Resumen:
In this chapter, basic concepts of advanced oxidation processes (AOP) are cited, such as photolysis, photocatalysis, and semiconductors used as photocatalysts. This is important since the wastewater pollution with drugs, coming from domestic use, hospitals, and industry is not only an environmental problem but social too. Pharmaceutical case study is shown to exemplify the photocatalytic degradation of different drugs contained in wastewater taken directly from some currents in the pharmaceutical industry, such as diclofenac, acetaminophen, naproxen, and ibuprofen, using modified TiO2 catalysts with different tin contents.