Influence of carbon content and irradiation modes on the antibiotic removal from water using VIS-activated TiO/expanded graphite composite photocatalysts.

TiO/expanded graphite (TiO/EG) composite films were applied to water treatment for sulfadiazine (SDZ) degradation in a continuous flat plate photochemical reactor. The films were synthesized by sol-gel method and deposited on borosilicate glass by airbrush spray coating technique, forming a TiO/C heterojunction. Increasing the amount of carbon promoted more efficient photocatalytic removal of SDZ under simulated sunlight, which increased from 9.

A review of hybrid enzymatic-chemical treatment for wastewater containing antiepileptic drugs.

Epilepsy is one of the most common neurological diseases worldwide and requires treatment with antiepileptic drugs for many years or for life. This fact leads to the need for constant production and use of these compounds, placing them among the four pharmaceutical classes most found in wastewater. Even at low concentrations, antiepileptics pose risks to human and environmental health and are considered organic contaminants of emerging concern.

Evaluation of the effectiveness of UV-C dose for photoinactivation of SARS-CoV-2 in contaminated N95 respirator, surgical and cotton fabric masks.

As part of efforts to combat the Covid-19 pandemic and decrease the high transmissibility of the new coronavirus, SARS-CoV-2, effective inactivation strategies, such as UV-C decontamination technologies, can be reliably disseminated and well-studied. The present study investigated the susceptibility of a high viral load of SARS-CoV-2 in filtering facepiece respirators (FFR) N95, surgical mask, cotton fabric mask and N95 straps under three different doses of UV-C, applying both real-time PCR (qPCR) and plaque formation assays to quantify viral load reduction and virus infectivity, respectively. The results show that more than 95% of the amount of SARS-CoV-2 RNA could be reduced after 10 min of UV-C exposure (0.

An overview on surfactants as pollutants of concern: Occurrence, impacts and persulfate-based remediation technologies.

Surfactants are molecules that reduce interfacial energy and increase solubility of other pollutants in water. These properties make them suitable for various domestic and industrial applications, soil remediation, pesticide formulation, among others. The increase in their use and the lack of strict regulations regarding their disposal and management is a matter of concern and requires more attention since the release and distribution of these compounds into the environment can modify important water quality parameters.

Environmental photochemical fate of pesticides ametryn and imidacloprid in surface water (Paranapanema River, São Paulo, Brazil).

In addition to direct photolysis studies, in this work the second-order reaction rate constants of pesticides imidacloprid (IMD) and ametryn (AMT) with hydroxyl radicals (HO), singlet oxygen (O), and triplet excited states of chromophoric dissolved organic matter (CDOM) were determined by kinetic competition under sunlight. IMD and AMT exhibited low photolysis quantum yields: (1.23 ± 0.

Sunlight-driven environmental photodegradation of 2-chlorobiphenyl (PCB-1) in surface waters: kinetic study and mathematical simulations.

Polychlorinated biphenyls (PCBs) are a family of highly toxic, resistant, and persistent organic pollutants, among which 2-chlorobiphenyl (PCB-1) is one of the simplest. Most studies on PCBs' photochemistry are limited to their direct photolysis, while the important role of reactive photo-induced species (RPS) (hydroxyl radicals, HO; singlet oxygen, O; and triplet excited states of chromophoric dissolved organic matter, CDOM*) in removing PCBs in natural waters through indirect photolysis has not yet been evaluated. In this work, the rate constants of the reactions between aqueous PCB-1 and RPS were obtained under simulated solar radiation (450-W Xenon lamp and an AM 1.

Enhancing the visible-light photoactivity of silica-supported TiO for the photocatalytic treatment of pharmaceuticals in water.

Catalyst samples based on SiO-supported TiO were prepared with the incorporation of Ag (metal), S (nonmetal), and ZnO@S (semiconductor and nonmetal). The materials were evaluated regarding their morphological, optical, and crystalline properties as well as their photoactivity under visible and ultraviolet light toward the degradation rate of a model emerging pollutant, acetaminophen (ACT). All modified materials exhibited improved performance over the undoped catalyst.

Dodecylpyridinium chloride removal by persulfate activation using UVA radiation or temperature: experimental design and kinetic modeling.

The degradation of dodecylpyridinium chloride (DPC) by SO and HO radicals, generated by UVA and thermal-activated persulfate (PS) was investigated. Temperatures of 30-50°C were used for the heat activation of PS. In the case of UVA/PS, the effects of [PS] and specific photon emission rate (E) were studied through a Doehlert design coupled with statistical analysis and response surface methodology.

A comprehensive dynamic kinetic model for the UVC/HO process: application to zinc bacitracin degradation in wastewater as a case study.

A dynamic kinetic model is presented for the UVC/HO-driven process. The model comprises 103 reactions, including background species, such as HCO/CO, NO, NO, SO, Cl, and HPO/HPO/PO anions, and effluent organic matter (EfOM) was validated based on experimental data obtained for the photooxidation of the nonribosomal peptide antibiotic zinc bacitracin (Zn-Bc, 34 μmol L). The set of ordinary differential equations for 38 species was combined with the molar balances describing the recirculating tubular photoreactor used.

Is ionizing radiation effective in removing pharmaceuticals from wastewater?

Wastewater and effluent discharges are the main causes of receiving water body pollution and important challenges in water quality management. Among the emerging contaminants, pharmaceuticals have increasingly drawn attention due to their incomplete removal during conventional biological treatment, inducing potential and actual risks to living organisms following residue discharges in river effluent. Electron beam irradiation (EBI) is a clean process technology for organic compound degradation and mineralization, as well as persistent pollutant detoxification.

Photochemical persistence of sulfa drugs in aqueous medium: kinetic study and mathematical simulations.

This study aimed at investigating the photochemical behavior of sulfa drugs containing five and six-membered heterocyclic substituents (sulfamethoxazole (SMX) and sulfadiazine (SDZ), respectively), in an aqueous medium. Despite their importance, studies devoted to the use of photochemical models to predict the environmental phototransformation of pollutants in surface waters, by combining laboratory results and natural aquatic systems parameters, are still scarce in the scientific literature. In this work, the second-order reaction rate constants of SDZ and SMX with hydroxyl radicals (OH), singlet oxygen (O), and triplet excited states of chromophoric dissolved organic matter (CDOM*) were experimentally determined at pH 7, using the competition kinetics approach.

UVC- and UVC/HO-Driven nonribosomal peptide antibiotics degradation: application to zinc bacitracin as a complex emerging contaminant.

Zinc bacitracin (Zn-Bc) belongs to the group of nonribosomal peptide antibiotics (NRPA), comprising a mixture of non-biodegradable congeners characterized by complex structures containing cyclic, polycyclic, and branched chains. However, reports on the use of AOPs for the degradation of NRPA are non-existent. In this context, the present work investigated the photodegradation of Zn-Bc in aqueous solution by direct photolysis and the UVC/HO process.

One-step procedure for peroxidase concentration, dye separation, and color removal by aqueous two-phase system.

The aim of our study is to develop a one-step procedure to remove and degrade dyes from wastewater using a low-cost and efficient system based on aqueous two-phase system (ATPS), a well-known technique used to concentrate and recover enzymes. We investigated the catalytic proprieties of rice bran peroxidase (RBP) and found that this homemade enzyme can remain bound to its substrate for up to 5 days in controlled environments, without denaturing and while maintaining stable oxidation reduction potential (ORP) and pH. This biomolecule showed affinity for the ATPS technique prepared with polyethylene glycol and salt, which improved the relative activity up to 170%.

Removal of sulfadiazine from simulated industrial wastewater by a membrane bioreactor and ozonation.

Ozonation can be used as a polishing treatment for degrading low-concentration pharmaceutical compounds recalcitrant to biological treatment, when large amounts of biodegradable organics have been previously removed by biological processes. Nevertheless, a systematic investigation has not yet been carried out for the coupled MBR + O process through an experimental design approach. Thereby, the purpose of this study is to evaluate the performance of different processes (membrane bioreactor-MBR, ozonation; and integrated MBR + O) for removing the antibiotic sulfadiazine (SDZ) from a synthetic wastewater matrix of industrial interest.

Degradation of bisphenol A by the UV/HO process: a kinetic study.

A theoretical and experimental study of bisphenol A (BPA) degradation by the UV/HO process in water is presented. The effects of the HO concentration and the specific rate of photon emission (E) on BPA degradation were investigated. A kinetic model derived from a reaction sequence was employed to predict BPA and hydrogen peroxide concentrations over time using an annular photochemical reactor in batch recirculation mode.

Photo-Fenton reaction at mildly acidic conditions: assessing the effect of bio-organic substances of different origin and characteristics through experimental design.

Urban-waste bio-organic substances (UW-BOS) have been shown to be capable of extending the photo-Fenton reaction to mildly acidic conditions. In this study, the effects of pH (3-7), UW-BOS, HO and iron concentrations on the photo-Fenton process were systematically assessed using a Doehlert experimental design and response surface methodology for two UW-BOS (CVT230 and FORSUD). Solutions of the model antibiotic sulfadiazine (SDZ) were irradiated in a solar simulator equipped with a 550 W Xenon lamp.

Micro-structured packed bed reactors for solar photocatalysis: impacts of packing size and material on light harnessing.

The application of photochemistry in larger scales relies on studies in photoreactor engineering. This report investigates the structural parameters of externally irradiated micro-structured photochemical packed bed reactors (PBRs). It reports on the impacts of the size and material of spherical packings on the reactor ability to harness incoming photons.

Environmental photochemical fate and UVC degradation of sodium levothyroxine in aqueous medium.

The synthetic hormone sodium levothyroxine (LTX) is one of the most prescribed drugs in the world and the most effective in hypothyroidism treatment. The presence of LTX in the environment has become a matter of major concern due to the widespread use of this hormone and by the fact that it is only partially removed in conventional water and sewage treatment plants. However, information regarding the photochemical fate of this hormone in environmental or engineered systems is scarce in the literature.

Direct and indirect photolysis of the antibiotic enoxacin: kinetics of oxidation by reactive photo-induced species and simulations.

The purpose of this study was to investigate the aqueous phase photochemical behavior of enoxacin (ENO), an antibiotic selected as a model pollutant of emerging concern. The second-order reaction rate constants of ENO with hydroxyl radicals (HO) and singlet oxygen (O) were determined at pH 3, 7, and 9. Also, the rate constants of the electron transfer reaction between ENO and triplet states of chromophoric dissolved organic matter (CDOM*) are reported for the first time, based on anthraquinone-2-sulfonate (AQ2S) as CDOM proxy.

Synthesis of Novel Periodic Mesoporous Organosilicas Containing 1,4,5,8-Naphthalenediimides within the Pore Walls and Their Reduction To Generate Wall-Embedded Free Radicals.

Novel periodic mesoporous organosilicas (PMOs) containing 1,4,5,8-Naphthalenediimide (NDI) chromophores as an integral part of the pore walls were synthesized in acidic conditions, in the presence of inorganic tetraethyl orthosilicate, using triblock copolymer surfactant Pluronic P-123 as a template. The NDI precursor, the bridged silsesquioxane N, N'-bis(3-triethoxysilylpropyl)-1,4,5,8-naphthalenediimide, was synthesized by reaction of 1,4,5,8-naphthalenetetracarboxylic dianhydride with excess 3-aminopropyltriethoxysilane. A series of samples containing up to 19% (weight %) of NDI were prepared (the materials were labeled PMONDIs).

A comparison between the four Geldart groups on the performance of a gas-phase annular fluidized bed photoreactor for volatile organic compound oxidation.

Heterogeneous photocatalytic oxidation (PCO) is a widely studied alternative for the elimination of volatile organic compounds (VOC) in air. In this context, research on novel photoreactor arrangements to enhance PCO rates is desired. Annular fluidized bed photoreactors (AFBPR) have yielded prominent results when compared to conventional thin film reactors.

Photochemical generation of reactive intermediates from urban-waste bio-organic substances under UV and solar irradiation.

Singlet oxygen (O), hydroxyl radicals (OH), and excited triplet states of organic matter (OM) play a key role in the degradation of pollutants in aquatic environments. The formation rates and quantum yields (Φ) of these reactive intermediates (RI) through photosensitized reactions of dissolved organic matter (DOM) have been reported in the literature for decades. Urban biowaste-derived substances (UW-BOS), a form of organic matter derived from vegetative and urban waste, have recently been shown to be efficient sensitizers in the photo-degradation of different contaminants.

Degradation and acute toxicity removal of the antidepressant Fluoxetine (Prozac(®)) in aqueous systems by electron beam irradiation.

Electron beam irradiation (EBI) has been considered an advanced technology for the treatment of water and wastewater, whereas very few previous investigations reported its use for removing pharmaceutical pollutants. In this study, the degradation of fluoxetine (FLX), an antidepressant marketed as Prozac(®), was investigated by using EBI at FLX initial concentration of 19.4 ± 0.

Photolysis of atrazine in aqueous solution: role of process variables and reactive oxygen species.

Photochemical advanced oxidation processes have been considered for the treatment of water and wastewater containing the herbicide atrazine (ATZ), a possible human carcinogen and endocrine disruptor. In this study, we investigated the effects of the photon emission rate and initial concentration on ATZ photolysis at 254 nm, an issue not usually detailed in literature. Moreover, the role of reactive oxygen species (ROS) is discussed.