Optimization Of Pretreatment Conditions For Extracting Humic Acid From Peat

Peat is the product of swamp development,which contains water and has not been thoroughly decomposed plant residues,humic acid and minerals.Humic acid is widely used in industry,agriculture,medicine,environment and other fields.In order to increase the efficiency of extracting humic acid from peat,sulfuric acid,hydrogen peroxide and nitric acid were used as pretreatment reagents.The acid concentration,solid-liquid ratio,water bath temperature and water bath time were combined to determine the extraction rate of total humic acid and free humic acid.The results are as follows:1.The optimum conditions for the extraction of total humic acid from peat pretreated with sulfuric acid were as follows:the solution was used 1.5 mol-L-1 sulfuric acid,the ratio of solid to liquid was 1:6 and the mixture was heated to 80?for 45 minutes;the optimum conditions for the extraction of free humic acid were as follows:the solution was used 0.75 mol·L-1 sulfuric acid,the ratio of solid to liquid was 1:8,and the mixture was heated to 80? for 10 minutes.2.The optimum conditions for the extraction of total humic acid from peat pretreated with hydrogen peroxide were as follows:the solution was used 0.5 mol·L-1 hydrogen peroxide,the ratio of solid to liquid was 1:3,and the mixture was heated to 60? for 80 minutes;the optimum conditions for the extraction of free humic acid were as follows:the solution was used 1.0 mol·L-1 hydrogen peroxide,the ratio of solid to liquid was 1:3,and the mixture was heated to 40? for 20 minutes.3.The optimum conditions for extracting total humic acid from peat pretreated with nitric acid were as follows:the solution was used 1.5 mol·L-1 nitric acid,the ratio of solid to liquid was 1:6,and the mixture was heated to 80? for 45 minutes;the optimum conditions for extracting free humic acid were as follows:the solution was used 1.5 mol·L-1 nitric acid,the ratio of solid to liquid was 1:5,and the mixture was heated to 60? for 80 minutes.4.The most ideal effect was 36.74%,The optimum conditions for extracting total humic acid from peat pretreated with nitric acid were as follows:the concentration of nitric acid was 1.5 mol·L-1,the ratio of solid to liquid was 1:6,the temperature of water bath was 80?,and the time of water bath was 45 minutes;Free humus to extract the most ideal result is 35.60%,the optimum conditions for extracting free humic acid were as follows:the concentration of nitric acid was 1.5 mol·L-1,the ratio of solid to liquid was 1:5,and the mixture was heated to 60? for 80 minutes.the extraction results of total humic acid and free humic acid are as follows:nitric acid pretreatment of>hydrogen peroxide pretreatment of>sulfuric acid pretreatment.