multi-walled carbon nanotubes

Water pollution by heavy metals is one of the most important environmental problems. Among the heavy metals, mercury (Hg) is a very toxic metal and its high concentration can lead to impaired pulmonary and renal dysfunction. The aim of this study was to determine the amount of Hg removal by carbon nanotubes coated with manganese (Mn) oxide from aqueous solutions.

In this study, multi-walled carbon nanotubes coated with Mn oxide were prepared and used to remove Hg from aqueous environments. In addition, the physical and structural characteristics of the nanotubes were determined by the X-ray diffraction (XRD). The impact of diverse variables was further investigated, including the initial concentration of Hg, the initial pH of the solution, contact time, mixing rate, as well as the amount of nano-composite and the impacts of confounders (nitrate and chloride). Finally, optimum conditions for each of these parameters were obtained by the Taguchi statistical method.

The XRD analysis showed that the nanotubes were properly coated with Mn oxide. Furthermore, the results demonstrated that under pH 7, the rate of mixing of 150 rpm, the contact time of 60 minutes, the amount of nano-composite of 60 mg, and the initial density of Hg 80 mg/L can be achieved by removing 95% Hg. Moreover, the confounder factors of nitrate and chloride reduced the amount of Hg removal by 4 and 5%, respectively.

Based on the results, the nanotubes coated with Mn oxide can be used as easy and strong absorbents for the rapid absorption of Hg from drinking water and industrial wastewater

 Tissue engineering was an idea and today becomes a potential therapy for several tissues in dentistry such as Periodontal Disease and oral mucosa.

Periodontal regeneration is one of the earliest clinical disciplines that have achieved the therapeutic application of tissue engineering. The aim of the presence study was to prepare electrospun Poly(3-hydroxybutyrate) (PHB)/1% Carbon nanotubes (CNTs) scaffolds for periodontal regeneration.

1% w/v of CNTs was added to the polymer solutions and electrospinning. Physical properties of the scaffolds were evaluated by Scanning electron microscopy (SEM) and universal testing machine. Chemical characterization of the scaffolds was also assessed by Fourier-transform infrared spectroscopy (FTIR). Biological properties of the scaffolds were also evaluated in vitro by culturing periodontal ligament stem cells (PDLSCs) on the scaffolds for 10 days and in vivo by Implanting the scaffolds in rat model for 5 weeks.

Results showed that the scaffolds were mimicked fibrous connective tissue of the (PDL). CNTs improved the mechanical properties similar to 23-55 years old human PDL. In vitro biocompatibility study showed more attachment and proliferation of the PDLSCs for PHB/1%CNTs scaffolds compared to the PHB controls. In vivo study showed that CNTs in the scaffolds caused mild foreign body type giant cell reaction, moderate vascularization, and mild inflammation.

In conclusion, the results showed that the PHB/1%CNTs composite scaffolds may be potentially useful in periodontal regeneration.

Today, finding suitable methods to decrease plant abiotic stress such as heavy metals or salinity is very necessary in arid and semi-arid regions. Thus, this research was conducted as a factorial experiment in the layout of a completely randomized block design to evaluate the role of Piriformospora indica fungus and multi-walled carbon nanotubes (MWCNTs) on decreasing plant abiotic stress in the soil treated with lead (Pb)-polluted sewage sludge. The treatment consisted of applying sewage sludge at the rates of 0, 15, and 30 t/ha, 3 levels of cadmium spiked in to the applied sewage sludge (0, 800 and 1600 mg Pb/kg), as well as 0%, 0.5%, and 1.5% (W/W) MWCNTs in the presence and absence of P. indica. The plant used in this experiment was barely. After 90 days of the experiment, the plant was harvested and its Pb concentration was measured using atomic absorption spectroscopy. Applying 0.5 and 1% (W/W) MWCNTs in the soil treated with 15 t/ha sewage sludge significantly decreased plant Pb concentration by 8.1% and 12.3%, respectively. In addition, the presence of P. indica had significant effects on decreasing plant Pb concentration since the lowest plant Pb concentration was observed in soil amended with 30 t/ha sewage sludge (800 mg Pb/kg) by receiving 1.5% (W/W) MWCNTs in the presence of P. indica. The results of this study showed that applying MWCNTs has significant effects on decreasing soil heavy metals or soil salinity that is a positive point in environmental studies.

our goal is to reduce the release rate of methotrexate (MTX) and increase cell death efficiency.

Carboxylated multi-walled carbon nanotubes (MWCNT-COOH) were functionalized with MTX as a cytotoxic agent, FA as a targeting moiety and polyethylene amine (PEI) as a hydrophilic agent. Ultimately, MWCNT-MTX and MWCNT-MTX-PEI-FA were synthesized. Methotrexate release studies were conducted in PBS and cytotoxic studies were carried out by means of the MTT tassay.

Methotrexate release studies from these two carriers demonstrated that the attachment of PEI-FA onto MWCNT-MTX reduces the release rate of methotrexate. The IC50 of MWCNT-MTX-PEI-FA and MWCNT-MTX have been calculated as follows: 9.89 ± 0.38 and 16.98 ± 1.07 µg/ml, respectively. Cytotoxic studies on MWCNT-MTX-PEI-FA and MWCNT-MTX in the presence of an IR laser showed that at high concentrations, they had similar toxicities due to the MWCNT’s photothermal effect. Targeting effect studies in the presence of the IR laser on the cancer cells have shown that MWCNT-MTX-PEI-FA, MWCNT-MTX and f-MWCNT have triggered the death of cancer cells by 55.11±1.97 %, 49.64±2.44 %, and 37±0.70 % respectively.

The release profile of MTX in MWCNT-MTX-PEI-FA showed that the presence of PEI acts as a barrier against release and reduces the MTX release rate. In the absence of a laser, MWCNT-MTX-PEI-FA exhibits the highest degree of cytotoxicity. In the presence of a laser, the cytotoxicity of MWCNT-MTX and MWCNT-MTX-PEI-FA has no significant difference. Targeting studies have shown that MWCNT-MTX-PEI-FA can be absorbed by cancer cells exclusively.

In the present research work, the mixed matrix membranes (MMMs) containing various amount of polyethersulfone (PES) and functionalized multi-walled carbon nanotubes (fMWCNTs) were fabricated and used to investigate the removal of cobalt ions from wastewater by nanofiltration process. Pristine MWCNTs and fMWCNTs were characterized by Fourier transformed infrared spectroscopy and thermogravimetric analysis. FESEM analysis revealed that the mixed matrix membranes have less surface defects and better membrane performance compared with neat polymeric in the removal of cobalt ions. Permeation test results showed that the MMM containing 22 wt. % PES and 0.6 wt. % fMWCNTs (with outer diameter of 10-20 nm) has the optimum performance from the permeability and cobalt removal point of view. In continuation, the effect of pressure, feed flow rate, cobalt concentration, permeation test time and feed solution pH on the removal of cobalt by selected the MMM was investigated. The obtained results indicated that only pressure has considerable effect on permeation flux. However, all parameters showed different influence on rejection percent of cobalt ions.