| Humic acid widely exists in natural water bodies,and can with be heavy metal ionsto form stable complex,and potassium permanganate pre-oxidation will affect the inter-action of humic acid to metal ions. The paper maked use of the test date ofICP-AES,zeta potentiometer, and spectral analysis of UV-visible spectra, IR spectraand fluorescence spectrum for the research on the characteristics study of the interactionbetween humic acid and metal ions in unoxidized and oxidation system, investigatingthe effect of pre-oxidation on the interaction of humic acid with Cd/As and the primarydiscussion on the influencing mechanism.The ICP-AES studies showed that pre-oxidation inhibited the interaction of humicacid with Cd.Higher pH,larger ionic strength,lower metal concentration and higherconcentration of HA in the appropriate range would advance the interaction. In the Assystem, pre-oxidation would promote the complexation of humic acid and the As.But inAs (â…¤) system,the degree of promoting declined. Zeta potentiometer results showedthat the pre-oxidation greater than unoxidized in Cd system;acidic functional groups ofhumic acid hydrolysis at higher pH causeed the zeta potential drops after the complex-ing reactions,and the pre-oxidation syetem greater than unoxidized.under the influencesof metal and ha concentration,the result reversed. In As (â…¤) system,the pH and haconcentration maked the zeta potential of pre-oxidation system greater than unox-idised,and zeta potential appeared reciprocating reversal phenomenon in pre-oxidationand unoxidised system under the influence of ionic strength. Under the influence ofpH,matal and HA concentration, the particle sizes were greater than or slightly largerthan unoxidation process in Cd system.Particle sizes of pre-oxidation process in As (â…¢)system were greater than unoxidized system, in As (â…¤) system contrast, less than theAs (â…¢) system.Ultraviolet-visible spectrum in primary discussion showed that the absorptionpeaks in pre-oxidation appeared obvious red shift phenomenon, and some absorptionpeaks were wide and flat. In the study of infrared spectrum,the number and distributionof functional groups of humic acid changed in pre-oxidation process,and the influenceof pre-oxidation may be mainly in the branched chain and aromatic benzene rings ofhumic acid. Fluorescence spectrum study showed that Cd is the quenching agent in hu-mic acid system,and the fluorescence intensity was greater in pre-oxidation process,thuspre-oxidation promoted the humic acid and Cd complexation,in As (â…¤) system contrast.Under the influence of pH can be speculated that there were three fluorescent groupsmaterial,and the especially hydroxyl complexation sites mainly focus on carboxyl andall kinds of hydroxy,especially phenolic hydroxyl group. |
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