| Humic acid is a kind of large molecular material,which is widely used.The oxidation of lignite can produce humic acid.Humic acid is not easy to dissolve in water,so humic acid is usually converted to water soluble humic acid to meet the practical application.Potassium humate can be used as water soluble fertilizer for agricultural production.It has a significant effect on improving the quality of crops.In order to meet the needs of modern agricultural production,potassium humate products with fast dissolution,high bioactivity and strong hard water resistance have been obtained.Firstly,the oxidation process of lignite was studied.The effect of different oxidation conditions on the content of carboxyl group,fulvic acid content and potassium humate yield in oxidized products was studied by using green oxidizer H2O2.Eventually the optimum process conditions for H2O2 oxidation lignite were determined: the ratio of coal to liquid was1:0.6,the oxidation temperature was 70 and the oxidation time was 60 min.Secondly,the modification of potassium humate was studied.Different additives such as sulfonated agent,dispersant,wetting agent and disintegration agent were selected.By comparing the different modified potassium humate in water suspension rate,wetting time,disintegration time and the surface tension of the liquid,The optimum additive was determined: Sulfonating agent Na2SO3 5%,dispersant NNO 5%,wetting agent SDBS 7.2%disintegrating agent(NH4)2SO4 5%.The flocculation and acid resistance of modified potassium humate were tested.and products with no flocculation in 12 degree hard water and products dissolved in weak acid solution were obtainedFinally,Study on the adsorption of anionic surfactant and nonionic surfactant on humic acid,using different isotherm models to fit the adsorption results,found that the adsorption of humic acid on anion surfactant SDBS for monolayer adsorption,the adsorption of nonionic surfactant Tween-20 adsorption for multi molecular layer. |
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