Sustainable materials for wastewater cleaning prepared from biowaste sourced soluble substances

Environmental protection is worldwide considered a primary issue of the sustainable development. In order to preserve our environment, a major challenge is to remedy the polluted environment by re-using wastes. In this work biowaste sourced soluble substances (CVT230) are used for the design of two types of heterogeneous photocatalysts for wastewater cleaning: an inorganic perovskite and a organic-inorganic hybrid. The materials were carefully characterized by XRD combined with Rietveld refinement, N2 adsorption, FT-IR spectroscopy, thermo gravimetric analysis, transmission electron microscopy and zeta potential analysis. Their photocatalytic activity was tested for the abatement of pollutants found in wastewaters, 4-methylphenol (4-MP), a representative phenolic compound and/or the Crystal Violet (CV), a cationic dye. The experiments were performed in aqueous solution irradiated by simulated solar light. The inorganic perovskite LaFeO3 was prepared by solution combustion synthesis [1], where La and Fe metal nitrate precursors react with the fuel to start a heat-induced chemical chain reaction. CVT230 has the triple role of fuel, chelating agent and microstructural bio-template. The surfactant properties of CVT230 favor the formation of micelles which act as a pattern on which, after burning, LaFeO3 with a porous structure is formed. The CVT230-derived LaFeO 3 showed a different photocatalytic behavior depending on the used substrate. Recently, CVT230 was tested as homogenous photosensitizer for the degradation of chlorophenols [2]. In this study organic-inorganic hybrids CVT230/SiO2 were obtained by grafting the CVT230 on different types of silica [3] both amorphous and with ordered mesopority (HMS and SBA-15), in order to have heterogeneous photocatalysts. The role of the silica morphology and textural properties on the catalytic performance of the prepared material, was studied. The obtained results pointed out that the synthesis of both efficient photocatalysts LaFeO3 and CVT230/SiO2 hybrids may be obtained through sustainable processes, owing to the availability of cost-effective and environmentally compatible substances isolated from urban biowastes. [1] F. Deganello, G. Marcì and G. Deganello, J. Eur. Ceram. Soc., 2009, 29, 439-450. [2] P. Avetta, F. Bella, A. Bianco Prevot, E. Laurenti, E. Montoneri, A. Arques and L. Carlos, ACS Sustainable Chem Eng., 2013, 1, 1545-1550. [3] M.L. Testa, V. La Parola and A.M. Venezia, Catal. Today, 2014, 223, 115-121.