Sulphonated poly(ethersulfone)/carbon nano-onions-based nanocomposite membranes with high ion-conducting channels for salt removal via electrodialysis.

Herein, we are reporting the carbon nano onions (CNO)-based sulphonated poly(ethersulfone) (SPES) composite membranes by varying CNO content in SPES matrix for water desalination applications. CNOs were cost-effectively synthesized using flaxseed oil as a carbon source in an energy efficient flame pyrolysis process. The physico- and electrochemical properties of nanocomposite membranes were evaluated and compared to pristine SPES. Moreover, the chemical characterisation of composite membranes and CNOs were illustrated using techniques such as nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FE-SEM), thermogravimetric analysis (TGA) and universal tensile machine (UTM). In the series of nanocomposite membranes, SPES-0.25 composite membrane displayed the highest water uptake (WU), ion exchange membrane (IEC) and ionic conductivity (IC) values that were enhanced by 9.25%, ~ 44.78% and ~ 6.10%, respectively, compared to pristine SPES membrane. The electrodialytic performance can be achieved maximum when membranes possess low power consumption (PC) and high energy efficiency (Ee). Therefore, the value of Ee and Pc for SPES-0.25 membrane has been determined to be 99.01 ± 0.97% and 0.92 ± 0.01 kWh kg-1, which are 1.12 and 1.11 times higher than the pristine SPES membrane. Hence, integrating CNO nanoparticles into the SPES matrix enhanced the ion-conducting channels.

Biomass-derived carbon nano-onions for the effective elimination of organic pollutants and oils from water.

Oil spillage and leakage of organic solvents have caused severe environmental and ecological damages. It is of great significance to develop a cost-efficient and green adsorbent material with high uptake efficiency to separate the oil-water mixture. In this work, biomass-derived CNOs were first time explored in the adsorption of organic pollutants and oils from water. Carbon nano-onions (CNOs) with hydrophobicity and oleophilicity were cost-effectively synthesized in an energy efficient flame pyrolysis process using flaxseed oil as a carbon source. The as-synthesized CNOs without any further surface modification have shown high adsorption efficiency in removing organic solvents and oils from the oil-water mixture. The CNOs could adsorb diverse organic solvents such as pyridine (36.81 mg g-1), dichloromethane (90.95 mg mg-1), aniline (76 mg mg-1), toluene (64 mg mg-1), chloroform (36.25 mg mg-1), methanol (49.25 mg mg-1), and ethanol (42.25 mg mg-1). The uptake capacity for petrol and diesel over CNOs was observed at 36.68 mg mg-1 and 58.1 mg mg-1, respectively. The adsorption of pyridine followed pseudo-second-order kinetics and Langmuir's isotherm model. Moreover, the adsorption efficiency of CNOs towards the remediation of pyridine was almost similar in real-water samples when tested in tap water, dam water, groundwater, and lake water. Similarly, the practical applicability for the separation of petrol and diesel was also verified in the real sample (sea water) and has been proven to be excellent. By simple evaporation, the recovered CNOs can be reused for more than 5 cycles. CNOs exhibit the promising potential to be used in practical applications for oil-polluted water treatment.

Sustainable carbon nano-onions as an adsorbent for the efficient removal of oxo-anions.

The increasing threats of oxo-anions in drinking water have posed a serious threat to human health, aquatic environment, ecology, and sustainability. Accordingly, developments of cost-effective and sustainable nanomaterials for water remediation are on top priority and highly sought in global research community. Carbon nano-onions (CNOs) are one of the emerging nanomaterials for water purification because of its unique morphology, surface reactivity, high density of surface-active sites, and microporous structure. Herein, flaxseed oil-derived CNOs are utilized as efficient adsorbent for the removal of toxic oxo-anions. Aside from the green and economic nature, CNOs provide high adsorption efficiency ~ 806.45 mg g-1 for the removal of [Formula: see text] (99.9%) from aqueous system at ambient temperature, neutral pH in 70 min. The adsorption of [Formula: see text] onto CNOs was well fitted in pseudo-second order kinetics and followed the Langmuir adsorption isotherm model. The adsorption process was determined to be exothermic and spontaneous from the resulting thermodynamic characteristics. Furthermore, the high hydrophobic nature of CNOs make it recycling simpler. The real-life applicability of CNOs towards [Formula: see text] removal was tested in tap water, river water, and dam water. With all these observed results, CNOs show promise for practical water remediation applications.

Multifunctional N-P-doped carbon dots for regulation of apoptosis and autophagy in B16F10 melanoma cancer cells and in vitro imaging applications.

Rationale: The present study reports the multifunctional anticancer activity against B16F10 melanoma cancer cells and the bioimaging ability of fluorescent nitrogen-phosphorous-doped carbon dots (NPCDs). Methods: The NPCDs were synthesized using a single-step, thermal treatment and were characterized by TEM, XPS, fluorescence and UV-Vis spectroscopy, and FTIR analysis. The anticancer efficacy of NPCDs was confirmed by using cell viability assay, morphological evaluation, fluorescent live-dead cell assay, mitochondrial potential assay, ROS production, RT-PCR, western-blot analysis, siRNA transfection, and cellular bioimaging ability. Results: The NPCDs inhibited the proliferation of B16F10 melanoma cancer cells after 24 h of treatment and induced apoptosis, as confirmed by the presence of fragmented nuclei, reduced mitochondrial membrane potential, and elevated levels of reactive oxygen species. The NPCDs treatment further elevated the levels of pro-apoptotic factors and down-regulated the level of Bcl2 (B-cell lymphoma 2) that weakened the mitochondrial membrane, and activated proteases such as caspases. Treatment with NPCDs also resulted in dose-dependent cell cycle arrest, as indicated by reduced cyclin-dependent kinase (CDK)-2, -4, and -6 protein levels and an enhanced level of p21. More importantly, the NPCDs induced the activation of autophagy by upregulating the protein expression levels of LC3-II and ATG-5 (autophagy-related-5) and by downregulating p62 level, validated by knockdown of ATG-5. Additionally, owing to their excellent luminescence property, these NPCDs were also applicable in cellular bioimaging, as evidenced by the microscopic fluorescence imaging of B16F10 melanoma cells. Conclusion: Based on these findings, we conclude that our newly synthesized NPCDs induced cell cycle arrest, autophagy, and apoptosis in B16F10 melanoma cells and presented good cellular bioimaging capability.

N,P-Doped Carbon Nanodots for Food-Matrix Decontamination, Anticancer Potential, and Cellular Bio-Imaging Applications.

We report a facile one-step thermal treatment method for the synthesis of biocompatible, fluorescent nitrogen-phosphorus-doped carbon nanodots (NPCDs) as multifunctional agents for the food matrix decontamination, cancer targeting, and cellular bio-imaging. NPCDs exhibit high toxicity towards L. monocytogenes, as illustrated by fluorescent live-dead cell counting, disruption of membrane permeability/potential, changes in the levels of cellular ions, genetic materials, and proteins, as well as intracellular production of reactive oxygen species. The tryptophan and protein peaks released in NPCDs treated cells contributed to indole ring breathing and correlated with induced cell death. NPCDs significantly inhibited bacterial biofilm formation on a solid substrate. NPCDs-coated low-density polyethylene (LDPE) film crosslinked with 1% aminopropyltriethoxy silane (APTES) via silane-hydroxyl linking as a food-grade wrap significantly reduced bacterial counts in a raw chicken food model. Furthermore, NPCDs induced apoptosis in HeLa cervical cancer cells, as confirmed by the distorted cell morphology, fluorescence microscopic analysis, presence of fragmented nuclei and the qPCR results of mRNA expression levels of apoptotic markers. Moreover, NPCDs were also applicable in utilized for the cellular bio-imaging of KM12-C colon cancer cells under confocal microscopy owing to their excellent luminescence properties. Overall, NPCDs represent a promising platform to reduce the environmental health risks associated with hazardous pathogens, anticancer targeting, and their application in cellular bio-imaging as multifunctional targets/nanocarriers.