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In this work, N-doped carbon microtubes have been synthesized using MoO3 microrods as the sacrificial template. Then, the Fe3O4 nanoparticles were integrated into N-doped carbon microtubes to obtain triple-walled Fe3O4@N-doped carbon@Fe3O4 microtubes via a high temperature decomposition process. Due to the coordination ability of nitrogen and the unique structures of the N-doped carbon microtubes, the Fe3O4 nanoparticles were closely attached to both the external and internal surfaces of the N-doped carbon microtubes and thus, assured a relatively good response to an external magnetic field. All these features make the nanocomposites well fitted for adsorption, catalysis, energy storage etc. Moreover, the N-doped carbon microtubes can be used as versatile templates to synthesize other triple-walled composites M@N-doped carbon@M microtubes (such as M = Cu(Cu2O), MnO2, MoS2), which greatly widens the applications of N-doped carbon microtubes. [ABSTRACT FROM AUTHOR]

This paper investigated microbial denitrification using electrochemical sources to replace organic matter as reductant. The work also involved developing a system that could be optimised for nitrate removal in applied situations such as water processing in fish farming or drinkingwater, where high nitrate levels represent a potential health problem. Consequently, the study examined a range of developments for the removal of nitrate from water based on the development of electrochemical biotransformation systems for nitrate removal. This also offers considerable scope for the potential application of these systems in broader bionanotechnology based processes. Furthermore, the work discussed the context of improved microbial fuel cell (MFC) performance, potential analytic applications, and further innovations using a bionanotechnology approach to analyse cell-electrode interactions. High nitrate removal rate of more than 95% was successfully achieved by using a MFC system modified with carbon nanomaterials. [ABSTRACT FROM AUTHOR]

Graphical abstract One dimensional Au nanoparticles-functionalized magnetic N-doped carbon nanotubes have been fabricated, which was employed as a novel matrix for enzyme immobilization to develop highly sensitive biosensors. Highlights • A convenient and efficient method was developed to prepare magnetic NCNTs@Fe 3 O 4 supported Au NPs. • One-dimensional NCNTs@Fe 3 O 4 @Au composite was exploited as a biosensing scaffold to entrap cyt c. • The magnetic NCNTs@Fe 3 O 4 @Au based sensor could avoid the modification on the electrode and realize the direct detection in the solution. • The resultant biosensors displayed good performance for the detection of H 2 O 2 with a low detection limit of 0.3 μM. Abstract In recent years, the fabrication of noble metal functionalized magnetic carbon nanotubes for a variety of novel biosensors has aroused considerable interest owing to their synergistic improved sensitivity. In the paper, the Fe 3 O 4 and Cu nanoparticles (NPs) were integrated into the NCNTs to obtain N-doped carbon@Fe 3 O 4 -Cu nanotubes (NCNTs@Fe 3 O 4 @Cu) through a one-pot high temperature decomposition procedure. Then, Au NPs were assembled on the magnetic NCNTs to obtain NCNTs@Fe 3 O 4 @Au composite by galvanic replacement with Cu NPs. The resultant composite had provided a friendly platform for enzyme immobilization to develop highly sensitive biosensors. After the cytochrome c(cyt c) was accumulated by NCNTs@Fe 3 O 4 @Au composite, the cyt c/NCNTs@Fe 3 O 4 @Au gathered to the surface of electrode with an external magnet. Thus, the sensitivity of designed biosensor could be further improved, and most of electrochemical interferences could be excluded. Benefiting from the unique hybrid structure of the composite, the direct electron transfer of cyt c was highly facilitated and the constructed biosensors exhibited good performance for the detection of H 2 O 2 with an extraordinary low detection limit of 0.3 μM, which revealed potential application for fabricating novel electrochemical biosensors. [ABSTRACT FROM AUTHOR]

In this paper, multifunctional nanotubes were prepared by directly combing iron oxide (Fe 3 O 4 ) nanoparticle(NPs) decorated carbon nanotubes (CNTs), and palladium (Pd) NPs together with polypyrrole (PPy) in a facile way. Firstly, magnetic CNT composite (CNTs/Fe 3 O 4 ) was synthesized by the high temperature decomposition process, then PPy could be easily immobilized on the magnetic CNTs. Furthermore, Pd NPs were accumulated on the surface of CNTs/Fe 3 O 4 @PPy to obtain one dimensional CNTs/Fe 3 O 4 @PPy/Pd composite. The composite extraordinary amplified the electrochemical response, providing a highly sensitive electrochemical platform for triclosan detection. This electrochemical sensors had the advantage of fast response, cheap instrument, low cost, simple operation, high sensitivity and real-time detection in situ condition. Moreover, the sensor exhibited a wide linear response range for triclosan (2.247 × 10 −9  M to 2.752 × 10 −7  M) with a detection limit of 1.417 × 10 −9  M, respectively. In addition, the electrochemical sensor reported herein was applied for the detection of triclosan in real samples, revealing promising applications in developing the sensor for environmental inspection and monitoring. [ABSTRACT FROM AUTHOR]

Magnetic carbon nanotubes composite (MWCNTs-Fe 3 O 4 ) was successfully prepared and characterized using different techniques. MWCNTs-Fe 3 O 4 displays entangled network of oxidized MWCNTs attached with Fe 3 O 4 clusters with specific surface area of 92 m 2 g −1 . The adsorption performance of as prepared composite was investigated for Hg(II) removal. Several experimental factors affecting Hg(II) adsorption process by MWCNTs-Fe 3 O 4 were studied including, adsorbent dosage, contact time, pH and metal ion concentration. A high adsorption capacity of 238.78 mg g −1 was obtained according to Langmuir model. In addition, pseudo-second-order and the Langmuir isotherm model were used to fit the adsorption kinetic and equilibrium data, respectively. The results recommend the successful application of MWCNTs-Fe 3 O 4 for Hg(II) removal via batch adsorption technique. [ABSTRACT FROM AUTHOR]