Electrochemically modified dissolved organic matter accelerates the combining photodegradation and biodegradation of 17α-ethinylestradiol in natural aquatic environment.

The photochemical conversion and microbial transformation of pollutants mediated by dissolved organic matter (DOM), including 17α-ethinylestradiol (EE2), are often accompanied in natural water. However, there are few studies to explore the connection and mechanism between the two processes. This research aims to investigate the mechanism of DOM after electrochemically modification mediated EE2 combining photodegradation and biodegradation in the environment and it want to explain the natural phenomena of DOM after electrochemical advanced treatment entering the water environment mediated EE2 natural degradation. The results showed that combining photodegradation with biodegradation rates of EE2 mediated by DOM and electrochemically modified DOM (E-DOM) were promoted obviously. The efficiency of EE2 biodegradation was shown to be strongly correlated with electron accepting capacity (EAC) of DOM. Electrochemical modification can increase the EAC of DOM leading to EE2 biodegradation accelerated, and it also can form more triplet-state DOM moieties to promote the EE2 photodegradation in irradiation conditions, due to the increasing of quinone-type structures in DOM. Moreover, cell polymeric secretion (CPS) secreted from the microorganism could be stimulated to an excited state by irradiation, and that also accelerated EE2 degradation. Photolysis combined with biochemical degradation yielded less toxic degradation products. This study shows that the emission of DOM in wastewater after electrochemical treatment could accelerate estrogen degradation and play a positive role on the pollutant transformation in the environment.

A model of natural degradation of 17-α-ethinylestradiol in surface water and identification of degradation products by GC-MS.

Over the past decade, the environment has been polluted by a wide spectrum of exogenous chemicals and environmental analysis has become one of the most progressive parts of analytical research. The aim of this work was to determine the kinetics of natural degradation, and to identify the degradation products of the massively used estrogenic drug, 17-α-ethinylestradiol. The photodegradation, oxidation and thermostability conditions were selected according to ICH requirements for pharmaceutical stability testing. A simple 72-h photodegradation study in purified water exhibited significant first-order kinetics with the kinetic constant k = 0.0303 h-1, and degradation halftime 22.8 h. The basic halftime could be reduced to 17.1 h by the addition of sea salt, and increase in temperature. Monohydroxy, dihydroxy and dehydrogenated derivatives of ethinylestradiol with intact steroidal structure were identified as major degradation products resulting from simple photodegradation. The addition of an oxidative agent significantly accelerated the degradation rate; combined with higher temperature, the degradation halftime was reduced to 1.1 h with the first-order kinetic constant k = 0.632 h-1. TOC analysis showed a notable decrease of organic mass (18% in 3 days) during oxidation experiments, and confirmed the degradation of steroidal structure.

Simultaneous Degradation of Estrone, 17ß-Estradiol and 17α-Ethinyl Estradiol in an Aqueous UV/H2O2 System.

UV/H2O2, which is an advanced treatment technology used to reduce multiple contaminants, is effective in potable water treatment. Simultaneous degradation effects and kinetics of three types of coexisting micropollutant estrogens (steroid estrogens, SEs), including estrone (E1), 17ß-estradiol (E2) and 17α-ethinyl estradiol (EE2), in deionized water were studied. Experiments were carried out with ultraviolet-C (UVC) radiation, together with hydrogen peroxide (H2O2), in a cylinder photoreactor. The results demonstrated that the degradation processes of all of the estrogens strongly fit first-order kinetics. Single solutions of E1, E2 and EE2 showed higher degradation rates and removal efficiencies under the same reaction conditions compared with those under mixed conditions. Coexisting combinations of estrogens were put into the UV/H2O2 system to estimate their possible competitive influences on each other by examining their removal efficiencies and reaction rate constant, k, values. E1 is predominantly reduced rapidly during the competition, while the presence of other estrogens has negligible impacts on E1; however, the degradation of E2 and EE2 is affected by the competitive background, not in relation to the types but to the existing amounts. In the UV/H2O2 system, photocatalysis of the estrogens can stably produce an intermediate X, with the highest quantity coming from E1, while considerably lower quantities are obtained from E2 and EE2.

Photocatalytic degradation and reactor modeling of 17α-ethynylestradiol employing titanium dioxide-incorporated foam concrete.

Photocatalytic degradation of 17α-ethynylestradiol (EE2) using TiO2 photocatalysts incorporated with foam concrete (TiO2/FC) was investigated for the first time. Scanning electron microscopy (SEM) study of the samples revealed a narrow air void size distribution on the surface of FC cubes on with 5 wt% addition of P25 TiO2, and TiO2 particles were distributed heterogeneously on the surface of TiO2/FC samples. The sorption and photocatalytic degradation of EE2 with UV-light irradiation by TiO2/FC cubes were investigated. Adsorption capacity of EE2 by the TiO2/FC and blank foam concrete (FC) samples were similar, while the degradation rates showed a great difference. More than 50 % of EE2 was removed by TiO2/FC within 3.5 h, compared with 5 % by blank FC. The EE2 removal process was then studied in a photoreactor modified from ultraviolet disinfection pool and constructed with TiO2/FC materials. An integrated model including a plate adsorption-scattering model and a modified flow diffusion model was established to simulate the photocatalytic degradation process with different radiation fields, contaminant load, and flow velocity. A satisfactory agreement was observed between the model simulations and experimental results, showing a potential for the design and scale-up of the modified photocatalytic reactor.

Development and modeling of a flat plate serpentine reactor for photocatalytic degradation of 17-ethinylestradiol.

A flat plate serpentine reactor modified from ultraviolet disinfection pool in municipal wastewater treatment plants was developed for the removal of 17-ethinylestradiol (EE2) for the first time. The photocatalytic degradation performance of EE2 was investigated in this serpentine reactor under different conditions such as inlet concentrations, loaded catalyst concentrations, incident radiations fluxes, and flow velocities. More than 98% of EE2 was removed under certain conditions within 120 min. An integrated model including a six-flux adsorption-scattering model and a modified flow diffusion model was established to investigate the effect of radiation field and flow velocities, respectively. A satisfactory agreement was observed between the model simulation and experimental results, showing a potential for design and scale-up of photocatalytic reactor for wastewater treatment.

Environmental factors affecting ultraviolet photodegradation rates and estrogenicity of estrone and ethinylestradiol in natural waters.

The environmental fate and persistence of steroidal estrogens is influenced by their photodegradation. This can potentially occur both in the presence of the ultraviolet (UV) portion of solar radiation and in tertiary wastewater treatment plants that use UV radiation for disinfection purposes. To determine patterns of UV photodegradation for estrone (E1) and 17α-ethinylestradiol (EE2), water samples containing these compounds were exposed to levels of UVB radiation that would simulate exposure to ambient sunlight. E1 degraded with a pseudo-first-order rate law constant that was directly proportional to UVB radiation intensity (R² = 0.999, P < 0.001) and inversely proportional to dissolved organic carbon (DOC) concentration (R² = 0.812, P = 0.037). DOC acted as a competitive inhibitor to direct photolysis of E1 by UV. In contrast to E1, EE2 was more persistent under similar UVB treatment. A reporter gene assay showed that the estrogenicity of UVB-exposed estrogens did not decrease relative to non-UVB-exposed estrogens, suggesting that some of the photoproducts may also have estrogenic potency. These results show that environmental degradation rates of steroidal estrogens are predictable from the UV intensity reaching surface waters, and the DOC concentrations in these surface waters.

Kinetic degradation model and estrogenicity changes of EE2 (17alpha-ethinylestradiol) in aqueous solution by UV and UV/H2O2 technology.

The photochemical degradation and estrogenicity removal of 17alpha-ethinylestradiol in aqueous solutions was investigated via ultraviolet (UV) photolysis and UV/H(2)O(2) process with a low-pressure UV lamp. The results indicated that the kinetics of both oxidation processes well fitted the pseudo-first-order kinetics. EE(2) can be partially removed by UV radiation alone with kinetic constants increasing from 0.0054 to 0.2753 min(-1) with the UV intensity increase. The EE(2) degradation rate enhanced from 0.0364 to 0.0684 min(-1) when H(2)O(2) was combined with the photolysis process (UV/H(2)O(2)), even though EE(2) was not oxidized when same amounts of H(2)O(2) existed in the aqueous solutions. The kinetic parameters of pseudo-first-order kinetics showed positive correlation to UV intensity and also H(2)O(2) concentration, however negative to the initial EE(2) concentration. A regression model was developed for pseudo-first-order rate constant as a function of the UV intensity, H(2)O(2) concentration and initial EE(2) concentration, which could be used to estimate the EE(2) degradation rate at various operational conditions. The yeast estrogen screen (YES) was employed to evaluate the estrogenicity of photolytic water samples. Results showed that more than 95% of the estrogenicity was removed after 40 min irradiation and the parent compound EE(2) was mainly responsible for the observed estrogenicity.

Phototransformation of selected pharmaceuticals during UV treatment of drinking water.

The kinetics of Ultraviolet C (UV-C)-induced direct phototransformation of four representative pharmaceuticals, i.e., 17alpha-ethinylestradiol (EE2), diclofenac, sulfamethoxazole, and iopromide, was investigated in dilute solutions of pure water buffered at various pH values using a low-pressure and a medium-pressure mercury arc lamp. Except for iopromide, pH-dependent rate constants were observed, which could be related to acid-base equilibria. Quantum yields for direct phototransformation were found to be largely wavelength-independent, except for EE2. This compound, which also had a rather inefficient direct phototransformation, mainly underwent indirect phototransformation in natural water samples, while the UV-induced depletion of the other pharmaceuticals appeared to be unaffected by the presence of natural water components. At the UV-C (254 nm) drinking-water disinfection fluence (dose) of 400 Jm(-2), the degree of depletion of the select pharmaceuticals at pH=7.0 in pure water was 0.4% for EE2, 27% for diclofenac, 15% for sulfamethoxazole, and 15% for iopromide, indicating that phototransformation should be seriously taken into account when evaluating the possibility of formation of UV transformation products from pharmaceuticals present as micropollutants.

Selective photocatalytic oxidation of steroid estrogens in water treatment: urea as co-pollutant.

The objective of the present research concerns the competitive photocatalytic oxidation (PCO) and adsorption of steroid estrogens (SEs) on titanium dioxide in presence of urea. The results showed the indifference of SEs towards the presence of urea in concentrations characteristic for the domestic sewage. The selective PCO of SEs appeared to be feasible in alkaline media, in which the PCO exhibited the highest efficiency. Ethanol used for hydrophobic SEs dissolution in water appeared to be interfering with the PCO.

Degradation of endocrine disrupting chemicals bisphenol A, ethinyl estradiol, and estradiol during UV photolysis and advanced oxidation processes.

The degradation of three endocrine disrupting chemicals (EDCs), bisphenol A, ethinyl estradiol, and estradiol, was investigated via ultraviolet (UV) radiation photolysis and the UV/hydrogen peroxide advanced oxidation process (AOP). These EDCs have been detected at low levels in wastewaters and surface waters in both the United States and European countries, can cause adverse effects on humans and wildlife via interactions with the endocrine system, and thus must be treated before entering the public drinking water supply. Because many EDCs can only be partially removed with conventional water treatment systems, there is a need to evaluate alternative treatment processes. For each EDC tested, direct UV photolysis quantum yields were derived for use with both monochromatic low-pressure (LP) UV lamps and polychromatic medium-pressure (MP) UV lamps and second-order hydroxyl radical rate constants were developed. These parameters were utilized to successfully model UV treatment of the EDCs in laboratory and natural waters. The polychromatic MP UV radiation source was more effective for direct photolysis degradation as compared to conventional LP UV lamps emitting monochromatic UV 254 nm radiation. However, in all cases the EDCs were more effectively degraded utilizing UV/H2O2 advanced oxidation as compared to direct UV photolysis treatment.

UV-light induced photodegradation of 17alpha-ethynylestradiol in aqueous solutions.

The photodegradation of 17alpha-ethynylestradiol (EE2) in aqueous solutions induced by UV-light was preliminarily studied in this paper by means of fluorescence, UV and infrared spectra. The result suggested that EE2 in aqueous solutions underwent photodegradation under irradiation with UV disinfection lamp (lambda = 254 nm, 30 W), but the photodegradation was not observed under high pressure mercury lamp (lambda > or = 365 nm, 250 W). The photodegradation of 1.6-20.0 mg/l EE2 in aqueous solutions at a given initial pH value of 6.8 was pseudo-first order reaction. Increasing the initial concentration of EE2 lowered the photodegradation rate. The photodegradation rate of EE2 reached the lowest value at pH about 5.0, higher pH values of 6.0-8.0 benefited the photodegradation. Ferric ions can promote the photodegradation of EE2 in aqueous solutions at pH value of 2.0-5.0.

Light stability of norethindrone and ethinyl estradiol formulation with FD&C colorants.

In general, light-sensitive tablets exhibit discoloration in the surface layer(s) only. A case is discussed where a quantitative interaction between a drug, ethinyl estradiol (in a combination tablet containing norethindrone and ethinyl estradiol), and a dye (FD&C Red No. 3) occurs, and discoloration exists throughout the tablet. The data suggest that accelerated light studies should be carried further than those dictated by predictive periods so that equilibrium levels can be deduced.