Edyta Kudlek

Influence of the catalyst type (TiO2 and ZnO) on the photocatalytic oxidation of pharmaceuticals in the aquatic environment

AbstractIn recent years, an increasing interest in the new group of contaminants appearing in the aquatic environments i.e. pharmaceuticals and personal care products has been observed. The effect of the long-term exposure of living organisms to sufficiently lower the concentration of pharmaceuticals, which are found to be highly reactive, is still unknown. In addition with no toxicological data of pharmaceuticals action on living organisms, including humans, their constant elimination from water dedicated to human consumption is required. In this article, the efficiency of chosen pharmaceutical compounds via photocatalysis process is discussed. The photolysis process was also performed in order to compare both solutions. Titanium dioxide (TiO2) and zinc oxide (ZnO) were used as catalysts. The photocatalytic process was also evaluated according to the toxic effect of the purified water by means of MICROTOX® analysis. The impact of the pharmaceutical concentration and oxidation time on the water samples to...

Chromatographic determination and toxicological potential evaluation of selected micropollutants in aquatic environment—analytical problems

AbstractIn this study, the analytical procedures for the improved extraction and determination of the selected micropollutants (anthracene, pentachlorophenol, octylphenol, benzo(a)pyrene, and diclofenac) in aqueous environment are proposed. These methods were based on application of gas chromatography coupled with mass spectrometry and solid phase extraction for isolation of tested analytes from water samples. Compared to standard procedures currently used in the range presented in this paper, the authors’ modifications of analytical procedures allowed increasing the recovery rate of analytes. Within modification of procedures, hyamine, methanol were used. The substances increase solubility of analytes in water, for instance. Toxicological potential of samples containing tested micropollutants in different environmental matrix was evaluated. Proposed analytical procedures allow the quantitative determination of five different compounds in aquatic environment with satisfactory repeatability and precision o...

The Presence of Compounds from the Personal Care Products Group in Swimming Pool Water

The global production of several thousands of Personal Care Products (PCPs) every year makes the release of PCPs to the environment an unavoidable by-product of a modernized lifestyle. Multiple studies have detected PCPs worldwide in various aquatic environments, including swimming pools. In the presented work, the concentrations of three selected compounds from the PCPs group were examined in 15 swimming pools with different functions. The aim of the study was to show the influence of various factors on the concentration levels of selected micropollutants. Two UV filters: BP-3 (oxybenzone), BP-8 (dioxybenzone) and one antioxidant BTH (dibutylhydroxytoluene) were selected for the research. The extraction of micropollutants from the swimming pool water matrix was carried out by Solid Phase Extraction (SPE). The extracts were analyzed using a gas chromatograph (GC) coupled to the mass detector (MS). BHT was the most common compound. Its concentration ranged from 3.8 ng/L to 5.5 ng/L. The most rarely occurring compound was BP-3. The concentration of this compound varied the most, from 18.5 ng/L to 1178.6 ng/L. BP-8 was present in 10 from 15 tested pools at the concentration level of 49.9–226.9 ng/L. The frequency of occurrence characterizing different micropollutants from PCPs group was higher in recreational pools than in sports pools. It was also observed that the applied water treatment technology may affect the presence of Personal Care Products in the swimming pool water. No impact of basic water quality parameters on the levels of tested pharmaceuticals has been shown in this research.

The impact of the circulation system on the concentration level of micropollutants in the swimming pool water treatment system

Each pool installation should ensure proper and constant circulation of water in a closed circuit system. However, the operation of such a system can potentially cause the accumulation of small -molecule micropollutants in the pool water treatment system. The aim of this work is to confirm or reject this argument. As part of preliminary tests, the content of organic and inorganic substances in swimming pool water was analyzed based on general indicators such as TOC, UV254 absorbance and conductivity. In the main stage of the research, pool water samples collected from four different points of the swimming pool installation were subjected to chromatographic analysis to determine the small-molecule micropollutants. The tap water used to fill the basin and regular replenishment of volume losses was also tested. This study was intended to exclude the tap water as a potential source of contamination in the pool water. Preliminary studies have shown almost a two-fold increase in the total organic carbon content and absorbance UV254 at the turn of six months, which undoubtedly indicates the accumulation of organic pollutants in pool water circulation systems. It was not observed in the case of inorganic compounds. As a result of the chromatographic analyzes of the pool water, the content of pharmaceuticals and personal care product was determined. It was found that the compensation tank is the place of the highest accumulation of the tested pharmaceuticals in the pool water treatment system , while the cosmetics component accumulated in the pool basin to the greatest degree. It was affected by the duration of the filter cycle.

Degradation pathways of pentachlorophenol and benzo(a)pyrene during heterogeneous photocatalysis

Organic micropollutants, in particular those of anthropogenic origin, may have a toxic influence on water organisms. Photochemical oxidation processes are one of the most effective methods of decomposition of a wide range of those compounds. During the oxidation process a large number of different by-products are generated, which can still be biologically active. The development of analytical techniques, including the reduction of the detection limit to several fg/L, allows the identification of even trace concentrations of compounds. The paper presents the determination of pentachlorophenol and benzo(a)pyrene degradation pathways during the process of heterogeneous photocatalysis carried out in the presence of titanium dioxide. The gas chromatography-mass spectrometry (GC-MS) analysis of post-processing samples indicated the formation of different by-products of the parent micropollutants. Moreover, the toxicity assessment demonstrates for both tested micropollutants an increase in the toxicity within the whole time of the UV irradiation process run.

Kinetics of the Photocatalytic Decomposition of Bisphenol A on Modified Photocatalysts

This paper presents the evaluation of the photocatalytic kinetics of bisphenol A decomposition in the presence of commercial titanium(IV) oxide and modified photocatalysts (composites). The following modification methods were used: mechanical mixing, calcination and impregnation. The decomposition process was carried out with the addition of photocatalysts and activated carbon at doses of 100 mg/dm3 and 25 mg/dm3, respectively. The photocatalytic process was performed in a reactor from the Heraeus Company (Warsaw, Poland) with a volume of 0.7 dm3. The reactor was equipped with an immersed medium-pressure mercury lamp with a power of 150 W (λ = 200–580 nm). The degree of bisphenol A decomposition was determined by chromatographic analysis preceded by solid-phase extraction SPE. The qualitative-quantitative analysis was performed using a high-performance liquid chromatograph HPLC (UV detector, λ = 218 nm) from Varian (Warsaw, Poland). The dependence of the BPA decomposition on the duration of irradiation was found, wherein the modified photocatalysts were the most effective (from 75 to 90% after 15 minutes). The order of photocatalyst efficiency has been proposed as follows: TiO2 < TiO2/AC < Cdextran-TiO2/AC < Cmethanol-TiO2/AC< Cethanol-TiO2/AC < TiO2-AC. The highest degree of decomposition was observed in the presence of TiO2/AC (99%). Numerous studies suggest that the results of the TiO2 photocatalytic oxidation of organic substances fit well with the Langmuir–Hinshelwood (L–H) kinetic model. The kinetic parameters of the photocatalysis process were carried out according to the L-H model. According to the pseudo-first-order parameters, the results showed that the decomposition of bisphenol A was most intensive in the first 15 minutes of the process.

Elimination of Bisphenol A from Wastewater through Membrane Filtration Processes

New priorities for the environment have resulted in a reassessment of modern technology for treatment of urban wastewater. Urban wastewater treatment mainly involves the elimination or reduction of anthropogenic organic micropollutants in the aquatic environment. In this paper, the effectiveness of bisphenol A elimination from wastewater, after biological treatment, through a complex ultrafiltration/reverse osmosis purification process was evaluated. The effectiveness of the wastewater treatment process in the tested system was also evaluated with a number of other physical and chemical analyses for pH, turbidity, colour, absorbance, TOC, phenol index, conductivity and the concentration of selected heavy metals. Within this study, the change in the hydraulic performance of the membranes was also investigated. The effectiveness of the reduction of bisphenol A concentrations during the process of ultrafiltration was small, due to the significant difference between the size of the pores of the membrane and the size of eliminated micropollutants. In the process of reverse osmosis, the wastewater treatment system reported that the concentration of bisphenol A was reduced by 68%. In the tested treatment system, the ultrafiltration/reverse osmosis completely removed colour, lead and chromium. Other contaminants were eliminated by more than 31%. In both membrane processes, there was evidence that the membrane pores were blocked, but this occurred to a greater extent during the process of reverse osmosis.

Estimation of physicochemical properties of 2-ethylhexyl-4-methoxycinnamate (EHMC) degradation products and their toxicological evaluation

The organic UV filters, commonly used in personal protection products, are of concern because of their potential risk to aquatic ecosystems and living organisms. One of UV filters is ethylhexyl-4-methoxycinnamate (EHMC) acid. Studies have shown that, in the presence of oxidizing and chlorinating factors, EHMC forms a series of products with different properties than the substrate. In this study, the toxicities of EHMC and its transformation/degradation products formed under the influence of NaOCl/UV and H2O2/UV systems in the water medium were tested using Microtox® bioassay and by observation of mortality of juvenile crustaceans Daphnia magna and Artemia Salina. We have observed that oxidation and chlorination products of EHMC show significantly higher toxicity than EHMC alone. The toxicity of chemicals is related to their physicochemical characteristic such as lipophilicity and substituent groups. With the increase in lipophilicity of products, expressed as log KOW, the toxicity (EC50) increases. On the basis of physicochemical properties such as vapour pressure (VP), solubility (S), octanol-water partition coefficient (KOW), bioconcentration factor (BCF) and half-lives, the overall persistence (POV) and long-range transport potential (LRTP) of all the products and EHMC were calculated. It was shown that the most persistent and traveling on the long distances in environment are methoxyphenol chloroderivatives, then methoxybenzene chloroderivatives, EHMC chloroderivatives, methoxybenzaldehyde chloroderivatives and methoxycinnamate acid chloroderivatives. These compounds are also characterised by high toxicity.

INFLUENCE OF INORGANIC COMPOUNDS ON THE PROCESS OF PHOTOCATALYSIS OF BIOLOGICALLY ACTIVE COMPOUNDS

Constant increase in concentration of organic micropollutants in the water environment influences the development of methods for their effective elimination from various matrices released into aquatic ecosystems. One of widely described in literature processes for the decomposition of hardly-biodegradable pollutants is the process of heterogeneous photocatalysis. The paper presents the influence of inorganic substances on the decomposition of polycyclic aromatic hydrocarbons (anthracene and benzo[a]pyrene), industrial admixtures – octylphenol and pharmaceutical compounds – diclofenac in the photocatalysis process conducted in the presence of TiO2. It has been shown that the presence of Cl– ions did not affect the photochemical reaction of the micropollutant decomposition. Whereas, the presence of CO3, SO4 and HPO4 ions inhibited the decolonization of octylphenol and diclofenac, while the degradation efficiency of anthracene and benzo[a]pyrene was reduced only by the presence of CO3 and HCO3 anions. The photooxidation of micropollutants in solutions containing Al3+ oraz Fe3+ cations proceeded with a much lower efficiency than that for solution without inorganic compounds. The analysis of the kinetics of the photocatalytic decomposition of selected micropollutants show a decrease in the reaction rate constant and an increase in their half-life due to the blocking of theactive semiconductor centers by inorganic compounds. In addition,the toxicological analysis inducated the generation of micropollutant oxidation by-products, which aggravate the quality of treated aqueous solutions.

THE MUNICIPAL SEWAGE TREATMENT PLANT EFFLUENT POLISHING IN ULTRAFILTRATION

The effluent from the municipal sewage treatment plant was comparatively treated in the ultrafiltration process using ceramic and polymer membranes. Filtration was carried out in the cross-flow system under the conditions of the transmembrane process pressure of 0.1 MPa in the case of the ceramic membrane and 0.2 MPa with the polymer membrane, at a temperature of 20°C. The effectiveness of the process has been assessed by means of various physical and chemical analyses (pH, turbidity, color, absorbance, TOC and phenol index). The toxicological assessment (by applying the bioluminescent bacteria Aliivibrio fischeri as an indicator organism) and microbiological assessment of tested samples were included. The hydraulic efficiency of membranes was studied during filtration. Is was specified that the efficiency of the process depends on the conditions of membrane filtration, wherein the better effects of the removal of organic pollutants have been noted in the case of polymer membrane than with the ceramic membrane. However, the polymer membrane, in comparison to the ceramic membrane, was more susceptible to pore blocking, which caused the reduction of hydraulic efficiency. Regardless of the type of membrane, the permeates were not toxic and did not contain microorganisms.