Study On Humic Acid And Fulvic Acid Extracted From Peat

Peat reserves of Inner Mongolia are as high as 128 million tons with the characteristic of large ore bodies and shallow burial,which provide resource condition for the deep processing of peat.However,it is a serious waste to use as a horticultural substrate in flowers,economic crop and other related fields without giving full play to the resource value.Due to rich in humic acid and fulvic acid,we expected to realize the superposition of peat conversion benefits and improve the overall economic benefits of peat resource through the staged conversion of chemical components of peat including organic matter and humic acid,laying the foundation for the industrial extraction of humic acid and fulvic acid from peat.The main research contents and conclusions of this paper are as follows:(1)With herbaceous peat,woody peat and moss peat as research object,the physicochemical properties of peat were characterized by scanning electron microscopy,Ultraviolet visible spectroscopy,Fourier transform infrared spectroscopy,X-Ray diffraction spectroscopy and X-ray photoelectron spectroscopy.Woody peat has a high content of lignin,humic acid,water-soluble humic acid and high degree of aromatization.Moss peat contains a higher content of cellulose,hemicellulose and organic matter.(2)Taking herbaceous peat as the research object,the effects of different alkali,acid on the spectral changes of peat humic acid in the process of humic acid extracted by alkali solution and acid precipitation was explored.The best extraction of alkali solution and acid precipitation was elected and the effects of methane fermentation and pretreated methane fermentation on the spectral changes of humic acid was compared.The results show that:Compared with peat humic acid,the yield of humic acid extracted by methane fermentation residue was decreased,the content of hydroxyl,methyl and methylene of humic acid was decreased,while the content of benzene ring and carbonyl and the aromatization degree of humic acid was increased.In addition,the aromatization degree of humic acid extracted from pretreated methane fermentation residue was the largest.The yield of humic acid extracted by phosphoric acid and lithium hydroxide is the highest.Humic acid extracted by nitric acid and lithium hydroxide has a higher purity.The benzene ring content of humic acid extracted by sulfuric acid and ammonium hydroxide is higher,and the methyl and methylene content of humic acid extracted by phosphoric acid and sodium carbonate is higher.The hydroxyl content of humic acid extracted by sodium pyrophosphate is higher than others.The aromatization degree of humic acids extracted by nitric acid,sodium carbonate and lithium hydroxide are lower than humic acid extracted by other extraction.(3)Taking herbaceous peat as the research object,the effects of different alkali extraction and liquid acid precipitation on the structure of fulvic acid extracted from peat,methane fermentation residue and pretreatment methane fermentation residue was analyzed through UV-Vis,FTIR and fluorescence spectrum.The results showed that the yield of fulvic acid obtained by methane fermentation residue was low,the content of hydroxyl,methyl and methylene decreased,with the aromatization degreeand the contents of benzene ring and carbonyl increase.The yield of fulvic acid extreated by pretreated methane fermentation residue was the lowest and the aromatization degree was the highest.The yield of fulvic acids extracted by phosphoric acid and potassium hydroxide are higher.The content of fulvic acids extracted by nitric acid precipitation,lithium hydroxide and sodium pyrophosphate are higher.The benzene ring content of fulvic acids extracted by nitric acid and barium hydroxide are higher,and the methyl and methylene contents of fulvic acid extracted by phosphoric acid and lithium hydroxide are higher.The content of fulvic acids extracted by nitric acid and sodium hydroxide are higher.the aromatization degree of fulvic acid extracted by sulfuric acid,hydrochloric acid acid,potassium hydroxide and sodium pyrophosphate are low.(4)With herbaceous peat,woody peat and moss peat as raw materials,the effects of different types of peat on the oxygen-containing functional groups,aromatic carbon rate,microcrystalline structure,carbon chain structure and aromatization degree of humic acid and fulvic acid were studied.The results showed that the contents of methylene,methoxy and phenolic hydroxyl groups of herbaceous peat humic acid were higher,the methoxy group content and yield of fulvic acid was higher.Humic acid extracted by woody peat has a higher yield and higher content of methyl,benzene ring,phenols or aromatic ethers and carbonyls;The fulvic acid obtained from woody peat has a higher content methoxy group,carbon-carbon double bond and benzene ring,and the degree of aromatization is larger.Moss peat fulvic acid has a high content of methyl and methylene.