Abstract--A study was undertaken to investigate the adsorption of hemin, protoporphyrin and hematoporphyrin by kaolinite and a Ca-montmorillonite in aqueous solutions buffered at pH 4 and 9.Although experimental restrictions at pH 4 prevented the complete characterization of the adsorption isotherms, kaolinite did exhibit a saturation of exchange sites by the cationic porphyrins. Both kaolinite and montmorillonite displayed a similar saturation of sites by the porphyrins in their anionic forms at pH 9. The major differences in the adsorption isotherms are attributed to differences in the exchange capacities of the clays.Adsorption of the porphyrins at pH 9 was inhibited largely by phosphate treatment of the clays; this effect is interpreted as blockage of the anion exchange sites by irreversibly-bound phosphate.
Supplementary Notes Abstracts MIX2 is a FORTRAN IV computer program that utilizes an aqueous model and the nstraints of mass balance and electrical balance to compute the pH and equilibrium stribution of inorganic species as a result of net reaction progress in the closed stem: CaO-MgO-Na2 0-K2O-C02-H2 SO,-HCl-H2 0. The program considers three general classes problems involving net reaction progress: 1) mixing of two solutions in fixed volume titration of one solution into another (variable volume), and 3) the addition or .btraction of a net stoichiometric reaction to or from an aqueous solution. In additior X2 will follow one phase boundary through any of the above classes of problems. This port presents the theory and method of calculation used by MIX2, describes the input the program, presents results of two test cases, and provides a program listing.
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