抄録
pH-and concentration-dependency of the adsorption of 16 phenolic acids on the three different type clay minerals, allophane (amorphous), halloysite (1: 1 type layer silicate) and illite (2: 1 type layer silicate), were investigated by batch method. Both the equilibrium pHs and concentrations were not kept constant. In order to compare the amount of adsorption at a defined pH and concentration, the two-dimensional.Ck interpolation and the linearly multiple regression equation were applied.
Three types of adsorption characteristics were observed relating to the pH-dependency. A-type showed the maximal adsorption in the region of pH 5 to 7. B-type showed the adsorption decreasing with pH increase. C-type showed the adsorption increasing with pH increase. The two-dimensional Ck interpolation was not applicable in the extrapolate region but applicable in the intrapolate region. The relationship among the amount of adsorption (n:μM/g), equilibrium pH and concentration (C: M) was represented by the following equation:
log (n)=a pH+b log (C)+c pHxlog(C)+d pH2+e
where a, b, c, d and e were the inherent constants applied between a phenolic acids and a clay minerals.
