In this study, a TiO₂ catalyst, modified with tungsten oxide (WO₃), was synthesized to reduce its bandgap energy (E_g) and to improve its photocatalytic performance. For the catalyst evaluation, the effect of the calcination temperature on the solar photocatalytic degradation was analyzed. The experimental runs were carried out in a CPC (compound parabolic collector) pilot-scale solar reactor, following a multilevel factorial experimental design, which allowed analysis of the effect of the calcination temperature, the initial concentration of amoxicillin, and the catalyst load on the amoxicillin removal. The most favorable calcination temperature for the catalyst performance, concerning the removal of amoxicillin, was 700 °C; because it was the only sample that showed the rutile phase in its crystalline structure. Regarding the loss of the antibiotic activity, the inhibition tests showed that the treated solution of amoxicillin exhibited lower antibacterial activity. The highest amoxicillin removal achieved in these experiments was 64.4% with 100 ppm of amoxicillin concentration, 700 °C of calcination temperature, and 0.1 g L⁻¹ of catalyst load. Nonetheless, the modified TiO₂/WO₃ underperformed compared to the commercial TiO₂ P25, due to its low specific surface and the particles sintering during the sol-gel synthesis.

Pharmaceuticals are considered among the group of emerging contaminants. Paracetamol is a moderate painkiller, which has been detected in ground and surface water. Photodegradation of paracetamol at a wavelength of radiation of 254 nm with TiO₂ nanotubes was studied by UV-spectroscopy, HPLC and measurement of the potential zeta in dependence of the solution pH. The efficiency of the photodegradation of paracetamol (20 mg L⁻¹) was 99% after 100 min exposure. Application of the Langmuir-Hinshelwood equation allowed the evaluation of the rate constant. Non-organic by-products were detected under the conditions of the chromatographic analysis. The photoreaction was faster at pH 6.5, a value at which adsorption was favored, leading to higher efficiency.

WO3/TiO2 is a composite photocatalyst that is being widely used in heterogeneous photocatalysis because it presents better photocatalytic properties than TiO2. For example, the probability of recombination of the electron/hole pairs is diminished and a more range of the solar spectrum is used for its excitation. However, this depend of variables such as tungsten oxide concentration, calcination temperature and synthesis method. This work is focused in establish the effect of WO3 on the morphological and structural characteristics of TiO2. WO3/TiO2 was synthesized by sol-gel method at different calcination temperatures and at different concentrations of tungsten oxide. The surface area, the possible transition between valence band and conduction band, particle size, elemental analysis and crystallography were examined through the BET, DRS, SEM-EDS and XRD analysis.

The photocatalytic degradation of potassium hexacyanoferrate (III) was assessed in a bench-scale compound parabolic collectors (CPC) reactor assisted with a light-emitting diode (LED) UV-A source emitting at 365 nm, and using a modified TiO₂ as a catalyst via the hydrothermal treatment of commercial Aeroxide P25. The experiments were performed under oxic and anoxic conditions in order to observe a possible reduction of the iron. The modified TiO₂ showed a specific surface area 2.5 times greater than the original Aeroxide P25 and its isotherm and hysteresis indicated that the modified catalyst is mesoporous. The bandgap energy (E_g) of the modified TiO₂ increased (3.34 eV) compared to the P25 TiO₂ band gap (3.20 eV). A specific reaction rate constant of 0.1977 min⁻¹ and an electrical oxidation efficiency of 7.77 kWh/m³ were obtained in the photocatalytic degradation. Although the TiO₂ P25 yields a photocatalytic degradation 9.5% higher than that obtained one with the modified catalyst (hydrothermal), this catalyst showed better performance in terms of free cyanide release. This last aspect is a significant benefit since this can help to avoid the pollution of fresh water by reusing the treated wastewater for gold extraction. A photocatalytic degradation of the cyanocomplex of 93% was achieved when the process occurred under oxic conditions, which favored the removal. Summarizing, the hydrothermal method could be a promising treatment to obtain TiO₂-based catalysts with larger specific areas.

La fotodegradación heterogénea solar de ácido dicloroacético (DCA) en un reactor placa plana a escala piloto, con los efectos de concentración inicial de sustrato y carga de catalizador TiO₂-P25 fue evaluada. El análisis cinético mostró que la degradación de DCA es controlada por los efectos del proceso fotocatalítico solamente. Además, la concentración inicial del sustrato y la carga de catalizador afectan favorablemente el proceso. No se presentaron degradaciones por fotólisis directa y la adsorción molecular no afectó el desempeño. El seguimiento se llevó usando TOC y ion cloruro. Se obtuvieron conversiones entre 60% y 90% confirmando la efectividad del tratamiento. Las técnicas de seguimiento de TOC y cloruros (Cl^-) mostraron la ausencia de intermediarios de reacción. El modelo matemático propuesto garantizó la predicción de los datos experimentales con un coeficiente de correlación de 0.92 y un error medio global de 2.3%.

Este estudio propone estrategias de mejora continua y sostenibilidad para la Planta Tratamiento de Agua Potable (ptap) de la Institución Universitaria Antonio José Camacho (uniajc), utilizando herramientas de Lean Manufacturing. El objetivo es impactar positivamente en variables críticas como el desperdicio, el consumo de agua, el consumo energético, la capacidad de la planta y la calidad del agua tratada. Se realizó una caracterización completa de la planta y se identificaron los problemas existentes. Mediante un análisis detallado se determinó que el desperdicio de agua y la calidad del producto eran los principales desafíos por abordar. Se aplicaron herramientas como el diagrama de proceso, Jidoka, Value Stream Mapping, diagrama de causa raíz, amef, control visual, Andon y mantenimiento autónomo para proponer soluciones y mejorar la eficiencia de la planta, reduciendo los costos operativos y los problemas ambientales asociados, permitiendo a la planta adaptarse a las crecientes demandas futuras. Además, se evaluó el consumo energético y se propusieron medidas para reducirlo. Los resultados de la implementación de estas mejoras muestran un beneficio claro en términos de costos y bienestar para la Universidad y sus estudiantes.