Tetrabromobisphenol A Removal Research Articles

Efficient removal of tetrabromobisphenol A (TBBPA) using sewage sludge-derived biochar: Adsorptive effect and mechanism

Sewerage sludge-derived biochars (SSDBCs) with high adsorption capacity and excellent recyclability were synthesized to remove tetrabromobisphenol A (TBBPA) in aqueous system. Scanning electron microscopy, elemental mapping via energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy were used to characterize the morphology, composition, and microstructures. The maximum adsorption capacity of SSDBCs was about 87.02 mg g−1 at 303 K and pH 7.5. The Langmuir isotherm demonstrated that the adsorption was mainly homogeneous and chemical processes. The kinetics of TBBPA removal well fitted the second-order dynamic model. Thermodynamic analysis showed that the adsorption was exothermic. The effect of π−π dispersive force and hydrogen bonding was proven as the main adsorption mechanism. Multiple cycle runs experiment revealed the excellent stability of recycled SSDBCs. This work provided a promising method of sludge resourceful treatment using an efficient, economic, cyclic, and convenient material for typical organic contaminant in the environment.

Efficient removal of tetrabromobisphenol A using microporous and mesoporous carbons: The role of pore structure

Abstract Tetrabromobisphenol A (TBBPA) is a widely used flame retardant yet a persistent pollutant in the environment. In this study, various microporous and mesoporous carbon-based materials were synthesized and their adsorption performance toward TBBPA was systematically evaluated. The adsorbents were characterized by transmission electron microscope, scanning electron microscope, X-ray diffraction, Raman spectroscopy, N2 adsorption/desorption and Zeta potential measurements. TBBPA adsorption over coal-based activated carbon (F300), coconut-shell-based activated carbon (AC) and CMK-3 followed Freundlich adsorption model, while TBBPA adsorption over zeolite-templated carbon (ZTC), single-walled carbon nanotube (SWNT) and multiwalled carbon nanotube (MWNT) could be well described by both Freundlich model and Langmuir model. Compared with F300 and AC, TBBPA diffusion on ZTC and CMK-3 is faster because of their ordered pore structure and higher average pore size. The surface-area-normalized adsorption capacity of TBBPA was higher on ZTC, AC and F300 than on CMK-3, SWNT and MWNT, which can be attributed to the stronger micropore-filling effect with the microporous carbonaceous materials. The presence of humic acids had little effect on TBBPA sorption over ZTC, F300, CMK-3 and AC, while suppressed TBBPA adsorption on SWNT and MWNT were observed. In the column adsorption test, ZTC was capable of continuously treating synthetic wastewater stream, indicating that ZTC had great potential to be used as an effective adsorbent for TBBPA removal.

Synthesis and characterization of Ag‐loaded p‐type TiO2 for adsorption and photocatalytic degradation of tetrabromobisphenol A

A p-type TiO2 with Ti vacancies (D-TiO2 ) was synthesized by a facile solvothermal treatment, and Ag/TiO2 with different Ag loading amount was prepared through a photo-reduction deposition method. The samples were characterized through scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The adsorption and photocatalytic characteristics of tetrabromobisphenol A (TBBPA) on D-TiO2 and Ag/TiO2 were investigated. The adsorption of TBBPA on Ag/TiO2 was significantly enhanced and was five times greater than that of pure TiO2 . The increase in pH significantly inhibited the adsorption of TBBPA. The 2%-Ag/TiO2 nearly completely degraded TBBPA in 10min under UV-Vis light (λ>360nm), and the apparent reaction rate constant (kapp ) reached 0.63min-1 . The significantly enhanced UV-Vis light catalytic properties of the Ag/TiO2 in comparison with that of TiO2 were attributed to the increased adsorption capacity and electron transfer ability of the Ag/TiO2 . Free radical trap experiments results showed that holes and superoxide radicals play a major role in the catalytic degradation of TBBPA by Ag/TiO2 . Moreover, the Ag/TiO2 catalyst exhibits high stability during TBBPA degradation even after three cycles. PRACTITIONER POINTS: Ti-defected TiO2 and Ag/TiO2 were synthesized using a solvothermal and photo-reduction deposition, respectively. Ag/TiO2 exhibited outstanding adsorption and photocatalytic activity for TBBPA removal under UV-Vis light. Holes and superoxide radicals play a major role inthe photocatalytic degradation of TBBPA.

Effect of mangrove species on removal of tetrabromobisphenol A from contaminated sediments.

The increase levels of tetrabromobisphenol A (TBBPA) in mangrove wetlands is of concern due to its potential toxic impacts on ecosystem. A 93-day greenhouse pot experiment was conducted to investigate the effects of mangrove plants, A.marina and K.obovata, on TBBPA degradation in sediment and to reveal the associated contributing factor(s) for its degradation. Results show that both mangrove species could uptake, translocate, and accumulate TBBPA from mangrove sediments. Compared to the unplanted sediment, urease and dehydrogenase activity as well as total bacterial abundance increased significantly (p<0.05) in the sediment planted with mangrove plants, especially for K.obovata. In the mangrove-planted sediment, the Anaerolineae genus was the dominant bacteria, which has been reported to enhance TBBPA dissipation, and its abundance increased significantly in the sediment at early stage (0-35 day) of the greenhouse experiment. Compared to A.marina-planted sediment, higher enrichment of Geobater, Pseudomonas, Flavobacterium, Azoarcus, all of which could stimulate TBBPA degradation, was observed for the K.obovata-planted sediment during the 93-day growth period. Our mass balance result has suggested that plant-induced TBBPA degradation in the mangrove sediment is largely due to elevated microbial activities and total bacterial abundance in the rhizosphere, rather than plant uptake. In addition, different TBBPA removal efficiencies were observed in the sediments planted with different mangrove species. This study has demonstrated that K.obovata is a more suitable mangrove species than A.marina when used for remediation of TBBPA-contaminated sediment.

Rapid removal of tetrabromobisphenol A by α-Fe2O3-x@Graphene@Montmorillonite catalyst with oxygen vacancies through peroxymonosulfate activation: Role of halogen and α-hydroxyalkyl radicals

We employed hydrolyzed iron-pillared montmorillonite/tetracycline complex (FeOOH-Mt-TC) as precursor to prepare iron oxide@Graphene@Montmorillonite composite (α-Fe2O3-x@Graphene@Mt) through pyrolysis strategy under nitrogen atmosphere. During the pyrolysis process, the involvement of hydrolyzed iron (FeOOH) and TC made the α-Fe2O3-x@Graphene@Mt composite have superior conductivity, higher percent of structural Fe(II) and abundant oxygen vacancies, resulting in highly-efficient degradation of tetrabromobisphenol A (TBBPA) in the presence of PMS. Meanwhile, O2•− played the leading role in the oxidation process when compared with •OH, SO4•− and 1O2. In addition, the released Br− from TBBPA and the addition of alcohol led to the formation of reactive halogen and α-hydroxyalkyl radicals, which contributed to the rapid removal of TBBPA. This study not only provided a novel strategy to prepare excellent iron-based catalysts for PMS activation, but also evaluated the application of reactive halogen and α-hydroxyalkyl radicals in the treatment of halogenated organic pollutants.

Facile synthesis of hydroxyl enriched microporous organic networks for enhanced adsorption and removal of tetrabromobisphenol A from aqueous solution

Here we report the rational design and facile synthesis of hydroxyl-enriched microporous organic networks (MON-OH and MON-2OH) for enhanced and efficient adsorption and removal of a typical brominated flame retardant tetrabromobisphenol A (TBBPA) from aqueous solution. Introducing of hydroxyl groups into MONs’ networks lead to the significant improvement of their hydrophilicity and adsorption capacity for TBBPA. Rely on the good hydrophobicity and predesigned hydrogen bonding sites, the synthesized MON-2OH gave a large adsorption capacity of 326.8 mg g−1 for TBBPA, which is much higher than MONs and many other reported sorbents. The adsorption of TBBPA on MON-2OH followed Langmuir and pseudo-second-order kinetic adsorption models. The TBBPA adsorption capacity was independent on ionic strength (0–30 mg g−1), humic acid (0–40 mg g−1) and pH (5.0–8.0). MON-2OH also gave good stability and reusability and owned good practicability for the removal of TBBPA from wastewater samples. Efficient adsorption and removal of other biphenol pollutants was also achieved on MON-2OH. The adsorption mechanisms of TBBPA on MON-2OH were also well elucidated. This work provides a promising way to design and synthesize efficient adsorbents for TBBPA, which may also promote the design, synthesis and application of functionalized MONs in environmental and material science.

Core–Shell Magnetic Amino-Functionalized Microporous Organic Network Nanospheres for the Removal of Tetrabromobisphenol A from Aqueous Solution

Development of functional porous materials for efficient elimination of environmental pollutants is of great importance in green chemistry and environmental protection. Here we report the design, synthesis, and application of a core–shell magnetic amino-functionalized microporous organic network nanosphere (Fe3O4@MON-NH2) for efficient magnetic adsorption of a typical brominated flame-retardant tetrabromobisphenol A (TBBPA) from aqueous solution. By integration of the hydrophobic networks and hydrogen binding sites within MON-NH2, the synthesized core–shell Fe3O4@MON-NH2 nanospheres gave good adsorption for TBBPA. The adsorption equilibrium of TBBPA (50 mg L–1) on Fe3O4@MON-NH2 was achieved within 1 min, showing ultrafast adsorption kinetics of Fe3O4@MON-NH2 for TBBPA. The adsorption of TBBPA on Fe3O4@MON-NH2 followed the pseudo-second-order kinetics and Langmuir adsorption models, giving a maximum adsorption capacity of 135.9 mg g–1 at 25 °C. The adsorption of TBBPA on Fe3O4@MON-NH2 was a spontaneous and endothermic process controlled by positive entropy. Encouraged by the large adsorption capacity, rapid adsorption kinetics, and the small effect of pH (5–10), dissolved organic matter, and ionic strength on the adsorption, the application of Fe3O4@MON-NH2 for TBBPA removal in real water samples was achieved. The used Fe3O4@MON-NH2 can be easily regenerated and reused at least four times without significant reduction of the adsorption capacity. These results revealed the potential of Fe3O4@MON-NH2 for adsorption and removal of environmental pollutants from aqueous solution.

Room-temperature synthesis of microporous organic network for efficient adsorption and removal of tetrabromobisphenol A from aqueous solution

Development of energy-saving and rapid strategies to synthesize novel porous materials for efficient adsorption and removal of environmental pollutants is of great challenge and interest either in environmental science or in chemistry. Here we report a facile room temperature stirring method for rapid synthesis of microporous organic networks (MONs) with large surface area, excellent hydrophobicity, good thermal and solvent stabilities for efficient adsorption and removal of a typical brominated flame retardant tetrabromobisphenol A (TBBPA) from aqueous solution. The adsorption kinetics, isotherms and thermodynamics, effects of pH, ionic strength, humic acid, regeneration and reusability of MONs for TBBPA were studied in detail. The adsorption of TBBPA on MONs followed the pseudo-second-order kinetic and Langmuir adsorption models. Rely on the good π-π and hydrophobic interaction between MONs and TBBPA, a maximum adsorption capacity of 227.3 mg g−1 was realized, which is the largest adsorption capacity for TBBPA among all the reported sorbents up to date now. The large adsorption capacity, rapid adsorption kinetics, good stability and reusability make MONs a highly potential adsorbent for TBBPA removal from aqueous solution. This work may also promote the synthesis and application of MONs in pollutants’ removal.

Identification of novel pathways for biotransformation of tetrabromobisphenol A by Phanerochaete chrysosporium, combined with mechanism analysis at proteome level

The investigation of tetrabromobisphenol A (TBBPA) removal by Phanerochaete chrysosporium (P. chrysosporium) was conducted. Under optimal conditions (pH 5, inoculum size of 5% (v/v), initial glucose concentration of 5 g/L, TBBPA concentration of 5 mg/L), >97% of initial TBBPA was removed after 3 days. The TBBPA metabolites, tetrabromobisphenol A glycoside, tribromobisphenol A glycoside and monohydroxylated tetrabromobisphenol A, were identified for the first time by fungi transformation as being produced by glycosylation and oxidative hydroxylation, respectively. Proteome analysis showed that P. chrysosporium significantly upregulated cytochrome P450 monooxygenase, glutathione S-transferases, UDP-glucosyltransferase, O‑methyltransferase and other oxidoreductases for TBBPA oxidative hydroxylation, reductive debromination, glycosylation, O‑methylation and oxidative cleavage for detoxification. Data from cytotoxicity tests with human hepatocellular liver carcinoma (HepG2) confirmed that TBBPA toxicity was effectively decreased by P. chrysosporium treatment. Bioaugmentation with P. chrysosporium significantly improved the removal efficiency of TBBPA in water microcosms to 63.1% within 12 h. This study suggests that P. chrysosporium might be suitable for the removal of TBBPA from contaminated water.

Application of a novel gene encoding bromophenol dehalogenase from Ochrobactrum sp. T in TBBPA degradation

Tetrabromobisphenol-A (TBBPA), a typical brominated flame retardant, leaked from commercial products into the environments has attracted people's attention around the world. Ochrobactrum sp. T capable of degradation and mineralization of TBBPA was isolated in our early work. In this study, the identification of TBBPA-degrading gene from the strain was further carried out by combining whole-genome sequencing with gene cloning and expression procedures. In total, 3877 open reading frames were found within 3.9 Mb genome and seven of them were identified as dehalogenating-relating genes. One gene with a significant ability to degrade TBBPA was designated as tbbpaA. Sequence alignments analysis showed that it shared 100% identity with haloacid dehalogenases. Furthermore, tbbpaA gene was cloned and expressed into E. coli to achieve a constructed strain. Like the original strain, the constructed strain could degrade TBBPA (6 mg L−1) with 78% of debromination efficiency and 37.8% mineralization efficiency within 96 h. Gene expression study revealed that tbbpaA was up-regulated in the presence of TBBPA. Overall, we report the identification of a functional TBBPA-degrading gene in an aerobe, which can deepen the knowledge of enhancing TBBPA removal by Strain T at the genetic level and facilitate in situ TBBPA bioremediation.

New insight into the cosolvent effect on the degradation of tetrabromobisphenol A (TBBPA) over millimeter-scale palladised sponge iron (Pd-s-Fe0) particles

The exploration of an effective treatment is necessary to eliminate the emerging environmental pollutant tetrabromobisphenol A (TBBPA). In this study, a direct reduction reaction was adopted to synthesize millimetre-scale palladised sponge iron (Pd0-s-Fe0), the main influencing factors were further explored, the degradation intermediates were identified in detail, and the cosolvent effect on the degradation mechanism was determined. The results show that (1) within a 30 min reaction, Pd(II) ions in aqueous solution were successfully decorated onto the s-Fe0 surface as supported by XPS, SEM, EDS, and ICP-OES analyses, (2) after 120 min of reaction, the normalized removal of TBBPA was ∼92.2% over 0.06 wt%-Pd0-s-Fe0, compared with 98.2% over 0.06 wt%-Pd-nZVI and 44.4% over bare nZVI. Moreover, the extend of debromination of TBBPA surprisingly increased as the ratio of the CH3OH:H2O cosolvent decreased, compared with the debromination rates that were greatly restricted in CH3OH (100%, v/v), CH2Cl2 (100%, v/v) and isopropanol (100%, v/v), respectively. Furthermore, the O-methylation reactions over Pd0-s-Fe0 produced unique intermediates, including 2,6-dibromo-4-(2-(3,5-dibromo-4-methoxyphenyl)propan-2-yl)phenol (MeO-TBBPA) and 5,5′-(propane-2,2-diyl)bis(1,3-dibromo-2-methoxy-benzene) (diMeO-TBBPA) with lower toxicity. This study greatly enriches knowledge regarding the degradation mechanism of TBBPA over millimetre-scale sponge iron.

Facile preparation of magnetic carbon nanotubes@ZIF-67 for rapid removal of tetrabromobisphenol A from water sample.

In this work, a novel magnetic carbon nanotube@zeolitic imidazolate framework-67 (MCNT@ZIF-67) composite was prepared facilely by a one-pot method using Fe3O4@SiO2 as the magnetic element, CNTs as the carbon matrix, and 2-methylimidazole (2-MIM) and cobaltous nitrate (Co(NO3)2·6H2O) as the organic and inorganic elements, respectively. The obtained MCNT@ZIF-67 composite was characterized by transmission electron microscopy (TEM), Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and vibrating sample magnetometry (VSM). Static adsorption experiments demonstrated that the maximum adsorption capacity of MCNTs@ZIF-67 for tetrabromobisphenol A (TBBPA) is 83.23mgg-1, and the sorption isotherm was fitted well by the Freundlich adsorption model. Dynamic adsorption experiments illustrated that the adsorption of TBBPA on MCNTs@ZIF-67 can reach equilibrium in 20min, and the adsorption kinetics of TBBPA were fitted well by a pseudo-second-order kinetic model. The adsorption of TBBPA on MCNTs@ZIF-67 showed favorable selectivity. The pH and the NaCl and NH4Cl common salts did not affect the TBBPA adsorption. Then, the proposed magnetic composite was applied as the adsorbent for the rapid removal of TBBPA in water samples, and the removal ratio of MCNTs@ZIF-67 for TBBPA in different spiked water samples with different volumes was above 95% with RSD < 5%. Furthermore, as a new removal sorbent, the removal reproducibility of MCNTs@ZIF-67 for TBBPA was favorable and stable, with only a 6.0% decrease after 6cycles.

Three-dimensional α-Fe2O3/amino-functionalization carbon nanotube sponge for adsorption and oxidative removal of tetrabromobisphenol A

Tetrabromobisphenol A (TBBPA) is one most widely used brominated flame retardant worldwide. In this study, a three-dimensional α-Fe2O3/amino-functionalization carbon nanotube (α-Fe2O3/CNT-N) sponge was synthesized and applied for adsorption removal of TBBPA from aqueous solution. The maximum adsorption capacity of TBBPA on the α-Fe2O3/CNT-N sponge was 41.35 ± 6.09 mg·g−1 at 303 K and pH 7.0 ± 0.1 and the adsorption capacity was maintained in the pH range of 3–7. The adsorbed TPPBA on the α-Fe2O3/CNT-N sponge can be easily degraded after adding peroxymonosulfate (PMS) to generate hydroxyl and sulfate radicals. The functional groups such as CONH2, CO and π–π∗ bonds played an important role in the activation of PMS. The α-Fe2O3/CNT-N sponge may be considered to use for water treatment due to its good adsorption capacity, easy separation from water and simple regeneration procedures.

Distribution, release and removal behaviors of tetrabromobisphenol A in water-sediment systems under prolonged hydrodynamic disturbances

Since tetrabromobisphenol A (TBBPA) has been increasingly used and found widely in the aquatic environment, it has attracted much attention due to its high toxicity to aquatic organisms. However, less work has been carried out for the TBBPA environmental fate in water-sediment systems. In this paper, the distribution, release and removal of TBBPA in different forms of the water-sediment system were investigated under three typical hydrodynamic conditions using a specialized racetrack-style flume. Three water-sediment systems which are water, suspended particulate matter (SPM) and sediment were taken into account in this study. The results of 34 days experiments showed that the equilibrium of physicochemical parameters was reached under different disturbance conditions within a relatively short period. The distribution ratio of TBBPA in three water-sediment systems will also reach a relatively equilibrium state over time under different disturbance conditions. The fluctuation range in each form was <1.26%. The TBBPA released to the water and SPM, increased remarkably with hydrodynamic enhancement due to adsorption and resuspension processes. Removal efficiency of TBBPA in each form was found to be observably accelerated with hydrodynamic disturbances. The half-lives (T1/2) in water, SPM and sediment ranged from 10.1 to 12.6 days in strong hydrodynamic condition, comparing to the static control, it ranges from 34.7 to 37.1 days. This phenomenon may result from the increase of dissolved oxygen (DO) and nutrient concentrations in overlying water affected by hydrodynamic force. The results of the experiment demonstrate that hydrodynamic disturbance may be an important driving factor which will influence the TBBPA environmental fate in aquatic environment.

Degradation of tetrabromobisphenol A by ferrate(VI) oxidation: Performance, inorganic and organic products, pathway and toxicity control

This study systematically investigated the degradation of tetrabromobisphenol A (TBBPA) by ferrate (VI) oxidation. The reaction kinetics between ferrate (VI) with TBBPA were studied under pseudo-first-order conditions in the pH range 5.5–10.5. Then, a series of batch experiments were carried out to investigate other factors, including the ferrate (VI) dosage, temperature and interfering ions. Additionally, the generation of inorganic products (bromide ion and bromate) was evaluated. The organic intermediates were identified, and possible pathways were proposed. In addition, the toxicity variation was analyzed with marine luminous bacteria (V. fischeri). Degradation of TBBPA by ferrate (VI) oxidation was confirmed to be an effective and environmentally friendly technique. The reaction was fitted with a second-order rate model. With a ferrate (VI) dosage of 25.25 μmol/L, TBBPA concentration of 1.84 μmol/L, an initial pH of 7.0, and a temperature of 25 °C, a 99.06% TBBPA removal was achieved within 30 min. The evaluation of inorganic products showed that the capacity of ferrate (VI) oxidation to yield bromide ions was relatively strong and could prevent the formation of bromate compared to photocatalytic and mechanochemical techniques. Eleven intermediates were identified, and the proposed degradation pathway indicated that TBBPA might undergo debromination, beta scission, substitution, deprotonation and oxidation. The results of toxicity testing showed that ferrate (VI) could effectively control the toxicity of the treated samples, although the toxicity increased in the initial reaction stage due to the accumulation and destruction of more toxic intermediates.

Efficient debromination of Tetrabromobisphenol A (TBBPA) by Au/Fe@biocarbon derived from bioreduction precious metals

The utilization of nano zero valent iron is recognized as a potential approach for debromination of Tetrabromobisphenol A (TBBPA). In this study, Pycnoporus sanguineus cells were employed for biosupported Au nano particles (bio-AuNPs) preparation, then calcinated for obtaining porous carbon doped with Au nano particles (Au@biocarbon) and generated Au@biocarbon supported zero-valent iron nanoparticles (Au/Fe@biocarbon). The role of Au/Fe@biocarbon during debromination was evaluated by comparing with Au@biocarbon, biocarbon and Fe@biocarbon. Results showed that Fe0 and Au0 are successfully loaded on the surface of porous biocarbon with well-dispersion and higher specific surface area. The removal and debromination efficiency of TBBPA driven by Au/Fe@biocarbon was up to about 99.85% and 97.18% within 100min, respectively. Higher dosage and acidic condition were more beneficial to removal of TBBPA with the most appropriated Au/Fe molar ratio of 2%, where the complete removal of TBBPA only took 20min. The mechanism of TBBPA debromination by Au/Fe@biocarbon was the joint function of adsorption of biocarbon and galvanic cell of biosupported Au/Fe bimetals. Therefore, Au/Fe@biocarbon could be an alternative to effectively boost rapid and complete debromination of TBBPA.

Multi-walled carbon nanotubes facilitated the removal of tetrabromobisphenol a mediated by horseradish peroxidase

In this study, we systematically investigated the effect of multiwall carbon nanotubes (MWCNTs) on the removal of tetrabromobisphenol A (TBBPA) mediated by horseradish peroxidase (HRP) at varying important conditions. The results suggested that the presence of MWCNTs significantly enhanced the removal of TBBPA mediated by HRP and the reaction rate constant was linear with the MWCNTs dosage. The enhancement of MWCNTs on the HRP-mediated reaction was attributed to two facts, one is that MWCNTs protected HRP from inactivation, the other is that the presence of MWCNTs made the homogeneous reaction of TBBPA be heterogeneous reaction by adsorbing TBBPA on its surface. Moreover, the influence of MWCNTs on TBBPA products distribution was further elucidated. We found that the species of reaction product had no difference between the HRP-mediated systems with and without the presence of MWCNTs. However, the presence of MWCNTs significantly decreased the yields of each product. These results give insight into the role of MWCNTs in HRP-mediated TBBPA reactions and provide theoretical foundation for potential development of novel enzymatic methods to control TBBPA contamination.MWCNTs enhanced the removal of TBBPA mediated by HRP/H2O2, because it protected HRP from inactivation and adsorbed TBBPA on its surface to form a heterogeneous reaction process.

Synthesis of millimeter-scale sponge Fe/Cu bimetallic particles removing TBBPA and insights of degradation mechanism

Tetrabromobisphenol A (TBBPA) was a potential persistent organic pollutants. This study synthesized s-Fe/Cu bimetallic particles by decorated sponge iron (s-Fe) with Copper (Cu) to degrade TBBPA. S-Fe/Cu bimetallic particles was further characterized by XRD, XPS, SEM and EDS. The optimal TBBPA removal efficiency was 95.9%. Among the theoretical Cu mass loading increasing from 0wt% to 6wt%, 4wt% mass loading was the best; with TBBPA initial concentration increased from 5mg/L to 30mg/L, TBBPA removal efficiency decreased from 91.2% to 73.0%; also, when dosage increased from 10g/L to 30g/L, removal efficiency increased from 58.1% to 95.9%; pH 6.5 were beneficial to degrading TBBPA and the s-Fe/Cu bimetallic particles showed strong catalytic ability after 4 reuse cycle. Kinetic analysis showed that the degradation of TBBPA obeyed pseudo-first-order kinetics. In addition, Liquid Chromatography Time-of-Flight Mass Spectrometry (LC/TOF/MS) detected degradation products including debromination products, hydroxylation products, single aromatic ring products and O-methylating product, which demonstrated that the main degradation pathway were debromination, hydroxyl, β-scission and O-methylation reactions.

Influence of co-existed tetrabromobisphenol A (TBBPA) and hexavalent chromium on the cellular characteristics of Pycnoporus sanguineus during their removal and reduction

Simultaneous TBBPA removal and Cr(VI) reduction by Pycnoporus sanguineus together with the effect of these co-existed pollutants on the fungal cellular characteristics were investigated in this study, aiming at illuminating the mechanism involved in the interactions between contaminants and microbial cells. The results revealed that Cr(VI) reduction and TBBPA removal declined from 92.5%, 75.4–30.6%, 44.8% when Cr(VI) concentration increased from 5 to 40mg/L, respectively. The removal efficiencies for Cr(VI) and TBBPA reached 61.4% and 94% separately under the optimum concentration of TBBPA at 10mg/L. Subsequent analyses indicated that the negative effect of Cr(VI) of high concentrations on Cr(VI) reduction and TBBPA removal was mainly attributed to the inhibition of fungal growth, intracellular proteins synthesis, cell viability and ATP enzyme activity. Compared with the moderate impact of TBBPA, the cell membrane of P. sanguineus was impaired severely and the surface morphology and intracellular structure changed dramatically in the presence of high concentration of Cr(VI) (above 10mg/L). This study also suggested that high level of TBBPA (15 and 20mg/L) promoted the synthesis of intracellular proteins and improved ATP enzyme activity within the first 48h of the reaction for enhancing the transportation and transformation of TBBPA.

Biodegradation of tetrabromobisphenol-A in sludge with spent mushroom compost

The objective of this study was to evaluate the degradation of tetrabromobisphenol-A (TBBPA) in sludge with spent mushroom compost (SMC). The TBBPA degradation rates were enhanced by addition of either SMC, SMC extract or extract-containing microcapsule, with SMC showing the highest TBBPA degradation rate in sludge. Bioreactor experiments revealed that the TBBPA removal rates in sludge with SMC were higher than in sludge alone. The TBBPA removal rates were enhanced with SMC when TBBPA was added in two portions. The bacterial composition differed in sludge with and without SMC. Geobacter and Mycobacterium were the major bacteria responsible for TBBPA degradation in sludge. This research offers feasible methods for the removal of TBBPA from sludge.