Bisphenol A Degradation Rate Research Articles

Biodegradation of bisphenol-A (BPA) in activated sludge batch reactors: Analysis of the acclimation process

In this work the effect of (a) the sludge age (SA) and the acclimation strategy on the acclimation process of activated sludge (AS) to bisphenol A (BPA), (b) the presence of biogenic substrates on the degradation of BPA, and (c) the acclimation on the degradation of biogenic substrates was studied. AS samples from reactors operated at SA of 30 and 45 d were acclimated to BPA using two strategies: constant or increasing the initial BPA concentration. Although acclimation to BPA was achieved using both strategies, no net biomass growth was detected. Specific BPA degradation rate of acclimated AS ranged between 65 and 90 mgBPA gTSS−1 d−1. BPA degradation was not affected by the biogenic substrates cheese whey or acetate; acclimation to BPA did not cause a negative effect on the biodegradation of these substrates. During the degradation of cheese whey, specific mean oxygen uptake rate (qo2mean) and specific mean substrate consumption rate (qSmean) of non-acclimated AS were similar to those corresponding to acclimated ones. When acetate was tested, qo2mean and qSmean values corresponding to acclimated AS were about twofold the values of the non-acclimated ones. This enhancement could occur because acetate is an intermediate of the metabolism of BPA.

Ultrasonic Degradation of Endocrine Disrupting Compounds in Seawater and Brackish Water

In this study, a series of experiments was conducted on the relative degradation of commonly known endocrine-disrupting com- pounds such as bisphenol A (BPA) and 17α-ethinyl estradiol (EE2) in a single-component aqueous solution using 28 and 580 kHz ultrasonic reactors. The experiments were conducted with three different types of model water: deionized water (DI), synthetic brack- ish water (SBW), and synthetic seawater (SSW) at pH 4, 7.5, and 11 in the presence of inert glass beads and humic acids. Significantly higher sonochemical degradation (93-97% for BPA) occurred at 580 kHz than at 28 kHz (43-61% for BPA), regardless of water type. A slightly higher degradation was observed for EE2 compared to that of BPA. The degradation rate of BPA and EE2 in DI water, SBW, and SSW after 30 min of ultrasound irradiation at 580 kHz increased slightly with the increase in pH from 4 (0.073-0.091 min-1 for BPA and 0.081-0.094 min -1 for EE2) to 7.5 (0.087-0.114 min -1 for BPA and 0.092-0.124 min -1 for EE2). In contrast, significant degradation was ob - served at pH 11 (0.149-0.221 min-1 for BPA and 0.147-0.228 min-1 for EE2). For the given frequencies of 28 and 580 kHz, the degradation rate increased in the presence of glass beads (0.1 mm and 25 g) for both BPA and EE2: 0.018-0.107 min -1 without beads and 0.052-0.142 min-1 with beads for BPA; 0.021-0.111 min-1 without beads and 0.054-0.136 min-1 with beads for EE2. A slight increase in degradation of both BPA and EE2 was found as the concentration of dissolved organic carbon (DOC, humic acids) increased in both SBW and SSW: 0.107-0.115 min-1 in SBW and 0.087-0.101 min-1 in SSW for BPA; 0.111-0.111 min-1 in SWB and 0.092-0.105 min-1 in SSW for EE2. After 30 min of sonicating the humic acid solution, DOC removal varied depending on the water type: 27% (3 mg L -1 ) and 7% (10 mg L -1 ) in SBW and 7% (3 mg L-1) and 4% (10 mg L-1) in SSW.

Biodegradation of bisphenol-A in river sediment

This research investigated the aerobic and anaerobic degradation of bisphenol-A (BPA) in river sediment. With the addition of 250 μg g−1 BPA, the percentages of BPA remaining in sediment from sites A, B, and C were 21.9 %, 3.5 % and 12.5 %, respectively, after 5 days of incubation under aerobic conditions; degradation was not significant after 140 days of incubation under anaerobic conditions. The aerobic degradation of BPA was enhanced by adding yeast extract (5 mg L−1), sodium chloride (1 %), cellulose (0.96 mg L−1), brij 30 (55 μM), brij 35 (91 μM), rhamnolipid (130 mg L−1), or surfactin (43 mg L−1), with rhamnolipid yielding higher BPA degradation than the other additives. 2,4-bis (1,1-dimethyl ethyl) phenol, an intermediate product resulting from the aerobic degradation of BPA was accumulated in sediments. Of the bacterial strains isolated from the sediment, strains J1, J2, J3, and J4 expressed the best aerobic degrading ability. The highest BPA degradation rate was found in the sediment by the addition of strains J1, J2, J3, and J4 combined, whereas the sediment without the addition of the 4 strains had the lowest biodegradation rate. This research offers feasible methods for the removal of BPA in river sediment for bioremediation.

Ultrasonic degradation of bisphenol A, 17β-estradiol, and 17α-ethinyl

This study examined the relative degradation of commonly known endocrine-disrupting compounds (EDCs) such as bisphenol A (BPA), 17β-estradiol (E2), and 17α-ethinyl estradiol (EE2) in single-component aqueous solution using 28, 580, and 1,000 kHz ultrasonic reactors. The degradation of EDCs follows a pseudo-first order rate kinetics; the order of degradation is EE2 ≥ BPA > E2. At different frequencies, the degradation of these compounds follows the order 580 kHz (92–97%) > 1,000 kHz (90–94%) > 28 kHz (62–67%) at an initial concentration of 1 μM of each compound with a contact time of 30 min. Additional experiments were performed to determine the effects of carbon tetrachloride (CCl4, H• scavenger) and tert-butyl alcohol (t-BuOH, HO• scavenger) on BPA, E2, and EE2 degradation at 580 kHz with a reaction time of 30min. The addition of t-BuOH slightly decreased the rate of BPA degradation as follows: no addition (97%), 0.01 mM (96%), and 0.1 mM (95%). At high t-BuOH concentrations of 1, 10, and 100 mM, the deg...

Degradation of bisphenol-A using ultrasonic irradiation assisted by low-concentration hydrogen peroxide

This study investigated the degradation of bisphenol-A (BPA) by ultrasonic irradiation in the presence of different additives (H 2O 2, air bubbles and humic acid) under various operating conditions, i.e., ultrasonic frequency, power intensity and power density. The results demonstrated that the BPA degradation followed pseudo first-order kinetics under different experimental conditions. The optimum power intensities were 0.9, 1.8, and 3.0 W/cm 2 at the frequencies of 400, 670, and 800 kHz, respectively. At the fixed frequency (800 kHz), the degradation rate of BPA was shown proportional to the increase of power density applied. With this manner, the BPA sonolysis could be facilitated at H 2O 2 dosage being lower than 0.1 mmol/L; while BPA degradation was hindered at H 2O 2 concentration in excess of 1 mmol/L. Additionally, BPA removal was shown to be inhibited by the presence of aeration and humic acid during ultrasonic irradiation. The present study suggested that the degradation rate of BPA assisted by ultrasonic irradiation was influenced by a variety of factors, and high BPA removal rate could be achieved under appropriate conditions.

Sonophotochemical Degradation of Bisphenol A with Solid Catalysts

In order to investigate the degradation of bisphenol A (BPA) solution under sono, photo, sonocatalytic, photocatalytic and sonophotocatalytic processes, the BPA concentration and the total organic carbon (TOC) concentration were analyzed. The degradation rate of BPA was higher at high frequency (1 MHz) than at low frequency (300 kHz). At high frequency the acoustic period is shorter, and a high H2O2 concentration is therefore produced in aqueous solutions, which can enhance the degradation rate. The degradation rates of BPA were 0.0060, 0.0258, and 0.0451 min-1 under the sonocatalytic (1 MHz), photocatalytic and sonophotocatalytic processes respectively. The combined system of the sonochemical and photocatalytic processes can enhance the degradation rate of BPA compared with individual processes (sono and photocatalytic processes). The order of degradation of BPA (CuO>ZnO≈TiO2) and TOC (TiO2>ZnO>CuO) differed for each of the three types of catalysts. The separation characteristics of catalysts were dissimilar for each of the two frequencies.

Degradation of bisphenol A in water by Fe(III)/UVA and Fe(III)/polycarboxylate/UVA photocatalysis

The photodegradation of the endocrine disrupting chemical Bisphenol A (BPA) under UVA irradiation in the presence of Fe(III) or Fe(III)-polycarboxylate systems was studied. The effect of Fe(III) concentration, aqueous pH and the presence of four carboxylic acids (oxalic, malic, tartaric and citric) were investigated. The Fe(III)/UVA system was able to effectively degrade BPA at pH 3 but failed at pH > 4. At any rate, no mineralization of BPA was achieved with the Fe(III)/UVA system. The presence of carboxylic acids greatly enhanced the BPA degradation rate because of the formation of photoactive Fe(III)-polycarboxylate complexes. Aqueous pH in the 3-7 range exerted a negative effect on the BPA degradation rate and TOC conversion in the presence of oxalic, malic and tartaric acids. Only slight effect of pH was observed in the presence of citric acid, being the BPA degradation rate significant even at pH 7.

Photocatalytic degradation of bisphenol A in a visible light/TiO 2 system

This study evaluates the photodegradation efficiency of bisphenol A (BPA) in a visible light/TiO 2 system. TiO 2 was generated by the sol–gel method and polyethyleneglycol (PEG) was used as a modulator. The effects of the molecular weight of PEG, the addition percentage of PEG, the pH of the solution and the TiO 2 dose were determined. For a given percentage of PEG added, the intensity of anatase followed the order TiO 2/PEG600 > TiO 2/PEG3500 > TiO 2/PEG200. The BPA degradation rates of visible light/TiO 2/PEG200 (10%), visible light/TiO 2/PEG600 (5%) and visible light/TiO 2/PEG3500 (0.5%) at pH 4 were 2.07, 3.01 and 2.90 h − 1 , respectively. After 12 h of reaction, the reductions of TOC in visible light/TiO 2, visible light/TiO 2/PEG200 (10%), visible light/TiO 2/PEG600 (5%) and visible light/TiO 2/PEG3500 (0.5%) systems were 38%, 56%, 65% and 64%, respectively. The concentrations of hydroxyl radicals in visible light/TiO 2, visible light/TiO 2/PEG200 (10%), visible light/TiO 2/PEG600 (5%) and visible light/TiO 2/PEG3500 (0.5%) systems were determined to be 50.1, 88.6, 78.8 and 75.1 μM, respectively. This study finds that adding PEG during the preparation of TiO 2 increased the photoactivity of the generated TiO 2 however, the optimal PEG addition percentage varied with the molecular weight of PEG.

Ozonation of aqueous solution containing bisphenol A: Effect of operational parameters

The degradation of bisphenol A (BPA) in aqueous solution by ozonation was studied. The study was conducted experimentally in a semi-batch reactor under different operational conditions, i.e., varying influent ozone gas concentration, initial BPA concentration, pH, and bicarbonate ion concentration. The results of the study indicated that ozonation could be used to effectively remove BPA from contaminated water. Keeping other operational parameters constant, the rate of BPA degradation linearly increased with ozone dosage. At pH value of 7.0, the second-order rate constants for the reaction of BPA with aqueous ozone were determined as 1.22 × 10 5, 1.71 × 10 5, and 2.59 × 10 5 M −1 s −1 for ozone gas dosages of 1.4, 2.2, and 5.1 mg L −1, respectively. Bicarbonate ion in the range of 1.0–8.0 mM (61–488 ppm) showed no significant effect on BPA degradation for concentrations of BPA used in the study (23.0–57.0 μM). It was also observed that the rate of BPA degradation increased with pH up to 7.0, resulting in rate constants of 0.48 × 10 5, 0.94 × 10 5, and 1.71 × 10 5 M −1 s −1 at pH values of 2.0, 5.0, and 7.0, respectively; and the rate constant decreased to 1.16 × 10 5 M −1 s −1 at pH of 10.0.

Photodegradation of Bisphenol A in the Montmorillonite KSF Suspended Solutions

The commercially available montmorillonite KSF is utilized as efficient acidic catalyst in organic synthesis chemistry. In this study it is used as a photoactive reagent in a heterogeneous system. A series of experiments of the degradation of bisphenol A (BPA) as a model organic pollutant in montmorillonite KSF suspended solutions under UV−vis irradiation (metal halide lamp, λ ≥ 365 nm) were investigated. It is found that BPA could be effectively photodegraded in suspension. The BPA photodegradation is dependent on the pH of the solution and dosage of clay minerals, and it is more effective for BPA to be degraded at pH 4; the degradation rate of BPA increased with the concentration of clays in the range of 0.5 g/L to 5 g/L. The photodegradation rate of BPA is fitted well into the Langmuir−Hinshelwood equation. Results also indicate that the carboxylate and dissolved oxygen could efficiently enhance the degradation rate, and the role of carboxylate in accelerating the photodegradation of BPA follows the order: pyruvate > oxalate > citrate.

Sorption and degradation of bisphenol A by aerobic activated sludge

Laboratory-scale batch experiments were conducted to investigate the sorption and degradation of bisphenol A (BPA) at μg/L range in an aerobic activated sludge system. The sorption isotherms and thermodynamics indicated that the sorption of BPA on sludge was mainly a physical process in which partitioning played a dominating role. The values of sorption coefficient K oc were between 621 and 736 L/kg in the temperature range of 10–30 °C. Both mixed liquor suspended solid (MLSS) and temperature influenced BPA sorption on sludge. The degradation of BPA by acclimated activated sludge could be described by first-order reaction equation with the first-order degradation rate constant of 0.80 h −1 at 20 °C. The decrease of initial COD concentration and the increase of MLSS concentration and temperature enhanced BPA degradation rate. The removal of BPA in the activated sludge system was characterized by a quick sorption on the activated sludge and subsequent biodegradation.

Degradation of bisphenol A and formation of hydrogen peroxide induced by glow discharge plasma in aqueous solutions

Degradation of bisphenol A (BPA) and simultaneous formation of hydrogen peroxide induced by glow discharge plasma in contact with aqueous solution were investigated. Experimental results indicated that the BPA degradation rate was higher in sodium chloride solution than that in sodium sulfate or phosphate solutions. However, the formation rates of hydrogen peroxide were on the opposite case. Both the BPA removal and the hydrogen peroxide production rates decreased in the presence of hydroxyl radical scavengers, indicating that hydroxyl radicals are the most probable oxidants responsible for BPA degradation and the precursors of hydrogen peroxide. Ferric ion showed better catalytic effect than that of ferrous ion, suggesting that the ferric ion was reduced by the intermediates formed during BPA degradation, which was confirmed by following the production of ferrous ion in the system. TOC of the solution gradually reduced with discharge time; however, without catalysts, the solution COD increased with discharge time and sharply decreased in the presence of iron salts. The major intermediate products were identified by LC/MS and the possible degradation mechanism was discussed.

Isolation of bisphenol A-tolerant/degrading Pseudomonas monteilii strain N-502

Bisphenol A (BPA) is a highly biotoxic compound that kills many microorganisms at a low concentration (1,000 ppm). We isolated BPA-tolerant/degrading Pseudomonas monteilii strain N-502 from about 1,000 samples collected from a field, sewage, and pond water. The isolated strain had strong BPA tolerance and high BPA-degrading activity. This strain was able to grow in a minimum medium containing BPA as the sole carbon source. Strain N-502 is an aerobic, motile, gram-negative, nonspore-forming, rod-shaped bacterium and was identified as P. monteilii, based on 16 S rRNA gene analysis. Strain N-502 completely degraded BPA 500 ppm in a 10-day, in culture system and was able to degrade BPA 100 ppm in a 2-h resting cell system. This strain also showed potent ability to degrade BPA 500 and 1,000 ppm in the resting cell system. Moreover, the initial BPA degradation rate was accelerated with the addition of Ca(2+), Mg(2+), and folic acid.

Mechanism of O 2-accelerated sonolysis of bisphenol A

The effects of dissolved gases on the sonochemical degradation of bisphenol A (BPA) were studied at a frequency of 500 kHz. BPA degradation rate increased in the order O 2 > Ar > air > N 2. The rate constant for oxygen (2.6 h −1) was approximately two fold higher than that for argon (1.2 h −1). A primary intermediate (2,3-dihydro-2-methylbenzofuran), a typical intermediate of BPA formed during attack by OH radicals, was detected only in the presence of oxygen, revealing that a different reaction path was responsible for the enhancement of decomposition.

Effect of iron oxides and carboxylic acids on photochemical degradation of bisphenol A

γ-FeOOH was initially prepared by hydrothermal process and then sintered at 280°C, 310°C, and 420°C, and four kinds of iron oxides were obtained and named as lepidocrocite, IO-280, IO-310, and IO-420. They were characterized by XRD, SEM, and BET techniques to disclose the crystal composition, morphology, and surface area. The XRD results show that IO-280 and IO-310 should consist of maghemite and hematite, while IO-420 should be pure hematite. With the increase of temperature, the specific surface area significantly decreased. To test the photocatalytic activity of iron oxides, bisphenol A (BPA) was selected as a model chemical. The results show that BPA photocatalytic degradation should depend strongly on pH value, light source, and the crystal structure of iron oxides and that IO-310 had the highest activity in the absence of oxalic acid under UV or visible light illumination. The dependence of BPA photodegradation on carboxylic acids in lepidocrocite-carboxylate systems was investigated. BPA degradation was promoted greatly by the addition of oxalic and citric acid, and slightly by tartaric, malonic, and malic acid. The first-order kinetic constant (k) of BPA degradation follows the order oxalic\( \ggg \)citric\( \gg \)tartaric>malonic>malic>without acid≈succinic acid. In iron oxide–oxalic acid systems, the reaction rate and efficiency of BPA degradation under UV light was much more than under visible light illumination, and the k value follows the order: lepidocrocite>IO-280>IO-310>IO-420 under both UV and visible illumination. It is concluded that BPA photodegrdation should be dependent on the kind of carboxylic acid, iron oxides, and light sources in iron oxide–carboxylate system. The photochemical investigation of iron oxide–carboxylate complex systems is essential to the full understanding of the interactive mechanism of iron oxides and organic pollutants on the surface of soil in subtropical and tropical regions.

Leaching of bisphenol A (BPA) from polycarbonate plastic to water containing amino acids and its degradation by radical oxygen species

In this study, (1) the change in the concentration of bisphenol A (BPA) leached from polycarbonate plastic (PCP) tube to water samples containing phosphate, sodium barbital, glycine, methionine or albumin at 37 °C as a function of time, and (2) the degradation rate of BPA leached from PCP tube to amino acid solutions in the presence of radical oxygen species (ROS) were investigated. The BPA leaching velocity (BPA-LV) from PCP tube to 50 mM glycine at pH 6 or 7 was twice that to control water, and the leaching was enhanced above pH 8. At pH 11, BPA-LV was significantly higher in 50 mM glycine and methionine solutions than in 50 mM NaOH. These results indicate that basic pH and amino acids contained in water could accelerate BPA leaching. The BPA-LV in phosphate buffer was different from the BPA-LVs in other buffers (barbital and glycine) at the same pH. BPA leached to the glycine or methionine solutions at pH 11 was degraded time dependently in a similar manner as the control water in the presence of ROS. The degradation of leached BPA was inhibited in the glycine solution, but was accelerated in the methionine solution. However, degradation of BPA added to freshly prepared methionine was inhibited in a similar manner to BPA in glycine. BPA degradation could be influenced by some kinds of amino acids, but glycine and methionine might be involved in BPA degradation in different ways.