Study On The Removal Characteristics And Mechanism Of Humic Acid With Different Properties By MIEX Resin

Humic acid is widely found in natural water sources and is the precursor of disinfection by-products of drinking water.The hydrophilicity and molecular weight of humic acid determine the choice of drinking water treatment method and process,and also determine the possible removal mechanism of humic acid by different methods and processes.So it is necessary to find an effective way to remove it Humic acid can interact with metal ions in the environment,such as Cr(VI),which affects the characteristics and removal of organics,and also has an important effect on the prevention and treatment of Cr(VI)pollution in water environment.Therefore,it is of great theoretical significance and practical value to explore the mechanism of the interaction between humic acid and Cr(VI)on the removal of humic acid with different propertiesIn this paper,the removal efficiency and mechanism of magnetic ion exchange resin for organic matter were studied systematically.MIEX resin was used as adsorbent,humic acid with different hydrophilicity and molecular weight was used as sorbent,and adsorption equilibrium was carried out by kinetics.Thermodynamic experiments were carried out to study the difference in the removal of humic acid by MIEX resin,and to reveal the essence and mechanism of the removal of humic acid by MIEX resin.At the same time,Zeta potential,Fourier transform infrared spectroscopy,three-dimensional fluorescence,ultraviolet-visible spectrophotometry and so on were used to investigate the single factor(different pH,and different Cr(VI)concentration).The effect of different ionic strength on the interaction of humic acid components with Cr(VI).Based on the above,the mechanism of the effect of sudden Cr(VI)on the removal of humic acid with different properties was discussedThe Zeta potential of the interaction between Cr(VI)and humic acid with different properties showed that with the increase of Cr(VI)concentration,except for 1 KDa-5 KDa humic acid,The absolute value of Zeta potential of other humic acid components showed a fluctuating trend of decreasing first,then increasing and final decreasing.The absolute value of Zeta potential of humic acid component<1 KDa and 1 KDa-5 KDa increased and the absolute value of Zeta potential of other components decreased gradually with the increase of pH.At the same time,the increase of ionic strength decreased the negative electric property of humic acid solution.The infrared spectra show that all the humic acid components contain oxygen-containing functional groups such as hydroxyl group,phenyl group,aromatic group and the like,and the absorption peak of the infrared spectrogram gradually decreases with the increase of the concentration of Cr(VI),the pH and the ionic strength.The results of UV and 3D fluorescence spectra showed that the aromatization degree of hydrophobic and macromolecular weight organic compounds was higher than that of,Cr(VI)and humic acid,but the degree of conjugation decreased.Dynamic quenching is the quenching mechanism of the interaction between humic acid components and Cr(VI)The effect of Cr(VI)on the removal of humic acid by MIEX resin showed that,Cr(VI)promoted the removal of macromolecule and hydrophobic humic acid by MIEX resin,but inhibited the removal of small and medium molecules and hydrophilic humic acid.With the increase of the dosage of the pH and MIEX resin,the adsorption amount of the MIEX resin to the humic acid decreased,and the MIEX resin preferentially adsorbs Cr(VI).Various characterization and analysis results showed that the MIEX resin was spherical in the scanning electron microscope,and contained carboxyl,benzene ring,amino group,ether bond,quaternary amine group and other functional groups.The vibration absorption peak of infrared spectrum of MIEX resin adsorbed humic acid was slightly deviated from that of other functional groups,such as carboxyl group,benzene ring,amino group,ether bond,quaternary amino group and so on.The pore size of MIEX resin surface decreased obviouslyThe above results show that the MIEX resin can effectively remove the organic matter of the affinity,the oleophobic organic matter and the small and medium molecular mass.The existence of Cr(VI)promotes the removal of the MIEX resin on the macromolecule and the hydrophobic humic acid,but the removal of the small and medium molecules and the hydrophilic humic acid is inhibited.