Síntese, caracterização e aplicação do Nanocompósito de Palygorskita/Dióxido de Titânio na degradação fotocatalítica de corantes têxteis

Abstract

One of the biggest environmental problems is due to industrial activity, in which water resources are contaminated with post-production waste, causing adverse effects to the ecosystem. The effluents of dyes present a great risk to the health of biodiversity, in most cases, they are toxic, persistent and deteriorating by conventional compounds, in addition to presenting themselves as carcinogenic substances. The development or improvement of techniques for treating effluent is of great interest, since it aims to search for low-cost routes that generate less waste or toxic byproducts. In this work, the photocatalytic discoloration of industrial dyes, Novacron blue (AZN) and Novacron yellow (AMN) were investigated using TiO2-based composites allowed in natural palygorskite (Pal-Ti10 and Pal-Ti30). The method consists of synthesizing the composites starting from a physical mixture of TiO2 and natural palygorskite in the presence of alcohol, for impregnation through calcination under conditions of temperature equal to 450 ºC and atmospheric air. The characterization techniques used in this work were: FTIR, DRX, FRX, MEV, particle size analysis and zeta potential. The photocatalysis for the AZN dye was investigated through the application of a factorial experimental design 24 , aiming at the best experimental conditions and finally applying them in another AMN industrial dye. The investigated AZN restrictions were 10 ppm and 30 ppm, the composites were synthesized using 10 and 30% (w/w) titanium dioxide in palygorskite, the two pH values were 2,0 and 6,0 and the lamp powers were 9 and 18 W. Tests performed at: pH 2.0; Pal-Ti30 composite; power 18 W and 10 ppm of dye, removal of 100% of the coloring of both dyes in 90 min. The bleaching process follows the kinetic model of pseudo-first order and as apparent constants (Kapp) were 0,0216 min-1 and 0,0193 min-1 for the AZN and AMN dyes, respectively. The results of the final treatment cost for tests harmful to the process are viable in efficiency and economy. The results of total organic carbon (TOC) dissipation of mineralization of 61,70% and 58,06% for AZN and AMN, respectively, in 90 min of treatment and the by-products were detected by GC-EM.