Jianshe Liu

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Organization: Donghua University

Department: College of Environmental Science and Engineering

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Chemicals
References

On the kinetics of organic pollutant degradation with Co2+/peroxymonosulfate process: When ammonium meets chloride

Co-reporter:Ying Huang, Fei Yang, Luoyan Ai, Min Feng, Chi Wang, Zhaohui Wang, Jianshe Liu

Chemosphere 2017 Volume 179(Volume 179) pp:

Publication Date(Web):1 July 2017

DOI:10.1016/j.chemosphere.2017.03.110

•Effects of ammonium and chloride ions on Co/PMS process were firstly reported.•An inhibitory effect of ammonium on the rate of AO7 degradation was observed.•It is recommended to monitor NH4+/Cl− in wastewater when Co/PMS is used.A large amount of chloride and ammonium ions were produced and released from industrial processes with non-biodegradable organic pollutants to affect efficiencies of advanced oxidation processes (AOPs). Here, the influences of chloride and ammonium ions on Co/peroxymonosulfate (Co/PMS) reaction system, a widely used AOPs to produce sulfate radicals, were investigated by examining the degradation efficiency of an azo dye (Acid Orange 7, AO7). The experimental results showed that a significant decrease in the degradation rate of AO7 was observed in the presence of NH4+, while a dual effect of chloride on AO7 bleaching appeared. The presence of NH4Cl was unfavorable for AO7 degradation at low concentration (<20 mM), whereas further addition of NH4Cl (>20 mM) apparently accelerated AO7 discoloration rate. The apparent effects of the two co-existing inorganic ions were determined by roles of the dominating ions at varied molar ratio of [NH4+]/[Cl−]. The present study may have technical implications for the treatment of industrial wastewater containing diverse ions in practice.

Trace bromide ion impurity leads to formation of chlorobromoaromatic by-products in peroxymonosulfate-based oxidation of chlorophenols

Co-reporter:Changling Fang, Zhaohui Wang, Min Feng, Ying Huang, Fei Yang, Jianshe Liu

Chemosphere 2017 Volume 182(Volume 182) pp:

Publication Date(Web):1 September 2017

DOI:10.1016/j.chemosphere.2017.05.065

•Reaction of trace Br− with PMS results in chlorophenol degradation.•Chlorobromoaromatic compounds are identified for the first time.•The possible reaction pathways of TCP and its derivatives are explained.Trace bromide (Br−) released from industrial effluents or brominated compounds is able to directly react with peroxymonosulfate (PMS) to generate a series of reactive oxidants which can oxidize and also halogenate organics. We report the identification and evolution of by-products during 2,4,6-trichlorophenol (TCP) degradation in the presence of PMS and trace Br−. The influencing factors, including Br− concentration and pH, were investigated. The depletion of TCP was accelerated with increasing trace Br− concentration (0–0.2 mM) and was affected by the initial pH (3.0–7.0). The chlorinated and brominated compounds were identified in simulated wastewater during treatment with PMS. Notably, the potential formation of chlorobromoaromatic by-products was demonstrated for the first time in the presence of PMS and trace Br−. The possible reaction pathways of TCP and its derivatives are discussed. These findings have important implications for the future applications of PMS-based oxidation processes.Download high-res image (159KB)Download full-size image

Effects of chloride on PMS-based pollutant degradation: A substantial discrepancy between dyes and their common decomposition intermediate (phthalic acid)

Co-reporter:Ying Huang, Zhaohui Wang, Qingze Liu, Xiaoxiao Wang, Zhijun Yuan, Jianshe Liu

Chemosphere 2017 Volume 187(Volume 187) pp:

Publication Date(Web):1 November 2017

DOI:10.1016/j.chemosphere.2017.08.120

•Effects of Cl− on degradation of dyes and their intermediate (PA) were different.•Less chlorinated products were formed during PA oxidation at high chloride level.•A possible degradation pathway of PA in Co/PMS process was proposed.A considerable effort has been devoted to elucidating the roles of chloride in oxidative degradation and chlorination of dyes. However, few investigations are available on kinetic analysis and transformation pathways of secondary degradation byproducts of dyes in saline wastewater treatment. Here the impact of chlorine on the degradation rate of phthalic acid, a typical dye degradation intermediate, by the Co2+/peroxymonosulfate (PMS) process was examined. Degradation efficiency, intermediate products, AOX (adsorbable organic halogen) formation and mineralization were considered. An overall negative impact was observed within the concentration of Cl− up to 100 mM, differing from the dual effect of chloride on dye degradation process as previously observed. The presence of high levels of Cl− led to a low production of AOX and a reduction of the formation of chlorinated by-products. The mineralization was also restrained when the Cl− concentration was increased. Degradation pathways for these processes are proposed. These findings provide valuable information about the degradation pathways of dyes and about the formation mechanism of chlorinated by-products in industrial saline wastewater treatment.

Isolation of Bacillus cereus P05 and Pseudomonas sp. X12 and their application in the ramie retting

Co-reporter:Qian Wang, Hong-gao Chen, Gang Fang, An-qing Chen, Peng Yuan, Jian-she Liu

Industrial Crops and Products 2017 Volume 97(Volume 97) pp:

Publication Date(Web):1 March 2017

DOI:10.1016/j.indcrop.2016.12.047

•Two strains that efficiently expressed pectinase and xylanase were isolated.•Conditions of bioaugmented retting with the two selected strains were optimized.•The key enzyme activities in bioaugmentation retting system were greatly improved.Two bacterial strains that express high levels of pectinase and xylanase, named P05 and X12, were isolated from the soil of a ramie garden using pectinase and xylanase selective medium. A bioaugmentation experiment for ramie retting using these bacterial strains showed a significant increase in retting rate when equal ratios of P05 and X12 were mixed into the retting solution at 20% of the volume. Using bioaugmentation, the retting process was completed at 60 h, reducing the retting period by 50%, and the gum removal ratio improved by 79.6%. In addition, the breaking strength of the resulting fiber was increased by 52.3%. Analysis of bacterial population structure and enzyme activity levels in the bioaugmented retting system showed that P05 and X12 quickly became the dominant bacteria within the retting solution microflora, and improved the microflora’s ability to produce key retting enzymes. The maximum pectinase and xylanase activities in the bioaugmented retting system were 80.84 U/mL and 50.51 U/mL, respectively, which were 68.98% and 64.21% higher respectively when compared to the control. Thus, addition of P05 and X12 into the retting solution resulted in accelerated gum degradation and fiber separation.

Performance and microbial community structures of hydrolysis acidification process treating azo and anthraquinone dyes in different stages

Co-reporter:Na Liu;Xuehui Xie;Bo Yang;Qingyun Zhang

Environmental Science and Pollution Research 2017 Volume 24( Issue 1) pp:252-263

Publication Date(Web):06 October 2016

DOI:10.1007/s11356-016-7705-y

In this study, performance of hydrolysis acidification process treating simulated dyeing wastewater containing azo and anthraquinone dyes in different stages was investigated. The decolorization ratio, CODCr removal ratio, BOD5/CODCr value, and volatile fatty acids (VFAs) production were almost better in stage 1 than that in stage 2. Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) confirmed the biodegradation of Reactive Black 5 (RB5) and Remazol Brilliant Blue R (RBBR) in hydrolysis acidification process. Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) analyses revealed that significant difference of microbial community structures existed in stage 1 and 2. The dominant species in stage 1 was related to Bacteroidetes group, while the dominant species in stage 2 was related to Bacteroidetes and Firmicutes groups. From the results, it could be speculated that different dyes’ structures might have significant influence on the existence and function of different bacterial species, which might supply information for bacteria screening and acclimation in the treatment of actual dyeing wastewater.

Synthesis of BiOBr/WO3 p–n heterojunctions with enhanced visible light photocatalytic activity

Co-reporter:Junlei Zhang, Lisha Zhang, Xiaofeng Shen, Pengfei Xu and Jianshe Liu

CrystEngComm 2016 vol. 18(Issue 21) pp:3856-3865

Publication Date(Web):26 Apr 2016

DOI:10.1039/C6CE00824K

A prerequisite for the development of photocatalysis techniques is to obtain photocatalysts with remarkable activity. Herein, we have reported BiOBr/WO3 p–n heterojunctions as novel and efficient visible-light-driven photocatalysts. The BiOBr/WO3 p–n heterojunctions have been prepared through an electrospinning–calcination–solvothermal method, and they all present a flower-like superstructure. The photocatalytic activities of these p–n heterojunctions are investigated by degrading rhodamine B (RhB), methyl orange (MO) and para-chlorophenol (4-CP) under visible light irradiation (λ > 400 nm), respectively. When RhB serves as the target pollutant, all BiOBr/WO3 p–n heterojunctions with different theoretical molar ratios of BiOBr and WO3 (1/0.5, 1/1, 1/2) exhibit higher photocatalytic activity than pure WO3 or BiOBr. Especially, the BiOBr/WO3 p–n heterojunction with a molar ratio of 1/1 displays the highest photocatalytic activity among all the as-synthesized catalysts, even higher than the activity from the mixture of two individual photocatalysts with the same weight of components (WO3 and BiOBr). In addition, when MO or 4-CP acts as the target pollutant, the BiOBr/WO3 p–n heterojunction with a molar ratio of 1/1 still exhibits excellent photocatalytic performance. Furthermore, the recycling experiment confirms that the BiOBr/WO3 p–n heterojunction is essentially stable during the photocatalytic process. The enhanced photocatalytic activity of the BiOBr/WO3 p–n heterojunction is predominantly attributed to the efficient separation of photogenerated electrons and holes. The photogenerated holes (h+) and superoxide radical anions (˙O2−) have been found to be the primary reactive species responsible for the nearly complete mineralization of RhB dye in water.

Characteristics of estrogenic/antiestrogenic activities during the anoxic/aerobic biotreatment process of simulated textile dyeing wastewater

Co-reporter:Na Liu, Xuehui Xie, Hong Jiang, Fang Yang, Chengzhi Yu and Jianshe Liu

RSC Advances 2016 vol. 6(Issue 30) pp:25624-25632

Publication Date(Web):02 Mar 2016

DOI:10.1039/C5RA25991F

The presence of estrogenic/antiestrogenic chemicals in textile dyeing wastewater has been well demonstrated according to previous studies. However, the characteristics of estrogenic/antiestrogenic activities during conventional biological treatment have been poorly investigated. In this study, the yeast two-hybrid assay (YES) was used to evaluate the agonistic and antagonistic estrogen activities during the anoxic/aerobic treatment of textile dyeing wastewater. The results indicated that the estrogenic activity of the textile dyeing wastewater was negligible throughout the anoxic/aerobic treatment, but the antiestrogenic activity increased obviously after the aerobic treatment. By fractionating the dissolved organic matter (DOM) in wastewater into different fractions, it was found that hydrophobic acids (HOA) and hydrophobic neutrals (HON) were the key fractions involved in increasing antiestrogenic activity of the wastewater during anoxic/aerobic treatment. Furthermore, the fluorescence spectroscopy analysis on wastewater samples and their fractions of soluble organic compounds suggested that HOA and HON fractions contained more humic/fulvic acid in aerobic effluent than that in anoxic effluent, which could mask estrogenic activity in aerobic effluent.

Doubling the power conversion efficiency in CdS/CdSe quantum dot sensitized solar cells with a ZnSe passivation layer

Co-reporter:Fei Huang, Juan Hou, Qifeng Zhang, Yuan Wang, Robert C. Massé, Shanglong Peng, Huanli Wang, Jianshe Liu, Guozhong Cao

Nano Energy 2016 Volume 26() pp:114-122

Publication Date(Web):August 2016

DOI:10.1016/j.nanoen.2016.05.012

•A ZnSe passivation layer was introduced in the TiO2/CdS/CdSe QDSSCs.•Energy band alignment not only prevents the transfer of electrons to the electrolyte but also facilitates holes transfer to the electrolyte.•Enhanced light absorption and reduced charge recombination leading to a high power conversion efficiency of 6.39%.The surface passivation layer in quantum dot sensitized solar cells (QDSSCs) plays a very important role in preventing surface charge recombination and, thus, improving the power conversion efficiency. The present study demonstrated the introduction of a ZnSe passivation layer prepared with a successive ionic layer absorption and reaction (SILAR) method in CdS/CdSe co-sensitized solar cells, though not likely in the ideal form of a conformal overlayer, have significantly enhanced the power conversion efficiency, which was found to be far more efficient than the most widely used ZnS passivation layer. Not only can the ZnSe passivation layer reduce surface charge recombination, but can also enhance the light harvesting. The short-circuit current density, open-circuit voltage, fill factor, and the corresponding photovoltaic conversion efficiency were all significantly improved with the introduction of a ZnSe passivation layer but varied appreciably with the layer thickness. When three SILAR cycle layer was applied, the power conversion efficiency is as high as 6.4%, which is almost doubled the efficiency of 3.4% for the solar cell without ZnSe passivation layer. For the comparison, the CdS/CdSe co-sensitized solar cells with optimum ZnS passivation layer was also fabricated, which generated a power conversion efficiency of 4.9%, much lower than 6.4% of ZnSe passivated QDSSCs. This work demonstrated that ZnSe would be a good alternative to ZnS as a passivation material.

Fe2O3–AgBr nonwoven cloth with hierarchical nanostructures as efficient and easily recyclable macroscale photocatalysts

Co-reporter:Huihui Zhao, Lisha Zhang, Xiaodong Gu, Shijie Li, Bo Li, Huanli Wang, Jianmao Yang and Jianshe Liu

RSC Advances 2015 vol. 5(Issue 15) pp:10951-10959

Publication Date(Web):06 Jan 2015

DOI:10.1039/C4RA13254H

A prerequisite for the development of photocatalytic application is to obtain efficient and easily recycled visible-light-driven (VLD) photocatalysts. Usually, nanosized photocatalysts exhibit excellent photocatalytic performances but cannot be easily recycled, and film-shaped nanostructured photocatalysts on substrates (or magnetic photocatalysts) can be easily recycled but have low surface area and/or high production cost. To solve this problem, herein we report on the design and preparation of nonwoven cloth based on semiconductor–semiconductor (Fe2O3–AgBr as the model) nanojunctions as efficient and easily recyclable macroscale photocatalysts with nanostructure. Fe2O3–AgBr nonwoven cloth has been prepared by a simple electrospinning–calcination method. Such macroscale cloth is free-standing and it consists of hierarchical pores with diameters of 600–750 nm and nanofibers with diameters of 150–350 nm. Furthermore, these nanofibers are constructed from Fe2O3 and AgBr nanoparticles with diameters of ∼60 nm. In addition, Fe2O3–AgBr nonwoven cloth has magnetic properties and a broadened visible-light photo-response range (400–750 nm). Under the irradiation of visible light, Fe2O3–AgBr nonwoven cloth exhibits higher photocatalytic activity than Fe2O3 nonwoven cloth and AgBr nonwoven cloth containing the same weight of visible-light-active component, for the degradation of rhodamine B (RhB) and parachlorophenol (4-CP). Higher photocatalytic activity of Fe2O3–AgBr nonwoven cloth should result from the synergic effects between Fe2O3 and AgBr due to the broadening photoabsorption and the energy level matching. Importantly, Fe2O3–AgBr nonwoven cloth can be easily transferred and/or recycled by the dipping/pulling method and/or external magnetic field, and it has excellent photocatalytic stability during recycling tests. Therefore, this work provides some insight into the design and development of novel, efficient and easily recyclable macroscale nonwoven cloths, for future practical photocatalytic application, for example, degrading organic pollutants in polluted rivers.

Flower-like Bi2S3/Bi2MoO6 heterojunction superstructures with enhanced visible-light-driven photocatalytic activity

Co-reporter:Junlei Zhang, Lisha Zhang, Nuo Yu, Kaibing Xu, Shijie Li, Huanli Wang and Jianshe Liu

RSC Advances 2015 vol. 5(Issue 92) pp:75081-75088

Publication Date(Web):28 Aug 2015

DOI:10.1039/C5RA13148K

A prerequisite for the development of photocatalytic technology is to obtain efficient visible-light-driven photocatalysts. Herein, we have reported a flower-like Bi2S3/Bi2MoO6 heterojunction as a novel and efficient visible-light-driven photocatalyst. The Bi2S3/Bi2MoO6 heterojunction has been prepared by a solvothermal method. It consists of flower-like superstructures with diameters ranging from 1 to 3 μm, which are built from Bi2MoO6 nanosheets with a thickness of about 15 nm decorated with Bi2S3 nanoparticles with diameters of ∼3.5 nm. Furthermore, the photocatalytic activity of the Bi2S3/Bi2MoO6 heterojunction has been evaluated through the degradation of rhodamine B (RhB) dye and colorless parachlorophenol (4-CP) under visible-light irradiation (λ > 400 nm). The results demonstrate that the Bi2S3/Bi2MoO6 heterojunction exhibits higher photocatalytic activity in degrading RhB and 4-CP than single Bi2S3 or Bi2MoO6. More importantly, the photocatalytic activity of the Bi2S3/Bi2MoO6 heterojunction is superior to the sum of the activities of two individual photocatalysts (Bi2MoO6 and Bi2S3). The recycling experiment confirms that the Bi2S3/Bi2MoO6 heterojunction is essentially stable during the photocatalytic process. Therefore, the Bi2S3/Bi2MoO6 heterojunction can be used as an efficient and stable visible-light-driven photocatalyst for the purification of the environment.

Enhanced catalytic ability of chitosan–Cu–Fe bimetal complex for the removal of dyes in aqueous solution

Co-reporter:Sadia Rashid, Chensi Shen, Xiaoguang Chen, Su Li, Yanhong Chen, Yuezhong Wen and Jianshe Liu

RSC Advances 2015 vol. 5(Issue 110) pp:90731-90741

Publication Date(Web):16 Oct 2015

DOI:10.1039/C5RA14711E

In this study, despite the high adsorption ability, efficient catalytic activity of a chitosan–metal complex has been developed through the chelation of chitosan polymer with bimetals Cu(II) and Fe(III). The removal of C. I. Reactive Black 5 (RB 5) by the chitosan–Cu–Fe complex/H2O2 system was studied in the pH range from 4 to 12. The maximal dye removal rate was achieved at an optimal concentration of Cu and Fe in the chitosan–Cu–Fe matrix, demonstrating the combination of sorptive enrichment and catalytic degradation. The results indicated that TOC removal and discoloration of the dye achieved 89.9% and 96.5% in a short reaction time. The pH sensitivity of the chitosan complex, the effect of the coexisting ions and the adsorption of other anionic dyes were also studied. X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were analyzed to study the structure of the chitosan bi-metal complex and a possible mechanism was proposed.

A novel photosensitized Fenton reaction catalyzed by sandwiched iron in synthetic nontronite

Co-reporter:Renlan Liu, Dongxue Xiao, Yaoguang Guo, Zhaohui Wang and Jianshe Liu

RSC Advances 2014 vol. 4(Issue 25) pp:12958-12963

Publication Date(Web):26 Feb 2014

DOI:10.1039/C3RA47359G

The conventional photo-Fenton reaction often suffers from the constraints of operation pH, low iron loading, ultraviolet availability in solar light and instability of iron-based catalysts. Here we report a novel heterogeneous Fenton reaction which works with a dye-photosensitized structural Fe(III)/Fe(II) redox cycling mechanism. The synthesized nontronite catalyst (NAU) was characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectra (FTIR), X-ray photoelectron spectroscopy (XPS) analysis, and thermal gravimetric analysis (TG). NAU exhibited excellent catalytic activity over a wide pH range (3.0–8.0) for highly efficient degradation of Rhodamine B by hydrogen peroxide (H2O2) under visible light irradiation (λ > 420 nm). The excited dye molecule donates electrons to structural iron sandwiched in NAU which further catalyzes H2O2 to generate highly reactive ˙OH radicals. This iron-rich clay mineral (total Fe, 24.4 wt%) is chemically and mechanically stable. There are no measurable iron leaching, nor any noticeable loss of activity and damage to the clay structure observed after 6 recycles. Therefore, NAU clay has outstanding merits for the practical treatment of organic dye pollutants at large scale.

Construction of two new 3D supramolecular networks with 3-pyridyl-4-yl-benzoic acid ligands: Synthesis, characterization, and luminescence

Co-reporter:J. Guo;S. J. Li;D. -L. Miao;J. S. Liu

Russian Journal of Coordination Chemistry 2014 Volume 40( Issue 1) pp:10-15

Publication Date(Web):2014 January

DOI:10.1134/S1070328414010011

Two new coordination polymers with 3-pyridyl-4-yl-benzoic acid (3,4-HPybz), namely, [Zn(3,4-Pybz)2 · 2H2O]n (I) and [Ag(3,4-Pybz)(3,4-HPybz)]n (II), have been synthesized and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, and single crystal X-ray diffraction. Compound I crystallizes in the triclinic system and has P1 space group. Complex I is an infinite 1D chain polymer and the infinite chains array uniformly in a 3D supramolecular network which posesses abundant O-H...O hydrogen-bonding interactions among the occupied and unoccupied carboxylate O atoms and the coordinated water molecules; compound II crystallizes in the triclinic system and has \(P\bar 1\) space group, II is an infinite chain with the repeat sequence of Ag1(I)-Ag2(I)-Ag1(I), in which weak intermolecular interactions play a key role in forming the final 3D supramolecular architectures. The photoluminescences and lifetime of I and II in the solid state have been investigated.

Novel Photo-Sulfite System: Toward Simultaneous Transformations of Inorganic and Organic Pollutants

Co-reporter:Yaoguang Guo, Xiaoyi Lou, Changling Fang, Dongxue Xiao, Zhaohui Wang, and Jianshe Liu

Environmental Science & Technology 2013 Volume 47(Issue 19) pp:11174-11181

Publication Date(Web):September 9, 2013

DOI:10.1021/es403199p

An efficient and green advanced oxidation process (i.e., photo-sulfite reaction) for the simultaneous oxidation of sulfite and organic pollutants in water is reported. The photo-sulfite system (UV–Fe(III)–sulfite) is based on the Fe-catalyzed sulfite oxidation and photochemistry of Fe(III) species. SO4•– and •OH radicals were identified in the photo-sulfite system with radical scavenging experiments using specific alcohols. This novel technology was consistently proven to be more favorable than the alternative Fe(III)–sulfite systems for the degradation of 2,4,6-trichlorophenol (2,4,6-TCP) and other organic pollutants at all conditions tested. The reactivity of photo-sulfite system was sustained due to the spontaneous switch of photoactive species from Fe(III)–sulfito to Fe(III)–hydroxo complexes with the depletion of sulfite and the decrease in pH. In contrast, in the absence of light the performance of the Fe(III)–sulfite system was greatly diminished after the consumption of sulfite. The formation of the Fe(III)–sulfito complex is a necessary step for initiating the photo-sulfite reaction. Inhibition of the oxidation of 2,4,6-TCP and methyl orange (MO) was observed in the presence of ligands that can stabilize one or more of the reactants: Fe(III), Fe(II), or sulfite. Our study provides a new facile route for the generation of SO4•– and simultaneous removal of organic and inorganic pollutants.

Surface decoration of Bi2WO6 superstructures with Bi2O3 nanoparticles: an efficient method to improve visible-light-driven photocatalytic activity

Co-reporter:Huanli Wang, Shijie Li, Lisha Zhang, Zhigang Chen, Junqing Hu, Rujia Zou, Kaibing Xu, Guosheng Song, Huihui Zhao, Jianmao Yang and Jianshe Liu

CrystEngComm 2013 vol. 15(Issue 44) pp:9011-9019

Publication Date(Web):29 Aug 2013

DOI:10.1039/C3CE41447G

Bi2WO6 superstructures have attracted extensive attention in the photocatalytic field, but their practical application has been limited by drawbacks such as an unsatisfactory visible-light photoresponse range. To address these drawbacks, we have developed a simple strategy by surface decoration of Bi2WO6 superstructures with Bi2O3 nanoparticles through a dip-coating–anneal method. The characterization results confirm robust construction of nanojunctions in the Bi2WO6 superstructure decorated with Bi2O3 nanoparticles (abbreviated as: Bi2WO6 SS–D–Bi2O3 NP) nanojunction system. Interestingly, this Bi2WO6 SS–D–Bi2O3 NP nanojunction system exhibits a broad-spectrum photoabsorption from the UV to visible-light region with an edge at ca. 650 nm, indicating a red shift of photoabsorption range compared with that of Bi2WO6 superstructures (edge at ca. 450 nm), nanoscale Bi2O3 powder (ca. 470 nm) and Bi2O3–Bi2WO6 composite microspheres (ca. 440 nm) prepared through a one-step hydrothermal route. Furthermore, by using Bi2WO6 SS–D–Bi2O3 NP as visible-light-driven (VLD) photocatalyst, the photodegradation efficiency of Rhodamine B (RhB) reaches 86% which is about 2.7 times as that (32.3%) by Bi2WO6 SS and 1.3 times that (64.4%) by Bi2O3–Bi2WO6 composite microspheres, in 20 min of reaction. Besides that, this nanojunction can still efficiently degrade the colorless pollutant parachlorophenol. In particular, the photocatalytic activity of the nanojunction is superior to the sum of the activities of two individual photocatalysts with the same weight of components (Bi2WO6 SS and Bi2O3 NP). Based on the above results and energy band diagram, two possible reasons have been proposed for the higher photocatalytic activity of Bi2WO6 SS–D–Bi2O3 NP nanojunction: (1) substantial broadening of the photoabsorption range and (2) efficient separation of photogenerated electron–hole pairs. This work provides some insight into the design of novel and efficient nanojunction photocatalysts with broadened photoabsorption range for enhancing VLD photocatalytic activity.

A highly sensitive differential pulse anodic stripping voltammetry for determination of 17β-estradiol (E2) using CdSe quantum dots based on indirect competitive immunoassay

Co-reporter:Nuanapa Chaisuwan, He Xu, Genying Wu, Jianshe Liu

Biosensors and Bioelectronics 2013 Volume 46() pp:150-154

Publication Date(Web):15 August 2013

DOI:10.1016/j.bios.2013.02.041

In this study a new and fast procedure was developed to determine trace 17β-estradiol (E2) concentrations using CdSe quantum dots (QDs) conjugation with bovine serum albumin (BSA)-E2. To increase the high efficiency of the method, the immunoassay design was restricted to an indirect competitive format. The E2 antigen and bioconjugate were incubated in a microtiter plate with an anti-E2 antibody and competition for antibody binding sites was established. The in situ bismuth-coated carbon electrodes were used for detecting the cadmium ions (Cd2+) released during the acid dissolution step. After optimization, the well-defined sharp anodic stripping voltammograms curves of the E2 concentration ranging from 50 to 1000 pg/mL was recorded, and the lowest detection limit was 50 pg/mL with 6% reproducibility and 7% repeatability. Finally, the assay was applied to tap water and wastewater samples. The detection limits were 52.56±0.125 pg/mL for tap water and 51.42±0.453 pg/mL for wastewater. These results show that the assay exhibited sensitive analytical performance in E2 detection with high sensitivity and accuracy with satisfactory results.Highlights► This is the first report on development of electrochemical immunoassay for sensitive detection of 17β-estradiol (E2). ► A ‘bioconjugate’ comprising of CdSe QDs and BSA-E2 was used in competitive immunoassay with anti-E2 antibody and E2 antigen. ► The decrease in sample E2 concentration increased the amount of CdSe-BSA-E2 captured with the anti-E2 antibody. ► In addition to highly efficient detection techniques, indirect detection of Cd2+ by DPASV method instead of E2-antigen was done. ► The experimental parameters were optimized to obtain the best signal and lowest detection limit.

Characterization of iron-sulfur cluster assembly protein isca from Acidithiobacillus ferrooxidans

Co-reporter:Lin Qian;Chunli Zheng

Biochemistry (Moscow) 2013 Volume 78( Issue 3) pp:244-251

Publication Date(Web):2013 March

DOI:10.1134/S000629791303005X

IscA is a key member of the iron-sulfur cluster assembly machinery found in bacteria and eukaryotes, but the mechanism of its function in the biogenesis of iron-sulfur cluster remains elusive. In this paper, we demonstrate that Acidithiobacillus ferrooxidans IscA is a [4Fe-4S] cluster binding protein, and it can bind iron in the presence of DTT with an apparent iron association constant of 4·1020 M−1. The iron binding in IscA can be promoted by oxygen through oxidizing ferrous iron to ferric iron. Furthermore, we show that the iron bound form of IscA can be converted to iron-sulfur cluster bound form in the presence of IscS and L-cysteine in vitro. Substitution of the invariant cysteine residues Cys35, Cys99, or Cys101 in IscA abolishes the iron binding activity of the protein; the IscA mutants that fail to bind iron are unable to assemble the iron-sulfur clusters. Further studies indicate that the iron-loaded IscA could act as an iron donor for the assembly of iron-sulfur clusters in the scaffold protein IscU in vitro. Taken together, these findings suggest that A. ferrooxidans IscA is not only an iron-sulfur protein, but also an iron binding protein that can act as an iron donor for biogenesis of iron-sulfur clusters.

p-Nitrophenol Enhanced Degradation in High-Voltage Pulsed Corona Discharges Combined with Ozone System

Co-reporter:Hongai Zheng;Yi Guo;Hui Zhu;Dazhao Pan

Plasma Chemistry and Plasma Processing 2013 Volume 33( Issue 6) pp:1053-1062

Publication Date(Web):2013 December

DOI:10.1007/s11090-013-9482-4

Degradation of p-nitrophenol (PNP) in aqueous solution by high-voltage pulse corona discharges (HVPD) combined with ozone was investigated in this study. Experimental results showed that 96 % of PNP (380 mg/L) can be degraded within 30 min using a combined technology. Additionally, the effects of initial concentration of PNP, synergistic effect of both techniques, and pH of the aqueous solution on PNP degradation were evaluated. This combined technology achieved better results than using two mineralization techniques in series which indicates that synergistic effect of HVPD and ozone promoted pollutant decomposition. On the other hand, weak alkalinity was favorable for PNP removal. In the end, intermediate products resulting from PNP degradation processes were analyzed by ion chromatography and high performance liquid chromatography-tandem mass spectrometry. Main intermediate products, including p-benzoquinone, nitro benzoquinone, trans-muconic acid, maleic acid, acetic acid, formic acid, NO2− and NO3− were identified. It was proposed a possible reaction pathway.

A Highly Sensitive Electrochemical Impedance Spectroscopy Immunosensor for Determination of 1-Pyrenebutyric Acid Based on the Bifunctionality of Nafion/Gold Nanoparticles Composite Electrode

Co-reporter:Ping Yang;Qiaoli Zheng;He Xu;Litong Jin

Chinese Journal of Chemistry 2012 Volume 30( Issue 5) pp:1155-1162

Publication Date(Web):

DOI:10.1002/cjoc.201100485

Abstract

A simple, highly sensitive and label-free electrochemical impedance spectroscopy (EIS) immunosensor was developed using Nafion and gold nanoparticles (nano-Au/Nafion) composites for the determination of 1-pyrenebutyric acid (PBA). Under the optimal conditions, the amount of immobilized antibody was significantly improved on the nano-Au/Nafion electrode due to the synergistic effect and biocompatibility of Nafion film and gold nanoparticles composites. The results showed that the sensitivity and stability of nano-Au/Nafion composite electrode for PBA detection were much better than those of nano-Au modified glassy carbon electrode (nano-Au/GCE). The plot of increased electron transfer resistances (R_ets) against the logarithm of PBA concentration is linear over the range from 0.1 to 150 ng·mL⁻¹ with the detection limit of 0.03 ng·mL⁻¹. The selectivity and accuracy of the proposed EIS immunosensor were evaluated with satisfactory results.

Degradation of reactive dyes by contact glow discharge electrolysis in the presence of Cl− ions: Kinetics and AOX formation

Co-reporter:Sadiqua N. Ramjaun, Ruixia Yuan, Zhaohui Wang, Jianshe Liu

Electrochimica Acta 2011 Volume 58() pp:364-371

Publication Date(Web):30 December 2011

DOI:10.1016/j.electacta.2011.09.052

The plasma generated around the anode during contact glow discharge electrolysis (CGDE) is a rich source of hydroxyl (OH) radicals that can efficiently degrade organic contaminants in aqueous solutions. The degradation of textile azo dyestuffs, Reactive Yellow 176 (Y3RS), Reactive Red 239 (R3BS) and Reactive Black 5 (B5), by anodic CGDE was investigated in the presence of chloride (Cl−) ions. The degradation kinetics of the dyes was dependent on the concentration of Cl− ions and on the respective dye being treated. R3BS degradation was inhibited by Cl− ions in the range of 0–0.01 M. When the Cl− ion concentration was less than 0.02 M, the dyes followed pseudo first-order degradation kinetics. For concentrations greater than 0.02 M, the degradation of Y3RS and B5 was significantly enhanced compared to the degradation of R3BS and deviated from first-order reaction kinetics. The presence of Cl− ions (0.03 M) did not appear to improve dye mineralization but resulted in the formation of adsorbable organic halogens (AOX). The results indicated that the AOX could be abated with prolonged electrolytic treatment. This observation is significant for the assessment of the environmental impact of this technology for wastewater treatment.

Sensitive Voltammetric Detection of Trace Heavy Metals in Real Water Using Multi-Wall Carbon Nanotubes/Nafion Composite Film Electrode

Co-reporter:He Xu;Qiaoli Zheng;Ping Yang;Litong Jin

Chinese Journal of Chemistry 2011 Volume 29( Issue 4) pp:805-812

Publication Date(Web):

DOI:10.1002/cjoc.201190162

Abstract

Multi-wall carbon nanotubes (MWCNTs) and Nafion composite film (MWCNTs/Nafion) were used for fabricating electrochemical sensors for the voltammetric detection of trace lead(II) and cadmium(II) in several water samples. The morphology and structure of MWCNTs/Nafion film were characterized by scanning electron microscopy (SEM) and infrared spectrum (IR). The electron transfer of MWCNTs/Nafion composite film was examined by cyclic voltammetry (CV) and electrochemical impedance spectrum (EIS). Various experimental parameters, which influenced the response of MWCNTs/Nafion/GC to target metals, were optimized. The results showed that the synergistic effect was obtained on the MWCNTs/Nafion/GC whose sensitivity and stability were better than those of Nafion-coated electrode (Nafion/GC) or CNTs/GC. Stability of the Pb(II) and Cd(II) stripping signals was excellent with relative standard deviations (RSD) within 5% (n=10) from one electrode preparation to another, and RSD of 30 µg·L⁻¹Pb(II) and Cd(II) were 2.8% and 3.2% for 20 repeated analysis on one single CNTs/Nafion/GC. Over 50 runs, the stability of Pb and Cd detection at the MWCNTs/Nafion conposites electrode was still satisfactory with RSD lower than 6.0%. The determination limits (S/N=3) of the proposed method were determined to be 100 ng·L⁻¹ for Pb and 150 ng·L⁻¹ for Cd. Finally, the MWCNTs/Nafion/GC was successfully applied to determine Pb(II) and Cd(II) in different water samples with recoveries of 97%–103% for Pb and 96%–104% for Cd.

Electrochemical synthesis of silver nanoparticles-coated gold nanoporous film electrode and its application to amperometric detection for trace Cr(VI)

Co-reporter:He Xu;QiaoLi Zheng;Ping Yang;SuJie Xing

Science China Chemistry 2011 Volume 54( Issue 6) pp:1004-1010

Publication Date(Web):2011 June

DOI:10.1007/s11426-011-4261-7

A simple and rapid approach for the electrochemical synthesis of Ag nanoparticles-coated gold nanoporous film (AgGNF) on a gold substrate was reported. The solid gold electrode (SGE) was directly anodized under a high potential of 5 V, and then reduced to obtain gold nanoporous film (AuNF) by freshly prepared ascorbic acid. The Ag nanoparticles (AgNPs) were grown on the AuNF electrode by potential-step electrodeposition. The resulting AgGNF composites electrodes were characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy and cyclic voltammetry (CV). As-prepared AgGNF electrode was used as a kind of superior sensor for Cr(VI) detection, which exhibited better electrocatalytic behavior than those of AuNF and SGE under identical conditions. Such a designed AgGNF nanocomposites electrode showed outstanding sensitivity (about 0.15 nA/ppb) and favorable reproducibility for Cr(VI) detection. The dependence of reduction current on Cr(VI) concentration is linear from 2 to 370 ppb with a low detection limit of 0.65 ppb. Interferences from other heavy metals ions (Cr3+, Cu2+, Pb2+, As3+ and Hg2+) associated with Cr(VI) analysis could be effectively diminished. The present method proves to be rapid, reliable, sensitive and low-cost.

A Simple and Sensitive Method for the Detection of Trace Pb(II) and Cd(II) based on Nafion-coated Antimony Film Electrode

Co-reporter:He Xu;Ping Yang;Qiaoli Zheng; Jianshe Liu;Litong Jin

Chinese Journal of Chemistry 2010 Volume 28( Issue 11) pp:2287-2292

Publication Date(Web):

DOI:10.1002/cjoc.201090378

Abstract

Nafion-coated antimony film electrode (NCAFE) was prepared in situ by simultaneously plated antimony with analytes, and applied to the determination of trace Pb(II) and Cd(II) in non-deaerated solutions by differential pulse anodic stripping voltammetry (DPASV). Various experimental parameters, which influenced the response of the NCAFE to those metals, were thoroughly optimized and discussed. The results indicated that the sensitivity and resistance to surfactants at the NCAFE were remarkably improved with relative to the antimony film electrode (AFE). In the presence of 5 mg·L⁻¹ gelatin, the peak heights at the NCAFE showed 4-fold enhancement for Pb and a 9-fold enhancement for Cd over a bare AFE. Reproducibility of the sensor was satisfactory, and the relative standard deviations were 4.8% for 20 μg·L⁻¹ Pb and 3.2% for 25 μg·L⁻¹ Cd (n=15) with preconcentration time of 180 s. The determination limits (S/N=3) of this sensor were determined to be 0.15 μg·L⁻¹ for Pb and 0.30 μg·L⁻¹ for Cd with accumulation time of 300 s. The NCAFE was successfully applied to determining Pb(II) and Cd(II) in vegetable and water samples with satisfactory results.

Can electrochemical oxidation techniques really decontaminate saline dyes wastewater?

Co-reporter:Sadiqua N. Ramjaun, Zhaohui Wang, Ruixia Yuan, Jianshe Liu

Journal of Environmental Chemical Engineering (September 2015) Volume 3(Issue 3) pp:1648-1653

Publication Date(Web):1 September 2015

DOI:10.1016/j.jece.2015.06.006

•Effect of chloride ions on electrochemical degradation kinetics of dye was examined.•MO degradation was significantly enhanced by higher concentrations of chloride.•32 chlorinated organic byproducts of MO were identified by GC–MS method.Formation of toxic chlorinated organic byproducts is of great concern when selecting electrochemical oxidation (EO) as decontamination technology for saline dye wastewater, but still not verified. To test the applicability of EO, methyl orange (MO) was used as a model dye for anodic contact glow discharge electrolysis (CGDE) and conventional electrolysis (CE) in the presence of chloride. The degradation kinetics and organic intermediates were analyzed. In the presence of chloride, the rates of dye degradation were significantly increased as CGDE and CE were applied. CE resulted in higher mineralization efficiency than CGDE which needs much energy input. Several refractory chlorinated aromatic and even aliphatic compounds were identified during MO degradation, as well as the other anthraquinone dye, alizarin red S (AR). Therefore, the issues of toxic chlorinated byproducts and energy cost should be preferentially evaluated prior to the selection of EO technologies.