Efecto del pH inicial y la concentración del catalizador en la fotodegradación de tres pesticidas comerciales

The photocatalytic degradations of three pesticides: 2,4-D, diuron, ametryne and a specific mixture of these ones, were carried out in a lab-scale reactor with artificial ultraviolet radiation. The effects of initial pH and catalyst concentration for each substrate were analyzed, and the degradation kinetics was modeled at the optimal operating conditions for each mineralization process. The parameters of the Langmuir-Hinselwood models fitted satisfactorily to the experimental data. The incidence of the studied variable was evaluated by analysis of variance (ANOVA). The catalyst concentration was the most important variable for the 2,4-D degradation, whereas for diuron, ametryne and the considered mixture was the initial pH. The degradations of the pesticides mixture were favored at an initial pH of 7 and 0.6 g/L of TiO2 concentration.En este trabajo se evaluó la degradación fotocatalítica de tres pesticidas y su mezcla: 2,4 D, diurón y ametrina, en un reactor a escala de laboratorio con luz ultravioleta artificial. Se estudiaron los efectos del pH inicial y la concentración del catalizador y se modeló la cinética en las mejores condiciones de degradación para cada sustrato empleado en este estudio. Se calcularon las constantes cinéticas y de adsorción de Langmuir-Hinselwood por ajuste de parámetros. Por otro lado, se evaluó el efecto de cada una de las variables mediante un análisis de varianza. Se encontró que la variable más importante para la degradación del 2,4-D, fue la concentración del catalizador; mientras que para el diuron, la ametrina y la mezcla fue el pH inicial de la suspensión. La degradación de la mezcla se favoreció con un pH inicial de 7 y una concentración de catalizador de 0.6 g/L

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

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

Modeling of direct solar radiation in a compound parabolic collector (cpc) with the ray tracing technique

The compound parabolic collector (CPC) is a widely used technology in photochemical applications, like photocatalytic reactions. For kinetic purposes in this kind of reaction, the radiation distribution has to be well known, since the reaction rate is strongly dependent on the photon absorption rate. The present work develops a mathematical model which allows simulating the reflection of direct solar radiation on a CPC. Using analytical geometry and vector calculation, equations were evaluated, first for calculating the Cartesian coordinates of the reflecting surface. Later these points are used to calculate incident and reflected rays layouts on the collector. Visual Basic (Excel environment) program was developed for data generation and plotting the reflected rays at any instant. The incident radiation on the receptor was plotted separately displaying the daily direct energy distribution in the absorber. Also the involute length (collector) was calculated with these data, which can be very useful information for collector construction. Results obtained after simulations show that the distribution of incident energy on the absorber surface depends on the surface reflectivity. The incident energy is larger at the top of the absorber than the bottom zone and it is more convenient higher surface reflectivities for more uniform energy distributions. This mathematical model can be a first approach for absorption models which include direct solar radiation in photochemical or photothermal applications

Scale-Up and Optimization for Slurry Photoreactors

Several aspects of scale-up and optimization of heterogeneous photocatalytic reactors are detailed in the following chapter. The relevance of the dimensionless numbers, the critical factors of the photoreactor design, and the optimization methods are explored from an engineering point of view. The apparent optical thickness is the most crucial dimensionless parameter for photoreactor design and optimization; therefore, the study will be more focused on this topic. Moreover, a real case for a commercial application of the solar photocatalysis will be presented in this chapter. This full-scale plant is currently operating as an industrial wastewater treatment plant in a flexographic company located in Cali, Colombia

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

IgA vasculitis: influence of CD40, BLK and BANK1 gene polymorphisms

CD40, BLK and BANK1 genes involved in the development and signaling of B-cells are identified as susceptibility loci for numerous inflammatory diseases. Accordingly, we assessed the potential influence of CD40, BLK and BANK1 on the pathogenesis of immunoglobulin-A vasculitis (IgAV), predominantly a B-lymphocyte inflammatory condition. Three genetic variants within CD40 (rs1883832, rs1535045, rs4813003) and BLK (rs2254546, rs2736340, rs2618476) as well as two BANK1 polymorphisms (rs10516487, rs3733197), previously associated with inflammatory diseases, were genotyped in 382 Caucasian patients with IgAV and 955 sex- and ethnically matched healthy controls. No statistically significant differences were observed in the genotype and allele frequencies of CD40, BLK and BANK1 when IgAV patients and healthy controls were compared. Similar results were found when CD40, BLK and BANK1 genotypes or alleles frequencies were compared between patients with IgAV stratified according to the age at disease onset or to the presence/absence of gastrointestinal or renal manifestations. Moreover, no CD40, BLK and BANK1 haplotype differences were disclosed between patients with IgAV and healthy controls and between patients with IgAV stratified according to the clinical characteristics mentioned above. Our findings indicate that CD40, BLK and BANK1 do not contribute to the genetic background of IgAV.Funding: This study was supported by European Union FEDER funds and “Fondo de Investigaciones Sanitarias” (grants PI18/00042 and PI21/00042) from “Instituto de Salud Carlos III” (ISCIII, Health Ministry, Spain). D.P.-P. is a recipient of a Río Hortega program fellowship from the ISCIII, co-funded by the European Social Fund (ESF, “Investing in your future”) (grant number CM20/00006). F.G. is supported by funds of the RICORS Program from ISCIII, co-funded by the European Union (grant number RD21/0002/0025). V.P.-C. is supported by funds of PI18/00042. S.R.-M. is supported by funds of the RETICS Program (RD16/0012/0009) (ISCIII, co-funded by the European Regional Development Fund (ERDF)). O.G. is a staff member of Xunta de Galicia (Servizo Galego de Saude (SERGAS)) through a research-staff stabilization contract (ISCIII/SERGAS) and his work is funded by ISCIII and the European Union FEDER fund (grant numbers RD16/0012/0014 (RIER) and PI17/00409). He is a beneficiary of project funds from the Research Executive Agency (REA) of the European Union in the framework of MSCA-RISE Action of the H2020 Program, project 734899—Olive-Net. R.L.-M. is a recipient of a Miguel Servet type II program fellowship from the ISCIII, co-funded by ESF (“Investing in your future”) (grant number CPII21/00004). Acknowledgments: We are indebted to the patients and healthy controls for their essential collaboration on this study. We also thank the National DNA Bank Repository (Salamanca) for supplying part of the control samples

IgA Vasculitis: Influence of CD40, BLK and BANK1 Gene Polymorphisms

CD40, BLK and BANK1 genes involved in the development and signaling of B-cells are identified as susceptibility loci for numerous inflammatory diseases. Accordingly, we assessed the potential influence of CD40, BLK and BANK1 on the pathogenesis of immunoglobulin-A vasculitis (IgAV), predominantly a B-lymphocyte inflammatory condition. Three genetic variants within CD40 (rs1883832, rs1535045, rs4813003) and BLK (rs2254546, rs2736340, rs2618476) as well as two BANK1 polymorphisms (rs10516487, rs3733197), previously associated with inflammatory diseases, were genotyped in 382 Caucasian patients with IgAV and 955 sex- and ethnically matched healthy controls. No statistically significant differences were observed in the genotype and allele frequencies of CD40, BLK and BANK1 when IgAV patients and healthy controls were compared. Similar results were found when CD40, BLK and BANK1 genotypes or alleles frequencies were compared between patients with IgAV stratified according to the age at disease onset or to the presence/absence of gastrointestinal or renal manifestations. Moreover, no CD40, BLK and BANK1 haplotype differences were disclosed between patients with IgAV and healthy controls and between patients with IgAV stratified according to the clinical characteristics mentioned above. Our findings indicate that CD40, BLK and BANK1 do not contribute to the genetic background of IgAV

Modeling the Photocatalytic Mineralization in Water of Commercial Formulation of Estrogens 17-β Estradiol (E2) and Nomegestrol Acetate in Contraceptive Pills in a Solar Powered Compound Parabolic Collector

Endocrine disruptors in water are contaminants of emerging concern due to the potential risks they pose to the environment and to the aquatic ecosystems. In this study, a solar photocatalytic treatment process in a pilot-scale compound parabolic collector (CPC) was used to remove commercial estradiol formulations (17-β estradiol and nomegestrol acetate) from water. Photolysis alone degraded up to 50% of estradiol and removed 11% of the total organic carbon (TOC). In contrast, solar photocatalysis degraded up to 57% of estrogens and the TOC removal was 31%, with 0.6 g/L of catalyst load (TiO2 Aeroxide P-25) and 213.6 ppm of TOC as initial concentration of the commercial estradiols formulation. The adsorption of estrogens over the catalyst was insignificant and was modeled by the Langmuir isotherm. The TOC removal via photocatalysis in the photoreactor was modeled considering the reactor fluid-dynamics, the radiation field, the estrogens mass balance, and a modified Langmuir–Hinshelwood rate law, that was expressed in terms of the rate of photon adsorption. The optimum removal of the estrogens and TOC was achieved at a catalyst concentration of 0.4 g/L in 29 mm diameter tubular CPC reactors which approached the optimum catalyst concentration and optical thickness determined from the modeling of the absorption of solar radiation in the CPC, by the six-flux absorption-scattering model (SFM)

Degradación fotocatalítica solar de cipermetrina comercial usada en el baño de ganado

Revista de la Facultad de Ingeniería de la Universidad de Cartagena No 7 Vol 2 (2012) Pag. 42 - 53La fotocatálisis solar heterogénea se empleó como alternativa de tratamiento para reducir el contenido de DQO en un efluente obtenido a partir del bañado de ganado con cipermetrina en una finca de la zona rural de Montería (Colombia). En este estudio se investigó la cinética de degradación fotocatalítica de la DQO en un reactor solar tipo Cilindro Parabólico Compuesto (CPC) a escala piloto. Se estimaron las constantes cinéticas correspondientes a un modelo Langmuir-Hinshelwood (L-H) modificado, las cuales son independientes del campo radiante en el reactor fotocatalítico. En las pruebas experimentales se ensayó con dos cargas de catalizador TiO2 Degussa P25 (0.4 y 0.6 g/l) y tres diluciones del efluente del baño del ganado (1/1000, 1/2000 y 1/3000 g/l). Las reducción más alta de DQO fue de 34,69% y se obtuvo con la dilución de 1/2000 g/l y 0,4 g/l de dosis de catalizador. Las constantes cinética y de adsorción obtenidas fueron kT = 2,2378 ppm·s-1W-0.5m1.5 y K = 4,0545×10-5 ppm-1, respectivamente. Estos valores se estimaron a partir de la regresión lineal del modelo L-H con una carga de catalizador de 0,4 g/l y se validaron con los resultados de 0,6 g/