Applicability evaluation of advanced processes for elimination of neurophysiological activity of antidepressant fluoxetine.

Presence of the antidepressant fluoxetine in different water bodies has raised significant concerns due to its detrimental effects on non-targeted organisms, especially on fish. When seeking for an appropriate technology able to remove fluoxetine residue from a complex water matrix, special attention needs to be paid to the elimination of the neurophysiological activity that eventually lies behind the noxious effects of the parent compound. Our aim was to probe the applicability of advanced oxidation techniques for this purpose using in situ generated free radical system based on OH-initiated peroxyl radical-mediated processes.

Synthesis of carboxymethylcellulose/starch superabsorbent hydrogels by gamma-irradiation.

Background: Superabsorbent hydrogels show a large potential in a wide array of applications due to their unique properties. Carboxymethylcellulose (CMC) is a commercially available water-soluble cellulose derivative of major interest in the hydrogel synthesis. High-energy irradiation allows the chemical crosslinking without the use of crosslinking agents, while the introduction of other natural or synthetic polymers offers a convenient way to modify the gels.

Synthesis and characterization of superabsorbent hydrogels based on hydroxyethylcellulose and acrylic acid.

Hydroxyethylcellulose (HEC)/acrylic acid (AAc) copolymer gels with superabsorbent properties were synthesized from aqueous solutions by radiation-initiated crosslinking. The effect of the acrylic acid content on gel properties was determined at different synthesis conditions. The partial replacement of the cellulose derivative with acrylic acid improved the gelation, leading to higher gel fraction and lower water uptake even in very low concentrations (1-5%).

On the complex OH/O-induced free radical chemistry of arylalkylamines with special emphasis on the contribution of the alkylamine side chain.

A full account of the OH-induced free radical chemistry of an arylalkylamine is given taking all the possible reaction pathways quantitatively into consideration. Such knowledge is indispensable when the alkylamine side chain plays a crucial role in biological activity. The fundamental reactions are investigated on the model compound N-methyl-3-phenypropylamine (MPPA), and extended to its biologically active analog, to the antidepressant fluoxetine (FLX).

Radiation Induced Degradation of Organic Pollutants in Waters and Wastewaters.

In water treatment by ionizing radiation, and also in other advanced oxidation processes, the main goal is to destroy, or at least to deactivate harmful water contaminants: pharmaceutical compounds, pesticides, surfactants, health-care products, etc. The chemical transformations are mainly initiated by hydroxyl radicals, and the reactions of the formed carbon centered radicals with dissolved oxygen basically determine the rate of oxidation. The concentration of the target compounds is generally very low as compared to the concentration of such natural 'impurities' as chloride and carbonate/bicarbonate ions or the dissolved humic substances (generally referred to as dissolved organic carbon), which consume the majority of the hydroxyl radicals.

Change in hydrophilicity of penicillins during advanced oxidation by radiolytically generated OH compromises the elimination of selective pressure on bacterial strains.

Advanced oxidation processes are promising technologies for removal of antibiotic residues from wastewater in terms of their high efficacy. However, recent studies have reported the remaining antibacterial activity of the products at early-stages of treatment. The present study investigates the effect of such products of model β-lactams (amoxicillin, ampicillin, cloxacillin) on bacteria introducing structure-based, and biological approaches involving Gram-positive and Gram-negative bacterial strains.

One-Electron Reduction of Penicillins in Relation to the Oxidative Stress Phenomenon.

Certain bactericidal antibiotics target mitochondrial components and, due to the leakage of electrons from the electron transport chain, one-electron reduction might occur that can lead to intermediates passing the electron to suitable acceptors. This study aimed at investigating the one-electron reduction mechanism of selected penicillin derivatives using pulse radiolysis techniques. Penicillins can accommodate the electron on each of their carbonyl carbon.

Drugs with susceptible sites for free radical induced oxidative transformations: the case of a penicillin.

Penicillins, as bactericidal antibiotics, have been widely used to treat infections for several decades. Their structure contains both aromatic and thioether moieties susceptible to free radical oxidation. The (•)OH induced oxidation mechanism of amoxicillin was investigated by pulse radiolysis techniques and by final product analysis performed after steady-state γ-irradiation.

Ionizing radiation induced degradation of diuron in dilute aqueous solution.

Background: Cutting edge technologies based on Advanced Oxidation Processes (AOP) are under development for the elimination of highly persistent organic molecules (like pesticides) from water matrices. Among them, ionizing radiation treatment represents a promising technology that requires no additives and can be easily adapted to an industrial scale. In these processes several reactive species are produced, mainly powerful oxidizing radicals inducing the degradation.

Analytical approaches to the OH radical induced degradation of sulfonamide antibiotics in dilute aqueous solutions.

By combining a large variety of analytical techniques this study aimed at elaborating methods to follow up the degradation of sulfonamides in an advanced oxidation process (AOP): irradiation with ionizing radiation in dilute aqueous solution. In this process, besides other radicals, hydroxyl radicals are produced. As pulse radiolysis experiments show the basic initial reaction is hydroxyl radical addition to the benzene ring, forming cyclohexadienyl radical intermediates.

Hydroxyl radical-induced degradation of fenuron in pulse and gamma radiolysis: kinetics and product analysis.

Radiolytic reactions of phenylureas were studied in detail with fenuron model compound in dilute aqueous solutions using pulse radiolysis for detection of the intermediates, gamma radiolysis with UV-Vis and HPLC-MS techniques for analysis of the final products. The kinetics of oxidation was followed by COD, TOC and toxicity measurements. During radiolysis of aerated solutions hydroxyl radical ((•)OH), eaq (-), H(•) and O2 (•-)/HO2 (•) reactive intermediates are produced, the degradation of solute takes place practically entirely through (•)OH reactions.