Degradation Of Tetrabromobisphenol A Research Articles

Degradation of TBBPA by nZVI activated persulfate in soil systems

Tetrabromobisphenol A (TBBPA) greatly impacts on ecosystems and human health due to its high environmental toxicity and persistence. Persulfate (PS) advanced oxidation technology to remove organic pollutants in soils has received intense attention. In this study, nanoscale zero-valent iron (nZVI) was synthesized through the borohydride reduction method to explore its activating potential towards PS to accelerate the degradation of TBBPA in soils. The degradation behaviors of TBBPA in soils were investigated by batch experiments. The degradation efficiency of TBBPA (5 mg kg−1) was 78.32% within 12 h under the following reaction conditions: 3 g kg−1 nZVI, 25 mM PS, and pH 5.5 at 25 °C. Notably, PS can be used effectively, and the pH changed slightly in the reaction system. Oxidative degradation of TBBPA is favored at higher temperatures and lower pH values, while it is inhibited when the amount of catalyst increases significantly. The coexisting heavy metal ions such as Zn(II) and Ni(II) inhibit TBBPA degradation, while Cu(II) accelerates the degradation. Radical scavenging and electron spin resonance (ESR) tests further confirmed the generation of SO4·−, ·OH, and O2·− in nZVI activated PS. The intermediates identified by gas chromatograph–mass spectrometry analysis indicated that TBBPA via debromination and the cleavage between the isopropyl group and one of the benzene rings complete degradation. These findings provide new insight into the mechanism of nZVI activation of PS and will promote its application in the degradation of refractory organic compounds.

Biodegradation and metabolism of tetrabromobisphenol A in microbial fuel cell: Behaviors, dynamic pathway and the molecular ecological mechanism

Tetrabromobisphenol A (TBBPA) has aroused widespread pollution in industrial wastewater. Microbial fuel cell (MFC) was proved powerful in organics degradation and simultaneous resource recovery during wastewater treatment. However, the TBBPA biotransformation potential, pathway and the related molecular mechanism remain poorly understood. In this study, the enhanced degradation and detoxification performance of TBBPA in MFC anode was confirmed, evidenced by the shorter degradation period (2.3 times shorter) and less generation of bisphenol A. UPLC-QTOF-MS analysis verified TBBPA metabolism went through reductive debromination, hydrolytic debromination, oxidative ring cleavage and o-methylation. Accompanied with those biochemical processes, the metabolites underwent dynamic changes. The distinctly decreased abundance and fewer interactions with other functional genera for the potential reductive dehalogenators (Pseudomonas, etc.) possibly led to the suppressed reductive debromination (5.1%) in the closed bioanode. Otherwise, the more abundant potential function bacteria with more collaborated interrelations, including hydrolytic dehalogenators (Acinetobacter, etc.), aromatics degrading bacteria (Geobacter, Holophaga, etc.) and electroactive bacteria (Geobacter, Desulfovibrio, etc.) made great sense to the enhanced hydrolytic debromination and detoxification of TBBPA. This study revealed that MFC anode was beneficial to TBBPA degradation and provided theoretical support for the decomposition and transformation of micro-pollutants in the municipal sewage treatment coupled with MFC process.

Efficient peroxydisulfate activation with nZVI/CuO@BC nanocomposite derived from wastes for degradation of tetrabromobisphenol A in alkaline environment

Peroxydisulfate (PDS) is a promising oxidant for sulfate radical based advanced oxidation processes (SAOPs), however its efficient activation is still a challenge. In this study, biochar-supported nano-zerovalent iron (nZVI) and copper oxide (CuO) nanocomposite (nZVI/CuO@BC), derived from low-cost wastes including scrap iron filings, copper leaching solution and corn stalks, was successfully fabricated for PDS activation to enhance tetrabromobisphenol A (TBBPA) degradation in alkaline environment. Under the conditions of 100 mg/L nZVI/CuO@BC, 0.2 mM PDS, pH 8.0 and 25 °C, 86.32% of PDS was activated and 98.46% of TBBPA was degraded within 45 min in nZVI/CuO@BC-activated PDS system. When the PDS concentration was 2 mM, the nZVI/CuO@BC-activated PDS system realized efficient debromination and mineralization of TBBPA at the ratio of 79.12% and 79.36%, respectively. The results of EPR studies and radical scavenger experiments revealed that both hydroxyl radical (·OH) and sulfate radical (SO4·-) were responsible for TBBPA degradation. The nZVI could active PDS indirectly through electron transfer mechanism and exhibited synergistic effects with CuO on PDS activation. Furthermore, the nZVI/CuO@BC-activated PDS system showed good potential to degrade TBBPA in real water environment. Therefore, nZVI/CuO@BC could be a novel strategy for efficient PDS activation and TBBPA degradation in alkaline environment.

Sulfidated nanoscale zero-valent iron dispersed in dendritic mesoporous silica nanospheres for degrading tetrabromobisphenol A

Sulfidated nanoscale zero-valent iron (S-NZVI) has attracted significant attention in pollutant remediation due to its higher electron selectivity than NZVI. However, the agglomeration behavior of S-NZVI particle limits its practical application. In this study, S-NZVI was synthesized and dispersed in dendritic mesoporous silica nanospheres (S-NZVI/DMSN) to remove tetrabromobisphenol A (TBBPA) in groundwater. The structural characterization and degradation results illustrated that the dendritic pores of DMSN not only improved the dispersion of S-NZVI particles, but also enhanced the accessibility of pollutants to S-NZVI. The specific surface area of the S-NZVI/DMSN reached 136.2 m2 g-1, which was 2.68 times larger than that of S-NZVI (50.8 m2 g-1). At a S/Fe molar ratio of 0.1 and Si/Fe mass ratio of 1.0, the TBBPA degradation efficiency by S-NZVI/DMSN reached 91.4%, which exceeded that of S-NZVI (66.3%), and the degradation rate constants (0.078 L (mg h)-1) was 2.86 times higher than that of S-NZVI (0.027 L (mg h)-1). The S-NZVI/DMSN could remain high TBBPA degradation performance (76.3%) after even five cyclic degradations. Approximately 70.5% of S-NZVI/DMSN and 1% of S-NZVI successfully passed through the sand column. The much better sustained reactivity and transportability of S-NZVI/DMSN indicated that it could penetrate soil aquifers and degrade TBBPA in groundwater.

Particle electrode materials dependent tetrabromobisphenol A degradation in three-dimensional biofilm electrode reactors

The completely biological degradation of Tetrabromobisphenol A (TBBPA) contaminant is challenging. Bio-electrochemical systems are efficient to promote electrons transfer between microbes and pollutants to improve the degradation of refractory contaminants. In particular, three-dimensional biofilm electrode reactors (3DBERs), integrating the biofilm with particle electrodes, represent a novel bio-electrochemical technology with superior treatment performances. In this study, the electroactive biofilm is cultured and acclimated on two types of particle electrodes, granular activated carbon (GAC) and granular zeolite (GZ), to degrade the target pollutant TBBPA in 3DBERs. Compared to GZ, GAC materials are more favorable for biofilm formation in terms of high specific surface area and good conductivity. The genus of Thauera is efficiently enriched on both GAC and GZ particles, whose growth is promoted by the electricity. By applying 5 V voltage, TBBPA can be removed by over 95% in 120 min whether packing GAC or GZ particle electrodes in 3DBERs. The synergy of electricity and biofilm in TBBPA degradation was more significant in GAC packed 3DBER, because the improved microbial activity by electrical stimulation accelerates debromination rate and hence the decomposition of TBBPA. Applying electricity also promotes TBBPA degradation in GZ packed 3DBER mainly due to the enhanced electrochemical effects. Roles of particle electrode materials in TBBPA removal are distinguished in this work, bringing new insights into refractory wastewater treatment by 3DBERs.

Nanoscale zero-valent iron/cobalt@mesoporous hydrated silica core–shell particles as a highly active heterogeneous Fenton catalyst for the degradation of tetrabromobisphenol A

Degradation of TBBPA by NZVI/NZVC@mHS CSP/H 2 O 2 heterogeneous Fenton system. • Synthesis of NZVI/NZVC@mHS CSP materials by one-pot method. • The core–shell structure of the material reduced aggregation and increased the specific surface area. • The mesoporous network structure effectively prevented the leaching of Co (II). • NZVI/NZVC@mHS CSP efficiently degraded TBBPA as Fenton-like catalyst. While the bimetal heterogeneous Fenton system degraded organic pollutants, the leaching of heavy metals caused secondary pollution. To resolve this problem, nanoscale zero-valent iron/cobalt@mesoporous hydrated silica core–shell particles (NZVI/NZVC@mHS CSP) were synthesized as a novel Fenton-like catalyst for the rapid degradation of Tetrabromobisphenol A (TBBPA). The performance of NZVI/NZVC@mHS CSP in the degradation of TBBPA and the mechanism of their action were investigated through scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. NZVI/NZVC@mHS CSP exhibited a regular spherical shape with a surface area (115.44 m 2 ·g −1 ) that was 5 times more than that of the ordinary NZVI/NZVC (23.59 m 2 ·g −1 ). The core of NZVI/NZVC was covered with a hydrated silica shell that formed a mesoporous network that effectively prevented the leaching of cobalt ions from the core. The best catalytic performance of NZVI/NZVC@mHS CSP was obtained by optimizing the iron-to-cobalt ratio, H 2 O 2 concentration, and the dosage of the catalyst. The optimized NZVI/NZVC@mHS CSP exhibited the greatest mineralization activity (97.13%) for TBBPA removal than those in NZVI/NZVC bimetal (84.49%) and pure NZVI/NZVC@mHS CSP (59.37%). Thus, our results demonstrated that NZVI/NZVC@mHS CSP exhibited excellent reactivity in potential application as a highly active heterogeneous Fenton catalyst for degradation of TBBPA in soil and groundwater.

Enhanced photoelectrocatalytic degradation of tetrabromobisphenol a from tip-decorated ZnO nanorod electrode with Bi2S3 nanoparticles

Tip-decorated ZnO/Bi2S3 photoelectrode was synthesized on a FTO substrate from chemical bath deposition and electrochemical deposition to investigate the photoelectrocatalytic (PEC) degradation of tetrabromobisphenol A (TBBPA). XRD, SEM, UV–vis and PL techniques were employed to evaluated the crystal structure, surface morphology, light absorbance properties and efficiency of carriers’ separation of the obtained electrode, respectively. The ZnO/Bi2S3 photoelectrode yielded a photocurrent density of 15.3 mA/cm2 upon ultraviolet and visible light irradiation, which was 6.6 and 10.9 times that of the original ZnO and Bi2S3, respectively. The enhanced photoelectrochemical properties is due to the improved light absorption of Bi2S3 nanoparticles and accelerated electron‐transfer pathway of ZnO nanorods. The stability of the photoelectrode was evaluated by recycling degradation experiments for 3 times. The intermediates of TBBPA degradation were also identified and a possible pathway was proposed.

Degradation of tetrabromobisphenol A by ferrate(VI)-CaSO3 process: Kinetics, products, and impacts on following disinfection by-products formation

Tetrabromobisphenol A (TBBPA) is one of the most widely applied brominated flame retardants and has been widely detected in water environment, which might pose risks of brominated disinfection by-products formation in water treatment system. Ferrate(VI)-CaSO3 (Fe(VI)-CaSO3) system could effectively degrade TBBPA at pH 7.0–9.0 but the decomposition rate of TBBPA dropped with increasing pH. The presence of 0.5 mg C/L humic acid (HA) had negligible impact on TBBPA removal, but the removal of TBBPA decreased to ~87% and 80% at pH 7.0 and 8.0, respectively, in the presence of 5.0 mg C/L HA. The transformation products of TBBPA detected in Fe(VI)-CaSO3 process revealed that TBBPA degradation mainly proceeded via electron abstraction, debromination, and ring-opening pathways and Br− was released. In the presence of TBBPA, Fe(VI)-CaSO3 pre-oxidation decreased the generation of all determined DBPs during chlorination at pH 8.0 but it lessened the generation of some DBPs and slightly increased the formation of the other DBPs at pH 7.0. The toxic risk analysis showed that Fe(VI)-CaSO3 pre-oxidation of TBBPA could reduce the toxic risk of DBPs in both synthetic water and natural water at pH 8.0, indicating that Fe(VI)-CaSO3 process has the potential to be applied in practical water treatment.

Enhanced degradation of tetrabromobisphenol A by magnetic Fe3O4@ZIF-67 composites as a heterogeneous Fenton-like catalyst

Magnetic Fe3O4@ZIF-67 composites were prepared, characterized, and used as heterogeneous catalysts to activate peroxymonosulfate (PMS) for the degradation of tetrabromobisphenol A (TBBPA). It was observed that all the added TBBPA (40 mg L−1) was completely degraded in 3 min in the Fe3O4@ZIF-67 (0.1 g L−1) + PMS (0.1 g L−1) system with a pseudo second-order degradation rate constant (k) of 110.3 L g−1 min−1, being nearly 10 times that (11.8 L g−1 min−1) in the ZIF-67 + PMS system and 2000 times that (0.06 L g−1 min−1) in the Fe3O4 + PMS system. The observed synergistic catalysis between Fe3O4 and ZIF-67 in Fe3O4@ZIF-67 enhanced not only the degradation of TBBPA, but also the TOC removal and the release of Br− during the degradation of TBBPA. Multiple reactive species including OH, SO4− and 1O2 were responsible for the degradation of TBBPA, but 1O2 was the dominant one. The synergistic catalytic mechanism of PMS activation by Fe3O4@ZIF-67 was proposed, which mainly involved the electron donating ability of Fe2+ in Fe3O4 for enhancing the Co3+/Co2+ cycle. Moreover, Fe3O4@ZIF-67 showed good recyclability and could be easily recycled by magnetic separation. This work provides an opportunity to construct highly efficient catalysts with magnetic recycling capability.

Efficient activation of peroxymonosulfate on cobalt hydroxychloride nanoplates through hydrogen bond for degradation of tetrabromobisphenol A

Heterogeneous activation of peroxymonosulfate (PMS) using cobalt-based nanomaterials is a promising strategy to degrade organic pollutants, in which the formation of Co(II)OH complex is a critical step. Here, cobalt hydroxychloride (Co2(OH)3Cl) nanoplates were synthesized by a one-pot precipitation method and exhibited high activity for the degradation of tetrabromobisphenol A (TBBPA) in the presence of PMS. The use of Co2(OH)3Cl and PMS caused a complete TBBPA degradation (40 mg L−1) at pH 9 in 2 min. The pseudo-first-order rate constant of TBBPA is 2.5 min−1, being 9, 14, and 6 folds larger than those for α-Co(OH)2, β-Co(OH)2, and Co3O4 as catalysts, respectively. The dissolved Co2+ (0.15 mg L−1) corresponds to 0.24% of the total cobalt in Co2(OH)3Cl and has negligible influence on the TBPPA degradation. Co2(OH)3Cl shows long-term stability (longer than 9 months) with the high activity after the oxidation treatment. The high activity of Co2(OH)3Cl attributes to the Cl− enhanced reactivity of surface Co(II)OH. The coordinated Cl− not only enhances the ability of surface Co(II)OH for anchoring both HSO5− and SO52− through the intermolecular hydrogen bond, but also improves electron transfer between Co(II) and PMS, leading to efficient generation of singlet oxygen for the TBPPA degradation.

Bioconcentration of 2,4,6-tribromophenol (TBP) and thyroid endocrine disruption in zebrafish larvae

2,4,6-tribromophenol (TBP) is generally used as a brominated flame retardant but is produced in the degradation of tetrabromobisphenol-A. Although TBP is frequently detected in the environment and in various biota, including fish species, we still know little about its toxicity and environmental health risk. Here we investigated the bioconcentration and effects of TBP on the thyroid endocrine system by using zebrafish as a model. Zebrafish embryos (2 h post-fertilization, hpf) were exposed to five concentrations of TBP (0, 0.3, 1, 10, and 100 μg/L) until 144 hpf. According to our chemical analysis, TBP underwent bioconcentration in zebrafish larvae. However, acute exposure to TBP did not affect the hatching of embryos or their risk of malformation, nor the growth and survival of larvae, indicating low developmental toxicity of TBP. The whole-body thyroxine (T4) contents were significantly increased in zebrafish larvae after exposure to TBP, indicating thyroid endocrine disruption occurred. Gene transcription levels in the hypothalamic-pituitary-thyroid (HPT) axis were also examined in larvae; these results revealed that the transcription of corticotrophin-releasing hormone (crh), thyrotropin-releasing hormone (trh), and thyroid-stimulating hormone (tshβ) were all significantly downregulated by exposure to TBP. Likewise, genes encoding thyronine deiodinases (dio1, dio2, and dio3a/b) and thyroid hormone receptors (trα and trβ) also had their transcription downregulated in zebrafish. Further, the gene transcription and protein expression of binding and transport protein transthyretin (TTR) were significantly increased after TBP exposure. Taken together, our results suggest the bioavailability of and potential thyroid endocrine disruption by TBP in fish.

Natural polyphenols enhanced the Cu(II)/peroxymonosulfate (PMS) oxidation: The contribution of Cu(III) and HO•

Copper ion (Cu(II)) in water or wastewater has been reported to trigger peroxymonosulfate (PMS) oxidation of organic contaminants (OCs). However, this process can only work in alkaline condition, which limits its potential application. In this study, we found that the introduction of natural polyphenols in the Cu(II)/PMS process can significantly promote the degradation of tetrabromobisphenol A (TBBPA), one of the most widely used brominated flame retardants, in the pH range of 4.3−9.0. With gallic acid (GA) as a representative natural polyphenol, the degradation of TBBPA by GA/Cu(II)/PMS process reached 84.6% in 10 min at initial pH of 4.3 (without pH adjustment), which was 2.2 times higher than that by Cu(II)/PMS process. Multiple reactive oxidants, including Cu(III), hydroxyl radical (HO•) and singlet oxygen, were generated in this process among which Cu(III) and HO• contributed to TBBPA degradation with Cu(III) playing the dominant role. GA accelerated the reduction of Cu(II) to Cu(I) due to the strong chelation and electron-donating capacity of ortho-hydroxyl groups in GA, and then Cu(I) was quickly oxidized by PMS to Cu(III) which can be further acid-catalyzed to produce HO•. TBBPA transformation mainly proceeded through electron abstraction, oxidative debromination and ring-opening reaction pathways. The feasibility of in-situ utilizing natural organic matter (NOM, enriched with polyphenol moieties) to accelerate the degradation of TBBPA by Cu(II)/PMS process in surface water and wastewater was confirmed. The findings of this study indicate that the coupling of NOM and Cu(II), which are present in contaminated water or wastewater, can potentially improve PMS oxidation of OCs in a wide range of pH.

Co-metabolic degradation of tetrabromobisphenol A by Pseudomonas aeruginosa and its auto-poisoning effect caused during degradation process

In this study, Pseudomonas aeruginosa was applied to degrade tetrabromobisphenol A (TBBPA) with glucose as a co-metabolic substrate. Influencing factors of co-metabolic degradation such as pH, TBBPA and glucose concentration were examined and the degradation efficiency under optimal condition reached about 50% on the 7th day. The study also proved that the extracellular action, rather than intracellular one, played a leading role in TBBPA degradation. Five metabolites including debromination and beta-scission products were identified in this study. The extracellular active substance pyocyanin was considered as the origin of H2O2 and OH·. The variation of concentrations of H2O2 and OH· shared the same trend, they increased in the early days and then declined gradually. On the 1st day, the OD600 of P.aeruginosa in the co-metabolic group was 6.0 times higher than the initial value while total organic carbon (TOC) decreased about 78%, which might lead to the occurrence of pyocyanin auto-poisoning. Flow cytometry was applied to detect the cellular state of P.aeruginosa during degradation. The increasing intracellular ROS showed that cells were suffering from oxidative stress and the change of membrane potential revealed that cellular dysfunction had occurred since the 1st day. This research indicated that the toxic effect on P.aeruginosa was probably not directly correlated with TBBPA, but was caused by pyocyanin auto-poisoning.

Mechanism investigation and stable isotope change during photochemical degradation of tetrabromobisphenol A (TBBPA) in water under LED white light irradiation

Light driven degradation is very promising for pollutants remediation. In the present work, photochemical reaction of tetrabromobisphenol A (TBBPA) under LED white light (λ > 400 nm) irradiation system was investigated to figure out the TBBPA photochemical degradation pathways and isotope fractionation patterns associated with transformation mechanisms. Results indicated that photochemical degradation of TBBPA would happen only with addition to humic acid in air bubbling but not in N2 bubbling. For photochemical reaction of TBBPA, singlet oxygen (1O2) was found to be important reactive oxygen species for the photochemical degradation of TBBPA. 2,6-Dibromo-4-(propan-2-ylidene)cyclohexa-2,5-dienone and two isopropyl phenol derivatives were identified as the photochemical degradation intermediates by 1O2. 2,6-Dibromo-4-(1-methoxy-ethyl)-phenol was determined as an intermediate via oxidative skeletal rearrangement, reduction and O-methylation. Hydrolysis product hydroxyl-tribromobisphenol A was also observed in the reductive debromination process. In addition, to deeply explore the mechanism, carbon and bromine isotope analysis were performed using gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) and gas chromatography-multicollector inductively coupled plasma mass spectrometry (GC/MC/ICPMS) during the photochemical degradation of TBBPA. The results showed that photochemical degradation could not result in statistically significant isotope fractionation, indicated that the bond cleavage of C-C and C-Br were not the rate controlling process. Stable isotope of carbon being not fractionated will be useful for distinguishing the pathways of TBBPA and tracing TBBPA fate in water systems. This work sheds light on photochemical degradation mechanisms of brominated organic contaminants.

G–C3N4– and polyaniline-co-modified TiO2 nanotube arrays for significantly enhanced photocatalytic degradation of tetrabromobisphenol A under visible light

An ordered g–C3N4– and polyaniline-modified titanium oxide nanotube array (g–C3N4– and PANI-co-modified TiO2 NTAs) was successfully synthesized and used as a photocatalyst. Polyaniline (PANI) was coated onto TiO2 NTAs by electrochemical polycondensation, and g-C3N4 was deposited via the soaking adsorption method. The photocatalysts were examined by several technologies. The experiments demonstrated that the amount of g-C3N4 and PANI, as well as the initial pH value, had significant effects on the photocatalytic efficiency. The resulting photocatalysts exhibited high visible light photocatalytic ability for tetrabromobisphenol A (TBBPA) for two reasons. First, PANI expanded the light absorption into the visible region. Second, rapid and efficient separation of photoinduced charges from the photogenerated potential difference were produced at the contact interface of g-C3N4 and PANI-co-modified TiO2 NTAs. The •OH, •O2− and h+ were dominant components for the photocatalytic degradation of TBBPA. In addition, the g-C3N4 and PANI-co-modified TiO2 NTAs have excellent long-term stability.

Titanium and iron-modified delaminated muscovite as photocatalyst for enhanced degradation of Tetrabromobisphenol A by visible light

A new heterostructured titanium–iron-based material dispersed in alkaline muscovite (Ti–Fe–Mus) was synthesized by a typical impregnation process, and characterized by X-ray diffraction, adsorption/desorption of liquefied nitrogen and thermogravimetric/differential thermal analysis. This characterization suggests that the Ti–Fe–Mus system does not present sufficiently ordered silicate layers, but has a delaminated structure. The specific surface area and porosity have been significantly improved compared to the virgin muscovite, and the outer surface appears to be the dominant active surface. In particular, the Ti–Fe–Mus system was examined as a photocatalyst for the degradation of Tetrabromobisphenol A (TBBPA) selected as a model compound by visible light exposure. The Ti–Fe–Mus system showed excellent photocatalytic activity for TBBPA degradation and optimum catalyst concentration was found at 0.4[Formula: see text]g L[Formula: see text]. More than 60% by weight of parent TBBPA with an initial concentration of 300[Formula: see text]ppm were eliminated after 120[Formula: see text]min at [Formula: see text]. Acid conditions have resulted in a faster elimination compared to alkaline and neutral conditions. Based on these results, it has been shown that titanium and iron modified delaminated muscovite (Ti–Fe–Mus) have strong potential for application as a powerful photocatalyst for the elimination of persistent organic pollutants present in the environment.

Efficient heterogeneous activation of peroxymonosulfate by modified CuFe2O4 for degradation of tetrabromobisphenol A

In order to enhance the catalytic activity of copper ferrite, CuFe2O4 doped with Ce, Sn, and Sb were prepared by sol-gel combustion method, and for the first time applied as heterogeneous catalysts to activate peroxymonosulfate (PMS) for tetrabromobisphenol-A (TBBPA) degradation in aqueous solution. Morphology, elementary composition, crystal structure, and specific surface area of the obtained catalysts were characterized. The influences of catalyst dosage, PMS concentration, initial pH, common inorganic anions, and natural organic matters (NOM) on pollutant removal were comprehensively investigated, as well as the degradation process in real wastewater. It was found that 90.1% of 15 mg/L TBBPA was removed at weak basic condition in the presence of 0.2 mM PMS and 0.075 g/L Sb-doped CuFe2O4, which exhibited the best catalytic activity among all the catalyst prepared. Furthermore, the active radical species responsible for TBBPA degradation were identified as sulfate radical and hydroxyl radical by using electron spin resonance (ESR) and scavenging tests. Possible catalysis mechanism was proposed based on X-ray photoelectron spectroscopy (XPS) analysis, indicating that the surface hydroxyl groups and the interactions among surface metal species, oxygen species, and PMS were critical for maintaining high catalytic activity. Based on intermediate identification, TBBPA degradation pathway was proposed. According to all the results, the Sb-doped CuFe2O4 with favorable catalytic ability, reusability and stability could be employed as a promising candidate for the activation of PMS to treat TBBPA-contaminated water.

High-efficient removal of tetrabromobisphenol A in aqueous by dielectric barrier discharge: Performance and degradation pathways

Brominated flame retardants are widely used in fire protection area, but also bring great threats to ecological environment and human health. In this study, the potential of brominated flame retardant removal in wastewater by dielectric barrier discharge (DBD) plasma was investigated, with Tetrabromobisphenol A (TBBPA) as a model pollutant. The experimental results showed that TBBPA could be effectively removed by the DBD plasma oxidation. Almost all of the TBBPA in wastewater could be successfully decomposed within 15 min’s oxidation treatment, and the decomposition process fitted well with the pseudo-first-order kinetic model. Relatively lower TBBPA initial concentration favored its decomposition; and the effect of solution pH value on the oxidation process was negligible in the selected pH range. Electron paramagnetic resonance analysis showed that O2–, OH, and 1O2 were produced in the DBD plasma process; and O2– was the main reactive species for TBBPA decomposition, OH and 1O2 also played important roles. The molecular structure of TBBPA was effectively destroyed, and some byproducts including bisphenol A, and dibromophenol were generated. The possible decomposition pathways for TBBPA degradation were proposed. Furthermore, the acute toxicity and bioaccumulation factor of intermediate byproducts were alleviated via the analysis of Toxicity Estimation Software Tool.

Colorimetric determination of tetrabromobisphenol A based on enzyme-mimicking activity and molecular recognition of metal-organic framework-based molecularly imprinted polymers.

A sol-gel method is presented to synthesize molecularly imprinted polymers (MIPs) composed with a copper-based metal-organic framework (referred to as MIP/HKUST-1) on a paper support to selectively recognize tetrabromobisphenol A (TBBPA). The imprinting factor is 7.6 and the maximum adsorption capacity is 187.3mgg-1. This is much better than data for other MIPs. The degradation of TBBPA is introduced in the procedure. Due to the selective recognition by the MIP, the enzyme-mimicking properties of HKUST-1 under the MIP layer became weak due to the decrease of residue imprinted cavities. And adsorbed TBBPA can be degraded under consumption of hydrogen peroxide (H2O2). The combined effect of H2O2 and HKUST-1 cause the coloration caused by catalytic oxidation of 3,3',5,5'-tetramethylbenzidine to become less distinct. This amplification strategy is used for the ultrasensitive and highly selective colorimetric determination of TBBPA. The gray intensity is proportional to the logarithm concentration of TBBPA in the range of 0.01-10ngg-1. The limit of detection is as low as 3pgg-1, and the blank intensities caused by TBBPA analogues are <1% of that caused by TBBPA at the same concentration, this implying excellent selectivity. The spiked recoveries ranged from 94.4 to 106.6% with relative standard deviation values that were no more than 8.6%. Other features include low costs, rapid response, easy operation and on-site testing. Graphical abstractSchematic representation of colorimetric determination of tetrabromobisphenol A (TBBPA) by paper-based metal-organic framework-based molecularly imprinted polymers (MIP/HKUST-1 composites) using 3,3',5,5'-tetramethylbenzidine (TMB) as a substrate.

Palladium/iron nanoparticles stimulate tetrabromobisphenol a microbial reductive debromination and further mineralization in sediment

Tetrabromobisphenol A (TBBPA) has aroused serious pollution in surface sediment. To date, whether and how iron-based nanoparticles could stimulate TBBPA in situ anaerobic biodegradation in sediment remains poorly understood. In this study, the distinctly enhanced TBBPA degradation activity with the rate constant k improved 4.7 times by fed with Pd/Fe nanoparticles (0.412 g L−1 dosage, 0.5 wt% Pd loading) was observed. TBBPA degradation first went through reductive dehalogenation with bisphenol A (BPA) as the metabolites, and after the addition of Pd/Fe nanoparticles, BPA was further degraded to 4-(allene)phenol and 2,2-bis(4-hydroxyphenyl) propanoic acid via UPLC-QTOF-MS analysis, suggesting the complete detoxification potential. By the addition of Pd/Fe nanoparticles, the large amount of H2 production (560 times higher) and the significant inhibition of methane generation facilitated the metabolism of potential reductive dehalogenators (Desulfovibrio, Clostridium, etc.), demonstrated by their increased ecological abundance and the tighter cooperative interrelations between each other. Meanwhile, the addition of Pd/Fe nanoparticles largely promoted the ecological abundance of Fe(III) reducing and aromatics degrading bacteria (Bacillus, Cryptanaerobacter, etc.), resulting in BPA further degradation. The bacterial ecological network further revealed that the potential BPA degrading bacteria shared the more positive interactions with the potential dehalogenators in the presence of Pd/Fe nanoparticles. The study firstly revealed the addition of Pd/Fe nanoparticles obviously enhanced the respiratory metabolic activities and cooperative interrelations of reductive dehalogenators and BPA degraders, which gives suggestions for in situ remediation and detoxification of BFRs in contaminated sediment.