A mineral contg. clinoptylolite 5, ash and volcanic glass 26, quartz 6, and montmorillonite 1301., SiO2:Al2O3 = 6.1, pore size 0.4-0.78 nm, was calcined (100, 200, 500, 650 or 850 degrees C), freed from mobile ions, converted into the Worm, and modified with MnO2. The 200 degrees C zeolite had the (-o)-potential 43.33 mV vs. the original 11.9-22 mV(over pH 2-12) and was more catalytic and adsorptive (as supported by IR spectra) toward Mn(II) and As(III) ions in 100 and 1 mg/l. solns., resp. The topical Mn oxide occurred in several varieties, gamma- MnO2 prevailing. Sorption and regeneration mechanisms were presented. The adsorbed As ions regenerated the catalytic properties in the modified zeolite.