V2O5, CeO2 and Their MWCNTs Nanocomposites Modified for the Removal of Kerosene from Water

In this paper, the application of multiwalled carbon nanotubes (MWCNTs) based on metal oxide nanocomposites as adsorbents for the removal of hydrocarbons such as kerosene from water was investigated. Functionalized MWCNTs were obtained by chemical oxidation using concentrated sulfuric and nitric acids. V2O5, CeO2, and V2O5:CeO2 nanocomposites were prepared using the hydrothermal method followed by deposition of these oxides over MWCNTs. Individual and mixed metal oxides, fresh MWCNTs, and metal oxide nanoparticle-doped MWCNTs using different analysis techniques were characterized. XRD, TEM, SEM, EDX, AFM, Raman, TG/DTA, and BET techniques were used to determine the structure as well as chemical and morphological properties of the newly prepared adsorbents. Fresh MWCNTs, Ce/MWCNTs, V/MWCNTs, and V:Ce/MWCNTs were applied for the removal of kerosene from a model solution of water. GC analysis indicated that high kerosene removal efficiency (85%) and adsorption capacity (4270 mg/g) after 60 min of treatment were obtained over V:Ce/MWCNTs in comparison with fresh MWCNTs, Ce/MWCNTs and V/MWCNTs. The kinetic data were analyzed using the pseudo-first order, pseudo-second order, and intra-particle diffusion rate equations.

Superior operational stability of immobilized l-asparaginase over surface-modified carbon nanotubes

Abstractl-asparaginase (ASNase, EC 3.5.1.1) is an enzyme that catalyzes the l-asparagine hydrolysis into l-aspartic acid and ammonia, being mainly applied in pharmaceutical and food industries. However, some disadvantages are associated with its free form, such as the ASNase short half-life, which may be overcome by enzyme immobilization. In this work, the immobilization of ASNase by adsorption over pristine and modified multi-walled carbon nanotubes (MWCNTs) was investigated, the latter corresponding to functionalized MWCNTs through a hydrothermal oxidation treatment. Different operating conditions, including pH, contact time and ASNase/MWCNT mass ratio, as well as the operational stability of the immobilized ASNase, were evaluated. For comparison purposes, data regarding the ASNase immobilization with pristine MWCNT was detailed. The characterization of the ASNase-MWCNT bioconjugate was addressed using different techniques, namely Transmission Electron Microscopy (TEM), Thermogravimetric Analysis (TGA) and Raman spectroscopy. Functionalized MWCNTs showed promising results, with an immobilization yield and a relative recovered activity of commercial ASNase above 95% under the optimized adsorption conditions (pH 8, 60 min of contact and 1.5 × 10–3 g mL−1 of ASNase). The ASNase-MWCNT bioconjugate also showed improved enzyme operational stability (6 consecutive reaction cycles without activity loss), paving the way for its use in industrial processes.

HCT116 Cells Cytotoxic Response to Multifuctionalized 5- Fluorouracil MWCNTs Conjugates In Colorectal Cancer

Nanomaterials are the foundations of Nanotechnology, which are measured in nanoscales, Carbon nanotubes are one of the interesting nanomaterials, studied for over 25 years because of their superlative properties such as high surface area, electrical and thermal conductivity, high biocompatibility, flexibility, resistance to corrosion and nanosize. According to research, carbon nanotubes are applied in sensing, water treatment, and drug delivery, mainly used to deliver the anticancer drugs. In our work, functionalization of multi walled carbon nanotubes done by covalent and non-covalent functionation methods, covalent functionalization showed better dispersing efficiency in aqueous medium and compatible with biological systems with damaging the crystal lattice of carbon nanotubes. Non covalent functionalization helps to derivatized with active compounds, surface adsorption or attachment of various molecules or antibodies, which subsequently helps in targeting the site and to produce therapeutic effects. Different formulations prepared by functionalized MWCNTs and multiple functionalization of MWCNTs done by binding the drug and antibodies to prepare functionalized MWCNTs 5-Fluorouracil complexes. The Cytotoxicity assay was carried out for the obtained new targeting formulations to analyze the effect of all the formulations on HCT116 cell line. The percentage death was determined based on the viability of the cells in the appropriate vehicle controls. In this study, we report the successful functionalization, binding of 5 Fluorouracil, antibodies to MWCNTs, and cells viability of all prepared formulations for the development of novel carbon based anticancer drug delivery system. Functionalized MWCNTs-5-Fluorouracil antibodies composite at concentration above 2.5 µg/mL exhibited ≥ 50% cytotoxicity post normalization with compound control to negate precipitation observed with the compound. All the formulations showed the precipitations indicating antitumor activity and biocompatibility.

Photoluminescent Properties of Hydroxyapatite and Hydroxyapatite/Multi-Walled Carbon Nanotube Composites

Hydroxyapatite (HAp) and hydroxyapatite/multi-walled carbon nanotube (MWCNT) composites were obtained by the co-precipitation method, followed by ultrasound-assisted and microwave radiation and thermal treatment at 250 °C. X-ray diffraction (XRD) confirmed the presence of a hexagonal phase in all the samples, while Fourier-transform infrared (FTIR) spectroscopy elucidated the interaction between HAp and MWCNTs. The photoluminescent technique revealed that HAp and the composite with non-functionalized MWCNTs present a blue luminescence, while the composite with functionalized MWCNTs, under UV-vis radiation shows an intense white emission. These findings allowed presentation of a proposal for the use of HAp and HAp with functionalized MWCNTs as potential materials for optoelectronic and medical applications.

Functionalized MWCNTs-quartzite nanocomposite coated with Dacryodes edulis stem bark extract for the attenuation of hexavalent chromium

Multiwalled carbon nanotubes/quartzite nanocomposite modified with the extract of Dacryodes edulis leaves was synthesized and designated as Q, which was applied for the removal of Cr(VI) from water. The adsorbents (PQ and Q) were characterized using the SEM, EDX, FTIR, TGA, XRD, and BET analyses. The XRD revealed the crystalline composition of the nanocomposite while the TGA indicated the incorporated extract as the primary component that degraded with an increase in temperature. The implication of the modifier was noticed to enhance the adsorption capacity of Q for Cr(VI) by the introduction of chemical functional groups. Optimum Cr(VI) removal was noticed at a pH of 2.0, adsorbent dose (50 mg), initial concentration (100 mg dm−3), and contact time (180 min). The kinetic adsorption data for both adsorbents was noticed to fit well to the pseudo-second-order model. The adsorption equilibrium data were best described by the Langmuir model. The uptake of Cr(VI) onto PQ and Q was feasible, endothermic (ΔH: PQ = 1.194 kJ mol−1 and Q = 34.64 kJ mol−1) and entropy-driven (ΔS : PQ = 64.89 J K−1 mol−1 and q = 189.7 J K−1 mol−1). Hence, the nanocomposite demonstrated potential for robust capacity to trap Cr(VI) from aqueous solution.

Manganese Deposition Content in Carbon Nanotubes Based Filters: Energy Dispersive X-ray and Rutherford Backscatter Spectrometry Investigations

Carbon nanotubes (CNTs) based filters have a prospective advantage compared to the commercial filters due to their lightweight and ability to work without electricity or heat. The manganese (Mn) removal from aqueous solutions by oxidized multi-walled carbon nanotubes (O-MWCNTs) was investigated. The filtration performance was studied under ambient conditions: the solution pH, the initial manganese concentration, and the MWCNT-filter mass. The samples of MWCNT-filters were investigated using energy dispersive X-ray spectroscopy (EDS) and rutherford backscatter spectrometry (RBS) to account for the manganese content within the MWCNT-filter. These techniques were conducted to study the oxidation effect on the morphology of MWCNTs and evaluate the oxygen functional groups and the average diameter distribution. Based on these examinations, the competence of Mn removal may exceed 91% for 50 ppm initial concentration of Mn, proposing that functionalized MWCNTs is a promising filter. The Mn removal was achieved at low pH with removal enhancement at the pH of 2. Functionalized MWCNTs based filters are promising candidate for heavy metal ions removal from industrial wastewater.