Research On Migration And Transformation Of Humic Acid In Porous Media Of Groundwater Based On Three-dimensional Fluorescence Technology

This paper mainly studied migration and transformation characteristics of humic acid in aqueous medium.To achieve the research purpose,we carried out the static adsorption test and dynamic column experiments.In this experiment,different concentration of humic acid solution are used as water samples,meanwhile,fine sand and marl rock are used as testing rock samples.Fine sand and marl rock are got from recharge area of groundwater from Pingdingshan coal basin.Three-dimensional fluorescence was took to test humic acid.In order to improve precision of three-dimensional fluorescence regional integral,we combined analytic hierarchy process?AHP?with regional integral.Then improved regional integral and 3DEEM were utilized to analysis experiment result.The results show that:?1?Fine sand and marlite adsorption of humic acid was affected by three factors.These factors include Oscillation time,sample quality and initial concentration.The adsorption equilibrium time of fine sandy is 150min,and 15min for marlite.However,adsorption quantity decreased with the increase of the sample.With the increase of initial concentration of humic acid,two kinds of medium adsorption of humic acid are increased linearly.And adsorptive property of marl is better than fine sand.?2?Migration of humic is mainly dispersion action in aqueous mediums.And dispersion interaction in fine sand and malm enhance simultaneously along with the increase of concentration of humic acid.When concentration of humic acid solution increases from34.6mg/L to 70.9 mg/L,The longitudinal dispersion coefficient of marl rock increases from0.75 cm²/h to 1.02 cm²/h,and the longitudinal dispersion coefficient of malm increases from0.56 cm²/h to 0.72cm²/h.?3?The three-dimensional fluorescence results of fine sand shows that the location of the main fluorescence peak do not change and fluorescence intensity changes with the change of the concentration merely.The three-dimensional fluorescence results of marl rock show that there appreas new fluorescence peak at 312 h and A new fluorescence peak?₂ comes along with peak?₁ disappearing.?4?The three-dimensional fluorescence regional integral results of marlstone show that from 192h to 600h,proportion of region V let up from 32.2%to 6.5%,however,proportion of region?add from 49.1%to 50.4%.Apparently,Humic acid has transformed in the marlstone.Humic acid is degraded into soluble metabolic products by microorganism.?5?Compared with the traditional region integral,the improved region integral method considers the position of the peak of spectrum and the interaction between the regions to determine the weight.It shows that recognition accuracy of the DOM type is 83.33%,improved method can be used to characterize migration and transformation of humic acid.