Mineralización fotocatalítica de agua residual contaminada con dicloxacilina comercial en un reactor solar CPC a escala piloto.

En el presente trabajo se estudió la mineralización de una muestra de agua residual contaminada con dicloxacilina comercial mediante fotocatálisis solar heterogénea con TiO2. Los ensayos se llevaron a cabo en un reactor tipo colector parabólico compuesto (CPC) ubicado el Laboratorio de Fotocatálisis Solar de la Universidad del Valle (Cali, Colombia). Se empleó un diseño experimental de Taguchi para analizar los efectos del pH inicial de la solución y la concentración del catalizador en la mineralización fotocatalítica de la muestra, considerando la energía UV acumulada como variable de ruido. Los resultados mostraron que se alcanzaron reducciones de carbono orgánico total (COT) de hasta 45%. De acuerdo con los valores de señal/ruido (S/R) obtenidos a partir del diseño de Taguchi, la mineralización se favoreció con un pH inicial de 5 y una concentración de catalizador de 0.3 g/l

Experimental data on the production and characterization of biochars derived from coconut-shell wastes obtained from the Colombian Pacific Coast at low temperature pyrolysis

Biochars are emerging eco-friendly products showing outstanding properties in areas such as carbon sequestration, soil amendment, bioremediation, biocomposites, and bioenergy. These interesting materials can be synthesized from a wide variety of waste-derived sources, including lignocellulosic biomass wastes, manure and sewage sludge. In this work, abundant data on biochars produced from coconut-shell wastes obtained from the Colombian Pacific Coast are presented. Biochar synthesis was performed varying the temperature (in the range: 280 �Ce420 �C) and O2 feeding (in the range: 0e5% v/v) in the pyrolysis reaction. Production yields and some biochar properties such as particle size, Zeta Potential, elemental content (C, N, Al, B, Ca, Cu, Fe, K, Li, Mg, Mn, Na, P, S, Ti, Zn), BET surface area, FT-IR spectrum, XRD spectrum, and SEM morphology are presented. This data set is a comprehensive resource to gain a further understanding of biochars, and is a valuable tool for addressing the strategic exploitation of the multiple benefits they hav

Effect of pyrolysis, impregnation, and calcination conditions on the physicochemical properties of TiO2/Biochar composites intended for photocatalytic applications

Biochars are outstanding materials obtained from the pyrolysis of biomass, possessing unique physicochemical properties that are attractive for many environmental applications, including photocatalysis. In this work, we have synthesized for the first time TiO2/Biochar composites using Aeroxide P25 TiO2 and biochars produced from the thermal treatment at low (or null) oxygen content of Colombian coconut shells. To explore and ultimately tune the final physicochemical properties of the TiO2/Biochars materials, a facile wet impregnation method was assessed, in which the following factors were evaluated: 1) Temperature and 2) %O2 in the pyrolysis of the biomass, 3) TiO2/Biochar ratio used in the impregnation and 4) Calcination temperature of the TiO2/Biochar composites. A comprehensive characterization of the novel composites was done, using techniques such as: XRD, XPS, BET, ATR-FTIR, diffuse reflectance, PL, SEM, and electrochemical analysis. The material synthesized with TPyrol = 350 ◦C, %O2 = 2.5, T/B = 0.8 and TCal of 800 ◦C presented notable properties such as low Eg, reduced recombination of e--h+ pairs, a high surface area, and a relatively high photogeneration of charges, and interestingly, it experienced phase transition from Anatase-Rutile to Anatase-Brookite. On the other hand, low TPyrol and high %O2 values conduct to hydrophilic functional groups on the TiO2/Biochar composites, whereas the use of higher TPyrol and TCal lead to a more hydrophobic character but promote the reduction of the recombination of photogenerated e--h+ pairs. As a result, this information is relevant for planning future applications of photocatalysis for degrading pollutants of different chemical nature.Minciencias-Fulbright-Universidad del Vall

Diseño, construcción y evaluación de un reactor fotocatalítico solar de placa plana para degradar ácido tereftálico

Tesis (Ingeniero Químico) --Universidad de Cartagena. Facultad de Ciencias E Ingenierías. Programa de Ingeniería Química, 2012El presente proyecto de investigación, fue realizado en la empresa POLISUIN S.A., el cual consistió en diseñar, construir y evaluar un reactor fotocatalítico de placa plana para degradar ácido tereftálico generado como residuo en uno de los procesos de la empresa. El diseño del equipo se hizo considerando datos consultados en la literatura, con pequeñas modificaciones para adaptarlo a las condiciones de la zona. El montaje se llevó a cabo siguiendo los parámetros establecidos en el diseño, y se evaluó realizando corridas para descontaminar el efluente industrial que contenía ácido tereftálico. Para construir el reactor, se procedió a realizar los diseños del distribuidor de la tubería perforada; se calculó el diámetro de la tubería y la potencia de la bomba requerida para mantener el régimen de flujo pertinente. El área total del reactor fue de 1.25 m2 y se construyó con una inclinación de 10.4°. Se realizaron corridas sin catalizador para estimar un blanco de degradación y con el catalizador para estimar el efecto de la fotocatálisis. Los resultados mostraron que el reactor de placa plana degrada aceptablemente el ácido tereftálico. Se obtuvo una alta degradación insensible a la variación de la energía acumulada, empleando un pH inicial bajo y una concentración de TiO2 de 0.3 g/l. Como componente adicional, se propuso un modelo para el perfil de velocidades en el flujo de la película descendente en la placa plana, abriendo campo al modelado completo del reactor

Solid-state photocatalysis for plastics abatement: A review

The COVID-19 pandemic has caused a dramatic increase in plastic wastes associated with the use of single-use masks, gloves, gowns, and other personal protective equipment (PPE). The accumulation of PPE, especially single-use masks, end up polluting environment, causing harm mainly to aquatic and terrestrial ecosystems. Due to the enormous concern about plastic pollution, many efforts are being made to develop efficient technologies to tackle it, among which solid-state photocatalysis is highlighted. Even though the outstanding results that have been obtained with the solid-state application of photocatalysis, there are fewer publications and reports on the use of it in comparison with aqueous and/or gaseous phase photocatalysis. Then, this review presents the most relevant works published on this topic and provide an in-depth analysis of solid-state photocatalysis for plastic abatement, including the incorporation of the usually hydrophilic photocatalyst into the hydrophobic plastic matrix, the common experimental procedures for evaluating its effectiveness (gravimetric, optical, spectroscopic, and mechanical methods) and the description of the intricate reaction mechanism suggested so far. The aim is increasing the awareness on this innovative topic among the academic/industrial community and advancing the research thereon