TiO2-carbon microspheres as photocatalysts for effective remediation of pharmaceuticals under simulated solar light

In this work, novel carbon microspheres supported TiO2 nanoparticles were prepared for the degradation of pharmaceuticals in water, selecting diclofenac, acetaminophen, and ibuprofen as target pollutants. Lignin, an important biomass byproduct from the paper industry and biorefineries, was transformed in carbon microspheres by a novel approach based on a Fe-activated hydrothermal carbonization followed by pyrolysis at 900 °C. These carbon microspheres were further covered with TiO2 by a solvothermal treatment. The effects of several parameters including hydrothermal carbonization time and mass ratio (TiO2:carbon) on the catalytic activity of TiO2-carbon microspheres were investigated. The results revealed that the combination of long carbonization time and high TiO2:carbon ratio achieved superior TiO2-carbon microspheres (Ti2-C20) catalytic performance. Ti2-C20 achieved complete degradation of ibuprofen (5 mg·L−1) and diclofenac (5 mg·L−1) within 3 h under solar light and mineralization percentages close to 50%. Moreover, the photocatalytic performance remained high after five reuse cycles and was barely affected by the presence of common inorganic ions in treated wastewater (such as Cl–, NO3– and HCO3–). The degradation pathway of diclofenac was proposed, involving C-N bond cleavage, and subsequent hydroxylation and cyclization reactions leading to the formation of aliphatic carboxylic acids. Overall, promising photocatalysts were obtained from a biomass byproduct for effective degradation of pharmaceuticals with the assistance of solar lightThis research was funded by the Spanish State Research Agency (PID2019-106186RB-I00/AEI/10.13039/501100011033). M. Peñas-Garzón is indebted to Spanish MECD for a FPU grant (FPU16/00576 grant) and to Spanish MICIU for funding the international stay (EST18/00048 grant) at the Department of Chemical and Environmental Engineering (ChEE), University of Cincinnati. Authors thank the Research Support Services of the University of Extremadura (SAIUEx) for its technical and scientific suppor

Routine dynamics in virtual teams: the role of technological artifacts

Purpose In this paper, the authors extend their understanding of the internal dynamics of routines in contexts characterized by increased levels of virtuality. In particular, the authors focus on the role of routine artifacts in the internal dynamics of routines to answer the question: How does extensive reliance on information and communication technologies (ICTs) due to physical distance influence the internal dynamics of the new product development (NPD) routine (i.e. interactions between performative, ostensive and artifacts of routines) enacted by a virtual team? Design/methodology/approach This paper is based on an 18-month ethnographic study of the NPD routine performed by a virtual team. The authors relied predominantly on qualitative, ethnographic data collection and analysis methods, using semi-structured interviews, non-participant observation, and the collection of archival data and company documents (formal procedures, guidelines, application designs etc). Qualitative research offers a valuable means to investigate dynamic processes in organizations due to its sensitivity to the organizational context and potential to focus on activities as they unfold. Findings The findings highlight the central role of routine artifacts (ICTs) in the routine dynamics of the NPD routine performed by virtual team. In particular, the authors show that the use of the particular types of ICTs enabled team members to confidently and meaningfully relate to the overall routine activity and coordinate their actions in a context characterized by physical distance and extensive reliance on communication and collaboration technologies. Originality/value The paper sheds light into role of routine artifacts in the routine dynamics in a context characterized by a high degree of virtuality. This work contributes to the literature on routine dynamics by theorizing about the processes through which routine artifacts (ICTs) afforded routine participants the ability to act confidently and meaningfully to the present and dynamically coordinate their actions with their fellow routine participants

A review of solar and visible light active TiO2 photocatalysis for treating bacteria, cyanotoxins and contaminants of emerging concern

Researchintothedevelopmentofsolarandvisiblelightactivephotocatalystshasbeensignificantlyincreased\ud inrecentyearsduetoitswiderangeofapplicationsintreatingcontaminantsofemergingconcern(CECs),\ud endocrine disruptingcompounds(EDCs), bacteriaandcyanotoxins.Solarphotocatalysisisfoundtobehighly\ud effectiveintreatingawiderangeofCECsfromsourcessuchaspharmaceuticals,steroids,antibiotics,phthalates,\ud disinfectants,pesticides,fragrances(musk),preservativesandadditives.Similarly,anumberofEDCsincluding\ud polycyclicaromatichydrocarbons(PAHs),alkylphenols(APs),bisphenolA(BPA),organotins(OTs),volatileor-\ud ganic compounds(VOCs),naturalandsyntheticestrogenicandandrogenicchemicals,pesticides,andheavy\ud metalscanberemovedfromcontaminatedwaterbyusingsolarphotocatalysis.Photocatalysiswasalsofound\ud effectiveintreatingawiderangeofbacteriasuchas Staphylococcusaureus,Bacillussubtilis,Escherichiacoli,\ud Salmonellatyphi and Micrococcuslylae. Thecurrentreviewalsocomparestheeffectivenessofvariousvisible\ud lightactivatedTiO2 photocatalystsfortreatingthesepollutants. Dopingorco-dopingofTiO2 usingnitrogen,\ud nitrogen–silver,sulphur,carbon,copperandalsoincorporation ofgraphenenano-sheetsarediscussed.Theuse\ud of immobilisedTiO2 for improvingthephotocatalyticactivityisalso presented.Decoratingtitaniaphotocatalyst\ud withgrapheneoxide(GO)isofparticularinterestduetoGO'sabilitytoincreasethephotocatalyticactivityof\ud TiO2. TheuseGOtoincreasethephotocatalyticactivityofTiO2 againstmicrocystin-LR(MC-LR)underUV-Aand\ud solarirciationisdiscussed.TheenhancedphotocatalyticactivityofGO–TiO2 comparedtothecontrolmaterialis\ud attributedtotheeffectiveinhibitionoftheelectron–holerecombinationbycontrollingtheinterfacialcharge\ud transferprocess.Itisconcludedthatthereisacriticalneedforfurtherimprovementoftheefficiencyofthese\ud materialsiftheyaretobeconsideredforbulkindustrialuse

Simulated solar photo-assisted decomposition of peroxymonosulfate. Radiation filtering and operational variables influence on the oxidation of aqueous bezafibrate

This work investigates the potential of the combination of peroxymonosulfate (PMS) and simulated solar radiation (λ > 300 nm) to remove bezafibrate from aqueous solution. Different solar light filters indicate a higher removal efficiency as the wavelength range used moves to the more energetic region of the solar spectrum. The system PMS/Daylight (300–800 nm) eliminates bezafibrate (1 mg L−1) in less than 30 min under the best conditions used in this study (CPMS = 4·10−4 M) with no pH control (acidic pH). The efficiency of the process significantly improves under alkaline conditions (pH = 10), likely due to a higher PMS photolysis rate. Experiments conducted at different initial concentration of PMS and bezafibrate suggest first order regarding PMS and different from 1 in the case of bezafibrate. Intermediates generated at the beginning of the process have been tentatively identified to propose a hypothetical reaction pathway and to estimate their toxicity

Peroxymonosulfate/solar radiation process for the removal of aqueous microcontaminants. Kinetic modeling, influence of variables and matrix constituents

New technologies to address the presence of pharmaceutical and personal care products (PPCPs) in wastewater are needed, especially in those cases in which water will be reused. In this work, the activation of peroxymonosulfate (PMS) with simulated solar radiation has been applied to the oxidation of a mixture of six PPCPs, i.e. caffeine, primidone, N,N-diethyl-3-methylbenzamide (DEET), methylparaben, clofibric acid and ibuprofen. The sole application of solar radiation, i.e. solar photolysis, only led to the oxidation of clofibric acid (complete degradation in 90 min). The combination of PMS and solar radiation resulted in the degradation of all target micropollutants. The complete degradation of this mixture at initial 100 ppb was achieved with 0.5 mM of initial PMS after 90 min. A kinetic study that acceptably simulates the experimental data under different conditions has been proposed. The effects of initial PPCP concentration (1 mg L−1-100 μg L−1), PMS dose (0.1−5 mM), and pH (3–9) were tested and kinetically simulated. Finally, the PPCPs removal study was carried out in two real water matrices (river and a secondary effluent of an urban wastewater treatment plant). A higher dose of PMS, ten times higher, was required to achieve complete degradation of the micropollutants if compared to ultrapure water

Degradation of contaminants of emerging concern by UV/H2O2 for water reuse: Kinetics, mechanisms, and cytotoxicity analysis.

Advanced oxidation using UV and hydrogen peroxide (UV/H2O2) has been widely applied to degrade contaminants of emerging concern (CECs) in wastewater for water reuse. This study investigated the degradation kinetics of mixed CECs by UV/H2O2 under variable H2O2 doses, including bisphenol A, estrone, diclofenac, ibuprofen, and triclosan. Reverse osmosis (RO) treated water samples from Orange County Water District's Groundwater Replenishment System (GWRS) potable reuse project were collected on different dates and utilized as reaction matrices with spiked additions of chemicals (CECs and H2O2) to assess the application of UV/H2O2. Possible degradation pathways of selected CECs were proposed based on high resolution mass spectrometry identification of transformation products (TPs). Toxicity assessments included cytotoxicity, aryl hydrocarbon receptor-binding activity, and estrogen receptor-binding activity, in order to evaluate potential environmental impacts resulting from CEC degradation by UV/H2O2. Cytotoxicity and estrogenic activity were significantly reduced during the degradation of mixed CECs in Milli-Q water by UV/H2O2 with high UV fluence (3200 mJ cm-2). However, in GWRS RO-treated water samples collected in April 2017, the cytotoxicity and estrogen activity of spiked CEC-mixture after UV/H2O2 treatment were not significantly eliminated; this might be due to the high concentration of target CEC and their TPs, which was possibly affected by the varied quality of the secondary treatment influent at this facility such as sewer-shed and wastewater discharges. This study aimed to provide insight on the impacts of post-UV/H2O2 CECs and TPs on human and ecological health at cellular level

New Insights into the Mechanism of Visible Light Photocatalysis

ABSTRACT: In recent years, the area of developing visible-lightactive photocatalysts based on titanium dioxide has been enormously investigated due to its wide range of applications in energy and environment related fields. Various strategies have been designed to efficiently utilize the solar radiation and to enhance the efficiency of photocatalytic processes. Building on the fundamental strategies to improve the visible light activity of TiO2-based photocatalysts, this Perspective aims to give an insight into many contemporary developments in the field of visible-light-active photocatalysis. Various examples of advanced TiO2 composites have been discussed in relation to their visible light induced photoconversion efficiency, dynamics of electron− hole separation, and decomposition of organic and inorganic pollutants, which suggest the critical need for further development of these types of materials for energy conversion and environmental remediation purposes

Industrial synthesis and characterization of nanophotocatalysts materials: titania

Despite the recent synthesis and identification of a diverse set of new nanophotocatalysts that has exploded recently, titanium dioxide (TiO2) remains among the most promising photocatalysts because it is inexpensive, non-corrosive, environmentally friendly, and stable under a wide range of conditions. TiO2 has shown excellent promise for solar cell applications and for remediation of chemical pollutants and toxins. Over the past few decades, there has been a tremendous development of nanophotocatalysts for a variety of industrial applications (i.e. for water purification and reuse, disinfection of water matrices, air purification, deodorization, sterilization of soils). This paper details traditional and new industrial routes for the preparation of nanophotocatalysts and the characterization techniques used to understand the physical chemical properties of them, like surface area, ζ potential, crystal size, and phase crystallographic, morphology, and optical transparency. Finally we present some applications of the industrial nanophotocatalysts

Zero-valent iron impregnated cellulose acetate mixed matrix membranes for the treatment of textile industry effluent

Novel green synthesized zero valent iron (ZVI) nanoparticles of distinct mass fractions of 0.5, 1.5 and 2.5 wt% are blended with cellulose acetate (CA) to prepare CA/ZVI mixed matrix membranes (MMMs). The thermal stability and roughness were improved by increasing the mass fraction of ZVI in CA. The morphology of the prepared CA/ZVI membranes has been studied using transmission electron microscopy (TEM). Pure water permeability (PWP) is increased when adding 0.5 wt% of ZVI nanoparticles. When 2.5 wt% is added, PWP decreased due to the aggregation of ZVI nanoparticles in the CA polymer matrix. The adsorption capacity of ZVI nanoparticles on the CA/ZVI membrane during polymer enhanced ultrafiltration of textile effluent is also investigated. The equilibrium adsorption isotherms are well fitted with the Freundlich model, implying the influence of active adsorptive sites of the ZVI nanoparticles

Intensification of photocatalytic processes for niche applications in the area of water, wastewater and air treatment [preface]

Photocatalysis and photoelectrocatalysis are attractive technologies with potential applications in several fields, such as environmental technology, chemical synthesis, energy, and medicine. Although thousands of research papers have been published reporting promising results, actual industrial applications still remain limited, principally in the area of environmental remediation. The lack of knowledge on photoreactor design among the wider scientific and industrial community and integration with conventional technologies are some of the factors that are limiting the adoption of these emerging technologies for remediation purposes