E.M. Siedlecka

Enhanced photo-degradation of contaminants in petroleum refinery wastewater

In order to rise efficiency of the wastewater treatment in a refinery plant, several oxidation experiments were done, testing their applicability as an additional pretreatment method. The influence of treatment with low concentrations of H2O2 combined with stirring and UV light on degradation of organic compounds present in the refinery wastewater was studied. Oxidation of the total petroleum hydrocarbons occurs at relatively low concentrations of H2O2, additional UV irradiation slightly accelerates the process due to the increased formation of hydroxyl radicals. 1,2-dichloroethane and t-butyl methyl ether degrade in the similar manner and except for the lowest H2O2 concentration used (1.17 mM), the reduction after 24 h is total. The degradation rate for dichloromethane is the lowest one, depending both on hydrogen peroxide concentration and the presence of UV. Its maximum reduction of 83% was obtained using the highest applied peroxide concentration of 11.76 mM.

Identification of ionic liquid breakdown products in an advanced oxidation system

Commonly used alkylimidazolium ionic liquids are poorly to negligibly biodegradable, and some are toxic, with the potential to poison typical biological test systems. Therefore, when ionic liquids are present in technological wastewaters they could break through classical wastewater treatment systems into natural waters and become potentially persistent pollutants. A recent study investigating different advanced oxidation processes found that the H(2)O(2)/UV system degraded dissolved imidazolium ionic liquids with the greatest efficiency. In the present study, high performance liquid chromatography was coupled with electrospray mass spectrometry to separate, analyse and identify degradation products following the treatment of ionic liquid solutions with H(2)O(2) in the presence of UV irradiation. It was found that hydroxylation in short-chain entities occurred mainly within the ring moiety, whereas in the case of longer alkylated cations, oxidation of the alkyl chain yielded several products. The potential transformation products were identified structurally by MS/MS analysis and are discussed in the light of their putative toxicity and biodegradability.

Electrochemical degradation of sulfonamides at BDD electrode: kinetics, reaction pathway and eco-toxicity evaluation.

The investigation dealt with electrochemical oxidation of five sulfonamides (SNs): sulfadiazine (SDZ), sulfathiazole (STZ), sulfamerazine (SMR), sulfamethazine (SMN) and sulfadimethoxine (SDM) in aqueous solution at boron-doped diamond (BDD) electrode. All studied sulfonamides were degraded according to a pseudo first order kinetics. The structure of SNs had no significant effect on the values of pseudo first order rate constants. Increased degradation efficiency was observed in higher temperature and in acidic pH. Due to the presence of chlorine and nitrate SNs were more effectively oxidized from municipal wastewater treatment plant (WWTP) effluents than from pure supporting electrolyte Na2SO4. The intermediates identified by LC-MS and GC-MS analysis suggested that the hydroxyl radicals attack mainly the SN bond, but also the aromatic ring systems (aniline, pyrimidine or triazole) of SNs. Finally, the toxicity of the SNs solutions and effluents after electrochemical treatment was assessed through the measurement of growth inhibition of green algae (Scenedesmus vacualatus) and duckweed (Lemna minor). Toxicity of SMR, STZ, SMN solutions before and after electrochemical oxidation and SDM solution after the process in L. minor test was observed. No significant toxicity of studied SNs was observed in algae test.

Application of chitin and chitosan as elicitors of coumarins and furoquinolone alkaloids in Ruta graveolens L. (common rue)

Common rue (Ruta gra veolens L.) accumulates various types of secondary metabolites, such as coumarins furanocoumarins, acridone and quinolone alkaloids and flavonoids. Elicitation is a tool extensively used for enhancing secondary‐metabolite yields. Chitin and chitosan are examples of elicitors inducing phytoalexin accumulation in plant tissue. The present paper describes the application of chitin and chitosan as potential elicitors of secondary‐metabolite accumulation in R. graveolens shoots cultivated in vitro . The simple coumarins, linear furanocoumarins, dihydrofuranocoumarins and furoquinolone alkaloids biosynthesized in the presence of chitin and chitosan were isolated, separated and identified. There was a significant increase in the growth rate of R. graveolens shoots in the presence of either chitin or chitosan. Moreover, the results of the elicitation of coumarins and alkaloids accumulated by R. graveolens shoots in the presence of chitin and chitosan show that both compounds induced a significant increase in the concentrations of nearly all the metabolites. Adding 0.01% chitin caused the increase in the quantity (μg/g dry weight) of coumarins (pinnarin up to 116.7, rutacultin up to 287.0, bergapten up to 904.3, isopimpinelin up to 490.0, psoralen up to 522.2, xanhotoxin up to 1531.5 and rutamarin up to 133.7). The higher concentration of chitosan (0.1%) induced production of simple coumarins (pinnarin up to 116.7 and rutacultin up to 287.0), furanocoumarins (bergapten up to 904.3, isopimpinelin up to 490.0, psoralen up to 522.2, xanhotoxin up to 1531.5) and dihydrofuranocoumarins (chalepin up to 18 and rutamarin up to 133.7). Such a dramatic increase in the production of nearly all metabolites suggests that these compounds may be participating in the natural resistance mechanisms of R. graveolens . The application of chitin‐ and chitosan‐containing media may be considered a promising prospect in the biotechnological production of xanthotoxin, isopimpinelin, psoralen, chalepin or methoxylated dictamnine derivatives.

Ionic Liquids: Methods of Degradation and Recovery

In recent years ionic liquids (ILs) have attracted considerable attention owing to their potential use in a diversified range of applications. It is believed that ILs can successfully replace volatile organic media in a wide range of chemical processes. They have been studied and applied in organometallic catalysis, organocatalysis and biocatalysis, where they provide unique reaction media offering better selectivity, faster rates and greater catalyst or enzyme stability in comparison to conventional solvents (Buszewski & Studzinska, 2008; Dupont et al., 2002; Liu et al., 2010; Mathews et al., 2000; Minami, 2009; Welton, 1999). The applications of ILs also include areas such as electrochemical transformation, fuel cells, solar cells, sensors and nanochemistry. They are emerging as lubricants, modifiers of mobile and stationary phases in the separation sciences, and are candidates for the dissolution of cellulose, starch and wood (Wassersheid & Welton, 2003). ILs are characterized by properties such as negligible vapour pressure and non-flammability under ambient conditions, high thermal conductivity, a wide electrochemical window and high polarity. They also have the ability to dissolve a wide diversity of materials, including salts, fats, proteins, amino acids, surfactants, sugars, polysaccharides and organic solvents. However, the most important attribute of ILs is the possibility of designing their properties to order. Thanks to the enormous number of cation and anion combinations, ILs can possess a wide spectrum of physical and chemical properties (solubility, polarity, viscosity or solvent miscibility), and they are already recognized by the chemical industry as new, target-oriented reaction media. The properties of ILs can be used for developing new processes that are technologically, environmentally and economically advantageous. Listed benefits include the possibilities of reusing and relatively easily recovering ILs, which effectively reduces the amount of waste generated during technological operations. It is, however, important to remember that ILs are still quite expensive media, and their recycling after regeneration or recovery makes such a technology economically all the more justified. Among available technologies, conventional processes such as distillation, membrane separation and extraction can be

Identification of Ruta graveolens L. Metabolites Accumulated in the Presence of Abiotic Elicitors

The study aimed to elucidate the effects of benzothiadiazole (BTH) and saccharin on the biosynthesis of simple coumarins, linear furanocoumarins, dihydrofuranocoumarins, and furoquinolone alkaloids in shoots of R. graveolens cultivated in vitro. The biosynthesized metabolites were analyzed and identified by GC‐MS and by comparison of Kovats indices. Eight coumarin metabolites were identified: bergapten, chalepin, isopimpinelin, pinnarin, psoralen, rutacultin, rutamarin, and xanthotoxin, and also four alkaloids: dictamnine, γ‐fagarine, skimmianine, and kokusaginine. Each of the tested BTH concentrations induced a significant production of furanocoumarins and furoquinolone alkaloids. The use of saccharin also increased the production of bergapten, isopimpinelin, pinnarin, psoralen, and xanthotoxin several times.

Application of BDD thin film electrode for electrochemical decomposition of heterogeneous aromatic compounds

The aim of the presented study is to investigate the applicability of electrochemical oxidation of aromatic compounds containing heteroatoms, e.g. waste from production of pesticides or pharmaceutics, at a borondoped diamond (BDD) electrode. The BDD electrodes were synthesized by microwave plasma enhanced chemical vapour deposition (MW PE CVD). Investigation of the electrode surface by optical microscopy and scanning electron microscopy (SEM) confirmed that the synthesized layer was continuous and formed a densely packed grain structure with an average roughness of less than 0:5 μm. The influence of important electrochemical parameters: current density, kind of reactor, pH or mixing operation, on the efficiency of the oxidation was investigated. The fouling of electrode’s surface caused by the deposition of organic material was observed during CV and galvanostatic experiments. At low current density the oxidation rate constant k was low, but the current efficiency was relatively high. The BDD can be used successfully to remove heterogeneous aromatic compounds existing either as molecules or cations. During 4 h of electrolysis 95% of aromatic compounds were electrochemically decomposed to mineral forms. It was observed that the influence of the initial pH on mineralization was marginal.

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.

Heterogeneous structure of O-Antigenic part of lipopolysaccharide of Salmonella Telaviv (Serogroup O:28) containing 3-Acetamido-3,6-dideoxy-D-glucopyranose.

The O-polysaccharide of Salmonella Telaviv was obtained by mild acid degradation of the lipopolysaccharide and studied by chemical methods (sugar and methylation analyses, Smith degradation, de-O-acetylation) and NMR spectroscopy. The structure of the O-polysaccharide was established. The repeating units that are proximal to the lipopolysaccharide core region mostly have a digalactose side chain and lack glucose, whereas those at the other end of the chain mostly do bear glucose but are devoid of the disaccharide side chain. This is the first structure established for the O-polysaccharide of a Salmonella serogroup O:28 (formerly M) strain characterized by subfactors O281 and O282. Knowledge of this structure and the structure of the O-polysaccharide of Salmonella Dakar (O281, O283) established earlier is crucial for determination of the exact structures associated with subfactors O281, O282, and O283 and elucidation of the genetic basis of the close relationship between Escherichia coli O71 and S. enterica O:28 O-antigens.

Removal of cytostatic drugs by AOPs: A review of applied processes in the context of green technology

ABSTRACT For decades, cytostatic drugs have been widely used in chemotherapy. However, many of these chemicals are classified as carcinogenic, mutagenic and teratogenic compounds, triggering widespread concerns about the drug-related occupational exposure and eco-toxicological risks to the environment. Moreover, cytostatics cannot be successfully removed from wastewater by conventional mechanical-biological wastewater treatment, which is due to the physicochemical properties of these drugs, e.g. low value of octanol-water partition coefficient (logKo/w), high solubility in water, low biodegradability, and sensitivity to photolysis. The present work is a review of data concerning the removal of cytostatic drugs by means of advanced oxidation processes (AOPs) that were reported in the period 2005–2016. Until now, AOPs-based methods for the cytostatic drug removal from water and wastewater, such as ozonation, UV/oxidant, UV/Fenton reaction, UV/photocatalyst, and electrochemical oxidation at active and non-active anodes, have been investigated. In this paper, we review the effectiveness of AOPs in the removal of cytostatic drugs from aqueous media. Moreover, we discuss the mechanisms of cytostatic drug decomposition based on the identified intermediates. The analysis of biodegradability and eco-toxicity of effluents after AOPs-based treatments is also presented.