Abstract
Multifunctional hybrid materials with applications in gas sensing or dye removal from wastewaters were obtained by incorporation into silica matrices of either Pt(II)-5,10,15,20-tetra-(4-allyloxy-phenyl)-porphyrin (PtTAOPP) or platinum nanoparticles (PtNPs) alone or accompanied by 5,10,15,20-tetra-(4-allyloxy-phenyl)-porphyrin (TAOPP). The tetraethylorthosilicate (TEOS)-based silica matrices were obtained by using the sol-gel method performed in two step acid-base catalysis. Optical, structural and morphological properties of the hybrid materials were determined and compared by UV-vis, fluorescence and FT-IR spectroscopy techniques, by atomic force microscopy (AFM) and high resolution transmission electron microscopy (HRTEM) and by Brunauer–Emmett–Teller (BET) analysis. PtTAOPP-silica hybrid was the most efficient material both for CO2 adsorption (0.025 mol/g) and for methylene blue adsorption (7.26 mg/g) from wastewaters. These results were expected due to both the ink-bottle mesopores having large necks that exist in this hybrid material and to the presence of the porphyrin moiety that facilitates chemical interactions with either CO2 gas or the dye molecule. Kinetic studies concerning the mechanism of dye adsorption demonstrated a second order kinetic model, thus it might be attributed to both physical and chemical processes.
Highlights
The remarkable interest in porphyrin-functionalized silica hybrid materials is justified by their main characteristics, such as biocompatibility, high chemical resistance and most of all their rich opto-electronical properties [1]
PtTAOPP-Silica Hybrid justified the investigations concerning the kinetics of the adsorption process
Our experimental results clearly show that the maximum of Methylene Blue (MB) uptake was obtained for both
Summary
The remarkable interest in porphyrin-functionalized silica hybrid materials is justified by their main characteristics, such as biocompatibility, high chemical resistance and most of all their rich opto-electronical properties [1]. 300 m2 /g) [2], tailored pore shapes and sizes, these hybrid porphyrin-silica materials have tremendous applications in detection (ascorbic acid) [3], the removal of toxic heavy metals [4] and catalysis [5,6,7]. A large interest has been shown for using these porphyrin-functionalized silica hybrid materials for the detection of CO2 [8], oxygen [9,10,11], hydrochloric acid [12] or for organic volatile substances (trinitrotoluene vapors [13] and hydrocarbon solvents [14]).
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