Removal Rate Of EE2 Research Articles

Visible-light-driven Bi2WO6/biochar composite photocatalyst efficiently degrades 17α-ethinylestradiol (EE2) and 17β-estradiol (E2) under persulfate synergy

Biochar (BC) composite photocatalysts have attracted much attention by virtue of their high efficiency in removing endocrine disruptors (EDCs). However, there has been a lack of systematic research on the mechanism and constitutive relationship of BC on photocatalysts, which has seriously impeded the development process in this field. In this study, Bi2WO6–BC2% composite photocatalysts were prepared by microwave-assisted hydrothermal method and used for degradation of 17α-ethinylestradiol (EE2) and 17β-estradiol (E2) in conjunction with persulfate synergy (PS). The removal rate of EE2 and E2 by Bi2WO6–BC2% was as high as 99.41 % (12 min) and 97.84 % (15 min), respectively. Systematic studies have shown that BC enhances the catalytic activity mainly through the following ways, increasing the specific surface area of the photocatalytic system, enriching the types of functional groups, enhancing the separation ability of photogenerated electron–hole pairs, and promoting the concentration of active free radicals. The results of the phytotoxicity experiments showed that compared to the EE2 or E2 pollutant solutions, the stem and root lengths of V. radiata increased by 93.63 % and 389.58 % in EE2 metabolites, and by 117.35 % and 160.38 % in E2 metabolites. Similarly, the stem and root lengths of P. vulgaris increased by 80.08 % and 174.91 % in EE2 metabolites, and by 188.92 % and 345.75 % in E2 metabolites. This work not only fills the gap in the study of the mechanism of action of BC, but also provides a green catalyst with very excellent photocatalytic efficiency and detoxification properties.

Controlling wettability of AgI/BiVO4 composite photocatalyst and its effect on photocatalytic performance

Abstract We report a simple method to modify the surface of 1:1 AgI/BiVO4 composites with 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (PFDS), 3-(methacryloyloxy)propyltrimethoxysilane (KH-570), and trimethylchlorosilane (TMCS). The physical and chemical properties of the photocatalysts before and after modification were characterized by XRD, XPS, SEM, FT–IR, UV–vis DRS, and water contact angle (WCA) measurements. After the modification, the WCA of the 1:1 AgI/BiVO4 composites increased from 34.0° to 95.0° (0.11 PFDS), 57.3° (3.5 KH-570), and 57.0° (2.5 TMCS). The surface with controllable wettability was obtained by optimizing the amount of modifier. The removal rate of 17α-ethinyl estradiol (EE2) was significantly increased within a certain range of wettability. The WCA ranges of 1:1 AgI/BiVO4 composites modified by PFDS, KH-570, and TMCS were 68.3–75.8°, 42.0–52.3°, and 42.0–54.7°, respectively, and the removal rate of EE2 was significantly higher. The photocatalytic activity was the best when the WCAs were 75.8° (0.05 PFDS), 51.0° (2.0 KH-570), and 48.1° (1.3 TMCS), and the removal rates of EE2 in 20 min under visible light were 90.0%, 92.9%, and 99.4%, respectively. These values were significantly better than those of unmodified 1:1 AgI/BiVO4 composite (74.7%) and pristine BiVO4 (8.4%). The results show that appropriate wettability improves photocatalytic activity.

Fabrication of the AgI/BiOI/BiPO4 multi-heterojunction with high photocatalytic activity

17α-acetylestradiol (EE2) as an environmental endocrine disruptor (EDCs) with strong estrogenic effect and stable chemical properties. Water treatment technologies involving photocatalytic decomposition of pollutants technology are widely used to degrade pollutants in water, having excellent research value and good applicability prospects. A series of photocatalysts (AgI/BiOI/BiPO4, AgI/BiOI and AgI/BiPO4) were prepared by a ion exchange route at room temperature and analyzed by different characterization methods. The results showed that AgI/BiOI/BiPO4 exhibited excellent properties: (1) improved visible light photoresponse, (2) improved stability and (3) reduced recombination rate of electron-hole pairs. AgI/BiOI/BiPO4 showed excellent photodegradation activity for the 17α-ethynylestradiol (EE2): The removal rate of EE2 was close to reach 100 % in 8 min under visible light. The value of reaction rate constant of AgI/BiOI/BiPO4 (2:2:2) was 11.5, 5.6, 2.5 and 1.7 times higher than AgI, BiOI, AgI/BiOI, and AgI/BiPO4, respectively. Finally, the possible photocatalytic mechanism of the AgI/BiOI/BiPO4 multiheterojunction was proposed.

Combined effect of ryegrass and Hyphomicrobium sp. GHH on the remediation of EE2-Cd co-contaminated soil

PURPOSE: Irrigation and fertilization accelerate the accumulation of environmental hormones such as 17α-Ethinyestradiol (EE2) and heavy metals such as Cd in soil, which in turn harms crops and human health. The objective of this study was to investigate the interaction of the plant ryegrass and EE2 degrading bacteria Hyphomicrobium sp. GHH on the remediation of EE2-Cd co-contaminated soil. MATERIALS AND METHODS: The concentration of EE2 in soil was set as 25 mg kg⁻¹, and the concentration of Cd was set as 0, 5, 20, and 80 mg kg⁻¹, respectively. Pot experiments were carried out to investigate the control treatment without GHH inoculation and/or ryegrass cultivation (C), GHH inoculation alone (B), ryegrass cultivation alone (P), and combined use of ryegrass with GHH (B + P) on the EE2 and Cd removal from soil. The plant biomass, EE2 and Cd concentration in root and shoot of ryegrass, the bioconcentration factor (BCF), translocation factor (TF), phytoextraction efficiency of EE2 and Cd, and removal rate of EE2 and Cd from soil, as well as the soil urease activity and microbial biomass carbon (MBC) content, were determined to evaluate the interaction of plant and microbe on the soil remediation. RESULTS AND DISCUSSION: After 28 days of treatment, in soil with spiked Cd at 5, 20, and 80 mg kg⁻¹, the removal rate of EE2 from soil was: B + P > P > B > C; the effect on the Cd removal was B + P > P, while Cd cannot be removed by microbes directly. In B + P treatment, the removal rate was 89%, 80%, and 71%, respectively for EE2, and 0.81%, 0.43%, and 0.38% respectively for Cd. EE2 and Cd were mainly stored in root of ryegrass because that all the TFs were P > B > C. 5 mg kg⁻¹ Cd increased soil urease activity and MBC content, and promoted the root growth. However, soil Cd at the concentration > 20 mg kg⁻¹ caused irreparable harm to ryegrass and microorganisms; as the consequence, the EE2 extraction by plant significantly decreased (P < 0.05). CONCLUSIONS: The combined use of ryegrass with GHH was effective to remediate the EE2-Cd co-contaminated soil.

The TiO2 (B) nano-belts with excellent performance prepared via alkaline stirring hydrothermal method and its application to remove 17α-ethynylestradiol.

In this work, TiO2 (B) nano-belts were synthesized by hydrothermal method under stirring, and static conditions and preparation conditions were optimized. The prepared materials were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), photoluminescence spectroscopy (PL), and N2 adsorption/desorption measurement. The photocatalytic performance was evaluated by removing synthetic estrogen 17α-ethynylestradiol (EE2), which is the most potent endocrine-disrupting chemical. The results show that the TiO2 nano-belt possesses pure metastable monoclinic TiO2 (B) and has uniform nano-belt shape with 80~120-nm diameters and 62.904m2g-1 of specific surface area. Under the best optimal preparation conditions (0.5g P25, 20mL 10molL-1 NaOH, hydrothermal temperature 180°C for 18h under stirring, 400°C calcination for 2h), the TiO2 (B) has better catalytic activity with 100.00% removal rate towards 3mgL-1 EE2 in 120min. The removal rates of EE2 over catalyst which was prepared under static condition and P25 are 74.66% and 70.71%, respectively. The photocatalytic degradation rate constant of TiO2 (B) prepared under stirring condition (0.0379min-1) is 4.51 times and 8.42 times than those of TiO2 prepared under static condition (0.0084min-1) and P25 (0.0045min-1). The excellent photocatalytic activity is mainly ascribed to longer one-dimensional nano-belt structure and effective suppression of photo-produced electron-hole.

Influence of natural organic matter on horseradish peroxidase-mediated removal of 17α-ethinylestradiol: Role of molecular weight

Ubiquitous natural organic matter (NOM) plays a crucial role in the peroxidase-mediated transformation of phenolic pollutants in aquatic environment. As a poorly defined polydispersed mixture of assorted organic substances with wide molecular weight (MW) distribution, NOM has far prevented researchers from finding out the primarily responsible components for the specific effect. In this work, MW fractionated NOMs (Mf-NOMs) were used to investigate their roles on horseradish peroxidase (HRP)-mediated transformation of 17α-ethinylestradiol (EE2). The removal rate of EE2 was restrained in the presence of pristine or Mf-NOMs, and the inhibitory mechanism was MW-dependent. Low Mf-NOMs restrained the enzymatic reaction by acting as competitive substrates, while high Mf-NOMs retained freely dissolved EE2 which reduced its availability for enzymatic reaction. The contribution of these two processes to the inhibition induced by pristine NOM was further quantified and found to be relevant to the reaction conditions, especially EE2 concentration. The findings of this work reveal more complex influences of NOM on the enzymatic reaction than ever demonstrated, which aids in understanding the fate of EE2 and other congener contaminants in natural and municipal water.

Preparation and characterization of CdS/BiOI composites with enhanced photocatalytic activity for degradation of 17α-ethinyl estradiol

A novel CdS/BiOI composite has been prepared via a chemical bath deposition method. The physical and chemical properties of as-prepared composites were characterized by XRD, SEM, TEM, EDS, XPS, UV–vis DRS, and PL. The synthesized CdS/BiOI composites exhibited superior photocatalytic activity in photodegrading of 17α-ethinyl estradiol (EE2) compared to pure CdS and pure BiOI, and the removal rate of EE2 could approach 100% after only 12 min of visible light irradiation using 3:1 CdS/BiOI composite as photocatalyst. The reaction rate constant over 3:1 CdS/BiOI composite was 6.3, 7.1 and 70.9 times higher than that of pure CdS, pure BiOI and P25 respectively. In addition, a Z-scheme charge separation mechanism was proposed on the basis of the experimental results and the theoretical calculation. Moreover, the prepared composite showed good stability and recyclability which are beneficial for its practical application.

Removal of 17α-ethynylestradiol from aqueous solutions by a hybrid PAC/UF process

This study investigated the removal of 17α-ethynylestradiol (EE2) from water using activated carbon adsorption and powdered activated carbon/ultrafiltration (PAC/UF). EE2 was easily adsorbed by PAC. The adsorption of EE2 fitted the Freundlich model well. The influences of initial EE2 concentration, filtration rate, PAC dose, natural organic matter (NOM), and sodium dodecyl benzene sulfonate (SDBS) were investigated. The EE2 concentration and filtration rate had no significant effect on EE2 removal, whereas the addition of PAC had a significant effect on EE2 removal. The removal rate of EE2 increased dramatically from 7.01% to 80.03% as the PAC dose was increased from 0 to 10 mg/L. Both SDBS and NOM decreased the EE2 removal efficiency. The removal efficiency of EE2 in the PAC/UF process decreased from 86.77% to 42.64% as the SDBS concentration was increased from 0 to 50 mg/L. It was concluded that activated carbon adsorption and PAC/UF can be used for the effective removal of EE2 from water.

Nitrate‐dependent degradation of 17α‐ethinylestradiol by acclimated activated sludge under anaerobic conditions

AbstractBACKGROUND: The synthetic estrogen 17α‐ethinylestradiol (EE2) is of great environmental concern. Batch experiments were conducted to investigate the removal of EE2 by activated sludge under anaerobic conditions with or without nitrate. The effect of temperature on EE2 removal was also estimated.RESULTS: No biodegradation of EE2 was observed in the absence of nitrate; owing to sorption onto the activated sludge, the overall removal EE2 rate was 62%; the sorption was fitted to both Freundlich and linear sorption models; the sorption rate decreased with the increase temperature. In the presence of nitrate, the overall removal rate of EE2 was greater than 97% after 72 h, mostly from biodegradation (95%); the biodegradation could be described by first‐order reaction kinetics with average rate constant of 0.0344 h−1; increasing temperature enhanced the rate constant and the removal rate could be as high as 96–98% in the temperature range 10–30 °C.CONCLUSION: EE2 was removed by activated sludge under anaerobic conditions. In the absence of nitrate, the removal of EE2 was a result of sorption onto activated sludge. In the presence of nitrate, biodegradation was the dominant process for EE2 removal. Higher temperature improves biodegradation rate, but reduces the sorption of EE2 onto activated sludge. Copyright © 2009 Society of Chemical Industry