[en] To achieve a suitable porous structure and high mechanical strength that is extremely valuable properties in adsorbent polymeric particles, poly(styrene-co-divinylbenzene) with high amounts of cross-linker and diverse proportions of diluent agent (porogen) were synthesized according to the methodology of the suspension polymerization technique. The structural characteristics of the particles and their adsorption properties for adsorption of Nickel ions were studied. Effect of solvent type and monomeric fraction on particles morphology and porosity was discussed. The solvents including n-heptane (HEP) and acetonitrile and monomer fraction was 50% and 30% of divinylbenzene (DVB). From the results obtained, we decided to apply an adsorbent with high mechanical strength and a porous structure appropriate for absorbing the Ni(II). The copolymer was characterized by Fourier transform infrared (FT-IR) analysis. We used scanning electron microscopy (SEM) and transmission electron microscopy (TEM) tests to study the morphology and particle size of the nanoparticles. According to the results, the copolymers synthesized with n-heptane have more porosity. Also an increase in the percentage of DVB caused finer pores. After synthesis of copolymer the applicability of these polymer beads to separation and concentration of Ni(II) is discussed. In separation of Ni(II) from aqueous solution, the effects of pH, temperature and time are discussed and thermodynamic and kinetic calculations are done and its isotherm are fitted with various equations.

[en] Highlights: • Fabrication of a novel composite membrane with In-situ polymerization. • Performance study of sulfonated polyethersulfone/polyrhodanine membrane comparing with neat one. • Assessment of antibacterial property with various methods. • Effect of rhodanine segment in the membrane scaffold on the hydrophilicity and antibiofouling. In this study, sulfonated-polyethersulfone/polyrhodanine (SPES/PRh) membranes with antibacterial behavior were fabricated. Polyethersulfone (PES) sulfonation was performed to enhance its hydrophilicity and next polyrhodanine nanoparticles (PRhNPs) were synthesized along with the sulfonated PES (SPES) by polyrhodanine (PRh) in situ polymerization. The sulfonation step also helps making composite membrane due to development of probable bondings and polymers engagements. The constructed membranes characterization was performed by FTIR, FESEM, contact angle, ¹H NMR, TGA and EDS analyses. SPES/PRh membrane had enhanced hydrophilicity and consequently better fluxes for aqueous solutions. The composite SPES/PRh membrane flux was improved to 139/78 L/m² h comparing 58.21 L/m² h for SPES one. Membrane operational performances, antibacterial and antibiofouling tests showed improved flux, better rejection and appropriate antibacterial and antibiofouling properties for SPES/PRh membrane. The 100% bacteria mortality for specified concentrations and appropriate inhibition zones up to 9 mm have been achieved. It is generally a suitable membrane to provide proper performance beside antibacterial and antibiofouling behavior.

[en] Microbial fuel cells (MFCs) are known as innovative alternatives to non-renewable energy by providing significant opportunities to convert chemical energy of organic or inorganic matters into electricity. Although they are capable of operating on diverse types of carbohydrates, they are able to function on complex substrates. However, low power density is one of their most challenging drawbacks. Using various types of catalytic materials is a typical method to overcome low performance of MFC. Mixture of graphene oxide (GO) and α-manganese dioxide nanotubes (α-MnO₂) was applied as a cathode catalyst. Oxygen reduction reaction and MFC’s output power were enhanced by constructing nanocomposite with high catalytic activity mixed with simple and cost-effective activated carbon (AC), which was 280-fold of the bare electrode. Moreover, MFC’s output was compared by applying ternary nanotube α-MnO₂/GO/AC catalyst with 5, 10, 15 and 20% of GO. Consequently, the composite with 10% GO achieved 148.4 mW m⁻² maximum power density which indicated the best performance among other amounts of GO.

[en] Adsorptive potential of maghemite decorated multiwalled carbon nanotubes (MWCNTs) for the removal of cadmium ions from aqueous solution was investigated. The magnetic nanoadsorbent was synthesized using a versatile and cost effective chemical route. Structural, magnetic and surface charge properties of the adsorbent were characterized using FTIR, XRD, TEM, VSM analysis and pH_P_Z_C determination. Batch adsorption experiments were performed under varied system parameters such as pH, contact time, initial cadmium concentration and temperature. Highest cadmium adsorption was obtained at pH 8.0 and contact time of 30 min. Adsorption behavior was kinetically studied using pseudo first-order, pseudo second-order, and Weber–Morris intra particle diffusion models among which data were mostly correlated to pseudo second-order model. Adsorbate-adsorbent interactions as a function of temperature was assessed by Langmuir, Freundlich, Dubinin–Radushkevich (D-R) and Temkin isotherm models from which Freundlich model had the highest consistency with the data. The adsorption capacity increased with increasing temperature and maximum Langmuir’s adsorption capacity was found to be 78.81 mg g"−"1 at 298 K. Thermodynamic parameters and activation energy value suggest that the process of cadmium removal was spontaneous and physical in nature, which lead to fast kinetics and high regeneration capability of the nanoadsorbent. Results of this work are of great significance for environmental applications of magnetic MWCNTs as promising adsorbent for heavy metals removal from aqueous solutions.Graphical Abstract

[en] Supercapacitors have recently become the focus of attention due to the exclusive features they possess as an energy storage device. Metal organic frameworks (MOFs) are generally known as a novel class of porous materials which can exhibit large pore volume, very good chemical stability, and high specific surface area, provided that the components are precisely selected. In this work, a ternary MnFe₂O₄/CNT/ZIF (MCZ) nanocomposite is prepared using a facile hydrothermal method for the application of supercapacitors devices, and the synthesized nanocomposite is used to evaluate the electrochemical properties. The surface morphology of synthesized materials is investigated through surface analysis and the results of structural analysis have proved the accuracy of nanocomposite formation that ZIF-67 nanocubes are synthesized with crystal structures with particle size of less than 500 nm and are surrounded by the CNT and MnFe₂O₄ nanoparticles. Cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS) were applied to investigate the electrochemical properties of the samples. This study indicates that MCZ nanocomposite has superior electrochemical performance, confirmed by the measured specific capacitance of 389 F g⁻¹ (330 C g⁻¹)_, energy density of 24.4 W h kg⁻¹, power density of 265 W kg⁻¹ and good cycle stability (remaining at 107% after 500 cycles) as compared to other electrodes, whereas shown lowest resistance in electrochemical impedance spectroscopy. The obtained results suggest that the ternary MCZ has the potential to be applied as a novel electrode material in supercapacitor applications to render high-performance and stable energy storage devices.

[en] Monodispersed porous silica microspheres (SM) were synthesized and further functionalized with amine moieties using triethylenetetramine (TETA) in order to obtain a novel adsorbent for Cd(II) elimination from aqueous media. The morphology, texture and structure of samples were characterized with the aid of Fourier transform infrared spectroscopy (FTIR), X-Ray diffraction (XRD), scanning and transmission electron microscopy (SEM, TEM), energy dispersive spectroscopy (EDS), and N₂ adsorption-desorption. The adsorption efficiency was investigated based on the effect of operational parameters including pH of the solution, the dose of adsorbent, adsorption time, initial concentration of Cd(II) ions and temperature. The equilibrium, kinetics and thermodynamics of Cd(II) adsorption were also studied. The maximum adsorption capacity of amine functionalized silica microspheres (AMSM) for Cd(II) was 35.6 mg g^-1. Cd(II) adsorption onto AMSM had highest consistency with Sips and Langmuir isotherms, while adsorption kinetics was best fitted with pseudo-second order model. Thermodynamics of adsorption revealed that Cd(II) adsorption on AMSM was spontaneous, feasible and exothermic with physical interactions and pore diffusion being the dominant mechanisms in the adsorption process. Results confirmed that AMSM adsorbent has the potential to be a suitable candidate for Cd(II) removal from aqueous solutions.

[en] Highlights: • ZnFe₂O₄/ZrO₂ nanocomposite was fabricated by a versatile hydrothermal method. • The structural, optical and magnetic properties was investigated. • Nanocomposite was successfully formed with particle size between 14 and 30 nm. • Combination of ZnFe₂O₄ with ZrO₂ dramatically reduced the band gap energy. • Superior magnetic behavior with high saturation magnetization was obtained. The main purpose of this study is to synthesize and investigate the structural, magnetic and optical features of ZnFe₂O₄-ZrO₂ mixed metal oxide nanocomposite. ZnFe₂O₄-ZrO₂ nanocomposite with different ratios was prepared by a simple and low cost hydrothermal method. The samples were characterized with the aid of Fourier Transform Infrared spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), Inductively coupled plasma-optical emission spectroscopy (ICP-OES), BET measurements and UV–Vis spectroscopy. The X-ray diffraction study showed that the crystalline structure of ZnFe₂O₄ and ZrO₂ nanoparticles and ZnFe₂O₄-ZrO₂ nanocomposites were well-formed. FTIR Spectroscopy and SEM images further confirmed the complete formation of zinc ferrite and zirconium oxide crystalline structure with nano spherical morphology. Moreover, the particle size of the nanocomposites was between 14 and 30 nm, estimated by DLS analysis. The highest saturation magnetization (Ms) (27 emu/g) was achieved for ZnFe₂O₄-ZrO₂ nanocomposite with (3:1) ratio with M_r and H_c values of 0.17 (emu/g) and 3.02 (Oe), respectively. Moreover, optical studies indicated that addition of narrow band gap ZnFe₂O₄ nanoparticles could effectively reduce the band gap and shift the excitation wavelength of the nanocomposite to visible light.

[en] Graphical abstract: - Highlights: • The γ-Fe_2O_3 nanoparticles were prepared in one step using ultrasonic radiation and coated by polyrhodanine. • Nanocomposite synthesized with core average diameter of 15 nm and polyrhodanine as shell with thickness of 1.5 nm • Application of products was investigated to separate zinc ions from aqueous solution in a fixed-bed column. • The Adams–Bohart, BDST, Thomas and Yoon–Nelson models used to predict model parameters. • The models were nearly in good agreement with the experimental data. - Abstract: An organic–inorganic core/shell structure, γ-Fe_2O_3/polyrhodanine nanocomposite with γ-Fe_2O_3 nanoparticle as core with average diameter of 15 nm and polyrhodanine as shell with thickness of 1.5 nm, has been synthesized via chemical oxidation polymerization and applied for adsorption of Zn ions from aqueous solution in a fixed-bed column. The properties of nanocomposite were characterized with transmission electron microscope (TEM), Fourier transform infrared (FT-IR) spectroscopy and vibrating sample magnetometer (VSM). The performance of the column was assessed under variable bed heights (10, 15 and 20 cm) and influent Zn concentrations (50, 100 and 150 ppm) at a constant flow rate (0.5 mL/min). The results demonstrated that the breakthrough curves are S-shaped and the breakthrough time increases with increasing bed height and decreases with increasing influent concentration. Moreover, the dynamics of the adsorption process were evaluated by using Adams–Bohart, bed depth service time (BDST), Thomas and Yoon–Nelson kinetic models. The models were nearly in good agreement with the experimental data.

[en] Highlights: • Smart aminosilane modified-SnO₂/Porous silica nanocomposite was synthesized. • High efficiency removal of lead ions and bacterial inactivation were obtained. • The maximum adsorption capacity was 653.62 mg g⁻¹. • Nanocomposite possessed exceptional disinfection ability toward E-Coli and S. aureus bacteria. - Abstract: The aim of the present study is to synthesize a new and proficient nanoadsorbent for rapid removal of heavy metals and disinfection of microorganisms. The proposed nanoadsorbent was fabricated using SnO₂ nanoparticles as the core, coated with mesoporous silica and further modified with 3-Aminopropyl triethoxysilane to render SnO₂/PSi/NH₂ nanocomposite. The nanocomposite was characterized using Fourier Transform Infrared (FTIR), X-Ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Nitrogen adsorption-desorption analysis. The potential of the resultant SnO₂/PSi/NH₂ nanocomposite for the convenient removal of Lead ions in a batch systems was investigated as a function of solution pH, contact time, adsorbent dosage, temperature and metal ion concentration. The adsorption behavior was in good agreement with Sips and Langmuir isotherm models. The maximum adsorption capacity of SnO₂/PSi/NH₂ was 653.62 mg g⁻¹. Furthermore, the desorption experiments demonstrated that the proposed nanocomposite could be used frequently for at least three consecutive cycles with minor losses in adsorption performance. The bacterial inactivation ability of SnO₂/PSi/NH₂ toward E-Coli and S. aureus bacteria was also evaluated using disk diffusion and linear cultivation tests, according to which the SnO₂/PSi/NH₂ nanocomposite possessed exceptional disinfection ability toward both bacteria, specifically S. aureus.

[en] Highlights: • An electrochemical method was used for the Pdt/Ni deposition on the PANI/SiO2. • The modified electrodes showed improved performance for methanol oxidation. • This improvement was due to the increase of electrodes active surface area. • Density functional theory calculation results were in good with experimental results. Polyaniline-Silica (PANI-SiO₂) nanocomposite was developed as a support for enhancing the performance of Pt/Ni electrocatalyst in direct methanol fuel cells (DMFCs). Bimetallic Pt/Ni electrocatalyst was deposited on the in-situ prepared PANI-SiO₂ nanocomposite via cyclic voltammetry (CV) method. The electro-oxidation of methanol was studied at room temperature using CV, linear sweep voltammetry (LSV), and chronoamperometry (ChA) tests. The Pt/Ni/SiO₂-PANI electrocatalyst resulted in an onset potential of −0.54 V and an excellent peak current density of 144 mA/cm² showing its outstanding catalytic activity. Moreover, the Pt/Ni/SiO₂-PANI electronic structure was theoretically investigated via density functional theory (DFT) calculations. The DFT results confirmed that employing the PANI-SiO₂ structure for bimetallic PtNi nanostructure could lead to increasing the reactivity of the resulting catalyst and decreasing the energy gap. This observation was well consistent with the experimental results. The experimental and theoretical data indicated that PANI-SiO₂, as an organic-inorganic hybrid catalyst support, considerably improved the stability and CO poisoning tolerance of the resulting electrocatalyst, both of which are crucial for practical alkaline direct methanol fuel cell applications.