Synergistic degradation of 2,4-dichlorophenoxyacetic acid in water by interfacial pre-reduction enhanced peroxymonosulfate activation derived from novel zero-valent iron/biochar.

Iron-based biochar exhibits great potential in degrading emerging pollutants and remediation of water environments. In this study, a highly efficient catalytic Fe0/biochar (MZB-800) was synthesized by the co-pyrolysis of poplar sawdust and K2FeO4 at 800 °C. A novel water purification technology of pre-reduction followed by PMS activation for MZB-800 was proposed to degrade the refractory 2,4-dichlorophenoxyacetic acid (2,4-D) pesticide. The corrosive effect of the strong oxidizing potassium salt endowed the MZB-800 surface with more Fe0 and porous structure, achieving greater 2,4-D adsorption binding energy. The removal efficiency of MZB-800 on 2,4-D was greater than that of biochar (BC) and conventional Fe0/biochar (Fe-BC) prepared by FeCl3·6 H2O as the precursor. The proposed novel water purification technology showed the synergistic effect between the interfacial pre-reduction and the PMS activation derived by MZB-800. Regarding 2,4-D degradation and dechlorination performance, the synergistic coefficient between pre-reduction and subsequent PMS activation for MZB-800 were 2 and 1.4 respectively. Based on the normalized kinetic analysis and the Langmuir-Hinshelwood model, we proposed the underlying mechanism of MZB-800 interfacial pre-reduction and subsequent PMS activation for synergistic removal of 2,4-D. The large amount of Fe2+ and hydroxyl density accumulated by the Fe0 and hydroquinone structures on the MZB-800 surface during the pre-reduction stage provided abundant active sites for the subsequent activation of PMS. The improved activation reaction rate generated more reactive oxygen species, further strengthening the removal efficiency of 2,4-D. This work manifested that the novel water purification technology of pre-reduction/PMS activation of iron-based biochar is feasible for removing emerging pollutants in the water environment. ENVIRONMENTAL IMPLICATION: Extensive abuse of 2,4-dichlorophenoxyacetic acid (2,4-D) herbicide with high solubility and refractory degradation has caused environmental pollution and ecological deterioration. This manuscript described a novel water purification technology, centered on high-efficiency Fe0/biochar and utilizing pre-reduction and PMS reactivation strategies to synergistically degrade 2,4-D, which had strong environmental relevance. By elucidating the synergistic removal mechanism, the research provided valuable insights into removing emerging pollutants, thus promoting environmental sustainability and safeguarding ecosystem health. Overall, it is of high importance to provide a feasible and efficient method for removing hazardous 2,4-D from water environments, which contributes to addressing pressing environmental problems.

Efficacy of the Simeox® Airway Clearance Technology in the Homecare Treatment of Children with Clinically Stable Cystic Fibrosis: A Randomized Controlled Trial.

BACKGROUND: Cystic fibrosis (CF) patients require regular airway clearance therapy (ACT). The aim of this study was to evaluate homecare therapeutic effects of a new ACT (Simeox®) added to the optimal standard of care, including home chest physiotherapy, in the treatment of clinically stable children. METHODS: Forty pediatric CF patients (8-17 years old) with stable disease were randomized 1:1 in a single-center, prospective, open-label, cross-over trial into two groups: with or without Simeox®. Lung function (impulse oscillometry, spirometry, body plethysmography, multi-breath nitrogen washout) results, health-related quality of life, and safety were assessed during the study after 1 month of therapy at home. RESULTS: A significant decrease in proximal airway obstruction (as supported by improvement in airway resistance at 20 Hz (R20Hz) and maximum expiratory flow at 75% of FVC (MEF75)) compared to the control group was observed after 1 month of therapy with the device. Lung-clearance index was stable in the study group, while it worsened in the control group. In addition, the device group demonstrated a significant increase in the Cystic Fibrosis Questionnaire-Revised (CFQ-R) physical score. No side effects were identified during the study. CONCLUSIONS: Simeox® may improve drainage of the airways in children with clinically stable CF and could be an option in chronic treatment of the disease.

Solar-driven photoelectrocatalytic degradation of anticancer drugs using TiO2 nanotubes decorated with SnS quantum dots.

In recent years, the growing interest in applying photoelectrocatalysis (PEC) to decompose organic pollutants has resulted in the need to search for new photoelectrode materials with high activity under visible light radiation. The presented research showed an increased photoelectrocatalytic activity under sunlight of Ti/TiO2 sensitized with SnS quantum dots, obtained by the successive ionic layer adsorption and reaction (SILAR) method. The presence of SnS caused the enhanced absorption of visible irradiation and the reduction of recombination of generated charges by a p-n heterojunction created with the TiO2. The highest efficiency of photoelectrocatalytic degradation of anticancer drugs (ifosfamide, 5-fluorouracil, imatinib) was achieved for the SnS-Ti/TiO2 photoelectrode with a SnS quantum dot size from 4 to 10 nm. In addition, a decrease of IF PEC degradation efficiency was observed with increasing pH and with the presence of Cl-, NO3-, HCO3- and organic matter in the treated solution. Studies of the PEC mechanism have shown that drug degradation occurs mainly as a result of the direct and indirect action of photogenerated holes on the SnS-Ti/TiO2 photoelectrode, and the identified degradation products allowed for the presentation of the degradation pathway of IF, 5-FU and IMB. Duckweed (Lemna minor) growth inhibition tests showed no toxicity of the drug solutions after treatment.

Ti/TiO2 nanotubes sensitized PbS quantum dots as photoelectrodes applied for decomposition of anticancer drugs under simulated solar energy.

One of the challenges in research into photoelectrocatalytic (PEC) degradation of pollutants is finding the appropriate photoanode material, which has a significant impact on the process efficiency. Among all others, photoelectrodes based on an ordered TiO2 nanotube arrays are a promising material due to well-developed surface area and efficient charge separation. To increase the PEC activity of this material, the SILAR method was used to decorate Ti/TiO2 nanotubes by PbS quantum dots (QD). The ifosfamide (IF) degradation rate constants was twice as higher for PbS-Ti/TiO2 (0.0148 min-1) than for Ti/TiO2 (0.0072 min-1). Our research showed the highest efficiency of PEC degradation of drugs using IIIPbS-Ti/TiO2 made with 3 SILAR cycles (PbS QD size mainly 2-4 nm). The 4 and 6 of SILAR cycles resulted in the aggregation of PbS nanoparticles on the Ti/TiO2 surface and decreased IF PEC degradation rate to 0.0043 and 0.0033 min-1, respectively. Research on PEC mechanism has shown that the drugs are degraded mainly by the activity of photogenerated holes and hydroxyl radicals. In addition, the identified drug intermediates made possible to propose a degradation pathways of anticancer drugs and the ecotoxicity test show no inhibition of Lemna minor growth of treated solutions.

Removal of 5-fluorouracil by solar-driven photoelectrocatalytic oxidation using Ti/TiO2(NT) photoelectrodes.

The efficient and safe degradation of drugs present in wastewater requires the design of a new material possessing high activity for that process. In addition to other methods, photoelectrocatalysis (PEC) merges the strengths of both photocatalytic and electrochemical methods, and the efficiency could be enhanced by the type of photoelectrode material. To address this challenge, three Ti/TiO2 nanotube-based photoelectrodes, differing in their tube morphology, were prepared by anodic oxidation and employed for the degradation of the 5-fluorouracil (5-FU) drug by the PEC process. The highest efficiency for 5-fluorouracil (5-FU) degradation by PEC was observed for the photoelectrode with a 1.7 µm length, 65 nm diameter and 8 nm wall thickness of TiO2 nanotubes, which were prepared by Ti foil anodization at 30 V. The effects of applied potential, irradiation intensity, initial pH and 5-FU concentration on PEC were investigated. Furthermore, our findings showed that the mechanism of photoelectrocatalysis in the presence of TiO2 nanotubes is based on ∙OH and h+ activity. To determine the 5-FU degradation pathway, the organic byproducts were identified by LC-MS analysis. Furthermore, the ecotoxicity evaluated during PEC dropped with decreasing 5-FU concentration.

Cytostatic drug removal using electrochemical oxidation with BDD electrode: Degradation pathway and toxicity.

In the presented study, electrochemical oxidation of five anticancer drugs (5-fluorouracil (5-FU), ifosfamide (IF), cyclophosphamide (CF), methotrexate (MTX), imatinib (IMB)) using boron doped diamond (BDD) electrode was investigated. In the first step the operating parameters of electrolysis were optimized. Studies have demonstrated a significant influence of applying current density, temperature, pH of solution and initial concentration of 5-FU on the process efficiency. A comparison of the decomposition rate of all the tested drugs showed a decrease in the pseudo-first order rate constants in the following order: k(IMB) > k(MTX) > k(CF) ≈ k(IF) > k(5-FU). Mineralization current efficiency (MCE) was determined for all the drugs based on the removal amount of total organic carbon (TOC) and their values decreased in the same order as values of drug degradation rate k. Based on the identified degradation products, electrochemical oxidation pathways of the decomposed drugs were proposed. In the case of CF, IF and 5-FU the degradation process occurred mainly through ketonization, hydroxylation and dehalogenation, while MTX and IMB were decomposed by attack of hydroxyl radicals on benzyl position in parent compounds. An important part of the research was the evaluation of eco-toxicity of electrochemically treated drug solutions against Lemna minor. Toxicity of initial 5-FU and MTX solutions towards L. minor were observed but after electrochemical treatment its toxicity decreased. The opposite trend was observed for CF and IF. In this case no significant toxicity was observed for the initial solutions of these drugs, while after electrochemical treatment an increase in growth inhibition of L. minor was found.

Molecular Cytogenetic Analysis of Cucumis Wild Species Distributed in Southern Africa: Physical Mapping of 5S and 45S rDNA with DAPI.

Wild Cucumis species have been divided into Australian/Asian and African groups using morphological and phylogenetic characteristics, and new species have been described recently. No molecular cytogenetic information is available for most of these species. The crossability between 5 southern African Cucumis species (C. africanus, C. anguria, C. myriocarpus, C. zeyheri, and C. heptadactylus) has been reported; however, the evolutionary relationship among them is still unclear. Here, a molecular cytogenetic analysis using FISH with 5S and 45 S ribosomal DNA (rDNA) was used to investigate these Cucumis species based on sets of rDNA-bearing chromosomes (rch) types I, II and III. The molecular cytogenetic and phylogenetic results suggested that at least 2 steps of chromosomal rearrangements may have occurred during the evolution of tetraploid C. heptadactylus. In step 1, an additional 45 S rDNA site was observed in the chromosome (type III). In particular, C. myriocarpus had a variety of rch sets. Our results suggest that chromosomal rearrangements may have occurred in the 45 S rDNA sites. We propose that polyploid evolution occurred in step 2. This study provides insights into the chromosomal characteristics of African Cucumis species and contributes to the understanding of chromosomal evolution in this genus.

The effect of iron and zinc supplementation and its discontinuation on liver antioxidant status in rats fed deficient diets.

PURPOSE: The aim was to investigate the effect of iron or combined iron/zinc supplementation on rat liver antioxidant status. METHODS: The 6-week male Wistar rats were examined in 3 stages: (1) 4-week adaptation to the diets (C-control AIN-93M diet, D-iron deficient and R-with 50% reduction in all vitamin and mineral amounts); (2) 4-week supplementation with the same regimen enriched with tenfold more iron or iron/zinc; (3) 2-week post-supplementation period (the same diets as in the stage I). RESULTS: Combined iron/zinc supplementation similarly to iron supplementation alone significantly (p values ≤ 0.05) increased the iron content in the liver in D and R rats after stages II and III. Moreover, iron/zinc supplementation compared to iron supplementation alone significantly decreased the liver concentration of 8-isoprostane (after stage II in D and after stage III in R rats), protein carbonyl groups (only after stage III in R rats) and 8-hydroxy-2-deoxyguanosine (after stage II in R and after stage III in D and R rats). In rats fed R-type of diets after stage II hepatic superoxide dismutase (SOD) and catalase (CAT) activity, but not glutathione peroxidation activity and total antioxidant capacity, was lower in iron and iron/zinc supplemented than in non-supplemented rats, whereas after stage III in iron/zinc supplemented SOD was lower and CAT activity was higher in comparison with non-supplemented and iron supplemented rats. CONCLUSIONS: The simultaneous iron/zinc supplementation can protect liver against peroxidative damage induced by high doses of iron during and after the intervention in rats fed iron-deficient diet and diet with reduced amounts of vitamins and minerals. The post-intervention observation is relevant because the effect may be delayed and visible only after this period.

Perfluorocarboxylic acids in cell growth media and technologically treated waters: determination with GC and GC-MS.

The present paper reports on an analytical method for the routine analysis of perfluorinated carboxylic acids (PFCAs). A rapid method for the derivatization, extraction and determination of PFCAs was developed. Technological samples were extracted with ethyl acetate and the anilides obtained were determined by gas chromatography-mass spectrometry (GC-MS) and gas chromatography with flame ionization detector (GC-FID). Residue levels in cell growth incubation media were determined by GC-FID. Confirmation analysis of PFCAs was carried out by GC-MS in selected ion monitoring (SIM) and total ion current (TIC) modes. The compounds were identified on the basis of retention time and comparison of primary and secondary ions. The results showed that this method provided a simple, rapid and sensitive way of analyzing PFCAs in different matrices.

Effect of chlorides and sulfates on the performance of a Fe3+/H2O2 Fenton-like system in the degradation of methyl tert-butyl ether and its byproducts.

The effect of chloride and sulfate ions on the oxidation of methyl tert-butyl ether (MTBE) and its degradation products in a Fenton-like system was studied. Although both chloride and sulfate ions inhibited the decomposition of H202, chlorides were found to be the more effective inhibitor of MTBE degradation. In the presence of sulfates, MTBE decomposition can be attributed to oxidation not only by hydroxyl radicals, but also likely by SO4*- species. In the presence of chloride ions, it is possible that the dichloride radical is formed, which is less reactive than OH*. In the system under investigation, t-butyl alcohol was found to be the major byproduct, followed by t-butyl formate and acetone. The degradation rates of all intermediates and their inhibition in the presence of inorganic ions are similar to those obtained for MTBE, although their distributions are related to the concentrations of inorganic salts added.