The treatment of contaminants in wastewater is usually performed by conventional techniques, however, adsorption has stood out as an alternative technique because it is a simple, effective and easily implemented method. Moreover, in view of the wide availability of low-cost waste materials generated in industrial processing, research is needed in order to promote the sustainable use of these solids. In this perspective, the development of composites with easy application and low production cost is a promising alternative. Thus, the objective of this work was to develop an adsorbent composite from boiler ash for application in the treatment of aqueous solution containing industrial dyes. The composite was obtained by dissolving expanded polystyrene and boiler ash in cyclohexane. In this book, the results of the research developed are presented.