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Demetallization and desulfurization of vacuum residuum from the Pavlodar Petrochemical Plant (Kazakhstan) was carried out by adsorbents based on zeolite modified with titanium compounds and vanadium oxide. The process was carried out at a temperature of 320-360°C for 1 to 3 hours at atmospheric pressure. The results of determining the physico-chemical characteristics of the modified adsorbents showed that, after modification, their specific surface area increases, but the specific pore volume decreases. The maximum degree of demetallization is observed when using an adsorbent based on zeolite modified with titanium oxides and vanadium oxides. The change in the structure of vanadylporphyrins in vacuum residuum composition after the demetallization process is determined. After demetallization etioporphyrins have C27-C32 with a center of mass at C29, phylloporphyrins have C28-C34, after treatment at 360 °C, the center of mass shifts towards an increase in the number of carbon atoms C31. [ABSTRACT FROM AUTHOR]