Because of the increasing demand for photovoltaic energy and the generation of end-of-life photovoltaic waste forecast, the feasibility to produce glass substrates for photovoltaic application by recycling photovoltaic glass waste (PVWG) material was analyzed. PVWG was recovered from photovoltaic house roof panels for developing windows glass substrates; PVWG was used as the main material mixed with other industrial waste materials (wSG). The glass was casted by air quenching, annealed, and polished to obtain transparent substrates samples. Fluorine-doped tin oxide (FTO) was deposited as back contact on the glass substrates by spray pyrolysis. The chemical composition of the glass materials was evaluated by X-ray fluorescence (XRF), the thermal stability was measured by differential thermal analysis (DTA) and the transmittance was determined by UV-VIS spectroscopy. The surface of the glass substrates and the deposited FTO were observed by scanning electron microscopy (SEM), the amorphous or crystalline state of the specimens were determined by X-ray diffraction (XRD) and the sheet resistance was evaluated by the four-point probe method. The sheet resistance of the deposited FTO on the wSG substrate was 7.84 ± 3.11 Ω/□, lower than that deposited on commercial soda-lime glass (8.48 ± 3.67 Ω/□), meaning that this material could present improved conduction of the produced electrons by the photovoltaic effect. This process may represent an alternative to produce glass substrates from waste materials that could be destined for photovoltaic applications, especially the production of ecological photovoltaic windows.

To reduce the environmental impacts from sodium silicate synthesis, a ceramic method was suggested, with sugarcane bagasse ash (SCBA) as the source of silicon dioxide and sodium carbonate. Although the production of sodium silicate is carried out on a large scale, it should be noted that its process requires temperatures above 1000 °C; it also requires the use of highly corrosive agents such as sodium hydroxide and chlorine gas to neutralize the remaining sodium hydroxide. In the present study, the synthesis temperatures were reduced to 800 °C with a reaction time of 3 h by pressing equimolar mixtures of previously purified SCBA and sodium carbonate; then, heat treatment was carried out under the indicated conditions. The resulting materials were analyzed with Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Among the crystalline phases, calcium disodium silicate was identified, in addition to sodium silicate; thus, it was inferred that the other components of the ash can interfere with the synthesis of silicate. Therefore, in order to obtain the highest composition of sodium silicate, a leaching treatment of the SCBA is required.

To reduce environmental impacts from sodium silicate synthesis it was suggested the use of sugarcane bagasse ash (SCBA) as a source of silicon dioxide and sodium carbonate using the ceramic method. Although the production of sodium silicate is carried out on a large scale, it should be noted that its process requires temperatures above 1000 °C or the use of highly corrosive agents such as sodium hydroxide and chlorine gas used to neutralize the remaining sodium hydroxide. In the present work, the synthesis temperatures were reduced to 800 °C with a reaction time of 3 hours by pressing equimolar mixtures of previously purified SCBA and sodium carbonate, then heat treatment was carried out under the indicated conditions. The resulting materials were analyzed by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Among the crystalline phases, calcium disodium silicate was identified, in addition to sodium silicate, so it was inferred that the other components of the ash can interfere with the synthesis of silicate. Therefore, to obtain the highest composition of sodium silicate, a leaching treatment of the SCBA is required.

Different chemical and physical treatments have been used to improve the properties and functionalities of steels. The anodizing is one of the most promising treatments, due to its versatility and easy industrial implementation, since it allows obtaining different microstructures on the surface, in order to be employed in different industrial sectors. The present work has studied the influence of the anodizing time (15, 30, 45 and 60 min), as well as the stirring speed (0, 200, 400 and 600 rpm), on the morphology and the resistance corrosion behavior of anodic layers grown in 304L stainless steel. The anodic layers were characterized morphologically, compositionally and electrochemically, in order to determine the influence of these parameters on their corrosion behavior in a 0.6 M NaCl saline solution. The results show that the generation of anodic layers at different times propitiates the definition of nonporous morphologies, while the phenomena of dissolution of the layers that increase with the time of anodizing. However, the resistance to corrosion decreases respect to the non-anodized 304L SS. On the other hand, the effect of the stirring speed during the generation of these anodic layers does not seem to influence the corrosion behavior in the saline medium studied.