One of the outstanding issues of concern by governments and society in general relates to the final destination of solid waste, which can bring severe impacts on social, political, economic and environmental dimensions. The sustainable development of enterprises and industries goes for the care of the planet, thus ensuring the quality of life for future generations and the planet. The disposal of municipal waste in landfills is the technique most commonly employed for the remediation of solid residues. The residues undergo decomposition beneath the soil and in the presence of water this generates leachate, which percolates down to the bottom of the landfill through drainage. This drained liquid is collected from the landfill installations and subjected to treatment, which involves physico-chemical and biological processes. Landfill leachate commonly contains heavy metals due to the incorrect disposal of products such as fluorescent bulbs and batteries. In this context, a method for the treatment of sludge originating from the physicochemical remediation of leachate using thermal plasma is proposed in this paper. The efficiency of the method was verified by monitoring the total organic carbon content, water content and density of the sludge. The quantity of metals present in the samples was determined before and after pyrolysis by thermal plasma using flame atomic absorption spectroscopy (FAAS), scanning electron microscopy (SEM) and X-ray fluorescence (XRF) spectrometry techniques. The results show that the leachate treatment method used was efficient, presenting the best results for the samples of iron and zinc.

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were evaluated as catalysts for the propanolysis of the organophosphate pesticide dimethyl 4-nitrophenyl phosphate (methyl paraoxon). The solid catalysts were characterized by energy-dispersive X-ray fluorescence (EDXRF), N 2 physisorption (BET and BJH methods), and scanning and transmission electron microscopy (SEM and TEM). Physical−chemical characterizations revealed that the erbium content is 11.7% w/w in the novel solid and results in improved catalyst performance when compared with Al 2 TiO 5 , with textural properties favorable for methyl paraoxon diffusion in agglomerates composed of polydisperse spherical nanoparticles. Kinetic measurements at 80 °C show that the Er 2 O 3 /Al 2 TiO 5 catalyst promotes a catalytic effect of at least 7 × 10 5 -fold when compared with the first-order rate constant of the spontaneous propanolysis of methyl paraoxon.

Three-dimensionally ordered macroporous materials for photonic or refractory applications have been developed by an innovative approach based on mullite sol-gel infiltration of direct photonic crystals followed by burn-out and calcination. Direct photonic crystals were obtained using polystyrene spheres templates either by vertical convective self-assembly or by drop casting. The samples were then infiltrated by spin coating with mullite sol-gels prepared with two different compositions (74 wt.% Al 2 O 3 , 26 wt.% SiO 2 and 80 wt.% Al 2 O 3 , 20 wt.% SiO 2 ). The inverse opal photonic crystals prepared with both sol-gels presented a highly ordered porosity and the high-alumina composition showed stability up to 1500°C. After inversion of the structure (polymeric template burn-out), the high-alumina composition showed roundness of the PS templated pores closer to an ideal sphere (Ø = 0.967) when compared to the low-alumina composition (Ø = 0.954). Although the inverse opal photonic crystals did not present a photonic bandgap, they showed structural stability at high temperatures, which enable their application as refractory materials.