Adsorption Of Tetrabromobisphenol A Research Articles

Pd/Uio-66/Ti Electrode for Electrocatalytic Debromination of Tetrabromobisphenol a

Metal organic frameworks (MOFs) have engendered great interest due to their high surface areas, tunable porous size, and functionalities. They are explored in a wide range of applications including absorption, gas storage or separation, catalysis, biomedicine and drug delivery. Presently, a large number of reports appraise the application of MOFs in the field of electrochemistry, from rechargeable batteries, supercapacitors to fuel cells. Among these various metal organic frameworks, UiO-66 as a type of highly stable zirconium-based MOF linking by 1,4-benzenedicarboxylate (BDC), has been extensively studied. It is reported that UiO-66 demonstrates high structural stability in water medium, thus, it shall be a feasible strategy to incorporate UiO-66 with other functional materials for the applications in aqueous medium, water treatment and water splitting for instance. Herein, palladium nanoparticles supported UiO-66 was fabricated on Ti plate electrode (Pd/UiO-66/Ti) in this study. White UiO-66, as a bridging layer with controlled size and thickness, was first deposited on Ti plate via an electrochemical film deposition method. UiO-66/Ti plates of different thickness were acquired by changing the ratio of electrochemical deposition solution. Pd/UiO-66/Ti was further made by dipping Pd2+ solution onto the UiO-66 surface and then reduced by impregnating in 0.1 % NaBH4 solution for two hours. The obtained dark Pd/UiO-66/Ti electrode was characterized by X-ray diffraction (XRD). And the electrochemical properties of the Pd/UiO-66/Ti cathode electrode were investigated through cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The results revealed that UiO-66 films with different thickness were successfully deposited on the Ti cathodes (UiO-66/Ti), Pd particles well dispersing on the surface of the UiO-66/Ti. The electro-catalytic performance was evaluated by electrocatalytic debromination of 5 mg/L tetrabromobisphenol A (TBBPA) in a 200 mL vessel, containing Pd/UiO-66/Ti as cathode, graphite as anode at a current of 6.67 mA/cm2. It was found that degradation rate of TBBPA was 80% within 60 min by Pd/ UiO-66/Ti cathode electrode. The excellent electro-catalytic performance could be ascribed to the adsorption of TBBPA on UiO-66 and the reaction with hydrogen at the palladium/UiO-66 interface. The results indicated that Pd/UiO-66/Ti should be a promising cathode for the application on electrochemical.

Effects of hydrodynamic disturbances and resuspension characteristics on the release of tetrabromobisphenol A from sediment

Tetrabromobisphenol A (TBBPA) exists widely in river and lake sediments; it has raised growing attention in recent years as emerging contaminant due to its possible threats to the aquatic environment and human health. Using a specialized simulator, the relationships between hydrodynamic disturbances and resuspension characteristics were simulated, with an emphasis on microscopic characteristics. Furthermore, TBBPA release from sediment was studied in relation to hydrodynamic disturbances and resuspension characteristics. The results show that stronger water disturbances caused an increase in suspended solids concentration (SSC) and produced different behaviors of particle size distribution (PSD) and media diameter (D50) in the slight and large-scale resuspension situations. As for microscopic resuspension characteristics, the specific surface area (SSA) of suspended particulate matter (SPM) was very different from that of smooth particles. This difference may result from the fractal nature of the SPM. The fractal dimension (FD) of SPM was found to have a significant correlation with turbulent kinetic energy. TBBPA release into overlying water and adsorption onto SPM both increased with hydrodynamic disturbances; but the release into overlying water is more dominant. The TBBPA concentrations in SPM under different hydrodynamic conditions were significant related to SSA, indicating that SSA is a key factor affecting the TBBPA adsorption capacity of SPM. TBBPA concentrations in sediment decreased slightly with the increased hydrodynamic dispersion. Findings from this research show the importance of considering the hydrodynamic disturbance and resuspension characteristics in understanding TBBPA release behavior in aquatic environment.

Pd/mesoporous carbon nitride: A bifunctional material with high adsorption capacity and catalytic hydrodebromination activity for removal of tetrabromobisphenol A

Palladium loaded mesoporous carbon nitride (Pd/MCN) with high adsorption capacity and excellent catalytic hydrodebromination activity was used for removal of tetrabromobisphenol A (TBBPA). The adsorption kinetic of TBBPA on Pd/MCN-x followed the pseudo-second-order kinetic model and the adsorption isotherm could be described by Langmuir adsorption model. The pore structure and surface functional groups of Pd/MCN-x could be optimized by calcination at different temperatures. The Pd/MCN-900 catalyst exhibited the highest TBBPA adsorption capacity of 242.1mg/g, which was 2⿿10 times larger than previous values achieved by other researchers. Both hydrophobic interaction and Ͽ-Ͽ interaction were responsible for the adsorption and the solution pH and coexisting ions had little influence on the adsorption. The catalytic hydrodebromination results showed that the TBBPA could be was completely debrominated to BPA over Pd/MCN-x and the catalytic activity of Pd/MCN-x was positive correlated to the adsorption behavior of TBBPA. The high adsorption capacity and catalytic hydrodebromination activity of Pd/MCN-x made it suitable for the treatment of TBBPA.

Novel N-doped CNTs stabilized Cu2O nanoparticles as adsorbent for enhancing removal of Malachite Green and tetrabromobisphenol A

A newly designed N-doped CNTs stabilized Cu2O nanoparticles (PVP@CNTs-Cu2O) were fabricated and used to remove organic pollutants such as Malachite Green (MG) dye and tetrabromobisphenol A (TBBPA). The introduction of PVP here not only could stabilize Cu2O nanoparticles, but also act as active sites for adsorption of organic pollutants. The hybrid mesoporous adsorbent exhibited excellent adsorption performances for MG and TBBPA, which were mainly because of the synergistic effects of inorganic species and polymer. The maximum adsorption capacities of MG and TBBPA by PVP@CNTs-Cu2O were 1495.46 and 116.72mg/g, respectively, significantly higher than pristine CNTs (417.58 and 68.03mg/g, respectively). The adsorption of MG was independent of ionic strength. In contrast, the increase in ionic strength significantly inhibited the adsorption of TBBPA. Freundlich isotherm model fitted well with the experimental data of both MG and TBBPA adsorption, indicating the heterogeneous surface of PVP@CNTs-Cu2O. PVP@CNTs-Cu2O demonstrated rapid adsorption rates for both MG and TBBPA, and their adsorption kinetics were analyzed by the pseudo-first-order, pseudo-second-order and Elovich kinetic models. The possible mechanisms of MG and TBBPA adsorption was further explored by means of FTIR and XPS. High adsorption capacity, rapid kinetics, good reusability as well as simple preparation were important advantages for the practical application in MG and TBBPA removal by PVP@CNTs-Cu2O.

Insights into tetrabromobisphenol A adsorption onto soils: Effects of soil components and environmental factors

Concerns regarding tetrabromobisphenol A (TBBPA), the most widely utilized brominated flame retardant in the world, are growing because of the wide application and endocrine-disrupting potential of this compound. To properly assess its environmental impacts, it is important to understand the mobility and fate of TBBPA in soil environments. In this study, the effects of soil components, dissolved organic carbon (DOC) and heavy metal cations on TBBPA adsorption onto two Chinese soils (red soil and black soil) were investigated using batch sorption experiments. The desorption behavior of TBBPA when the two soils are irrigated with eutrophicated river water was also investigated. The results showed that pH greatly affects the adsorptive behavior of TBBPA in soils. Iron oxide minerals and phyllosilicate minerals are both active surfaces for TBBPA sorption, in addition to soil organic matter (SOM). DOC (50mgOCL−1) exhibited a limited effect on TBBPA sorption only under neutral conditions. TBBPA sorption was only minimally affected by the heavy metals (Cu2+, Pb2+ and Cd2+) in the studied pH range. Eutrophicated river water significantly enhanced the desorption of TBBPA from red soil due to the change in soil solution pH. These findings indicate that mobility of TBBPA in soils is mainly associated with soil pH, organic matter and clay fractions: it will be retained by soils or sediments with high organic matter and clay fractions under acidic conditions but becomes mobile under alkaline conditions.

Sorption enhancement of TBBPA from water by fly ash-supported nanostructured γ-MnO2

Tetrabromobisphenol A (TBBPA), an emerging contaminant, has been detected frequently in the environmental media. This study reports the adsorption kinetics, equilibrium and thermodynamics of TBBPA on fly ash modified by nanostructured MnO2 (FA@nM). The resulting nano-adsorbent was characterized by means of the Fourier transform infrared spectra (FT-IR), XRD and scanning electron microscope (SEM). The adsorption results showed that the equilibrium adsorption capacity has been significantly improved by increasing the initial TBBPA concentration and contact time. While a large reduction of TBBPA uptake was observed in alkaline conditions and at high temperatures and ionic strength. The equilibrium between TBBPA and FA@nM was achieved in approximately 40min with removal of 98% of the TBBPA. The sorption kinetics were well described by a pseudo-first-order rate model, while both Langmuir and Freundlich models described the sorption isotherms well at 298K. Thermodynamic parameters suggested that the adsorption of TBBPA is exothermic and spontaneous at the temperatures studied. As fly ash is a low-cost material that is often available on-site, it offers an interesting alternative to high-cost advanced wastewater treatment systems for removing such organic pollutants.

Development of carbon nanotubes/CoFe2O4 magnetic hybrid material for removal of tetrabromobisphenol A and Pb(II)

Multi-walled carbon nanotubes (MWCNTs) coated with magnetic amino-modified CoFe2O4 (CoFe2O4–NH2) nanoparticles (denoted as MNP) were prepared via a simple one-pot polyol method. The MNP composite was further modified with chitosan (CTS) to obtain a chitosan-functionalized MWCNT/CoFe2O4–NH2 hybrid material (MNP–CTS). The obtained hybrid materials were characterized by Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectrogram (FT-IR) Analysis and X-ray Photoelectron Spectroscopy (XPS) Analysis, Vibrating Sample Magnetometer (VSM) Analysis and the Brunauer–Emmett–Teller (BET) surface area method, respectively. The composites were tested as adsorbents for tetrabromobisphenol A (TBBPA) and Pb(II), and were investigated using a pseudo-second-order model. The adsorption of TBBPA was well represented by the Freundlich isotherm; the Langmuir model better described Pb(II) absorption. MNP–CTS adsorbed both TBBPA and Pb(II) (maximum adsorption capacities of 42.48 and 140.1mgg−1, respectively) better than did MNP without CTS. Magnetic composite particles with adsorbed TBBPA and Pb(II) could be regenerated using 0.2M NaOH solution and were separable from liquid media using a magnetic field.

Adsorption of tetrabromobisphenol A on soils: Contribution of soil components and influence of soil properties

The adsorption of tetrabromobisphenol A (TBBPA) on several typical Chinese soils and soil mineral and organic components were comprehensively investigated in the present study. The adsorption isotherms were well described by the Freundlich equation and the corresponding adsorption capacity constant Kf ranged from 2.46 to 357.30L/kg and 16.52 to 136,731.98L/kg for the original soils and the soil components, respectively. Correlation analysis between the adsorption capacity and soil properties indicates that soil pH and soil organic carbon (SOC) content were the predominant factors determining TBBPA adsorption on the soils. At constant pH of 7.0, the soils with higher SOC content exhibited stronger adsorption affinity for TBBPA, suggesting the significant importance of SOC in the adsorption. The adsorption affinity of TBBPA became weaken for a given soil with increasing pH due to the enhanced electrostatic repulsion between the anionic TBBPA species and soil surface. Humins and black carbon of SOC played a predominant role in while soil minerals contributed slightly to the adsorption of TBBPA on the soils. The results of this study will provide a better understanding of the behaviors of TBBPA in soils.