| Our experimental team found that solid ammonium sulfate mixed with solid calcium carbonate,under the condition of spraying and stirring,the gas with irritating odor was continuously released.This paper mainly studies the continuous reaction between ammonium sulfate solid and calcium carbonate solid,it was found that ammonia nitrogen in the reaction body could be converted into ammonia gas to continue to participate in the earth nitrogen cycle,and the ammonia nitrogen and phosphorus in the water body could be removed by this reaction.This study provides a new idea for the purification of natural water body.The specific contents of the study are as follows:1.Sustained reactions between ammonium sulfate and calcium carbonate solid has been investigated in a laboratory scale,and the effects of different stirring rate and different particle size of calcium carbonate on the reaction degree were investigated.The results show that the products are ammonia gas and carbon dioxide gas.The solid product was observed by X-ray diffraction and scanning electron microscope.The main products of calcium carbonate surface accumulation were rod-shaped calcium sulfate.The reaction can be carried out continuously,mainly due to the peeling of the calcium sulfate film due to friction.It was found that when the stirring rate was 350 r/min and the particle size of calcium carbonate was1?m<d<5?m,the reaction conversion was the highest.2.The previous results show that ammonium sulfate reacts with calcium carbonate to release ammonia gas.The experimental results are used to remove excess ammonia nitrogen in the water and carry out the pilot-scale experiment.The experiment of removing ammonia nitrogen from 150L water sample of Xinshuihe River in Daning County was carried out by using a semi-circular pipeline with a length of 5m and a diameter of 30cm,and laying calcium carbonate ore in the pipeline to simulate the channel.The results show that the ammonia nitrogen content in the water decreases by 0.72 mg/L and the removal rate is 11.4%within a week when the water is continuously flowing through the channel covered with calcium carbonate ore.In the experiment,the removal efficiency of ammonia nitrogen is better when the particle size of calcium carbonate is 2 cm,the velocity of water flow is faster,and the removal effect is better when the pH of water body is 6.3.We apply this method to a large-scale natural body of water.The calcium carbonate is paved in a channel of 2.8 km in the East Han section of Hui River,Shanxi Province,and an artificial wetland of 27000 m~2is constructed.From July 2018 to December 2018,the nitrogen and phosphorus contents of river inlet and outlet,wetland entrance and outlet were analyzed.It was found that river course and wetland had certain effect on purifying water body and removing nitrogen and phosphorus.The content of nitrogen and phosphorus decreased by0.40 mg/L and 0.40 mg/L after the river flow,and decreased by 0.13 mg/L and 0.08 mg/L after flowing through the constructed wetland,which indicated that compared with the constructed wetland,the nitrogen and phosphorus content of the water body decreased significantly.The effect of natural channel on reducing nitrogen and phosphorus is more obvious.In addition,the method can convert ammonia nitrogen into ammonia gas and return to land,and participate in the process of earth nitrogen cycle again. |
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