Degradation Of 2-mercaptobenzothiazole Research Articles

Rational design of a donor-acceptor structured poly(3-bromothiophene) modified g-C3N4 for enhanced photocatalytic degradation of 2-mercaptobenzothiazole

Donor-acceptor (D-A) structure has gained momentous attention due to its controllable optical band gap and impressive carrier separation performance. The intramolecular charge transfer within photocatalysts could be modulated by constructing a D-A structure, thereby enhancing their performance in degrading pollutants. In our recent research, using poly(3-bromothiophene) (PTh-Br) and dicyandiamide (DCD) as precursors, a series of D-A structures (CN-PTh-Br(x)) based on polythiophene donors and carbon nitride acceptors were obtained by one-pot synthesis for first-time. The density functional theory calculations further demonstrate that PTh-Br segment (an electron donor) donates electrons to tri-s-triazine rings (an electron acceptor). The introduction of electron-rich polythiophene groups and electron-withdrawing Br atoms on carbon nitride skeleton can propel the transfer and separation of holes and electrons. Moreover, the polythiophene groups with high conjugation length can optimize the optical absorption of CN-PTh-Br(x) at 450–600 nm, thus markedly heightening the visible-light utilization efficiency of the materials. The photocatalytic performance of CN-PTh-Br(x) was assessed through the photodegradation of 2-mercaptobenzothiazole (MBT) under visible-light illumination. The photodegradation performance of CN-PTh-Br(0.5) stood out among all the samples, demonstrating a remarkable ability to remove 99.8% of MBT within 45 min.

BaFe12O19/BiOBr S-scheme heterojunction magnetic nanosheets for high-efficiency photocatalytic degradation of 2-mercaptobenzothiazole

Visible-light-driven (VLD) BaFe12O19/BiOBr composite catalysts with different mass ratios of BaFe12O19 are prepared via hydrothermal and calcination method. The constructed S-type heterojunction enables BaFe12O19/BiOBr photocatalysts to perform effective space charge transfer and higher redox ability. Especially, the obtained BaFe12O19/BiOBr composites exhibited the high photocatalytic activity (95 %) to degrade 2-mercaptobenzothiazole (MBT) only after 3 min of visible light irradiation, which was much better than pure BaFe12O19 (10.6 %) and BiOBr (49 %). What's more, the BaFe12O19/BiOBr composites can be separated magnetically, thus achieving the practical significance of efficient separation and recovery. Photocatalytic activity experiments demonstrated that the prepared composites also showed good photocatalytic degradation performance towards Tetracycline hydrochloride (TC), Ciprofloxacin (CIP) and Eosin. Overall, the separable BaFe12O19/BiOBr composite photocatalysts will be promising candidate materials in sewage purification.

Fe Single Atoms Reduced by NaBH4 Mediate g-C3N4 Electron Transfer and Effectively Remove 2-Mercaptobenzothiazole

In this study, a simple and low-energy synthesis scheme of Fe single-atom anchored carbon nitride was reported to improve the photocatalytic performance of g-C3N4. Synthesized Fe single-atom doped graphite carbon nitride (Fe-SACs/g-C3N4) showed high activity and stability for the degradation of 2-mercaptobenzothiazole (MBT); under visible light irradiation, 99% of MBT could be degraded within 35 min, and the degradation ability basically did not decline after five cycles, mainly due to the synergistic effect of the Fe single atoms and carbon nitride. The results of X-ray absorption fine structure (EXAFS), X-ray photoelectron spectroscopy (XPS), and density functional theory calculations show that the single-atom Fe forms Fe-N4 coordination with pyridine nitrogen to generate a new electron transfer channel, which can significantly improve the in-plane separation and transfer of carriers, finally enhancing the generation of superoxide radicals. This is confirmed by time-resolved photoluminescence, photoelectron chemistry, and electron spin resonance measurements. The main intermediates of MBT degradation were determined using a liquid chromatograph–mass spectrometer (LC-MS), and a possible photocatalytic mechanism based on the quenching experiment and electron paramagnetic resonance (EPR) test was proposed. A deep understanding of the contribution of Fe single-atom sites with clear local coordination structures will help to design effective catalysts for photocatalytic performance.

Pyrrole nitrogen coordinated Fe on carbon nitride mediated singlet oxygen formation for efficient degradation of 2-mercaptobenzothiazole

We report a rational and scalable synthetic approach to prepare Fe-decorated carbon nitride materials assisted by carbonized polyamine (C-Fe@PDA-CN). The material exhibited extremely high activity and stability for the degradation of 2-mercaptobenzothiazole (MBT) and other organic pollutants (phenol, BPA, MB, and RhB) under visible light irradiation. Furthermore, escape from CN to C-Fe@PDA provides an electron transfer channel to facilitate carrier separation and accelerate the generation of active species, as confirmed by photoluminescence, photoelectrochemical, and electron paramagnetic resonance (EPR). Fe exists in the material coordinated with the pyrrole nitrogen of polydopamine. This coordination structure is conducive to the generation of singlet oxygen (1O2). It is confirmed by steady-state phosphorescence spectroscopy (PH) that 1O2 originates from electron transfer. Superoxide radicals are generated by electron transfer and then oxidized into 1O2 by holes. The main intermediates of MBT degradation were identified by the LC-MS method, and a possible photocatalytic mechanism based on quenching experiments and EPR tests was proposed.

Attapulgite-interpenetrated g-C3N4/Bi2WO6 quantum-dots Z-scheme heterojunction for 2-mercaptobenzothiazole degradation with mechanism insight

The rational utilization of graphitic carbon nitride (g-C3N4) and quantum dots (QDs) semiconductors to highlight their merits as efficient photocatalysts remains attractive and challenging. Targeted integration of g-C3N4 and QDs with expanded interfacial contact and multi-channel electron transfer is an effective means to boost the transfer efficiency of photogenerated electrons and achieve prominent photocatalytic activity. In this article, novel attapulgite (ATP)-interpenetrated Bi2WO6 QDs/g-C3N4 nanocomposites (BWQ/g-C3N4/ATP, designated as BCAs) are successfully fabricated through a simple and effective in situ hydrothermal growth method. The nanorod-structured ATP acts as numerous bridges to intercalate into the interlayers and expands inner space of g-C3N4. Theoretical calculation results indicate that an interfacial internal electric field (IEF) is formed where electrons transfer from g-C3N4 to Bi2WO6. Originating from the intact interfacial contact of the expanded g-C3N4 and highly dispersed BWQ with reinforcing electronic transferability of ATP, the optimal sample of BCA5 with higher specific surface area, more active sites and electron transfer channels, and stronger light harvestability, exhibits a nearly-100% degradation of organic contaminant of 2-Mercaptobenzothiazole in water, 35-, 17- and 3-fold rate constant higher than that the pristine g-C3N4, BWQ and Bi2WO6/g-C3N4 counterparts, respectively. Various characterization techniques are employed to put forward the mechanisms in depth on MBT degradation route and IEF-induced photocatalytic Z-scheme over the BCA5 under photoexcitation.

Effect of Surfactants on Dye-Photosensitized Degradation of 2-Mercaptobenzothiazole

Effect of Surfactants on Dye-Photosensitized Degradation of 2-Mercaptobenzothiazole

Efficient Degradation of 2-Mercaptobenzothiazole and Other Emerging Pollutants by Recombinant Bacterial Dye-Decolorizing Peroxidases.

In recent years, concerns are being raised about the potential harmful effects of emerging pollutants (EPs) on human and aquatic lives. Extensive research is being conducted on developing efficient remediation strategies to target this new class of toxic pollutants. Studies focused on biological (enzyme-based) methods have shown potential as greener and possibly more economical alternatives to other treatment approaches, such as chemical methods. The current study focused on the use of recombinantly produced novel bacterial peroxidases, namely dye-decolorizing peroxidases (DyPs), to study their effectiveness in degrading a number of diverse EPs. In this context, a sensitive bioanalytical Liquid chromatography—tandem mass spectrometry (LCMSMS)-based method was developed to simultaneously detect a mixture of 31 EPs and to examine their degradability by a panel of seven different recombinant bacterial DyPs (rDyPs). We show that up to 8 of the 31 tested EPs could be degraded by at least one of the DyPs tested. The results also indicated that not all rDyPs behaved similarly in their abilities to degrade EPs, as some rDyPs (such as SviDyP and CboDyP) showed a promising potential to degrade EPs while others (such as ScDyP) were almost ineffective. Additionally, the role of redox mediators for effective emerging pollutant degradation by rDyPs was also examined, which showed dramatic improvement in the DyP-mediated degradation of five different EPs. Detailed analysis of 2-mercaptobenzothiazole degradation by SviDyP showed that six distinct breakdown products were generated. The present study showed for the first time that recombinant bacterial DyPs can be used for wastewater remediation by degrading a range of different EPs.

Synergistic effects of Ag-doped and morphology regulation of graphitic carbon nitride nanosheets for enhanced photocatalytic performance

In this study, a simple protocol for synthesizing silver doped and morphological regulation to improve the photocatalytic performance of g-C3N4 was reported. The as-synthesized single atom dispersed Ag doped graphitic carbon nitride nanosheets (Ag-CNNS) showed excellent performance for the degradation of 2-Mercaptobenzothiazole (MBT) and Rhodamine B (RhB) under visible light irradiation, mainly attributing to the synergistic effect of Ag doping and porous carbon nitride nanosheets (CNNS). On one hand, Ag doping promoted the capture and transfer of photogenerated electrons in g-C3N4. On the other hand, the presence of crimped nanosheets enabled g-C3N4 to have a larger specific surface area and shorten the charge diffusion distance from bulk to surface. Moreover, the increased photocurrent response proved that carriers had higher transport efficiency and interfacial catalytic reactivity. Cycle experiments confirmed that the 1% Ag-CNNS sample has good photocatalytic stability and reusability. Possible photocatalytic mechanism was proposed basing quenching experiment.

Confinement of ultrasmall CoFe2O4 nanoparticles in hierarchical ZnIn2S4 microspheres with enhanced interfacial charge separation for photocatalytic H2 evolution

The charge carriers’ separation efficiency, light absorption capacity and microstructure of photocatalysts are important factors affecting the photocatalytic performance. Herein, we prepared the hierarchical ZnIn2S4 (ZIS) microspheres-confined CoFe2O4 nanoparticles (CFO NPs) p-n junction (CFO/ZIS) with enhanced charge carriers’ separation and extensive visible light response. Surprisingly, the 1% CFO/ZIS exhibits the optimal photocatalytic H2 evolution (PHE) activity, which is about over 3.7 times higher than pure ZIS. Furthermore, the apparent quantum yield (AQY) of the1% CFO/ZIS reaches 5.0% at 420 nm. In addition, the effects of various sacrificial reagent on the PHE were investigated in depth. And the formed photocatalytic reaction path of p-n junction effectively prevents the photocorrosion of ZIS. Hence, the photocatalytic activity and crystalline structure of 1% CFO/ZIS have no obvious change after five photocatalytic cycles, which shows that the photocatalyst possesses excellent chemical stability. Moreover, the as-prepared p-n junction shows outstanding photocatalytic performance for the degradation of 2-mercaptobenzothiazole (MBT). According to a series of experiments and characterizations, a possible photocatalytic mechanism for the CFO/ZIS p-n junction was proposed.

Preparation of magnetically recoverable and Z-scheme BaFe12O19/AgBr composite for degradation of 2-Mercaptobenzothiazole and Methyl orange under visible light

Here, a series of BaFe12O19/AgBr magnetic recyclable composites were designed for the removal of 2‑Mercaptobenzothiazole (MBT) and Methyl orange (MO) under visible light. The vibrating sample magnetometer test demonstrated that composites exhibit superior magnetic recyclability. Among all composites, 10% BaFe12O19/AgBr exhibited the highest reaction rate (0.1005 min−1) of MBT degradation, which was about 3.32 and 71.79 times higher than that of pure AgBr (0.0302 min−1) and BaFe12O19 (0.0014 min−1), respectively. Besides, the composites also exhibited obviously improved photocatalytic MO degradation properties. The excellent photocatalytic activity could be ascribed to the efficient separation of photo-induced charge carriers, which was certificated by cyclic voltammogram (CV), transient photocurrent tests, electrochemical impedance spectroscopy (EIS) and photoluminescence (PL) spectra. Capture experiments proved that O2−, h+ and OH are the main active species in the process of MBT degradation, which matches well with the results of electron spin resonance (ESR) measurements. Moreover, the test of Mott-Schottky plots verified the flat band potentials of catalysts. At last, a possible Z-scheme reaction mechanism for the photocatalytic system was proposed. This work will provide theoretical guidance for the construction of magnetically recyclable Z-type photocatalysts.

Fabrication of a Z-scheme MoS2/CuO heterojunction for enhanced 2-mercaptobenzothiazole degradation activity and mechanism insight

A Z-scheme MoS2/CuO photocatalyst is successfully developed using a hydrothermal and calcination method, which has excellent activity (96%) in the degradation of 2-mercaptobenzothiazole (MBT) under visible light irradiation.

Photocatalytic degradation of 2-Mercaptobenzothiazole by a novel Bi2WO6 nanocubes/In(OH)3 photocatalyst: Synthesis process, degradation pathways, and an enhanced photocatalytic performance mechanism study

Designing and developing an efficient photocatalytic system for degrading organic pollutants was a research hotspot in the field of environmental governance. In this study, a novel Bi2WO6/In(OH)3 composite photocatalyst was first fabricated via facile calcination-hydrothermal synthesis method. The 9-Bi2WO6/In(OH)3 composite had superior photocatalytic performance for degrading the 2-Mercaptobenzothiazole (MBT) under visible-light irradiation. The degradation rate constant of 9-Bi2WO6/In(OH)3 was 0.02192 min−1, which was 2.3 times than that of pure Bi2WO6 (0.00948 min−1). The improvement in photocatalytic performance was due to the synergistic effect of the surface heterojunction and the electron-transfer medium. The density functional theory (DFT) showed that the difference in energy levels between the conduction bands and valence bands of Bi2WO6 nanocubes (010) and (001) could build the surface heterojunction, which was in favor to promote the electron-hole pairs separation. And the In(OH)3 not only acted as a supporter to prevent the agglomeration of small size Bi2WO6 nanocubes, but also served as electron-transfer mediator to inhibit the recombination of electrons and holes. This study provided a reference value for the development and utilization of Bi-based photocatalysts. Considering the properties and structural characteristics of Bi-based photocatalysts and hydroxides, Bi2WO6/In(OH)3 composite photocatalysts were design reasonably, which provided a variety of the types of photocatalysts.

A visible-light-driven Z-scheme CdS/Bi12GeO20 heterostructure with enhanced photocatalytic degradation of various organics and the reduction of aqueous Cr(VI)

A series of Z-scheme CdS/Bi12GeO20 heterostructures were successfully obtained by a simple hydrothermal method. The Z-scheme CdS/Bi12GeO20 heterostructures show outstanding photocatalytic performance for degrading the various organic pollutants of the waste water, and for the reduction of aqueous Cr(VI) under visible light. For degradation of 2-Mercaptobenzothiazole (MBT), the Z-scheme 30CdS/Bi12GeO20 heterostructure exhibits the superior rate constant, which is about 22.67 and 4.6 times higher than that of the pure Bi12GeO20 and CdS, respectively. Meanwhile, as we expected, the Z-scheme 30CdS/Bi12GeO20 heterostructure also displays the enhanced photocatalytic performance for degradation of Levofloxacin (LEV), Ciprofloxacin (CIP), Tetracycline (TC) and reduction of aqueous Cr(VI). The enhancement of photocatalytic performance is attributed to the high redox capacity and the strong interfacial interaction between CdS and Bi12GeO20, which can effectively improve the separation of photo-induced electron-hole pairs. Additionally, the photocatalytic mechanism over the Z-scheme CdS/Bi12GeO20 heterostructure is provided. The research work may provide a promising approach to fabricate other Z-scheme heterostructures with efficient photocatalytic performance.

Insight into the effect of co-doped to the photocatalytic performance and electronic structure of g-C3N4 by first principle

Developing low-cost and high-efficiency g-C3N4 (CN) semiconductor with modification has been proved to possess the potential advantage for environmental remediation in recent years. Herein, element doping of CN framework was found significantly on controlling its electronic structure. The new two-dimensional photocatalyst of Co-doped CN (Co-CN) applicable in photocatalytic reactions for 2-Mercaptobenzothiazole degradation was designed and synthesized. It was for the first time revealed that the Co-N bonding could lead to enhance significantly photoelectric properties, the rate for electron-hole pairs separation and photocatalytic activity in comparison with bulk CN. The characterization and density functional theory (DFT) results insight into the reason that the 3d electrons of the doped Co has excellent contribution to adjust the band gap of Co-CN. The present work provide a broadening window for Metal-doped CN with outstanding performance.

Fabrication of the metal-free biochar-based graphitic carbon nitride for improved 2-Mercaptobenzothiazole degradation activity

The present study describes a metal-free biochar-based photocatalyst of g-C3N4-C, in presence of an abundant fade magnolia as carbon precursor via facial in-situ together growth method. As a consequence, the g-C3N4-C shows a better degradation efficiency to 2-Mercaptobenzothiazole (90%) than pure g-C3N4 (49%) under the visible light. The improved photocatalytic performance of g-C3N4 is attributed to the biochar can significantly against the g-C3N4 reunion and stacking during high temperature treatment, because the biochar can act as the attachments that make the g-C3N4 flat and no accumulation, which will further increase the active sites. Additionally, photo-electrochemical measurements proved the separation efficiency of electron-holes of g-C3N4 is enhanced by introduced of biochar, due to its good electron transmission ability. Moreover, the ESR measurement and capture experiment further confirmed the active radicals on degradation of MBT are h+ and O2−. This work may provide a promising approach for wastewater treatment by waste utilization of solid biomass and increasing the photocatalytic performance of g-C3N4.

A Theoretical study on the degradation of 2-mercaptobenzothiazole and 2-mercaptobenzimidazole by [rad]OH in vacuo and aqueous media

The hydrogen atom transfer mechanism for the reaction between 2-mercaptobenzothiazole (MBT) and OH and between 2-mercaptobenzimidazole (MBZ) and OH has been investigated theoretically for the first time for the purpose of understanding the degradation pathway for MBZ and MBT to thiyl radical species. The objectives of the work have been to elucidate the geometries of the species involved in the reaction and to characterise them with respect to their energetic, geometric, electronic and reaction-kinetic properties. More importantly, the study compares and contrasts the two hydrogen transfer mechanisms through which the degradation of MBZ and MBT could be achieved: the direct hydrogen atom transfer (hydrogen abstraction) and the OH addition followed by water elimination (addition–elimination). The study has been performed in vacuo and in aqueous solution using the DFT/ωB97X−D and DFT/M06−2X methods in conjunction with the 6-311++G(3df,2p) basis set. The results of the study indicate that the geometry of the considered species only minimally depends on the medium and is similar in the results of both calculation methods. The pre-reactive complexes for the direct H atom transfer mechanism and for the addition-elimination mechanism are significantly different. The activation energy depends on the medium; for instance, it is often greater in aqueous solution than in vacuo; the calculated values of the activation energy depend also on the calculation method. In water solution, the direct hydrogen atom abstraction mechanism is kinetically preferred to the addition-elimination mechanism, suggesting that the studied reactions most likely proceed through the direct hydrogen atom abstraction mechanism. The estimated rate constant for the MBZ + OH reaction is also in close agreement with the experimentally determined value. The spin density distribution on the thiyl species is significantly delocalized away from the centre of H atom abstraction. The SH bond dissociation enthalpy (BDE) is slightly higher for MBT than for MBZ, although both values are below the experimentally determined SH BDE value.

Synthesis and characterization of Cr-ZSM-5 composite in fluoride medium and its performance in oxidation reaction of 2-mercaptobenzotiazole

PurposeThe purpose of this paper is to synthesize Cr-ZSM-5 using hydrothermal synthesis in acidic fluoride medium and the investigation of its catalytic performance in heterogeneous oxidation of 2-mercaptobenzothiazole in the presence of H2O2.Design/methodology/approachThe framework was characterized by chemical composition, FT-IR, UV-visible spectroscopy, N2 adsorption (BET), and diffraction x-ray (DRX). FT-IR spectroscopy shows the characteristic band of Si-O-Cr linkage around 960-990 cm−1 and bands around 688-690 and 627 cm−1, indicating the presence of extraframework chromium oxide. UV spectra show a shoulder around 244-257 and bands around 360-380 nm, assigning the tetrahedral coordinated environment in (O2−=Cr6+) − (Cr5+-O−1), charge transfer transition state (CT) of isolated Cr (VI) inside the structure of Cr-ZSM-5.FindingsThe catalytic degradation of 2-mercaptobenzothiazole by H2O2 heterogenous oxidation using catalyst Cr-ZSM-5 showed the formation of bis (benzothiazoyl) disulfide with 95 percent yield.Originality/valueThe application of this process in the environment (catalysis, adsorption, and degradation of organic compounds).

Microaerobic degradation of 2-Mercaptobenzothiazole present in industrial wastewater

Microaerobic degradation of 2-Mercaptobenzothiazole (2-MBT) was investigated using an isolated bacterial strain CSMB1. It was identified as Alcaligenes sp. MH146 by genomic analysis. The isolate degraded 50mg/L concentration of 2-MBT which was measured in terms of Total organic carbon (TOC) (700mg/L). A maximum degradation of 86% with a residual TOC concentration of 101mg/L was obtained after 72h, with the biomass growth of 290mg/L. The presence of specific activity of catechol 2, 3 oxygenase was observed in all the tested derivatives of benzothiazoles and the benzene ring opening was observed through meta cleavage. By analyzing the 72h incubated culture supernatant, 2-MBT, and all its biotransformed products were degraded into polar compounds. With the analytical results obtained, a possible microaerobic degradative pathway was proposed and illustrated for 2-MBT. It is concluded that microaerophilic isolate CSMB1 was able to degrade 2-MBT and its intermediates by utilizing them as sole carbon and energy.

Degradation of 2-mercaptobenzothiazole in aqueous solution by gamma irradiation

Industrial wastewaters containing 2-mercaptobenzothiazole (MBT), a widely used chemical additive, usually cannot be treated properly by conventional biological methods, thus cause an environmental risk. Ionizing radiation was proposed as a method for abatement of several refractory pollutants from water. The paper investigated MBT degradation using irradiation technology. The decomposition kinetics was described, and the transformation and the change of biodegradability were discussed. The results of gamma radiation experiments on MBT-containing aqueous solutions indicated that reactive radicals resulting from water radiolysis effectively degrade MBT and improve the biodegradability of the solutions. At a 20mg/L MBT concentration, the removal of 82% was achieved at the absorbed dose of 1.2kGy. The results of specific oxygen uptake rate (SOUR) test showed that MBT was decomposed into biodegradable products, after irradiation at 20kGy. Radicals attacked the sulfur atoms of the studied molecule leading to the release of sulfate ions, but the mineralization of organic carbons was rather weak. Initial concentration significantly affected the degradation efficacy of MBT by gamma radiation.

Relationship between oxidative degradation of 2-mercaptobenzothiazole and physicochemical properties of manganese (hydro)oxides

Environmental context. Manganese (hydro)oxide is one kind of the most important natural minerals that are capable of oxidising organic contaminants with a wide range of functionality. However, the oxidative reactivity of manganese (hydro)oxides for organic pollutant degradation may depend on their individual physicochemical properties. It is important to determine a relationship between their oxidative reactivity and physicochemical properties. Abstract. The oxidative reactivity of manganese (hydro)oxides is important for geochemical transformation of organic pollutants. Here, 2-mercaptobenzothiazole (MBT) degradation by six manganese (hydro)oxides, including γ-MnOOH, β-MnO2, α-MnO2, γ-Mn2O3, δ-MnO2, and MO-700, were investigated with different initial MBT concentrations, manganese (hydro)oxide dosages and pH values. The results show the oxidative reactivity of manganese (hydro)oxides towards MBT degradation strongly depends on their physicochemical properties. Specific surface area and reduction potential of manganese (hydro)oxides were positively correlated with MBT degradation rates, whereas pH at the point of zero charge (pHPZC) of manganese (hydro)oxides and apparent activation energy (Ea) were negatively correlated. A high average oxidation state with the same chemical valence always corresponds to high oxidative reactivity. Such findings provide some insights into understanding the transport and fate of organic pollutants in the presence of different manganese (hydro)oxides in the natural environment.