PIGMENTOS HÍBRIDOS ORGÂNICO-INORGÂNICO BASEADOS EM ÓXIDOS DE ZINCO E CORANTE TÊXTIL E ÓXIDO DE ZINCO DOPADO COM FERRO, APLICADOS COMO PIGMENTOS EM TINTA IMOBILIÁRIA

Abstract

Zinc oxide (ZnO) was synthesized by the gelling method from organic and inorganic precursors. The same was characterized by XRD techniques which evidenced an efficient formation of hexagonal phase wurtzita main phase for ZnO, with no evidence of secondary phases. From the BET analysis, ZnO showed a relatively high surface area, which makes ZnO a possible adsorbent, without taking into account factors such as pH, temperature, type of dye, etc. SEM results, irregular shape and size occurring in plates with grooves and deposits on them, which may be related to carbonaceous residues. ZnO applied as a dye adsorbant showed satisfactory results monitored by UV-Vis at concentrations of 100 to 250 mg/L of Congo red dye (VC) in aqueous solution. The post-adsorption colored solid was oven dried at 70 °C for 24 hours and thereafter reused as a white pigment where it was dispersed in 5 and 10% by mass of pigment, exhibiting good dispersion and recoating power when applied in gypsum blocks, in different adsorption tests the pigments presented different colorations, but the dispersion and opacity properties remained. Another pigment formed from the ZnO was by doping the ZnO with an iron (III) salt from the gelation synthesis by varying the organic precursor (citrus pectin and starch) to evaluate the possible color changes and the properties of these pigments. Fe01 and Fe02 obtained similar properties (DRX, BET, MEV and UV-Vis in the reflectance mode) but showed different colorations, suggest that in the Fe01 synthesis there was a greater iron insertion in the ZnO matrix.