Unveiling the potential of machine learning in cost-effective degradation of pharmaceutically active compounds: A stirred photo-reactor study.

In this study, neural networks and support vector regression (SVR) were employed to predict the degradation over three pharmaceutically active compounds (PhACs): Ibuprofen (IBP), diclofenac (DCF), and caffeine (CAF) within a stirred reactor featuring a flotation cell with two non-concentric ultraviolet lamps. A total of 438 datapoints were collected from published works and distributed into 70% training and 30% test datasets while cross-validation was utilized to assess the training reliability. The models incorporated 15 input variables concerning reaction kinetics, molecular properties, hydrodynamic information, presence of radiation, and catalytic properties. It was observed that the Support Vector Regression (SVR) presented a poor performance as the ε hyperparameter ignored large error over low concentration levels. Meanwhile, the Artificial Neural Networks (ANN) model was able to provide rough estimations on the expected degradation of the pollutants without requiring information regarding reaction rate constants. The multi-objective optimization analysis suggested a leading role due to ozone kinetic for a rapid degradation of the contaminants and most of the results required intensification with hydrogen peroxide and Fenton process. Although both models were affected by accuracy limitations, this work provided a lightweight model to evaluate different Advanced Oxidation Processes (AOPs) by providing general information regarding the process operational conditions as well as know molecular and catalytic properties.

Experimental data on activity catalyst TiO2/Fe3O4 under natural solar radiation conditions.

In this document, the photocatalytic activity of TiO2/Fe3O4, prepared by the mixing of the pure oxides, was studied. The photocatalytic degradation of aqueous Methylene Blue (MB) solutions (10 and 30 ppm) was performed, the TiO2/Fe3O4 catalysts in 80/20, 50/50 and 20/80 mass ratios were used during the test, artificial sunlight and natural solar radiation were tested at laboratory and pilot plant scale respectively. Besides, the kinetic reactions were evaluated according to the Langmuir-Hinshelwood model, the apparent velocity constants (kapp) were obtained for the TiO2/Fe3O4 catalysts. In the laboratory test, the TiO2/Fe3O4 catalyst (80/20) had a performance for 93.04% of discoloration, kapp = 0.0238 min-1, while for TiO2/Fe3O4 (50/50, 20/80) had an 83.46%, 65.00% for discoloration of MB and the kapp values were 0.0154 min-1 and 0.0098 min-1, respectively. In the solar test at pilot scale, the percentages of discoloration of 24.32%, and 57.78%, with kapp values of 0.00037 min-1, 0.00121 min-1 respectively were obtained for TiO2/Fe3O4 (80/20), a MB solution of 30 ppm, a load of 0.1 g/L and 0.3 g/L of the catalyst respectively.

Wild microorganism and plankton decay in ballast water treatments by solar disinfection (SODIS) and advanced oxidation processes.

Ballast water (BW) is a dead weight used by ships to provide stability in their journeys. It poses health, economic and ecological problems. Since 2017, the International Maritime Organization-IMO mandated management of BW. This research compares plankton mortality and microorganism inactivation in different BW treatments to identify possible decay models. Treatments include solar radiation (Srad), UV, H2O2 and advanced oxidation processes (AOPs). In the wild populations, the disinfection capacity was measured in natural seawater pumped from the Santa Marta port zone in Colombia. AOPs showed different models and effectiveness according to the treatment and microorganism. Plankton larger than 50 µm was the most resistant; therefore, it must be removed first by a previous filter. Wild microorganisms showed log-linear and log-linear tail decay models for most AOPs in E. coli. For Vibrio, the models were log-lineal tail and biphasic models.

Experimental data on the relationship between dyes sensitizers and wavelength during the photocatalytic degradation of diclofenac.

Sensitizers are being used to improve the photocatalytic activity of semiconductors in the visible light region of the solar spectrum. Different types of dyes are reported as sensitizer agents, such as ruthenium complex molecules, porphyrins and Pt complexes, which are critically assessed because they are hazardous substance. Therefore, it is necessary to replace these compounds with safer sensitizer like organic dyes. This work evaluated the photocatalytic degradation of diclofenac using two different types of organic dyes (Perinaphtenone and Eosin-Y) as sensitizer agents. The catalyst concentration [0.15; 0.35 g/l], source of light (UVA - Vis) and type of dye were evaluated. The data obtained can be useful to classify organic dyes that could be employees as sensitizers and which is the wavelength more adequate to use as an energy source. The Kapp for the reaction has values between 1*10-3 to 5*10-3 min-1 for UVA, 3*10-4 to 3*10-3 min-1 for Vis and 2*10-3 to 6*10-3 min-1 for UV-Vis.

Experimental data on the photoelectrochemical oxidation of phenol: Analysis of pH, potential and initial concentration.

The data collected in the present work correspond to percentages of phenol degradation by means of photoelectrochemical oxidation (PEC). Also, the information related to the energetic and kinetic performance of this advanced oxidation process (AOPs) is shown. The tests were divided into two stages: 1. Supporting electrolytes tests to determine the electrolyte that presents a better response to photocurrent and 2. Degradation of phenol to obtain the adequate conditions for the elimination of the contaminant. A central rotary composite design with uniform precision at two levels was used to analyze the influence of the initial pH, electrode potential and the initial concentration of substrate. Finally, with all the data obtained, calculation of degradation rates and the electrical energy per order EEO were made.

Anoxic photocatalytic treatment of synthetic mining wastewater using TiO2 and scavengers for complexed cyanide recovery.

The wastewater from gold exploitation is well known for the toxic nature of recalcitrant cyanide metallic complexes. In this work the selectivity in the photocatalytic degradation of gold mining wastewater (Fe(CN)63-) using suspended TiO2 with alcoholic and organic acid scavengers in a mini-CPC photoreactor with a 30 W UV-A LED as an artificial source of light was evaluated. The study was done in four stages: 1. load catalyst determination, 2. combination of scavengers in a typical photocatalytic degradation, 3. evaluation of scavenger concentration and 4. kinetic study. The decomposition into CN- and Fe removal of the cyanocomplex were tracked. It was observed that formic acid (FA) and t-butanol (t-ButOH) were the best scavengers for the photocatalytic degradation under anoxic conditions. The best concentrations of acceptors used in the study were 10 mM FA and 10 mM t-ButOH at 20 W m-2 of UV-A power, reaching 80% degradation of Fe(CN)63-, 40% Fe removal and 18 ppm of free cyanide CN release to the liquid phase. The electrical efficiency of oxidation per order (EEo) was increased by about 50% with the addition of scavengers instead of traditional anoxic photocatalytic treatment. It was proved that the photocatalytic decomposition of the Fe cyanocomplex was done through the photoreduction path of the metal complex.

An approach to utilize the artificial high power LED UV-A radiation in photoreactors for the degradation of methylene blue.

Utilization of UV LED light is trending in the development of photoreactors for pollutant treatment. In this study, two different geometries were studied in the degradation of methylenebBlue (MB) using high power UVA LED as a source of light. The dosage, initial concentration, electric power, and H2O2 addition were evaluated in the two geometries: a mini CPC (Cilindrical Parabolic Collector) and a vertical cylindrical with external irradiation both coupled with LED UVA. Best degradation was obtained for 0.3 g L-1 TiO2, 40 min, and 15 ppm of MB of initial concentration in the standard batch reactor. It was found that the best system was a cpc geometry. Also, hydrogen peroxide was used as an electron acceptor and 97% degradation was obtained in 30 min with 10 mM H2O2 and 0.4 g TiO2/L. Power of the LEDs was also evaluated and it was found that 20 W m-2 is the best operational condition to achieve the best MB degradation avoiding the oxidant species recombination.