Title : Photocatalytic activities under solar light of NaLi1.07Co2.94(MoO4)5 nanoparticles
Abstract:
In this work, we report the photocatalytic degradation of Acid Brown dye (AB) found in leather industry wastewater under sunlight and in presence of new prepared nanoparticles. The new photocatalyst has been synthesized by a solid state reaction method and from the mixture of Na2CO3, LiNO3, Co(NO3)2.6H2O and (NH4)6Mo7O24. First, the reactants were dissolved in distilled water. Then the resulting mixture was dry evaporated at 80°C for 12 h. Then, the obtained residue was manually ground and heated at 400°C for 12 h. Thereafter, this powder is again reground and heated at 500°C. Finally, it was slowly cooled to room temperature. The synthesized photocatalyst was characterized using X-ray Powder Diffraction (XRPD), Raman, FTIR, Scanning Electron Microscopy (SEM), UV–vis–NIR spectrophotometry. The title compound was crystallized in the triclinic system, space group P-1. The structure can be described by the succession of different types of layers connected by sharing vertices and edges to lead a three-dimensional framework with tunnels in which the Na þ cations reside. Raman and IR studies confirm the existence of MoO42- functional groups. The title compound is a wide-band-gap semiconductor with a value around 3.3 eV. SEM image and qualitative EDX analysis show that the nanoparticles (NPs) are distributed in a homogeneous way with large agglomeration and uniform porous structure. The EDAX spectrum revealed the presence only the elements: Na, Mo, Co and O with no impurities detected. The photocatalytic decomposition of Acid Brown organic dye load in tannery wastewater was studied. A maximum of 56% removal dyes was attained after 5 h. With the addition of hydrogen peroxide as an oxidant, the degradation efficiency increased to 90%. The photodegradation kinetics followed the pseudo first order with a constant rate k equal to 2.9 10-1 h-1 and 1.5 10-1, respectively with and without adding H2O2. An important reduction in the chemical oxygen demand (COD) were observed. In fact, maximum removal of COD (80%) was observed with the addition of H2O2.This environment friendly and economical photocatalyst can be efficiently applied to the treatment of real leather industry wastewater with a notable reduced.
