Amine-functionalized Multi-walled Carbon Nanotubes Research Articles

An investigation of the impact of functionalized MWCNT reinforcement on interlaminar strength of glass/epoxy composites: a comparative view

ABSTRACT In the present investigation, diverse functionalized states of multi-walled carbon nanotubes (MWCNT) were employed in fabricating glass/epoxy composites, with the MWCNT consistently incorporated at a 0.5 wt.% concentration. These functionalization states included pristine, hydroxyl, amine, and carboxylic conditions, systematically compared against neat glass/epoxy composites. The findings elucidated that all three functionalizations positively influenced the enhancement of interlaminar shear strength, mode-I interlaminar fracture toughness, and mode-II interlaminar fracture toughness properties. Notably, the amine-functionalized MWCNT exhibited superior performance relative to other formulations. The composite reinforced with amine MWCNT demonstrated significant improvements in ILSS, mode-I ILFT, and mode-II ILFT by 41.82%, 37.75%, and 40.93%, respectively. These enhancements are attributed to factors such as the presence of a more functional group, the quantity of individual MWCNT, and the introduction of additional damage mechanisms, including MWCNT pullout and bridging.

Synergistic regulation of nanocomposite interlayered forward osmosis membranes with 1D/2D nanostructures for enhanced heavy metal retention

The treatment of heavy metal wastewater poses a significant challenge due to its adverse environmental consequences and potential hazards to human well-being, necessitating effective and sustainable solutions. Forward osmosis (FO) is an efficient and low-energy separation technology that serves as an effective strategy to address this issue. However, it still faces the trade-off between water permeability and selectivity, which directly impacts the solute separation efficiency and retention characteristics. In this study, a covalent organic framework (COF) interlayer was introduced via in-situ growth, and the surface properties of polyamide (PA) were synergistically regulated by amine-functionalized multi-wall carbon nanotubes (MWCNT-NH2), resulting in a 1D/2D nanocomposite interlayered FO membrane with a high crosslinking density, improved hydrophilicity, excellent stability, and antifouling properties. The synergistic effect of COF and MWCNT-NH2 led to an increase in the concentration of MPD participating in interfacial polymerization (IP) and a decrease in MPD diffusion rate. These improvements led to enhanced water permeability and selectivity, as well as outstanding retention efficiencies for heavy metal ions (Cr3+, Ni2+), exceeding 99.2 %. Therefore, this study holds significant implications for targeted application development of high-efficiency FO membranes in the future, demonstrating practical value in the treatment of heavy metal wastewater and environmental pollution control.

Evaluating the microwave absorbing performance of polymer-free thin Fe3O4−MWCNT NCs in X-band region

In the past decade, hierarchical structure formation of magnetic (Fe3O4) and carbon based electrically conducting nanocomposites (NCs) has been widely used in microwave shielding applications due to the presence of lightweight, huge surface area, heterogenous interface surface etc. Current research is focused on reducing the thickness of the shielding material without compromising its performance. Herein, the fabrication of a 500 μm thick, polymer-free, stand-alone electromagnetic interference (EMI) shielding pellets of Fe3O4 - amine functionalized multiwalled carbon nanotube (MWCNT) NCs is reported with an average shielding efficiency of 60.7 dB for 8 to 12 GHz. The amine-functionalized MWCNT has superior electric conductivity due to the presence of reduced surface oxidation groups and superior charge carrying by free electrons in the amine groups. The structural and magnetic properties of all the materials were confirmed by XRD, Raman, FESEM, HRTEM, VSM and VNA techniques. The chemical interaction of Fe3O4−MWCNT was confirmed by the presence of the Fe–O–C bond from the O 1s spectrum from XPS analysis. The Fe3O4 nanoparticles (NPs) are homogeneously incorporated on the MWCNT surface, forming composite structures, which improve interface polarization, electron charge carrying, and impedance matching due to the presence of chemical interaction.

High strength, anti-static, thermal conductive glass fiber/epoxy composites for medical devices: A strategy of modifying fibers with functionalized carbon nanotubes

Abstract A series of aliphatic amine-functionalized multiwalled carbon nanotubes (MWCNTs) wherein varied secondary amine numbers were grafted on the MWCNTs’ surface were synthesized and further dispersed onto the glass fibers for reinforcing epoxy-based composites. By tuning secondary amine numbers of aliphatic amines, the dispersion of MWCNTs and ultimately mechanical, thermal, and conductive properties of epoxy-based composites could be adjusted. Using an optimal secondary amine number of aliphatic amine (triethylenetetramine), the interlaminar shear strength, tensile strength, and flexural strength of epoxy-based composite increased by 43.9%, 34.8%, and 35.0%, respectively; the work of fracture after interlaminar shear tests increased by 233.9%, suggesting strengthening/toughening effects of functionalized MWCNTs; significant reduction in surface resistance and increased thermal conductivity were also obtained, implying the superior conductive properties for composites. This work offers a new strategy for designing fiber-reinforced composites with high strength, excellent antistatic properties, and good thermal conductivity for medical device applications.

Influence of microstructure and thermoelectric properties on the power density of multi-walled carbon nanotube/ metal oxide hybrid flexible thermoelectric generators

The quest for a low-cost, flexible thermoelectric generator using eco-friendly metal oxide-based materials for low-temperature applications has motivated this work. The work compares the performance of amine-functionalized multi-walled carbon nanotubes (MWCNT-NH2) and metal oxide nanoparticles (CuO, NiO, and Fe2O3) ink-based hybrid flexible thermoelectric generators. Study reveals that the thermoelectric performance of a flexible thermoelectric generator improves by fine-tuning the materials crystallite size, bandgap, carrier concentration, carrier mobility, resistivity, the Seebeck coefficient, and micro-porosity of the ink film, which could be materialized by using hybrid thermoelectric materials. Among the three fabricated devices, MWCNT-NH2/NiO hybrid flexible thermoelectric generator exhibits a maximum power output of 1.44 nW at ΔT= 100 °C. The maximum power density displayed by MWCNT-NH2/NiO hybrid device is 59.3 nW/cm2 at ΔT= 100 °C, which is 23.28% and 332.8% higher than that of MWCNT-NH2/CuO and MWCNT-NH2/Fe2O3-based devices, respectively. The performance of MWCNT-NH2/NiO is comparatively superior to some previously reported works.

A novel electrochemical sensing platform based on covalent organic frameworks/WC/NH2-MWCNT for highly selective determination of acetaminophen and 4-aminophenol

In this article, a novel and simple electrochemical sensing platform has been developed for the simultaneous and sensitive determination of acetaminophen (ACOP) and 4-aminophenol (4-AP). The porous covalent organic frameworks (COFs) material with β-ketoenamine-linkage was successfully synthesized via 1,3,5-triformylphloroglucinol (TFP) and 2,6-diaminoanthraquinone (DAAQ) and named as TFP-DAAQ-COF. High conductivity walnut shells-derived carbon (WC), amine-functionalized multi-walled carbon nanotubes (NH2-MWCNTs) with multiple active sites and TFP-DAAQ-COF were combined to obtain composite materials, which were used to modify bare glass carbon electrodes (GCE) and realize the electrochemical analysis of ACOP and 4-AP. The experiments showed that the composite electrode had a strong synergistic effect and exhibited a good electrocatalytic oxidation ability for the two target analytes. The linearity ranges of ACOP and 4-AP were 0.5 ∼ 200 μM and 1.0 ∼ 250 μM, respectively and the detection limits (S/N = 3) were 0.12 μM and 0.18 μM. In addition, the sensor showed acceptable reproducibility, stability and excellent selectivity. The recovery was satisfactory, when it was used to analyze the contents of ACOP and 4-AP in real samples, indicating that the sensor was feasible in practical applications.

Polyethylenimine-Crosslinked 3-Aminopropyltriethoxysilane-Grafted Multiwall Carbon Nanotubes for Efficient Adsorption of Reactive Yellow 2 from Water.

This research intended to report amine-functionalized multiwall carbon nanotubes (MWCNTs) prepared by a simple method for efficient and rapid removal of Reactive Yellow 2 (RY2) from water. EDS analysis showed that the N content increased from 0 to 2.42% and from 2.42 to 8.66% after modification by 3-Aminopropyltriethoxysilane (APTES) and polyethylenimine (PEI), respectively. BET analysis displayed that the specific surface area, average pore size, and total pore volume were reduced from 405.22 to 176.16 m2/g, 39.67 to 6.30 nm, and 4.02 to 0.28 cm3/g, respectively. These results proved that the PEI/APTES-MWCNTs were successfully prepared. pH edge experiments indicated that pH 2 was optimal for RY2 removal. At pH 2 and 25 °C, the time required for adsorption equilibrium was 10, 15, and 180 min at initial concentrations of 50, 100, and 200 mg/L, respectively; and the maximum RY2 uptake calculated by the Langmuir model was 714.29 mg/g. Thermodynamic studies revealed that the adsorption process was spontaneous and endothermic. Moreover, 0-0.1 mol/L of NaCl showed negligible effect on RY2 removal by PEI/APTES-MWCNTs. Five adsorption/desorption cycles confirmed the good reusability of PEI/APTES-MWCNTs in RY2 removal. Overall, the PEI/APTES-MWCNTs are a potential and efficient adsorbent for reactive dye wastewater treatment.

Electrocatalytic Platform Based on Silver-Doped Sugar Apple-like Cupric Oxide Embedded Functionalized Carbon Nanotubes for Nanomolar Detection of Acetaminophen (APAP)

Economical and nanomolar-level determination of the analgesic drug, acetaminophen (APAP), is reported in this work. A novel ternary nanocomposite based on silver-doped sugar apple-like cupric oxide (CuO)-decorated amine-functionalized multi-walled carbon nanotubes (fCNTs) was sonochemically prepared. CuO nanoparticles were synthesized based on the ascorbic acid-mediated low-temperature method, and sidewall functionalization of CNTs was carried out. Important characterizations of the synthesized materials were analyzed using SEM, TEM, HAADF-STEM, elemental mapping, EDX, lattice fringes, SAED pattern, XRD, EIS, UV-Vis, micro-Raman spectroscopy, and FTIR. It was noted the sonochemically prepared nanocomposite diligently fabricated on screen-printed carbon electrode showcased outstanding electrocatalytic performance towards APAP determination. The APAP sensor exhibited ultra-low limit of detection of 4 nM, wide linear concentration ranges of 0.02-3.77 and 3.77-90.02 μM, and high sensitivity of 30.45 μA μM-1 cm-2. Moreover, further evaluation of the sensor's performance based on electrochemical experiments showcased outstanding selectivity, stability, reproducibility, and repeatability. Further, excellent practical feasibility of the proposed APAP sensor was affirmed with excellent recovery larger than 96.86% and a maximum RSD of 3.67%.

Electrochemical performance of rGO/AFCNT composite and fabrication of supercapacitor electrode

An aqueous electrolyte-based supercapacitor electrode of graphene and amine-functionalized multiwall carbon nanotubes (AFCNT) is reported. Amine groups were covalently introduced on the surface of Carbon nanotubes (CNT) by diazonium reaction. In-situ reduction of graphene oxide over amine functionalized carbon nanotube template resulted the final composite. At current density of 1 A/g the electrode showed 384 F/g specific capacitance. The electrode had an energy density of 53.33 Wh/kg and power density of 499.13 W/kg. The electrode evinced almost 90% of capacitance retention even at elevated current density of 5 A/g. • Composite of Graphene/- NH 2 functioned MWCNT developed for supercapacitor electrode. • Composite shows specific capacitance of 384 F/g at a current density of 1 A/g. • Introduction of hydrophilic amine group prevents the restacking of graphene layers effectively. • The electrode shows retention of 90% capacitance at current density as high as 5 A/g.

Human hair rich in pyridinic nitrogen-base DNA biosensor for direct electrochemical monitoring of palbociclib-DNA interaction

Carbon material derived from the waste-based biomass human hair (H), which is naturally rich in pyridinic nitrogen, provides a significant benefit in biosensor applications with its dominant conductivity character. The carbon material was synthesized from human hair waste by the hydrothermal carbonization (HTC) method, which is a promising green synthesis. A morphological characterization of the carbon materials was performed. In this study, H and amine-functionalized multi-walled carbon nanotubes (NH2-MWCNT) were combined for the first time as a modifier, which enhanced the glassy carbon electrode (GCE) surface area for deoxyribonucleic acid (DNA) biosensor studies. Palbociclib (PLB) is clinically used in the treatment of breast cancer. The novel electrochemical nanobiosensor was used to investigate the dsDNA-PLB interaction to evaluate the possibility that PLB causes conformational changes in DNA structure and/or oxidative damage. The interaction was conducted based on the voltammetric signals of deoxyguanosine (dGuo) and deoxyadenosine (dAdo) by differential pulse voltammetry (DPV) on a bare and H + NH2-MWCNT modified GCE. The proposed analytical method was applied to a pharmaceutical dosage form with a satisfactory recovery of 98.25 %. The nanobiosensor was tested in the presence of some interfering agents. The binding mechanism of dsDNA-PLB was also evaluated by spectroscopic and theoretical calculations.

Green Synthesis, Characterization, and Catalytic Activity of Amine-multiwalled Carbon Nanotube for Biodiesel Production

An amine-functionalized multiwalled carbon nanotube (MWCNT) was prepared for use as a basic heterogeneous catalyst for the conversion of Cocos nucifera (coconut) oil and Hibiscus cannabinus (kenaf) oil to biodiesel. The 3-aminopropyltrimethoxysilane (3-APTMS) was chosen to form an amine-reactive surface to bind with hydroxyl (−OH) and carboxyl (−COOH) groups of oxidized MWCNT. Silanization took place using a green surface modification method in which supercritical carbon dioxide fluid was utilized under the following conditions: 55 °C, 9 MPa, and 1 h. The synthesized catalyst was characterized using Thermogravimetric analysis (TGA), Fourier transform infrared (FTIR), Field emission scanning electron microscopy–energy dispersive x-ray (FESEM-EDX), Time-of-flight secondary ion mass spectrometry (TOF-SIMS), X-ray powder diffraction (XRD), and Brunauer–Emmett-Teller (BET). Transesterification of coconut oil using 10 wt% NH2-MWCNT catalyst (3 wt% APTMS), 12:1 molar ratio of methanol and oil at 63 °C for 1 h resulted in a >95% conversion. On the other hand, the same catalyst was used in the transesterification of kenaf oil, and formation of ammonium carboxylated salt was observed. The effects of temperature, pressure, and silane concentration on surface modification of MWCNT were evaluated in terms of the catalyst’s basic site density and fatty acid methyl ester conversion. The results indicate that reaction temperature and silane concentration had the most significant effects. Copyright © 2022 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Improved CO2 adsorption capacity and fluidization behavior of silica-coated amine-functionalized multi-walled carbon nanotubes

The adsorption capacity and fluidization behavior of silica-coated amine-functionalized multi-walled carbon nanotubes (MWCNTs) were studied in this work. The coupling of both studies is fundamental for the practical application of CO2 sorbents in fluidized beds. Sorbents were prepared by hydrolysis of tetraethylorthosilicate (TEOS) onto acid-treated multi-walled carbon nanotubes followed by impregnation with monoethanolamine (MEA). The effects of different loading amounts of MEA and TEOS on CO2 uptake were investigated using thermogravimetric analysis under a simulated flue gas composed of 15%CO2/85% N2. At the optimal loadings of TEOS (30 ml) and MEA (30 wt%) on MWCNTs, 2.67 wt% of CO2 was captured at 25 °C, while the adsorption capacity of the pristine MWCNTs before any modification was negligible. Adsorption/desorption tests repeated 25 times also showed that the prepared sorbent has excellent stability during the cyclic operation; 9.42% reduction of the uptake was reported. Fluidizability of the most promising sorbent was also assessed when adding hydrophobic silica nanoparticles (NPs). Maximum bed expansion of 3.9 was achieved in the presence of 7.5 wt% silica NPs which was comparable by the amount of 2.24 belonged to raw MWCNTs. Enhancement of fluidity may be attributed to the decreased van der Waals attraction forces between the particles of sorbent. Besides, the CO2 adsorption capacity of the sorbent mixed with 5 wt% silica NPs was surprisingly increased by approximately 8%, reaching ~3 wt% of CO2.

Surface functionalization of CNTs with amine group and decoration of begonia-like ZnO for detection of antipyretic drug acetaminophen

Detection of hepatotoxic antipyretic drug acetaminophen (APAP) at nanomolar level is detailed in this paper. We have prepared a novel nanocomposite with excellent electrocatalytic property for the detection of APAP based on amine-functionalized multi-walled carbon nanotubes (NH2-MWCNTs) decorated zinc oxide (ZnO). Surface functionalization of carbon nanotubes with amine group using ultrasound-assisted approach and synthesis of begonia flower-like ZnO nanoparticles based on arginine-assisted aqueous solution method were performed. Techniques including UV–Vis, micro Raman spectroscopy, FTIR, XRD, elemental mapping, and SEM were used to record significant characterizations of synthesized materials for analysis. The outstanding surface controlled electrocatalysis of APAP at ZnO NPs/NH2-MWCNTs modified SPCE was evident from the well-defined redox peak currents observed at low potentials during electrochemical investigations. Moreover, the resultant ultra-low detection limit of 1 nM and very high sensitivity of 89.64 μA μM−1cm−2 showcase the excellent performance of proposed APAP sensor. We have investigated all the salient features of the APAP sensor as part of this work and it exhibited good stability, reproducibility, repeatability, and excellent anti-interference property. The practical feasibility of APAP detection was also evaluated by conducting experiment on real samples including APAP tablet, human urine, and human serum.

Amine-functionalized multi-walled carbon nanotubes (EDA-MWCNTs) for electrochemical water splitting reactions

A study on the in situ decoration of ethylenediamine (EDA) on acid functionalized multi-walled carbon nanotubes (O-MWCNTs) for overall water splitting reactions at all pH as an efficient and inexpensive metal-free multifunctional electrocatalyst.

The pulmonary toxicity of carboxylated or aminated multi-walled carbon nanotubes in mice is determined by the prior purification method

BackgroundInhalation of multi-walled carbon nanotubes (MWCNTs) poses a potential risk to human health. In order to safeguard workers and consumers, the toxic properties of MWCNTs need to be identified. Functionalization has been shown to either decrease or increase MWCNT-related pulmonary injury, depending on the type of modification. We, therefore, investigated both acute and chronic pulmonary toxicity of a library of MWCNTs derived from a common pristine parent compound (NC7000).MethodsMWCNTs were thermally or chemically purified and subsequently surface functionalized by carboxylation or amination. To evaluate pulmonary toxicity, male C57BL6 mice were dosed via oropharyngeal aspiration with either 1.6 or 4 mg/kg of each MWCNT type. Mitsui-7 MWCNT was used as a positive control. Necropsy was performed at days 3 and 60 post-exposure to collect bronchoalveolar lavage fluid (BALF) and lungs.ResultsAt day 3 all MWCNTs increased the number of neutrophils in BALF. Chemical purification had a greater effect on pro-inflammatory cytokines (IL-1β, IL-6, CXCL1) in BALF, while thermal purification had a greater effect on pro-fibrotic cytokines (CCL2, OPN, TGF-β1). At day 60, thermally purified, carboxylated MWCNTs had the strongest effect on lymphocyte numbers in BALF. Thermally purified MWCNTs caused the greatest increase in LDH and total protein in BALF. Furthermore, the thermally purified and carboxyl- or amine-functionalized MWCNTs caused the greatest number of granulomatous lesions in the lungs. The physicochemical characteristics mainly associated with increased toxicity of the thermally purified derivatives were decreased surface defects and decreased amorphous content as indicated by Raman spectroscopy.ConclusionsThese data demonstrate that the purification method is an important determinant of lung toxicity induced by carboxyl- and amine-functionalized MWCNTs.

Influence of amine functionalized multi-walled carbonnanotubes on the mechanical properties of carbonfiber/epoxy composites

This experimental work focuses on how to develop an improved grade of Carbon fiber/epoxy compound material with superior mechanical characteristics, by adding small amounts of functionalized multi-walled carbon nanotubes (MWCNTs) into it. These composites could have potential applications in the missile and aerospace industry. Different percentages (0.25, 0.5, 1, and 2%) of amine-functionalized MWCNTs are infused into the epoxy resin (LY556). Sonicator is used to ensure good homogeneity and then hardener is added to the mixture, and then manually stirred. This mixture is finally layed upon carbon fiber mat by the wet layup process and cured in a hot press to produce the samples. Interlaminar shear strength (ILSS) and three-point bending tests are performed on a UTM both on amine-functionalized and unfilled CNT C-fiber/epoxy compound. The results show that amine-functionalized MWCNTs improved the mechanical properties of C-fiber/epoxy composites. The highest improvement of 12.84% in flexural strength is obtained with 0.25% amine-functionalized MWCNT and of 11.67% in ILSS with 0.5% amine-functionalized MWCNTs. Five samples are tested amongst which the standard deviation for flexural strength is found to be minimum (3.9) in 0.25% amine CNTs and for ILSS it is minimum (1.41) in 0.5% amine CNTs. The influence of such amine functionalization produced positive overall trends among the entire mechanical qualities assessed.

Sensitive electroanalytical assay, evaluation of thermodynamic and mechanism parameters of leukotriene receptor antagonist Zafirlucast

An electrochemical nanosensor for monitoring zafirlukast (ZAF) concentration in biological fluids was developed by the modification of the glassy carbon electrode (GCE) surface via layer-by-layer approach. The GCE surface was first modified with amine-functionalized multi-walled carbon nanotubes (NH2–fMWCNTs), and then sodium dodecylsulfate doped over-oxidized polypyrrole film (SDS-ooPPy) was electrosynthesized on the NH2–fMWCNTs/GCE. The morphology and characterization of prepared nanosensor were done by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The developed sensor has an excellent electrocatalytic activity towards the oxidation of ZAF, resulting in enhancing the electrochemical response, due to the synergistic effect between NH2–fMWCNTs and SDS-ooPPy and more negative charge density of ooPpy on a 1D structure of NH2–fMWCNTs. The parameters affecting the electrochemical behavior of ZAF including pH, the amount of NH2–fMWCNTs, the concentration of SDS and pyrrole (Py) monomer, and the number of cycles required in the electropolymerization step for the modification of electrode were optimized. The redox mechanism pathway for the electro-oxidation of ZAF and the thermodynamic study was performed by CV. The calibration graph of ZAF determination by square wave voltammetry (SWV) under the optimized condition using SDS–ooPPy/NH2–fMWCNTs/GCE provided a linear range of 1.0 × 10−7 M to 1.0 × 10−5 M. The sensitivity of 4442 μA mM−1 cm−2 and a LOD of 20.0 nM (S/N = 3) were obtained. Finally, the proposed nanosensor was used successfully for monitoring of ZAF in biological fluids with acceptable recovery data.

Improvement in mechanical and thermal properties of epoxy hybrid composites by functionalized graphene and carbon-nanotubes

Thermo-mechanical properties of amine functionalized multi-layered graphene (Af-MLG) and amine functionalized multi walled carbon nanotube (Af-MWCNT) epoxy hybrid composites is investigated. Ratio of hybrid fillers is being kept as 1:1 with a variation in wt% from 0.25 to 2.0. An optimum dispersion of hybrid nanofillers in epoxy matrix environment by using a probe sonicator has confirmed through TEM images. The presence of amine group in their corresponding composites (Af-M(Gr:CNT)/Ep-C) is confirmed through Fourier transform Infrared spectroscopy (FTIR), while amorphous nature of composite has been substantiate by using X-ray diffraction (XRD). Scanning electron microscope and transmission electron microscopy (SEM) images of Af-M (Gr: CNT)/Ep-C shows interaction between graphene sheet and MWCNT. Thermal decomposition temperatures of composites are investigated by using thermo-gravimetric analysis (TGA). A maximum increase of 52.8% in tensile strength for composites with 0.5 wt% loading of hybrid fillers shows collegial effects of both fillers when used in combination. Composites with 1.0 wt% loading of hybrid fillers demonstrate the highest flexural strength and thermal properties (degree of degradation of composites) as compared to the neat epoxy samples.

Fabrication of thin-film nanocomposite nanofiltration membranes incorporated with aromatic amine-functionalized multiwalled carbon nanotubes. Rejection performance of inorganic pollutants from groundwater with improved acid and chlorine resistance

A thin-film nanocomposite nanofiltration (TFN-NF) membrane was fabricated through blending a novel aromatic amine-functionalized multiwalled carbon nanotubes (AAF-MWCNTs) and an aliphatic amine-functionalized multiwalled carbon nanotubes (AF-MWCNTs). The polyamide layer was synthesised by interfacial polymerisation (IP) between piperazine and trimesoyl chloride monomers. The improved resistance of NF membranes to chlorine and acid were characterised by X-ray photoelectron spectroscopy (XPS), field emission-scanning electron microscopy, atomic force microscopy, attenuated total reflectance-Fourier transform infrared spectroscopy, contact angle, and zeta potential measurements. XPS analysis confirmed chlorine and acid resistance properties, as well as an improvement in the polyamide network cross-linking degree of the new nanofiltration membranes incorporated with AAF-MWCNTs (AAF–NF). The membrane transport properties and the performance on the rejection of HAsO4−2, NO3−, and NH4+ from solutions mimicking polluted groundwater were evaluated. Membrane performance to the target pollutants were determined by the solution-electro-diffusion (SED) model coupled with reactive transport. The results showed that AAF–NF membranes, with long-lifetimes, could be applied for the removal of As(V) from polluted groundwater. Water permeate flux and the arsenic rejection of the AAF–NF membrane increased by 15% when it is compared with a typical commercial semi-aromatic polyamide nanofiltration membranes (Desal DL).

Synthesis of amine-functionalized multi-walled carbon nanotube/3D rose flower-like zinc oxide nanocomposite for sensitive electrochemical detection of flavonoid morin

A novel composite consisting of three dimensional (3D) hierarchical rose flower-like zinc oxide decorated with amine-functionalized multi-walled carbon nanotubes (NH2-MWCNT/ZnO) was synthesized and applied to the effective electrochemical detection of morin, a flavonoid with health-promoting and therapeutic activities. We have used a hydrothermal technique to synthesize the 3D rose flower-like ZnO, which was then composited with NH2-MWCNT through a sonochemical method. The morphology and structure of the prepared materials were characterized using scanning electron microscopy (SEM), elemental mapping, X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) surface area analysis, Fourier-transform infrared spectroscopy (FT-IR), and Raman spectroscopy. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques were employed for the evaluation of electrochemical properties of the NH2-MWCNT/ZnO nanocomposite. Under optimal conditions, the NH2-MWCNT/ZnO modified screen printed carbon electrode (SPCE) exhibits a broad linear response from 0.2 to 803.4 μM, excellent selectivity of 2.71 μAμM−1cm−2, and a very low limit of detection (LOD) of 0.002 μM. The practicability of the fabricated sensor has been confirmed by selectivity and real sample analyses. Furthermore, the developed sensor also shows good operational and storage stability.