Study On The Adsorption Of Zhaotong Lignite Humic Acid On Clay Minerals/soil

The compounding of organic matter and clay minerals is one of the important steps in the process of improving soil organic carbon,affecting the ph ysicochemical properties and biological processes of the soil.The similarity in struct ure and properties ween brown coal and soil HA?an important component of soil organic matter?makes brown coal HA a supplement to soil organic carbon.In this paper,the adsorption behavior of Zhaotong brown coal HA on clay minerals was studied.After certain patterns,brown coal HA was applied to these soils?Kunming peal orchard soil,Lincang rice soil and Daqing garden soil?for adsorption,which provided theoretical and experimental evidence for the use of brown coal HA.This article uses Zhaotong brow n coal HA as adsorbent,kaolinite?rich in 1:1type layered silicate clay mineral kaolinite?,montmorillonite?1:2 t ype layered silicate clay mineral?and bauxite?Adsorption of non-lamellar silicate clay mineral gibbsite?as adsorbents,to study the effec ts of different initial conditions?concentration and p H?and reaction conditions?liquid-solid ratio and temperature?of HA on the adsorption capacit y?ph ysical adsorption and chemical adsorption?of three kinds of clay minerals and the impact of s ystem?s ystem p H,clay minerals and HA?changes.Subsequentl y,the adsorption experiment of soil?Kunming peal orchard soil,Lincang rice soil and Daqing garden soil?under the optimized condition was performed,and the reactants and reaction products were anal yze d and characterized.Research shows:?1?Under certain conditions,the initial concentration,liquid-solid ratio and system temperature of HA are positivel y correlated with the chemical adsorption of the three clay minerals in the composite process of HA with clay minerals;the initial p H of HA is negativel y correlated;the initial concentration of HA is positivel y correlated with the ph ysical adsorption of the three clay minerals;the initial p H of HA is negativel y correlated with the ph ysical adsorption of kaolin and bauxite;the liquid-solid ratio has little effect on the ph ys ical adsorption of the three clay minerals;the s ystem temperature is negativel y correlated with the ph ysical adsorption of kaolin and bauxite;the initial p H and temperature of humic acid have little effect on the ph ysical adsorption of montmorillonite.?2?Under certain conditions,the amount of HA is positivel y correlated with the p H buffering propert y of HA in the composite process of HA with clay minerals.The system temperature of HA are negativel y correlated with the p H buffering propert y of HA.?3?After kaolin,montmorillonite,bauxite and their mixed minerals were anal yzed by XRD,mesopore and macropore and p H,parallel experiment was carried out on the adsorption of HA by kaolin,montmorillonite,bauxite and mixed minerals.The results show that the chemical adsorption amount of clay minerals is closel y related to the specific surface area,composition and its own p H.The absorbance E4/E6 of non-adsorbed HA decreases,which ind irectl y shows that the molecular weight of HA increases;the GPC molecular weight and molecular weight distribution of non-absorbed humicacid change;there is an increase in both the Z+1average molecular weight and molecular weight distribution of HA,which is not adsorbed by bauxite,and it is speculated that there is a complexation of HA with Al³⁺.?4?The infrared analysis of the reactants and reaction products show that the water peaks of kaolinite,bauxite and mixed minerals with HA are enhanced,while the water peaks of montmorillonite and HA complexes are weakened,indicating that after the adsorption of HA,the hydrophilicit y of bauxite and mixed minerals is enhanced,while the hydro philicit y of montmorillonite with interlayer water is weakened;non-adsorbed HA hydrogen bond association band and oxygen functional groups'?C=O and C-O?characteristic peaksare weakened,indicating that carboxylic acid?C=O?and other functional groups in HA may be involved in chemical adsorption,which is not adsorbed by alumina minerals.Among the HAs whichare not adsorbed by the bauxite mineral,based on the C=C,the characteristic peaks of carboxylic acid?C=O?and phenol group?C-O?are weakened most obviousl y.It is suggested that carbox yl and other functional groups of HA may participate in chemical adsorption.?5?After the anal ysis of XRD and mesopore and macropore of Kunming peal orchard soil,Lincang rice soil and Daqing garden soil,theadsorption experiment of these soilson HA under optimized conditions was carr ied out.The results show that the chemical adsorption capacit y of Kunming pear orchard soil is greater than the sum of chemical adsorption capacit y of Lincang rice soil and Daqing garden soil;The absorbance E4/E6 of non-adsorbed HA decreases,indirectl y i ndicating that the molecular weight of HA increases;the GPC molecular weight distribution and Z+1average molecular weight of non-adsorbed HA increases,suggesting there is a complexation of HA with high-priced metal ions.