Physicochemical Properties of Marl and Travertine and their Thermally Modified Forms in the Perspective of Phosphorus Removal from Wastewater

Abstract

The paper presents physicochemical studies of nine reactive materials for removing phosphorus from wastewater and water. The materials under analysis are raw forms of marl and travertine along with their thermally treated forms at temperatures of 500 °C, 650 °C, 700 °C (travertine), 700 °C, 900 °C, 1000 °C (marl) and the commercial material Polonite ® . The scope of the research included morphological analysis and elemental composition, specific surface area, pore volume and diameter, losses on ignition and the amount of elements leached from materials. The results of the research allowed assessing the impact of physicochemical properties and thermal modification on the efficiency of phosphorus binding by these materials. All the tested sorbents show the highest calcium content among the elements with the ability to bind phosphorus. The size of the specific surface does not determine the efficiency of phosphorus retention by the tested materials; therefore it is advisable to study the mechanism of its binding. The thermal modification process, along with the increase in the treatment temperature, improves the regularity of marl and travertine structures, which also manifests itself in increasing the efficiency of phosphorus removal.