Characterization of clay deposits from Egypt and assessment of their potential application for waste water treatment: How dissolved organic matter determines the interaction of heavy metals and clay minerals

The main aim of this study was to investigate the potential of using clay minerals abundant in local soils in Egypt as low cost materials to reduce Cu, Ni and Zn pollution of soil and groundwater originating from polluted wastewater; specifically focusing on the influence of the interaction of clay minerals and heavy metals with OM already present in the soil, or in the wastewater itself. To achieve this aim, the following specific objectives were formulated: • To identify and characterize the different clay mineral types in the context of their application in local wastewater treatment in Egypt. • To investigate the influence of the presence of DOM and the timing of its application (before or concurrently with the HMs) on the mobility of Cu, Ni and Zn in clay-rich deposits using a static batch approach. • To unravel the effect of the timing of the addition of DOM on the competitive adsorption of Cu, Ni and Zn onto different sorbent compositions in a kinetic system using a dynamic column approach. • To investigate the role of the presence and timing of addition of DOM during loading of clay mineral-based wastewater treatment columns on the subsequent removal of the HMs from the columns, focusing both on regenerating clay minerals used in wastewater treatment, and (re)mobilization of HMs previously immobilized in clay rich soils.