Clay minerals for pharmaceutical wastewater treatment

A large number of pharmaceutical drugs, especially the antibiotics, have been used to treat diseases in humans, animals, and plants for a long time. The metabolic degradation rate of these drugs in humans and animals is very low, they could be released into the environment directly through feces or urine in the form of prototype or secondary metabolites, and they can be enriched in the environment, resulting in resistance of a variety of bacteria to antibiotics. This consequently brings a variety of health risks to human beings directly or indirectly. The most important behavior of antibiotics in the environment is adsorption, which not only affects the residence time, distribution, migration, and transformation of these compounds in the environment, but also affects their biological activities in the environment. Clay minerals show remarkable adsorption capacities and ion exchange performances for cationic drugs due to their unique layered structure and high cation exchange ability, and further have broad application prospects in wastewater treatment. Based on the structures and properties of clay minerals, such as rectorite, montmorillonite, palygorskite, illite, kaolinite, bentonite, and other clays, this chapter reviews the research on pharmaceutical drugs especially for the antibiotics' adsorption on clay minerals or soils with clay components in them.