Mechanistic study of visible light driven photocatalytic degradation of clofibric acid using Fe-based metal organic frameworks (MOFs).

Although a series of past studies proved the potential usage of Fe-based metal-organic frameworks (MOFs) as photocatalysts, there remains a knowledge gap of the photocatalytic mechanism stemming from the challenge to separate the simultaneous sorption and photocatalytic degradation. Thus, this article aimed to suggest a novel approach by desorbing target molecules during photocatalysis to excavate the underlying mechanisms of sorption and photocatalytic degradation. In this study, two Fe-based MOFs, MIL-101(Fe) and MIL-101(Fe)-NH2, were selected to remove clofibric acid under visible light irradiation. Prior to photocatalysis, sorption mechanism was uncovered based on the sorption kinetic, isotherm, thermodynamic interpretation, and of its dependence on solution pH. The results inferred that the primary sorption mechanism was through the π-π interaction between the benzene ring of clofibric acid and the organic ligand of Fe-based MOFs. Based on these results, photocatalytic mechanism could be independently or jointly assessed during the photocatalytic degradation of clofibric acid. Subsequently, the application of the Tauc method and XPS spectra revealed that the bandgap structure of Fe-based MOFs had the potential to oxidize clofibric acid by producing ROS through the electron excitation upon visible-light illumination. On top of that, the amine functionalization of Fe-based MOF altered the structural moiety that led to an additional strong acid-base interaction with clofibric acid but a decrease in the bandgap limiting the ROS production during photocatalytic activity.

Are 20-hydroxyecdysone and related genes potential biomarkers of sublethal exposure to lipid-altering contaminants?

In Daphnia magna, 20-hydroecdysone (20E) is the main molting hormone and its metabolism is of interest to identify new biomarkers of exposure to contaminants. The present study aimed to (i) assess baseline levels of 20E and transcription levels of four related-genes (shade, neverland, ultraspiracle, and ecdysteroid receptor); and (ii) evaluate effects in D. magna after 21 days of exposure to fenarimol (anti-ecdysteroid) and a mixture of gemfibrozil and clofibric acid (lipid-lowering drugs) at sublethal concentrations. Endpoints included transcription of the target genes and quantification of 20E, mortality, and reproduction of daphnids. Baseline results showed that average responses were relatively similar and did not vary more than 2-fold. However, intra-day variation was generally high and could be explained by sampling individuals with slightly different stages of their development. Exposure tests indicated a significant decrease in daphnid reproduction following chronic exposure to a concentration of 565 µg/L of fenarimol. However, no difference was observed between the control and exposed groups for any of the investigated genes, nor for the levels of 20E after 21 days of exposure. Following exposition to gemfibrozil and clofibric acid at 1 µg/L, no changes were observed for the measured parameters. These results suggest that changes in transcription levels of the target genes and concentrations of 20E may not be sensitive endpoints that can be used as biomarkers of sublethal exposure to the target compounds in D. magna. Measuring multiple time points instead of a single measure as well as additional molecular endpoints obtained from transcriptomic and metabolomic studies could afford more insights on the changes occurring in exposed daphnids to lipid-altering compounds and identify efficient biomarkers of sublethal exposure.

Fe3O4 supported UiO-66 (Zr) metal-organic framework for removal of drug contaminants from water: fuzzy logic modeling approach.

The increase in production and consumption of pharmaceuticals and personal care products causes environmental problems. In this study, naproxen and clofibric acid adsorption were studied using Fe3O4-supported UiO-66 (Zr) metal-organic framework (Mag-UiO-66). The adsorption processes were carried out in batch mode at pH value 3.0. The optimum adsorbent quantities, equilibrium periods, pseudo-first-order (PFO), pseudo-second-order (PSO), and intra-particles diffusion kinetic models were calculated. Non-linear Langmuir, Freundlich, Dubinin-Radushkevich (D-R), and Sips isotherm equations were applied to experimental data. Thermodynamic analyses of naproxen and clofibric acid adsorption were also carried out in this study. The Langmuir isotherm qm values were found as 14.15 mg/g for naproxen at 308 K and 41.87 mg/g for clofibric acid at 298 K. Both of the adsorption processes were exothermic. MISO (multi-input single-output) fuzzy logic models for removal of both naproxen and clofibric acid adsorptions were designed based on the experimental data to estimate the removal uptake values. It is noteworthy that the results obtained through designed fuzzy logic models matched well with the experimental data and the findings of this study emphasize the validity of designed fuzzy logic models.

Prevalence of organic micropollutants in the Yamuna River, Delhi, India: seasonal variations and governing factors.

This work primarily emphases on evaluating the prevalence of organic micropollutants (OMPs) in the perennial Yamuna River (YR) that flow through the national capital of India, Delhi. Sixteen sampling campaigns (non-monsoon, n = 9; monsoon n = 7) were organized to understand the seasonal variations with special emphasis on monsoon. We have found fifty-five OMPs in the monsoon; while forty-seven were detected in non-monsoon. Fifty-seven screened and quantified OMPs in the most polluted stretch of River Yamuna included the pharmaceutically active compounds, pesticides, endocrine-disrupting chemicals, phthalates, personal care products, fatty acids, food additives, hormones, and trace organics present in hospital wastes. During monsoon months, compounds for which concentrations exceeded 50 µg/L were: adenine (64.6 µg/L), diethyl phthalate (62.9 µg/L), and octamethyltrisiloxane (56.9 µg/L); and the same for non-monsoon months was only for 1-dodecanethiol (52.3 µg/L). The average concentration of OMPs in non-monsoon months indicate PhACs>PCPs>Pesticides>Fatty acids>Hospital waste>Hormones>Pesticides>EDCs. In monsoon months due to surface runoff and high volume of untreated wastewater discharges few more OMPs concentrations were detected which mainly includes PhACs (clofibric acid, diclofenac sodium, gemfibrozil, ketoprofen), pesticides (aldrin, metribuzin, atrazine, simazine). Due to dilution effect in the monsoon months, average concentrations of 3-acetamido-5-bromobenzoic acid (PhACs) was reduced from 45.22 µg/L to 14.07 µg/L, whereas some EDCs such as 2,4- Di-tert-amylphenol, 3,5- di-tert-butyl-4-hydroxybenzyl alcohol, Triphenylphosphine oxide, Benzophenone were found in much higher concentrations in the monsoon months. Octamethyltrisiloxane (PCPs) was detected 50 times higher in concentration in the monsoon months. Interestingly, the concentration of about 50 % of the OMPs was more in the monsoon samples than in non-monsoon samples which is contrary to the general understanding that monsoon-induced dilution lowers the concentrations of OMPs. In RY water higher magnitude of diclofenac sodium, ibuprofen, ketoprofen, and clofibric acid was found than Europe and North America rivers. Hormones such as estriol and estrone in RY water are found 70 to 100 times higher than the maximum reported concentrations in the US streams. Finally, various OMPs responded differently to the monsoon season as evident from multivariate analyses.

Can aged microplastics be transport vectors for organic micropollutants? - Sorption and phytotoxicity tests.

Microplastics have been investigated over the last decade as potential transport vectors for other pollutants. However, the specific role of plastic aging, in which plastics change their characteristics over time when exposed to environmental agents, has been overlooked. Therefore, sorption experiments were herein conducted using virgin and aged (by ozone treatment or rooftop weathering) microplastic particles of LDPE - low-density polyethylene, PET - poly(ethylene terephthalate), or uPVC - unplasticized poly(vinyl chloride). The organic micropollutants (OMPs) selected as sorbates comprise a diversified group of priority substances and contaminants of emerging concern, including pharmaceutical substances (florfenicol, trimethoprim, diclofenac, tramadol, citalopram, venlafaxine) and pesticides (alachlor, clofibric acid, diuron, pentachlorophenol), analyzed at trace concentrations (each ≤100 µg L-1). Sorption kinetics and equilibrium isotherms were obtained, as well as the confirmation that the aging degree of microplastics plays a major role in their sorption capacities. The results show an increased sorption of several OMPs on aged microplastics when compared to pristine samples, i.e. the sorption capacity increasing from one or two sorbed substances (maximum 3 µg g-1 per sorbate) up to nine after aging (maximum 10 µg g-1 per sorbate). The extent of sorption depends on the OMP, polymer and the effectiveness of the aging treatment. The modifications (e.g. in the chemical structure) between virgin and aged microplastics were linked to the increased sorption capacity of certain OMPs, allowing to better understand the different affinities observed. Additionally, phytotoxicity tests were performed to evaluate the mobility of the OMPs sorbed on the microplastics and the potential effects (on germination and early growth) of the combo on two species of plants (Lepidium sativum and Sinapis alba). These tests suggest low or no phytotoxicity effect under the conditions tested but indicate a need for further research on the behavior of microplastics on soil-plant systems.

Construction of heterojunction photoanode via facile synthesis of CoOx/CN nanocomposites for enhanced visible-light-driven photoelectrochemical degradation of clofibric acid.

Visible-light-driven photoelectrocatalytic (PEC) oxidation has been explored extensively to develop highly active materials. Herein, a visible-light-active p-Co3O4 and n-g-C3N4 heterojunction (CoOx/CN) photoanode, constructed by simple one-pot calcination, was shown to remove clofibric acid (CA) from water through a PEC process. Compared with pristine g-C3N4, the optimal photoanode (15%-CoOx/CN) exhibited stable and effective PEC performance and CA degradation performance, a 100-fold enhancement in photocurrent density, and around 1.5-fold decreased efficiency over 6 h. The p-n heterojunctions were shown to increased the charge density and conductivity of g-C3N4 for rapid charge transfer. Furthermore, interface contact broadened the visible light absorption and accelerated charge carrier transfer. Notably, the catalysts established p-n heterojunctions, which hindered the bulk recombination of photoinduced carriers and improved the charge separation efficiency. The CoOx/CN photoanodes showed a pair of redox peaks at a potential of 0.3 V vs. Ag/AgCl, indicating good Co3O4 redox behavior under alkaline conditions. The 15%-CoOx/CN photoanode displayed excellent PEC performance of up to 0.16 mA cm-2 in 0.1 M KOH solution at 1.23 V vs. RHE (reversible hydrogen electrode) and long-term stability for up to 12 h. The CoOx/CN photoanodes maintained excellent PEC activities for CA removal, even under acidic and alkaline conditions conditions (pH 3-10). Probable degradation pathway of CA was proposed according to the main degradation intermediates. This study shows that the synergistic effect of p-n heterojunctions in photoelectrodes provides a new approach to the rational application of new photoanode candidates and PEC performance optimization.

Clofibric acid increases molecular species of phosphatidylethanolamine containing arachidonic acid for biogenesis of peroxisomal membranes in peroxisome proliferation in the liver.

The biogenesis of peroxisomes in relation to the trafficking of proteins to peroxisomes has been extensively examined. However, the supply of phospholipids, which is needed to generate peroxisomal membranes in mammals, remains unclear. Therefore, we herein investigated metabolic alterations induced by clofibric acid, a peroxisome proliferator, in the synthesis of phospholipids, particularly phosphatidylethanolamine (PE) molecular species, and their relationship with the biogenesis of peroxisomal membranes. The subcutaneous administration of clofibric acid to rats at a relatively low dose (130 mg/kg) once a day time-dependently and gradually increased the integrated perimeter of peroxisomes per 100 µm2 hepatocyte cytoplasm (PA). A strong correlation was observed between the content (µmol/mg DNA) of PE containing arachidonic acid (20:4) and PA (r2 = 0.9168). Moreover, the content of PE containing octadecenoic acid (18:1) positively correlated with PA (r2 = 0.8094). The treatment with clofibric acid markedly accelerated the formation of 16:0-20:4 PE by increasing the production of 20:4 and the activity of acyl chain remodeling of pre-existing PE molecular species. Increases in the acyl chain remodeling of PE by clofibric acid were mainly linked to the up-regulated expression of the Lpcat3 gene. On the other hand, clofibric acid markedly increased the formation of palmitic acid (16:0)-18:1 PE through de novo synthesis. These results suggest that the enhanced formation of particular PE molecular species is related to increases in the mass of peroxisomal membranes in peroxisome proliferation in the liver.

The combination of sesamol and clofibric acid moieties leads to a novel potent hypolipidemic agent with antioxidant, anti-inflammatory and hepatoprotective activity.

Oxidative stress and inflammation have been considered the main factors in the liver injury of clofibrate (CF). To obtain a novel antihyperlipidemic agent with antioxidant, anti-inflammation and hepatoprotection, the combination of sesamol and clofibric acid moieties was performed and achieved sesamol-clofibrate (CF-Sesamol). CF-Sesamol showed significant hypolipidemia effects in hyperlipidemia mice induced by Triton WR 1339, reducing TG by 38.8% (P < 0.01) and TC by 35.1% (P < 0.01). CF-Sesamol also displayed an alleviating effect on hepatotoxicity. The hepatic weight and hepatic coefficient were decreased. The amelioration of liver function was observed, such as aspartate and lactate transaminases (AST and ALT), alkaline phosphatase (ALP) and total proteins (TP) levels. Liver histopathological examination showed that hepatocyte necrosis, cytoplasmic loosening, nuclear degeneration and inflammatory cell infiltration reduced obviously by treatment with CF-Sesamol. Related molecular mechanisms on hepatoprotection showed that CF-Sesamol up-regulated Nrf2 and HO-1 expression and down-regulated p-NF-κB p65 expression in hepatic tissues. CF-Sesamol has significant antioxidant and anti-inflammatory effects. Plasma antioxidant enzymes such as SOD and CAT increased, anti-lipid peroxidation product MDA decreased. The expression of TNF-α and IL-6 inflammatory cytokines in liver was significantly lower than that in the CF group. The results indicated that CF-Sesamol exerted more potent antihyperlipidemic effects and definite hepatoprotective activity partly through the Nrf2/NF-κB-mediated signaling pathway.

FABP regulates fatty acid metabolism and oxidative response via PPARα/RXR signaling in Litopenaeus vannamei following environmental exposure of clofibric acid.

Clofibric acid (CFA), a drug and personal care product, has been identified as ubiquitous in the aquatic system and surface water, causing pollution to the environment. In this study, after environmental (4 µg/L) levels of CFA challenge, the LvFABP, LvACS gene expressions, total haemocyte count (THC), relative enzymes (SOD1 and GST) activities in Litopenaeus vannamei were observed to decrease. In the meantime LvFATP, LvRXR expression and the level of NEFA were upregulated in L. vannamei body. LvFABP expression in vivo was knocked down by dsRNA-mediated RNA interference (RNAi), which led to significantly decreased levels of PPARα (including LvFATP, LvRXR and LvACS). When exposed to environmental CFA after 4 days, LvFABP knocked down group had a sharp upregulation of LvFATP, LvRXR, LvACS expression, GST activity and NEFA amount, following decreased THC and SOD1 activity. These results suggested that environmental concentration CFA may have some toxicological effect on L. vannamei, following fatty acids metabolism and oxidative stress responses by LvFABP via the PPARα/RXR signaling pathway, including LvFATP, LvRXR and LvACS.

Preparation and characterization of activated carbon developed from cotton cloth residue activated with phosphoric acid: adsorption of clofibric acid.

Cotton cloth waste was used as a precursor to prepare activated carbon (ACCs) chemically activated with phosphoric acid. Adsorption behavior of prepared ACCs was correlated with physicochemical proprieties. The pore volume and BET surface of ACCs were determined by nitrogen adsorption isotherms and scanning electron microscopy was used to observe their surface morphologies. Fourier transform infrared (FTIR) spectroscopy analysis and pH point zero charge (pHPZC) were conducted to determine chemical properties. Under the optimal conditions: 50% impregnation ratio and thermal treatment under N2 flow at 600 °C during 60 min, the activated carbon prepared exhibits a high surface area 1,150 m2/g, 0.501 cm3/g micropore volume and an excellent adsorption performance. The adsorbed amount of clofibric acid is found to be 9.98 and 83 mg/g at, respectively, initial CA concentration of 10 and 100 mg/L at pH 3.0 and 20 °C. Diffusion and chemisorption are the steps controlling the adsorption of CA onto ACC 50% and the equilibrium data were well described by Freundlich isotherm.

Kinetic and mechanistic insights into the abatement of clofibric acid by integrated UV/ozone/peroxydisulfate process: A modeling and theoretical study.

The feasibility of integrated UV/ozone (O3)/peroxydisulfate (PDS) process for abatement of clofibric acid (CA) was systematically explored in this study with focus on the kinetic simulation and oxidation mechanisms. The results indicated the UV/O3/PDS process was of prominent treatment capability with pseudo-first-order rate constant of CA degradation increased by 65.9% and 86.0% compared to UV/O3 and UV/PDS processes, respectively. A chemical kinetic model was developed and successfully employed to predict CA elimination as well as the specific contributions of UV, hydroxyl radical (•OH) and sulfate radical (SO4•-) under different PDS dosage, pH, natural organic matters, bicarbonate and chloride conditions in UV/O3/PDS process. According to quantum chemical calculation, radical addition on ortho site of isopropoxy substituent and single electron transfer were corroborated to be the dominant reaction channels for the oxidation of CA by •OH and SO4•-, respectively. Additionally, the reactive sites and transformation pathways of CA were proposed via Fukui function calculation and UPLC-Q-TOF-MS analysis. Moreover, the performance of UV/O3/PDS process was further evaluated with regard to the energy demand and bromate formation. This study first proposed a kinetic model in UV/O3/PDS process and elucidated the regioselectivity and products distribution of CA during oxidative treatment.

A single pretreatment with clofibric acid attenuates carbon tetrachloride-induced necrosis, but not steatosis, in rat liver.

The present study investigated whether a single pretreatment with clofibric acid suppresses liver injury in rats after CCl4 intoxication. Rats received a single pretreatment with clofibric acid (100 mg/kg, i.p.) 1 h prior to a CCl4 (1 mL/kg, p.o.) challenge, and were euthanized 24 h after the CCl4 administration. A single pretreatment with clofibric acid effectively suppressed increases in the serum aminotransferase activities and the severity of necrosis following the CCl4 challenge, whereas the pretreatment did not protect against CCl4-induced fatty liver. The clofibric acid pretreatment did not affect blood concentrations of CCl4 in the early stage after CCl4 dosing, or the level of the CCl4 reaching the liver 1 h after the CCl4 challenge. Moreover, the clofibric acid pretreatment did not affect the intensity of the covalent binding of the [14C]CCl4 metabolite to microsomal proteins and lipids. The clofibric acid pretreatment did not alter microsomal cytochrome P450 2E1 activity. Based on these results, we conclude that protection against CCl4-induced hepatocellular necrosis by a clofibric acid pretreatment does not require its repeated administration, and that a single and brief pre-exposure to clofibric acid prior to CCl4 dosing markedly suppresses necrosis without affecting the development and progression of steatosis.

Acute and chronic effects of environmental realistic concentrations of clofibric acid in Danio rerio: Behaviour, oxidative stress, biotransformation and lipid peroxidation endpoints.

Due to their widespread use, pharmaceuticals can be metabolized, excreted and ultimately discarded in the environment, thereby affecting aquatic organisms. Lipid-regulating drugs are among the most prescribed medications around the world, controlling human cholesterol levels, in more than 20 million patients. Despite this growing use of lipid-regulating drugs, particularly those whose active metabolite is clofibric acid, the potential toxicological effects of these pharmaceuticals in the environment is not fully characterized. This work intended to characterize the toxicity of an acute (120 hours post-fertilization) and chronic (60 days post-fertilization) exposures to clofibric acid in concentrations of 10.35, 20.7, 41.4, 82.8, and 165.6 µg L-1 in zebrafish (Danio rerio). The concentrations which were implemented in both exposures were based on predicted environmental concentrations for Portuguese surface waters. The acute effects were analysed focusing on behavioural endpoints (small and large distance travelled, swimming time and total distance travelled), biomarkers of oxidative stress (activity of the enzymes superoxide dismutase, Cu/Zn- and Mn SOD; catalase, CAT; glutathione peroxidase, Se- and total GPx), biotransformation (activity of glutathione S-transferases, GSTs) and lipid peroxidation (thiobarbituric acid reactive substances, TBARS). Chronically exposed individuals were also histologically analysed for sex determination and gonadal developmental stages. In terms of acute exposure, significant alterations were reported, in terms of behavioural alterations (hypoactivity), followed by an overall increase in all tested biomarkers. Chronically exposed organisms did not show alterations in terms of sex ratio and maturation stages, suggesting that clofibric acid did not act as an endocrine disruptor. Moreover, the metabolism of clofibric acid resulted in increased levels of both forms of SOD activity, especially for animals exposed to higher levels of this drug. An increase of CAT activity was observed in fish exposed to low levels, and a decrease in those exposed to higher amounts of clofibric acid. Both GPx forms had their activities increased. The enzyme of biotransformation GSTs were increased at low levels of clofibric acid but inhibited at higher amounts of this substance. Lipid peroxidation levels were also changed, with an induction of this parameter with increasing amounts of clofibric acid. Changes also occurred in behavioural endpoints and patterns for control organisms and for those exposed to clofibric acid were significantly distinct, for all types (light and darkness) of exposure, and for the two analysed endpoints (small and large distance). Results from this assay allow inferring that clofibric acid can have an ecologically relevant impact in living organisms exposed to this substance, with putative effects on the metabolism of individuals, affecting their behaviour and ultimately their survival.

Degradation of pharmaceuticals from wastewater in a 20-L continuous flow bio-electro-Fenton (BEF) system.

The bio-electro-Fenton (BEF) technology has proven to be an effective and energy-saving method for treating wastewaters containing a single pharmaceutical in the lab-scale. However, the continuous degradation of pharmaceuticals in a scaled-up BEF has never been reported. In this study, a 20-L dual-chamber BEF reactor was designed and tested for treating six model pharmaceuticals. The effect of key operational factors including applied voltage, cathode Fe2+ dosage, initial pharmaceuticals concentration and hydraulic retention time (HRT), were assessed. By implementing 0.1 V voltage, 0.3 mM Fe2+ and HRT of 26 h, the six selected pharmaceuticals (500 µg L-1 for each) were removed completely. Moreover, transformation products during clofibric acid degradation, such as 4-chlororesorcinol, were detected and the relevant transformation pathway was proposed. Additionally, it successfully removed these pharmaceuticals in the real wastewater matrix. This paper contributes to scaling-up the BEF process for continuous and effective treating pharmaceuticals-contaminated wastewater.

Comparative study of alleviation effects of DMTU and PCIB on root growth inhibition in two tall fescue varieties under cadmium stress.

In plants, tolerance to cadmium (Cd) stress is closely related to indole-3-acetic acid (IAA) and hydrogen peroxide (H2O2). However, it is unclear whether Cd-resistant and -sensitive varieties respond differently to Cd stress. In this study, the effects of dimethylthiourea (DMTU, a H2O2 scavenger) and p-chlorophenoxy isobutyric acid (PCIB, an IAA signaling inhibitor) on root growth, endogenous hormones and antioxidant system were investigated to decipher how DMTU and PCIB treatments alleviate the inhibition of root elongation in Cd-resistant (Commander) and -sensitive (Crossfire III) tall fescue varieties under Cd stress. Both varieties subjected to 10 µM Cd treatments for 12 h presented a substantial decrease in root elongation coupled with a reduction in brassinosteroid (BR) and zeatin riboside (ZR) contents, but the changes in IAA and abscisic acid (ABA) contents under Cd stress were opposite in the two varieties. In addition, the H2O2 content and antioxidant enzyme activities significantly increased in both varieties. However, pretreatment with PCIB or DMTU mitigated the inhibition of root elongation caused by Cd, accompanied by the significant changes of aforementioned physiological parameters. PCIB significantly reduced the IAA content in 'Commander', while DMTU significantly increased the IAA content in 'Crossfire III' and effectively relieved the inhibition of root elongation. But both treatments decreased the Cd-induced H2O2 accumulation. These results indicated that DMTU or PCIB can alleviate the Cd-inhibited root elongation in two varieties whose resistance differed under Cd stress, but they presented differences in the response of hormones, especially IAA, which may be due to the different adaptation mechanisms of two varieties in response to Cd stress.

Photocatalytic Reactor Modeling: Application to Advanced Oxidation Processes for Chemical Pollution Abatement.

A methodology for photocatalytic reactor modeling applied to advanced oxidation processes for chemical pollution abatement is presented herein. Three distinct reactor configurations typically employed in the field of air and water purification-wall reactors, slurry reactors, and fixed-bed reactors-are considered to illustrate the suggested approach. Initially, different mechanistically derived kinetic expressions to represent the photocatalytic rate of pollutant degradation are reviewed, indicating the main assumptions made by the authors in the published contributions. These kinetic expressions are needed to solve the mass balances of the reactant species in the photocatalytic reactors. As is well known, at least one of the steps of the reaction mechanism requires evaluation of the rate of electron-hole generation, which depends on the photon absorption rate: a volumetric property for reactions with the catalyst particles in aqueous suspension or a surface property for systems with a fixed catalyst deposited on an inert support. Subsequently, the different techniques for evaluating the optical properties of slurry and immobilized systems, and the numerical methods applied to calculate the photon absorption rate, are described. The experimental and theoretical results of pollutant degradation in each reactor type are then presented and analyzed. Finally, the definition, calculation, and relevance of different efficiency parameters are briefly reviewed. Using these illustrative examples, we emphasize the need for a systematic and rigorous approach for photocatalytic reactor modeling in order to overcome the inherent drawbacks of photocatalysis and to improve the overall efficiency of the process.

Prolonged exposure of Stenotrophomonas maltophilia biofilms to trace levels of clofibric acid alters antimicrobial tolerance and virulence.

The presence of pharmaceuticals in water sources, including in drinking water (DW), is increasingly being recognized as an emerging and global concern for the environment and public health. Based on the principles of the "One Health" initiative, the present work aims to understand the effects of clofibric acid (CA), a lipid regulator, on the behavior of a selected bacterium isolated from drinking water (DW). Biofilms of the opportunistic pathogen Stenotrophomonas maltophilia were exposed to CA for 12 weeks at 170 and 17000 ng/L. The effects of CA were evaluated on planktonic S. maltophilia susceptibility to chlorine and antibiotics (amoxicillin, ciprofloxacin, erythromycin, kanamycin, levofloxacin, oxacillin, spectinomycin, tetracycline and trimethoprim-sulfamethoxazole), biofilm formation, motility, siderophores production and on the adhesion and internalization of the human colon adenocarcinoma cell line (HT-29). It was found that CA did not affect planktonic S. maltophilia tolerance to chlorine exposure. Additionally, no effects were observed on biofilm formation, motility and siderophores production. However, biofilms formed after CA exposure were more tolerant to chlorine disinfection and lower CFU reductions were obtained. Of additional concern was the effect of CA exposure on S. maltophilia increased tolerance to erythromycin. CA exposure also slightly reduced S. maltophilia ability to invade HT-29 cells. In conclusion, this work reinforces the importance of studying the effects of non-antibiotic contaminants on the behavior of environmental microorganisms, particularly their role as drivers affecting resistance evolution and selection.

UiO-66: An Advanced Platform for Investigating the Influence of Functionalization in the Adsorption Removal of Pharmaceutical Waste.

Highly efficient and selective removal of pharmaceuticals and personal care products (PPCPs) from wastewater is a great challenge and is significant. In this study, we chose UiO-66-R, which contains eight isostructural metal-organic frameworks (MOFs) with variable functional groups (-R), as a platform for systemically investigating the influence of functionalization on its adsorption behavior with respect to three classic PPCPs. We conducted kinetic, modeling, and structure-function relationship studies on PPCP removal using MOFs. The adsorption kinetics, including the adsorption rate, affinity, and separation factor ( RL), were comprehensively analyzed and simulated. The design and function of MOFs can greatly promote their adsorption capacity and the efficiency of PPCPs. The structure-function relationship study revealed that hydrogen bonding, electrostatic, and π-π interactions between MOFs and PPCP molecules played important roles in the adsorption process and significantly influenced the adsorption efficiency. This study paves a new way for the application of MOFs with respect to the removal of PPCP pollution and provides guidance for the design of new porous materials for environmental treatment and separation applications.

The influence of four pharmaceuticals on Chlorellapyrenoidosa culture.

There has been a developing technology in algae with pharmaceuticals wastewater. However, the effect and the underlying mechanism of pharmaceuticals on algae are not well understood. To investigate the effect and mechanism of pharmaceuticalson microalgae, four pharmaceuticals of clofibric acid (CLF), ciprofloxacin (CIP), diclofenac (DCF) and carbamazepine (CBZ) on C. pyrenoidosa culture were analyzed. At low concentrations (<10 mg/L), the pharmaceuticals, especially the DCF, exhibited positive effects on both the structure and function of algal cultures; algal growth (i.e., chlorophyll a accumulation, lipid accumulation) and activities of antioxidant enzymes were stimulated. The algal metabolite differences of various DCF concentrations were investigated and a total of 91 substances were identified, whose samples were clustered and clearly separated. The key metabolomics pathway analysis found that the DCF promoted the carbohydrate and fatty acid metabolic pathway in C. pyrenoidosa under relatively low concentrations (<10 mg/L). However, the algae metabolomics pathway was disturbed significantly under the action of a high concentration of DCF (>100 mg/L). The study detected the effects of four pharmaceuticals on C. pyrenoidosa and demonstrated that the usage of metabolomics analysis complemented with DCF could be an effective approach to understand the mechanism of molecular evolution in C. pyrenoidosa for microalgal biomass and bioenergy from wastewater in researches of biological resources.

Initial Bud Outgrowth Occurs Independent of Auxin Flow from Out of Buds.

Apical dominance is the process whereby the shoot tip inhibits the growth of axillary buds along the stem. It has been proposed that the shoot tip, which is the predominant source of the plant hormone auxin, prevents bud outgrowth by suppressing auxin canalization and export from axillary buds into the main stem. In this theory, auxin flow out of axillary buds is a prerequisite for bud outgrowth, and buds are triggered to grow by an enhanced proportional flow of auxin from the buds. A major challenge of directly testing this model is in being able to create a bud- or stem-specific change in auxin transport. Here we evaluate the relationship between specific changes in auxin efflux from axillary buds and bud outgrowth after shoot tip removal (decapitation) in the pea (Pisum sativum). The auxin transport inhibitor 1-N-naphthylphthalamic acid (NPA) and to a lesser extent, the auxin perception inhibitor p-chlorophenoxyisobutyric acid (PCIB), effectively blocked auxin efflux from axillary buds of intact and decapitated plants without affecting auxin flow in the main stem. Gene expression analyses indicate that NPA and PCIB regulate auxin-inducible, and biosynthesis and transport genes, in axillary buds within 3 h after application. These inhibitors had no effect on initial bud outgrowth after decapitation or cytokinin (benzyladenine; BA) treatment. Inhibitory effects of PCIB and NPA on axillary bud outgrowth only became apparent from 48 h after treatment. These findings demonstrate that the initiation of decapitation- and cytokinin-induced axillary bud outgrowth is independent of auxin canalization and export from the bud.