Photocatalytic Degradation of 2,4-Dichlorophenol on NiAl-Mixed Oxides Derivatives of Activated Layered Double Hydroxides

Advanced oxidation processes such as photocatalysis have assumed enormous importance in the scientific field as viable sustainable alternatives to be applied to the elimination of persistent organic pollutants present in water reservoirs for human consumption. Persistent organic compounds like pesticides that belong to the chlorophenol family are a global public health priority since they are associated with serious diseases like cancer and can even cause death at low concentrations of prolonged exposure. This work proposes the use of activated Ni/Al layered double hydroxides as photocatalysts for the degradation of 2,4-dichlorophenol. The study variables associated with the properties of the catalysts were the Ni/Al metal ratio as well as the synthesis conditions. To determine the structural properties of catalytic precursors and catalysts, the techniques of XRD, FTIR, UV-DR, DGTA, TPD, SEM-EDS and TEM were used. The photodegradation tests were carried out in a Bach type reactor with a high energy uv lamp. The results of the photocatalytic degradation of 2,4-dichlorophenol in aqueous solution showed good photocatalytic activity with a degradation efficiency of up to 94% attributed to the presence of Ni in the crystalline and amorphous structures of NiO–NiAl₂O₄ oxides by means of a combined oxidation-reduction mechanism due to the effect of holes and superoxide and hydroxyl radicals not associated with the memory effect of reconstruction of layered double hydroxides.