Plasma-Induced Grafting of Cyclodextrin onto Multiwall Carbon Nanotube/Iron Oxides for Adsorbent Application

Adsorption of Emerging Ionizable Contaminants on Carbon Nanotubes: Advancements and Challenges

The superior adsorption capacity of carbon nanotubes has been well recognized and there is a wealth of information in the literature concerning the adsorption of unionized organic pollutants on carbon nanotubes. Recently, the adsorption of emerging environmental pollutants, most of which are ionizable, has attracted increasing attention due to the heightened concerns about the accumulation of these emerging contaminants in the environment. These recent studies suggest that the adsorption of emerging ionizable contaminants on carbon nanotubes exhibit different characteristics than unionized ones. For example, a new charge-assisted intermolecular force has been proposed for ionizable compounds because some adsorption phenomenon cannot be easily explained by the conventional force theory. The adsorption of ionizable compounds also displayed much stronger dependence on solution pH and ionic strength than unionized compounds. This article aims to present a brief review on the current understanding of the adsorption of emerging ionizable contaminants to carbon nanotubes and discuss further research needs required to advance the mechanistic understanding of the interactions between ionizable contaminants and carbon nanotubes.

Effect of superparamagnetic nanoparticles on the physicochemical properties of nano hydroxyapatite for groundwater treatment: adsorption mechanism of Fe(ii) and Mn(ii)

Magnetic hydroxyapatite (MHAP) was found to be an ideal adsorbent for Fe(ii) and Mn(ii) in ground water from the El-Kharga Oasis in Egypt.

A combination of β-cyclodextrin functionalized magnetic graphene oxide nanoparticles with β-cyclodextrin-based sensor for highly sensitive and selective voltammetric determination of tetracycline and doxycycline in milk samples

Highly sensitive and selective determination of tetracycline and doxycycline in milk samples using solid phase extraction followed by differential pulse voltammetric determination on a β-cyclodextrin modified carbon paste sensor.

Biodegradable poly(butylene succinate-co-terephthalate) nanofibrous membranes functionalized with cyclodextrin polymer for effective methylene blue adsorption

PBST and PBST/CDP nanofibrous membranes were prepared for the first time. PBST/CDP membranes were fabricated by means of in situ polymerization. The morphologies of membranes were dependent on the CDP content. PBST/CDP membranes exhibited excellent adsorption capacity.

Preparation of a novel anti-fouling β-cyclodextrin–PVDF membrane

A novel β-cyclodextrin (β-CD)–PVDF membrane was preparedviaan interfacial reaction, using Trimesoyl Chloride (TMC) and β-CD as cross-linking and modification agents, respectively. The membranes were modified by a simple dip-coating method.

Plasma-induced grafting of polyacrylamide on graphene oxide nanosheets for simultaneous removal of radionuclides

PAM/GO is a suitable material for simultaneous removal of metal ions from aqueous solutions.

Iron-oxide-supported nanocarbon in lithium-ion batteries, medical, catalytic, and environmental applications

Owing to the three different orbital hybridizations carbon can adopt, the existence of various carbon nanoallotropes differing also in dimensionality has been already affirmed with other structures predicted and expected to emerge in the future. Despite numerous unique features and applications of 2D graphene, 1D carbon nanotubes, or 0D fullerenes, nanodiamonds, and carbon quantum dots, which have been already heavily explored, any of the existing carbon allotropes do not offer competitive magnetic properties. For challenging applications, carbon nanoallotropes are functionalized with magnetic species, especially of iron oxide nature, due to their interesting magnetic properties (superparamagnetism and strong magnetic response under external magnetic fields), easy availability, biocompatibility, and low cost. In addition, combination of iron oxides (magnetite, maghemite, hematite) and carbon nanostructures brings enhanced electrochemical performance and (photo)catalytic capability due to synergetic and cooperative effects. This work aims at reviewing these advanced applications of iron-oxide-supported nanocarbon composites where iron oxides play a diverse role. Various architectures of carbon/iron oxide nanocomposites, their synthetic procedures, physicochemical properties, and applications are discussed in details. A special attention is devoted to hybrids of carbon nanotubes and rare forms (mesoporous carbon, nanofoam) with magnetic iron oxide carriers for advanced environmental technologies. The review also covers the huge application potential of graphene/iron oxide nanocomposites in the field of energy storage, biomedicine, and remediation of environment. Among various discussed medical applications, magnetic composites of zero-dimensional fullerenes and carbon dots are emphasized as promising candidates for complex theranostics and dual magneto-fluorescence imaging.

Characteristics of cesium ion sorption from aqueous solution on bentonite- and carbon nanotube-based composites

The technology development of Cs(+) capture from aqueous solution is crucial for the disposal of nuclear waste and still remains a significant challenge. Previous researches have been proven that ion exchanges with the cations and hydroxyl exchange are the main sorption mechanisms for Cs(+). Therefore, how important are the cation exchange and the hydroxyl exchange mechanisms to Cs(+) sorption? And whether can we improve the sorption capacity of the material by increasing the amount of hydroxyl groups? With these in mind, we herein designed the chitosan-grafted carbon nanotubes (CS-g-CNTs) and the chitosan-grafted bentonite (CS-g-bentonite) by plasma-induced grafting method. The interactions of Cs(+) with CNTs, bentonite, CS-g-CNTs and CS-g-bentonite composites were investigated. The sorption of Cs(+) is mainly dominated by strong cation exchange in monovalent Group I and divalent Group II. And the cation-exchange mechanism is much more effective than the hydroxyl group exchange. The effect of hydroxyl groups is dependent on the property of the matrix. We cannot improve the Cs adsorption capacity of material for Cs(+) only by increasing the amount of hydroxyl groups in any case. The spatial structure and the cation-exchange capacity of the material are important factors for choosing the sorbent for Cs(+) removal from radioactive waste water.

Preparation of magnetic porous carbon from waste hydrochar by simultaneous activation and magnetization for tetracycline removal

In the present work, a novel magnetic porous carbon (MPC) with maghemite (γ-Fe2O3) particles is facilely prepared from hydrochar (a solid residue of hydrothermal carbonization of biomass) in one step through simultaneous activation and magnetization. The resultant MPC is characterized and utilized as an adsorbent for tetracycline (TC) removal from aqueous solutions. The BET surface area and micropore volume of the MPC are found to be 349 m(2)g(-1) and 0.16 cm(3)g(-1), respectively. The adsorption kinetics data could be well described by the pseudo-second-order model, and the TC adsorption onto MPC is an endothermic and spontaneous process. The enhanced surface area of the MPC, as well as its graphite-like structure, may contribute to the adsorption capacity of TC. After adsorption, MPC could be effectively separated by applying a magnetic field.

Preparation, characterization of electrospun meso-hydroxylapatite nanofibers and their sorptions on Co(II)

In this work, mesoporous hydroxylapatite (meso-HA) nanofibers were prepared via calcination process with polyvinyl alcohol/HA (PVA/HA) hybrid nanofibers fabricated by electrospinning technique as precursors, and the removal efficiency of meso-HA nanofibers toward Co(II) was evaluated via sorption kinetics and sorption isotherms. Furthermore, the sorption behaviors of Co(II) on meso-HA nanofibers were explored as a function of pH, ionic strength, and thermodynamic parameters. There existed hydrogen bonds between HA and PVA matrix in precursor nanofibers which could change into meso-HA nanofibers with main pore diameter at 27nm and specific surface area at 114.26m(2)/g by calcination process. The sorption of Co(II) on meso-HA was strongly dependent on pH and ionic strength. Outer-sphere surface complexation or ion exchange was the main mechanisms of Co(II) adsorption on meso-HA at low pH, whereas inner-sphere surface complexation was the main adsorption mechanism at high pH. The sorption kinetic data were well fitted by the pseudo-second-order rate equation. The sorption isotherms could be well described by the Langmuir model. The thermodynamic parameters (ΔH°, ΔS° and ΔG°) calculated from the temperature-dependent sorption isotherms suggested that the sorption process of Co(II) on meso-HA nanofibers was spontaneous and endothermic.

Determination of trace amounts of Se(IV) by hydride generation atomic fluorescence spectrometry after solid-phase extraction using magnetic multi-walled carbon nanotubes

A sensitive and simple method using magnetic multi-walled carbon nanotubes, as an adsorbent, has been successfully developed for extraction and preconcentration trace amounts of Se(IV) with detection by hydride generation atomic fluorescence spectrometry. The prepared nanoparticles were confirmed by Fourier transform infrared spectra, X-ray diffraction spectrometry, vibrating sample magnetometry, and transmission electron microscopy. These magnetic nanocomposites can be easily dispersed in aqueous samples and retrieved by the application of external magnetic field via a piece of permanent magnet. The main factors affecting the signal intensity such as sample pH value, adsorbent amount, eluent concentration and volume, sample volume, and coexisting ions have been investigated and established. The absorbent could be repeatedly used at least 100 times. The enhancement factor of the proposed method for Se(IV) was 100. The method had a linear calibration plot in the range from 0.05 to 10.0 μg L(-1) with a standard deviation of 2.3% at 0.5 μg L(-1) (n=11). The limit of detection was as low as 0.013 μg L(-1). Accuracy of the method was evaluated by the analysis of water samples and certified reference materials.

Multifunctional carboxymethyl cellulose-based magnetic nanovector as a theragnostic system for folate receptor targeted chemotherapy, imaging, and hyperthermia against cancer

A multifunctional biocompatible nanovector based on magnetic nanoparticle and carboxymethyl cellulose (CMC) was developed. The nanoparticles have been characterized using TEM, SEM, DLS, FT-IR spectra, VSM, and TGA studies. We found that the synthesized carboxymethyl cellulose magnetic nanoparticles (CMC MNPs) were spherical in shape with an average size of 150 nm having low aggregation and superparamagnetic properties. We found that the folate-tagged CMC MNPs were delivered to cancer cells by a folate-receptor-mediated endocytosis mechanism. 5-FU was encapsulated as a model drug for delivering cytotoxicity, and we could demonstrate the sustained release of 5-FU. It was also observed that the FITC-labeled CMC MNPs could effectively enter cells, and the fate of nanoparticles was tracked with Lysotracker. The CMC MNPs could induce significant cell death when an alternating magnetic field was applied. These results indicate that the multifunctional CMC MNPs possess a high drug loading efficiency and high biocompatibility and with low cell cytotoxicity and can be considered to be promising candidates for CMC-based targeted drug delivery, cellular imaging, and magnetic hyperthermia (MHT).