Crystal Violet (CV) is widely used for various purposes and enters into the aquatic systems from the effluents of textile, paint, medical and biotechnological industries. A considerable amount of this dye is lost during manufacturing and processing operations. Contaminated wastewater containing CV must be treated before releasing in the environment because it is highly cytotoxic and carcinogenic to mammalian cells, present mitotic poisoning nature and is nonbiodegradable being classified as a recalcitrant molecule. This chapter reports the removal of CV dye from water using surfactant-modified zeolite from coal fly ash (MZSF), surfactant-modified zeolite from coal bottom ash (MZSB) and nanosilica from sugarcane waste ash (SiO2NP). The adsorbent materials were characterized to obtain chemical and mineralogical composition and others physicochemical properties. The adsorption kinetic of CV onto adsorbents was discussed using the pseudo-first order, pseudo-second order, and Elovich models. The Langmuir and Freundlich isotherm models were used to describe the equilibrium adsorption data. The maximum adsorption capacities were 36.7 mg g-1 and 21.1 mg g-1 for CV/MZSF and CV/MZSB, respectively. The adsorption process of CV/SiO2NP achieves equilibrium in 60 min of contact time, and the maximum adsorption capacity was 117.98 mg g-1. Application of the adsorbent materials synthesized from agricultural waste and coal combustion products can ensure the sustainability and cost-effectiveness of treating effluent containing CV dye, especially effluent from the textile industries generated in large quantity.Coordena????o de Aperfei??oamento de Pessoal de N??vel Superior (CAPES)CAPES: 001