Adsorption of phenol onto rice straw biowaste for water purification

The adsorption technique has been studied using waste rice straw to adsorb phenol from aqueous solutions at room temperature. Batch adsorption studies were carried out under varying experimental conditions of contact time, operational temperature, pH of phenol solution, initial phenol concentration, adsorbent dose, and particle size. The time to reach equilibrium was found to be 3?h. Results showed that the equilibrium data for phenol-sorbent systems fitted the Freundlich model and Langmuir model within the concentration range studied. Adsorbed phenol could be regenerated by desorption with the help of 1M NaOH. The studies showed that the rice straw can be used as an efficient adsorbent material for removal of phenol and phenolic compounds from water and wastewater.     

Photopolymerization behavior and phase separation effects in novel polymer dispersed liquid crystal mixture based on urethane trimethacrylate monomer

Polymer dispersed liquid crystals (PDLCs) are often formed by polymer induced phase separation, based on photopolymerization of multifunctional acrylate monomers. The emerged morphology is controlled by the interplay between polymerization rate and phase separation dynamics, which depends on different parameters such as monomer structure and functionality. In this work, a new PDLC formulation containing urethane trimethacrylate (UTMA) monomer is introduced, which has different molecular weight evolution, polymer gel point, and polymerization kinetics in comparison with some common ester acrylate (such as TMPTA and DPHPA) based PDLC compositions. UTMA is synthesized and characterized by Fourier transform infrared, ¹H‐NMR, and ¹³C‐NMR spectroscopic techniques. Simultaneous examination of polymer evolution and LC phase separation by real‐time infrared spectroscopy shows that the UTMA based PDLC, which contains trifunctional urethane acrylate monomer, has greater amount of bond conversion, polymerization rate, and liquid crystal (LC) phase separation in comparison with TMPTA based PDLC. In spite of the acrylate monomers, which show gel point conversions as low as 1.83–5.72%, UTMA reaches to its maximum rate at 19.5% conversion, which causes higher phase separation and therefore greater LC domain size. The experimental results are explained more precisely by means of SEM and optical microscopy analyses. The results are confirmed by electro‐optics measurements. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Electrochemical determination of rutin by using NiFe2O4 nanoparticles-loaded reduced graphene oxide

A binary transition metal oxide containing nickel and iron (NiFe₂O₄) and hybridization of this nanomaterial with reduced graphene oxide (rGO) are synthesized by the hydrothermal method. X-ray diffraction (XRD) and Raman spectroscopy confirm the successful synthesis of these materials. Also, scanning electron microscope (SEM) and transmission electron microscope (TEM) images illustrated the particle morphology with the particle size of 20 nm. The synthesized material is then examined as a sensor on the surface of the glassy carbon electrode to detect a very small amount of rutin. Some electrochemical tests such as cyclic voltammetry, differential pulse voltammetry (DPV), and impedance spectroscopy indicate the remarkable accuracy of this sensor and its operation in a relatively wide range of concentrations of rutin (100 nM-100 µM). The accuracy of the proposed electrochemical sensors is approximately 100 nM in 0.1 M PBS, (pH?=?3) which is relatively impressive and can be reported. Also, the stability rate after 100 DPV was about 95?%, which is a considerable and relatively excellent value. Considering the very good results, it seems that the NiFe₂O₄-rGO can be considered as a new proposal in the development of accurate and inexpensive electrochemical sensors.

     

The Role of Mn–Mg–Ti–Zr Substitution on Structural and Magnetic Features of BaFe12−x (MnMgTiZr) x/4 O 19 Nanoparticles

Substituted barium hexaferrite nanoparticles with composition of BaFe_12?x (MnMgTiZr) _x/4 O ₁₉ (x = 0–2.5 in a step of x = 0.5) were synthesized by co-precipitation method. The structural, magnetic, and microwave absorption properties of samples were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), vibrating sample magnetometer (VSM), and vector network analysis (VNA). The XRD results show that the magnetoplumbite structures for all samples have been formed. The crystallite size of nanoparticles lies in the range of 26–31 nm. FE-SEM graphs indicated that the particle sizes were almost less than 100 nm and increased with an increase in Mn–Mg–Ti–Zr substitution. The result of hysteresis loops revealed that for x>1, M _s decreased with an increase in x content; furthermore, it was found that as the amount of dopant increased from x = 0 to x = 2.5, H _c decreased from 4.8 to 0.81 kOe. Based on microwave measurement on reflectivity, doped samples had much more effective reflection loss values than undoped ferrites. It was also found that the maximum reflection loss (?30.1 dB) was achieved by ferrite with the maximum amount of substitution. The obtained results reflected that the proposed composites can be introduced as electromagnetic wave absorption materials.     

Intelligent anticancer drug delivery performances of two poly(N-isopropylacrylamide)-based magnetite nanohydrogels

This article evaluates the anticancer drug delivery performances of two nanohydrogels composed of poly(N-isopropylacrylamide-co-itaconic anhydride) [P(NIPAAm-co-IA)], poly(ethylene glycol) (PEG), and Fe₃O₄ nanoparticles. For this purpose, the magnetite nanohydrogels (MNHGs) were loaded with doxorubicin hydrochloride (DOX) as a universal anticancer drug. The morphologies and magnetic properties of the DOX-loaded MNHGs were investigated using transmission electron microscopy (TEM) and vibrating–sample magnetometer (VSM), respectively. The sizes and zeta potentials (ξ) of the MNHGs and their corresponding DOX-loaded nanosystems were also investigated. The DOX-loaded MNHGs showed the highest drug release values at condition of 41?°C and pH 5.3. The drug-loaded MNHGs at physiological condition (pH 7.4 and 37?°C) exhibited negligible drug release values. In vitro cytotoxic effects of the DOX-loaded MNHGs were extensively evaluated through the assessing survival rate of HeLa cells using the MTT assay, and there in vitro cellular uptake into the mentioned cell line were examined using fluorescent microscopy and fluorescence-activated cell sorting (FACS) flow cytometry analyses. As the results, the DOX-loaded MNHG1 exhibited higher anticancer drug delivery performance in the terms of cytotoxic effect and in vitro cellular uptake. Thus, the developed MNHG1 can be considered as a promising de novo drug delivery system, in part due to its pH and thermal responsive drug release behavior as well as proper magnetite character toward targeted drug delivery.     

Integrated design and control of reactive distillation processes using the driving force approach

Superior controllability of reactive distillation (RD) systems, designed at the maximum driving force (design-control solution) is demonstrated in this article. Binary or multielement single or double feed RD systems are considered. Reactive phase equilibrium data, needed for driving force analysis and design of the RD system, is generated through an in-house property prediction tool. Rigorous steady-state simulation is carried out in ASPEN plus in order to verify that the predefined design targets and dynamics are met. A multiobjective performance function is employed to evaluate the performance of the RD system in terms of energy consumption, sustainability metrics (total CO₂ footprint), and control performance. Controllability of the designed system is evaluated using indices like the relative gain array (RGA) and Niederlinski index (N_I ), to evaluate the degree of loop interaction, as well as through dynamic simulations using proportional-integral (PI) controllers and model predictive controllers (MPC). The design-control of the RD systems corresponding to other alternative designs that do not take advantage of the maximum driving force is also investigated. The analysis shows that the RD designs at the maximum driving force exhibit enhanced controllability and lower carbon footprint than the alternative RD designs.     

Family interactions and the course of schizophrenia in African American and white patients.

Relatives' critical and intrusive behavior with patients, patients' odd or unusual thinking with relatives, and the course of schizophrenia were examined. Seventy-one African American and White patients (each with 1 relative) completed 2 problem-solving discussions. Relatives' critical and intrusive behavior with patients and patients' odd or unusual thinking with relatives were assessed, and patients were followed for 2 years. For African American patients, high levels of relatives' critical and intrusive behavior were associated with better outcome. For White patients, low levels of both relatives' critical and intrusive behavior and patients' odd or unusual thinking with relatives were associated with better outcome. The results suggest that during family interactions, seemingly negative behaviors may be perceived as a sign of caring and concern by African Americans. For Whites, the combination of patients' odd or unusual thinking with relatives and relatives' critical and intrusive behavior toward patients may be especially predictive of an adverse course. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Morphology transition control of polyaniline from nanotubes to nanospheres in a soft template method

A soft template route is reported for the fabrication of polyaniline nanospheres via the oxidative polymerization of aniline in the presence of β‐naphthalenesulfonic acid (β‐NSA) as both surfactqant and dopant, and ammonium persulfate as oxidant at 2–5 °C. Control over the morphology and size of the nanoparticles was achieved by changing the reaction medium via addition of an organic cosolvent (i.e. ethanol or ethylene glycol) and by controlling the concentrations of aniline and β‐NSA and the molar ratio of β‐NSA to aniline. By this means the size of the β‐NSA–aniline micelles and the way that aniline monomer interacts with the micelles were controlled. In fact the lower dielectric constant of organic cosolvent, due to reduction of the possibility of dissociation of ionic species, causes the monomer to exist mostly as neutral aniline molecules rather than as anilinium cations. The neutral aniline molecules form aniline‐filled micelles with β‐NSA, which act as soft templates for the formation of polyaniline nanospheres. Scanning and transmission electron microscopies, dynamic light scattering, and Fourier transform infrared and UV‐visible spectroscopies were used to characterize the products. The mechanism of morphology transition from nanotubes to nanoparticles is discussed based on the experimental observations. © 2014 Society of Chemical Industry     

Synthesis and characterization of supported heteropolymolybdate nanoparticles between silicate layers of Bentonite with enhanced catalytic activity for epoxidation of alkenes

A new heterogeneous catalyst (PVMo/Bentonite) consisting of vanadium substituted heteropolymolybdate with Keggin-type structure Na₅[PV₂Mo₁₀O₄₀]·14H₂O (PVMo) supported between silicate layers of bentonite has been synthesized by impregnation method and characterized using X-ray diffraction, Fourier-transformed infrared spectroscopy, scanning electron microscopy, UV–vis diffuse reflectance spectroscopy, transmission electron microscopy and elemental analysis. X-ray diffraction and scanning electron microscopy analysis indicated that PVMo was finely dispersed into layers of bentonite as support. The PVMo/Bentonite used as an efficient heterogeneous catalyst for epoxidation of alkenes. Various cyclic and linear alkenes were oxidized into the corresponding epoxides in high yields and selectivity with 30% aqueous H₂O₂. The catalyst was reused several times, without observable loss of activity and selectivity. The obtained results showed that the catalytic activity of the PVMo/Bentonite was higher than that of pure heteropolyanion (PVMo).