A MINERALOGICAL INVESTIGATION OF RECYCLING PALYGORSKITE AND MONTMORILLONITE MEDIA FOR THE PURPOSE OF REMOVAL OF PHARMACEUTICALS IN WATER RESOURCES

Pharmaceutical pollution in water resources is a major problem that has arisen from the inability of wastewater treatment plants to effectively remove these compounds. Trace amounts of pharmaceuticals derived from wastewater are believed to have negative impacts on human and ecological health. There are a variety of processes that are being studied to remove pharmaceuticals from wastewater, including adsorption by clay minerals. The minerals palygorskite and montmorillinite are ideal for this study owing to several properties and previous work has shown great promise for these minerals as reactive media for the removal of pharmaceuticals. One challenge in the implementation of these minerals is that large volumes of waste would be produced once the media has reached the end of product life. However it may be possible to recycle the palygorskite and montmorillonite media by reheating and driving off adsorbed molecules. A preliminary investigation of a mixture of palygorskite and montmorillonite was heated from 100 to 500 degrees Celsius to determine the effects of heat treatment on the clay. SEM and TEM data along with XRD patterns were used to compare chemical and structural differences caused by the heat treatment process. Overall textures and chemical compositions of room temperature materials are very similar to previous work on the palygorskite and montmorillonite source. Although major color changes occur in high temperature samples, extensive structural changes are not observed in powder X-ray diffraction data. TEM investigation on high temperatures samples suggests some amorphous Fe-oxide formation on palygorskite crystals. This preliminary work suggests heat treatment may be a viable option for recycling palygorskite and montmorillonite media for pharmaceuticals wastewater treatment.