Adsorption of phenol and P-chlorophenol from aqueous solutions on polymer adsorbent

In the present study, a commercial Amberlite XAD-4 resin was investigated for its ability to remove phenol and p-chlorophenol in aqueous solution. The adsorption dynamics obeyed the pseudo-second order rate equation and the adsorption rate constant of phenol was a little greater than that of p-chlorophenol. The adsorption isotherms can be correlated to Freundlich isotherm. The adsorption capacity for p-chlorophenol was larger than that for phenol at the same temperature and equilibrium concentration

Adsorption study of phenol and some phenol derivatives on Fe3O4/C nanocomposites

Magnetite/carbon nanocomposites, prepared by a simple combustion synthesis technique, were tested for the removal of phenol and of some phenol derivatives: p-chlorophenol (p-CP), 3-aminophenol (3-AP), p-nitrophenol (p-NP), 2,6-dimethylphenol (DMP) and 2,4,6- trimethylphenol (TMP) from aqueous solutions. The effect of different parameters, including the magnetite/carbon ratio, initial concentration of pollutant and the contact time on the removal efficiency was investigated. The adsorption kinetics was described by the pseudosecond-order model and the equilibrium data were well fitted with the Langmuir isotherm in case of phenol, the Sips isotherm in case of 3-aminophenol and the Redlich-Peterson isotherm in case of p-nitrophenol. The good adsorption capacity and easy separation using a magnet, recommend the magnetite/carbon nanocomposites as promising candidates for the removal of phenol and its derivatives from polluted water

Enhanced adsorption of methyl orange from aqueous solutions using a functionalized styrene-divinylbenzene copolymer

The adsorption efficiency of the styrene-divinylbenzene copolymer functionalized with carboxylic acid groups (SDVBF) was investigated for methyl orange (MO) removal from aqueous solutions. The effects of contact time and of the initial concentration on the amount of MO adsorbed were studied. The kinetics of MO adsorption onto SDVBF copolymer was described by the pseudo-second order model. It was demonstrated that Redlich-Peterson model is the most suitable to describe the adsorption of MO onto SDVBF copolymer. The maximum adsorption capacity of the SDVBF adsorbent, resulted from the Langmuir isotherm was 53.12 mg g-1

Preclinical Aspects on Magnetic Iron Oxide Nanoparticles and Their Interventions as Anticancer Agents: Enucleation, Apoptosis and Other Mechanism

The broad area of magnetic iron oxide nanoparticle (M-IONP) applications and their exclusive physico-chemical characteristics (superparamagnetic properties per se, solubility and stability in aqueous solutions, and high bioavailability in vivo) make these nanoparticles suitable candidates for biomedical uses. The most employed magnetic iron oxides in the biomedical field are magnetite and maghemite. Cancer represents a complex pathology that implies multiple mechanisms and signaling pathways, this complexity being responsible for the increased resistance to therapy and the lack of an effective curative treatment. A potential useful alternative was considered to be the use of magnetic iron nanoparticles. The M-IONPs proved to be effective as contrast agents in magnetic resonance imaging, as drug delivery carriers for different therapeutic agents, in magnetic cell separation assays, and are suitable to be engineered in terms of size, targeted delivery and substance release. Moreover, their in vivo administration was considered safe, and recent studies indicated their efficiency as anticancer agents. This chapter aims to furnish an overview regarding the physico-chemical properties of M-IONPs (mainly magnetite, maghemite and hematite), the synthesis methods and their in vitro biological impact on healthy and cancer cell lines, by describing their potential mechanism of action—enucleation, apoptosis or other mechanisms

P-nitrophenol adsorption on polystyrene-co-divinylbenzene functionalized copolymers

The removal of phenolic compounds form wastewater is of significant importance due to the damages caused to the environment and human life [1-3]. The polymeric adsorbents were intense studied in the adsorption processes and are now considered efficient in the removal of different pollutants from wastewater, including phenolic compounds [4-6]. In this study we introduce two new polystyrene-co-divinylbenzene copolymers, functionalized with carboxylic groups. The two copolymers, PC12 (with 12% divinylbenzene) and PC6.7 (with 6.7% divinylbenzene) were characterized and tested as adsorbents for the removal of p-nitrophenol from aqueous solution. The effect of different parameters on the removal efficiency was investigated. The kinetics and adsorption isotherm were also evaluated. The copolymers were characterized by means of IR spectroscopy. FTIR spectra were carried out using a Shimadzu Prestige-21 spectrometer in the range 400–4000 cm-1, using KBr pellets and resolution of 4 cm-1. N2 adsorption–desorption isotherms of copolymers were performed on Micromeritics ASAP 2020 instrument. The specific surface area was calculated using the Brunauer–Emmett–Teller (BET) method and the pore size distribution using the Barrett–Joyner–Halenda(BJH) method from the desorption curves. Thermal analysis (TG/DSC) was carried out using a NETZSCH-STA 449C instrument. The curves were recorded in the range of 25–1200 °C with a heating rate of 10 K min-1, using platinum crucibles. The experiments were carried out in artificial air at a flow rate of 20 mL min-1. The morphology of the nanopowders was investigating by scanning electron microscopy (SEM), using a FEI Quanta FEG 250 microscope. The adsorption experiments were performed at 25 °C, using 50 mg adsorbent added at 25 mL p-nitrophenol solution with initial concentrations of 100 mg L-1. All experiments were performed at a 200 rpm shaking speed for 8 h to ensure the equilibrium of the adsorption process. The p-nitrophenol concentration was monitored by spectrophotometric analysis using a Schimadzu UV–VIS Spectrophotometer. The absorbance values were measured according to the maximum UV-absorption, at the wavelength of 316 nm. The copolymers proved a good adsorption capacity. The removal efficiency of pnitrophenol using PC6.7 adsorbent was 86% while using PC12 was 78%. The experimental data were fitted with Langmuir, Freundlich, Redlich-Peterson and Sips isotherms. The maximum adsorption capacity of p-nitrophenol, resulted from Langmuir isotherm was 213.4 mg g-1 using PC6.7 adsorbent and 80.8 mg g-1 using PC12

Combustion Synthesis of SrAl2O4: Eu2+, Dy3+ Phosphorescent Pigments for Glow-in-the-Dark Safety Markings

This study deals with SrAl2O4: Eu2+, Dy3+ phosphor pigments prepared by an optimized perchlorate-assisted combustion synthesis and tested for developing glow-in-the-dark safety markings. Recipes with different oxidizer/fuel ratios were designed to create an in-situ reducing-reaction atmosphere and promote Eu3+ → Eu2+ reduction, which is responsible for the specific long-lasting, green emission of the pigments. The obtained data proved the efficiency of glycine-rich mixtures (up to 200% glycine excess), which led to improved optical features, as compared to the reference stoichiometric sample. The best results in terms of emission intensity and decay time were obtained in the case of 100% glycine excess. The sample with optimum emission characteristics was successfully tested in making glow-in-the-dark coatings applied to two different substrates and using pigment concentrations between 10 and 33% weight

Combustion Synthesis of SrAl₂O₄: Eu²⁺, Dy³⁺ Phosphorescent Pigments for Glow-in-the-Dark Safety Markings

This study deals with SrAl2O4: Eu2+, Dy3+ phosphor pigments prepared by an optimized perchlorate-assisted combustion synthesis and tested for developing glow-in-the-dark safety markings. Recipes with different oxidizer/fuel ratios were designed to create an in-situ reducing-reaction atmosphere and promote Eu3+ → Eu2+ reduction, which is responsible for the specific long-lasting, green emission of the pigments. The obtained data proved the efficiency of glycine-rich mixtures (up to 200% glycine excess), which led to improved optical features, as compared to the reference stoichiometric sample. The best results in terms of emission intensity and decay time were obtained in the case of 100% glycine excess. The sample with optimum emission characteristics was successfully tested in making glow-in-the-dark coatings applied to two different substrates and using pigment concentrations between 10 and 33% weight

Lanthanum Ferrite Ceramic Powders: Synthesis, Characterization and Electrochemical Detection Application

The perovskite-type lanthanum ferrite, LaFeO3, has been prepared by thermal decomposition of in situ obtained lanthanum ferrioxalate compound precursor, LaFe(C2O4)3·3H2O. The oxalate precursor was synthesized through the redox reaction between 1,2-ethanediol and nitrate ion and characterized by chemical analysis, infrared spectroscopy, and thermal analysis. LaFeO3 obtained after the calcination of the precursor for at least 550–800 °C/1 h have been investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). A boron-doped diamond electrode (BDD) modified with LaFeO3 ceramic powders at 550 °C (LaFeO3/BDD) by simple immersion was characterized by cyclic voltammetry and tested for the voltammetric and amperometric detection of capecitabine (CCB), which is a cytostatic drug considered as an emerging pollutant in water. The modified electrode exhibited a complex electrochemical behaviour by several redox systems in direct relation to the electrode potential range. The results obtained by cyclic voltammetry (CV), differential-pulsed voltammetry (DPV), and multiple-pulsed amperometry proved the electrocatalytic effect to capecitabine oxidation and reduction and allowed its electrochemical detection in alkaline aqueous solution

Removal of Colored Organic Pollutants from Wastewaters by Magnetite/Carbon Nanocomposites: Single and Binary Systems

This work develops a methodology for selective removal of industrial dyes from wastewaters using adsorption technology based on magnetic adsorbents. The magnetic nanoparticles embedded within a matrix of activated carbon were tested as adsorbents for removal of industrial dyes from aqueous solutions. The effects of four independent variables, solution pH, initial concentration of pollutant, adsorbent dose, contact time, and their interactions on the adsorption capacity of the nanocomposite were investigated in order to optimize the process. The removal efficiency of pollutants depends on solution pH and increases with increasing the carbon content, with initial concentration of the pollutants, the temperature, and the dose of magnetite/carbon nanocomposites. Pseudo-second-order kinetic model was fitted to the kinetic data, and adsorption isotherm analysis and thermodynamics were used to elucidate the adsorption mechanism. The maximum adsorption capacities were 223.82 mg g−1 for Nylosan Blue, 114.68 mg g−1 for Chromazurol S, and 286.91 mg g−1 for Basic Red 2. The regeneration and reuse of the sorbent were evaluated in seven adsorption/desorption cycles. The optimum conditions obtained for individual adsorption were selected as starting conditions for simultaneous adsorption of dyes. In binary systems, in normal conditions, selectivity decreases in the order: Red Basic 2 > Nylosan Blue > Chromazurol S