Abstract: Monolithic nanoporous material, which is self-standing (i.e. self-supported or cohesive), solid and transparent, essentially devoid of cracks, transparent to UV radiation, obtained by the Sol-Gel process, the material having a basic nature and including a reagent capable of generating a stained product by forming a bond with phenol, a basic compound or mixture of basic compounds and a compound or mixture of oxidant compounds, method for preparation and use in the detection and in the selective depollution of phenol or one of its derivatives.