On the Uptake Mechanisms of Organics from Natural Water -Investigations with Strong and Weak Base Ion Exchangers and Their Corresponding Copolymers

摘要

In laboratory column experiments,ion exchange resins and the corresponding non-functionalized copolymers were compared in order to investigate the uptake mechanisms of organics during the water deminer-alization process.To improve the detection limit,~(14)C-labeled model substances beta-alanine,starch,syn thetic humic acid type M42)were used.These com pounds are supposed to represent the TOC fractions of neutrals/amphiphilics,polysaccharides and humics following the LC-OCD method.The uptake was investi gated depending on the salinity and pH,the concentra tion of the organics,and the loading temperature.The main results are:-At neutral pH,a near 100 % removal of p-alanine and starch by ion exchange and/or adsorption was observed,whereas humic acid was taken up by ion exchange to an extent of about 10 %.-In acidic conditions,p-alanine and starch were com pletely removed up to the breakthrough point of the sulfate ions.These elute the organics.Humic acid will be removed owing to precipitation.-The last mechanism allows the removal of humic acid by the copolymers too.These are inefficient in regard to the uptake of p-alanine and starch.-The variation in the concentration of the organics as well as that in the loading temperature have only a subordinate influence on the uptake.