reaction-saturated bentonite was not regenerable.