Fabrication of functional carbon/magnetic nanocomposites as a promising model of utilization of used crosslinked polymers

The utilization of used crosslinked functional polymers (CFP) applied as sorbents or ion-exchangers is a great challenge arising from the need to protect the environment. In this paper we report a very promising way of obtaining carbon/magnetic composites based on metal (Co2+; Ni2+; Fe3+) derivatives of butadiene rubber-based phosphorus-containing polymer, which were treated as the model used CFP. We proposed a facile one-step thermal degradation approach to transform used CFP into carbon/magnetic composites (CMC). The obtained CMCs contained a mixture of metal phosphates and metal phosphides that exhibited strong magnetic properties due to the presence of nanosized metal derivatives with diameters of 100⁻140 nm. Structural and morphological changes of CFP and CMC after thermal degradation were investigated by the FTIR technique, X-ray Diffraction analysis, Scanning Electron Microscope, and Atomic Force Microscope⁻Magnetic Force Microscope. Moreover, thermal degradation kinetics parameters were determined to optimize the efficiency of the process

Adsorption of arsenazo (III) due by phosphorus-containing polymer sorbent

Phosphorus-containing polymer sorbent was employed for removal hazardous Arsenazo (III) dye from water. The adsorption characteristics were determined by the study at different parameters such as effect of solution pH, effect of initial dye concentration, sorbent dose, phase contact time, and temperature. The equilibrium data were analyzed on the basis of various adsorption isotherm models, namely Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich. The highest monolayer adsorption capacity has been obtained (24.75 mg g-1) at 55°C. Different thermodynamic parameters such as free energy, enthalpy, and entropy have been calculated and it was concluded that when temperature rises, adsorption increases, indicating the endothermic nature of the process. Kinetic parameters were derived by pseudo-first-order, pseudo-second-order and intraparticle kinetic models. Scanning Electron Microscopy and Fourier Transform Infrared spectroscopy were used to characterize the sorbent and also to validate the adsorption mechanism

Magnetic Adsorbent Decorated with Poly(N-Isopropylacrylamide) (PNIPAM) Brushes for the Vortex-Assisted Solid Phase Extraction (VASPE) of Lead in Water, Cigarettes and Soil with High-Resolution Continuum Source Flame Atomic Absorption Spectrometry (HR-CS FAAS) Detection

Here is reported the synthesis of a magnetic phosphorus-containing adsorbent decorated with poly(N-isopropylacrylamide) (PNIPAM) brushes via surface-initiated atom transfer radical polymerization (SI-ATRP) and its application for vortex assisted solid phase extraction of lead in water, cigarettes and soil. The adsorbent was characterized using Fourier-transform infrared spectroscopy (FT-IR) and energy dispersive x-ray (EDX) spectroscopy. A high-resolution continuum source flame atomic absorption spectrometer (HR-CS FAAS) was used for the quantification of lead. All factors affecting the extraction efficiency including the solution pH, adsorbent dose, sample volume, vortex time, and elution protocols were optimized. The limits of detection (LOD) and quantification (LOQ) were determined to be 0.05 µg L−1 and 0.18 µg L−1, respectively. The preconcentration and enhancement factors were 20 and 18. Validation was performed using TMDA 64.3 fortified water and INCT-OBTL-5 tobacco leaves certified reference materials with satisfactory recoveries. The method was shown to be sensitive, efficient and reproducible

Solid phase extraction of uranium(VI) on phosphorus-containing polymer grafted 4-aminoantipyrine

Phosphorus-containing polymer grafted 4-aminoantipyrine has been synthesized and used for solid phase extraction of U(VI) prior to its UV-Visible spectrophotometric determination by using arsenazo(III). The adsorbent was characterized by using FT-IR and SEM analysis. The influence of parameters including pH, adsorbent dose, amount of complexing reagent, sample volume and matrix effect have been optimized. The detection limit was determined as 1.4 mu g L-1 with pre-concentration factor of 30 and RSD of 1.4 %. The accuracy was checked by the analysis of GBW07424 soil and TMDA-64.2 environmental water certified reference materials. The method was applied to natural water and soil samples

Development of Phosphate-containing Polymer-based Solid Phase Extraction Procedure for the Separation, Enrichment, and Determination of Cadmium in Water and Food Samples by FAAS

A phosphorous-containing polymer (PhCP) has been used as an adsorbent for solid phase extraction (SPE) of cadmium at ultratrace levels. Cd2+ in aqueous solution was combined with 8-hydroquinoline and adsorbed on the PhCP column, then the desorption step was carried out with 3 mL of 3M HNO3. Several analytical factors affecting the adsorption and enrichment efficiency of trace levels of cadmium include the pH of the solution, 8-hydroquinoline concentration, concentration of the eluent, and sample volume which were optimized to obtain good selectivity and quantitative extraction yield. The adsorption capacity of the PhCP sorbent was 9.0 mg/g, the limit of detection (LOD) 0.41 mu g/L with a preconcentration factor of 20. The relative standard deviation of 25 mu g/L Cd was 4.23%. The presented procedure was validated by the analysis of certified reference materials and the standard addition method. The analytical results showed good agreement with the certified values and the recoveries were in the range of 97-100%. The method was successfully applied for the enrichment and determination of cadmium in water and food samples and analysis by FAAS

Design, Structural Characteristic and Antibacterial Performance of Silver-Containing Cotton Fiber Nanocomposite

In the present study, cotton fiber was treated with phosphorus trichloride in the presence of oxygen. As a result of the subsequent hydrolysis of modified cotton fibers, phosphorus-containing fragments with acidic groups and chlorine atoms were introduced onto their surface. Afterward, silver-containing composites based on raw and modified cotton fibers were prepared using the chemical reduction method. The obtained samples were characterized in detail by Fourier transform infrared spectroscopy, ultraviolet–visible spectroscopy, X-ray powder diffraction, as well as by thermogravimetric analysis, scanning electron microscopy, and energy-dispersive X-ray analysis. A comparative bioassay experiment of four samples for gram-negative (Escherichia coli) bacteria, gram-positive (Staphylococcus aureus) bacteria, and the fungus Candida albicans was carried out. These results showed the predominant antibacterial activity of the phosphorylated sample and the composite based on it. Thus, the development of these antibacterial cotton fibers using readily available reagents under relatively mild conditions could be used as potential industrial applications for the production of everyday medical textiles

Effect of functional groups on the thermal degradation of phosphorus- and phosphorus/nitrogen-containing functional polymers

In the present study the thermal behavior of phosphorus- and phosphorus/nitrogen-containing functional polymers was studied. The polymers were synthesized via oxidative chlorophosphorylation reaction of butadiene rubber and were subsequently subjected to hydrolysis, aminolysis and/or alcoholysis in order to introduce appropriate functionalities. The successful modifications of the polymer and presences of the respective functional groups were determined using Fourier transform infrared spectroscopy. It was found that the product of hydrolysis of the modified butadiene rubber contains acidic groups in its structure while the products of aminolysis and alcoholysis contain both acidic and amine and/or alcohol-derived moieties. The kinetic analyses of the thermal decomposition reaction were evaluated using thermogravimetric analysis and subsequently Friedman and Ozawa–Flynn–Wall methods revealing three-stage degradation process. Calorimetric measurements were performed for the studied polymers, and mass spectrometric analyses were used to identify the decomposition products for phosphorus-containing polymer. The overall results allowed to reveal the influence of the attached phosphorus- and phosphorus/nitrogen-containing functional groups to the thermal degradation of the cross-linked polymers