Chemistry of Solid Materials
Volume:2 Issue: 2, Spring 2015

Chelating resins have been considered to be suitable materials for the recovery of heavy metals in water treatments. A chelating resin based on modified poly(styrene-alt-maleic anhydride) with Melamine was synthesized. This modified resin was further reacted with 1,2-diaminoethan in the presence of ultrasonic irradiation for the preparation of a tridimensional chelating resin on the nanoscale for the recovery of heavy metals from aqueous solutions. The adsorption behavior cobalt (II) ions was investigated by the synthesis of chelating resins at various pH’s. The prepared resins showed a good tendency for removing the cobalt (II) ions from aqueous solution, even at acidic pH. The resin was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction analysis.The adsorption process of cobalt (II) on SMA, SMA-M and SMA-M- E were tested with Langmuir isotherm model and the isotherm constants were deduced from this.

Fe3O4 nanoparticles were prepared hydrothermally and characterized by X-Ray diffraction spectroscopy (XRD), and scanning electron microscopy (SEM). It was found that these nanoparticles can act as an efficient catalyst in the degradation of Methylene blue dye in aqueous solution in a Fenton like system in presence of 30% perhydrol. Uv-Vis spectroscopy was used to determine the concentration of dye during optimization of different affecting factors such as pH, catalyst loading, and amount of the oxidant. Based on these results, 0.6 g/L of the catalyst and 0.32 mmol/L of the oxidant at pH=4.8 were selected as the optimum conditions and this resulted in a considerable degradation in less than 20 minutes. The catalyst was also found to be recyclable with no considerable decrease in its efficiency in successive runs.

SiO2/ZnS core/shell nanostructures have been synthesized at room temperature by a simple wet chemical method. The prepared materials are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (IR), UV–vis spectroscopic and transmission electron microscopy (TEM) studies. X-ray diffraction pattern exhibits peaks correspond to the cubic phase of ZnS. The morphological studies revealed the uniformity in size distribution with core size of 250 nm and shell thickness of 14 nm. From UV–Vis spectra the band gap energies are calculated. The band gap of ZnS has been determined as 3.70 eV directly from the absorption maximum of ZnS, λmax = 335 nm. The band gap of the bulk ZnS is 3.54 eV.

Nano hydroxyapatite and Silicon-substituted hydroxyapatite nanocomposites with various amount of Si contents (0, 2, 4 and 6 mole % as named as HS0, HS2, HS4 and HS6) were prepared via in situ hybridization method and were analyzed by XRD, FTIR, SEM and AFM techniques. Size distribution of the products demonstrated that hydroxyapatite particles size was between 2 and 53.5 nm with further mean size about 23 nm, while these results, were found to be present around 45, 32 and 38 nm for HS2, HS4 and HS6 respectively. The XRD results specified that some change occurred in the hydroxyapatite lattice with varying Si content in composites samples and explained incorporation of silicon did not appear significantly affect upon the diffraction pattern. SEM micrograph indicated many small particle crystallites existed in the aggregated surface that improved surface modification of composite products that might be due to the high solubility of the nanoparticles in the organic solvents. Subsequently soaking in Human Serum Albumin caused tiny particles observation in a new formation, as the new form of apatite layer covered the samples. In addition, it is quite obvious that the all peaks in FTIR remained after immersion, while peaks intensity was decreased.

A nano-hybrid based on polystyrene derivatives and magnetite was introduced as a new sorbent for pretreatment and determine the trace amount of malachite green from aqueous solution by spectrophotometry after preconcentration by solid phase extraction (SPE). UV–Vis spectrophotometer was used for determination of MG concentration after desorption of the dye by hydrochloric acid solution in the solutions. Different variables affecting the separation/pre-concentration conditions, including pH of the sample solution, amount of the sorbent, extraction and desorption times, sample volume, and elution conditions were obtained in the range of 1–2000 ng/mL dye, with the correlation coefficient of 0.998. The enrichment factor of 133 was achieved. The limit of detection was 0.2 ng·mL−1 and the relative standard deviation for the determination of malachite was 1.4 % (n=6(. Langmuir, Freundlich, adsorption isotherm models were studied and the experimental results were addressed by Freundlich isotherm model. The maximum sorption capacity of the adsorbent for malachite green was 148.6 mg. g-1, indicating high potential of MSMA in the adsorption of malachite green. The adsorption kinetics was studied with the pseudo-first-order, pseudo-second-order models. The method was successfully applied to determine malachite green in natural waters and satisfactory recoveries were obtained >98 %.from this.

In this work for the first time, Fe3O4@SiO2 core-shell nanoparticles functionalized with isatin groups as a magnetic nanosorbent was applied for the simultaneous extraction of trace amounts of cadmium (II). The characterization of this nanosorbentwas studied using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The effect of several factors such as pH, amount of sorbent, extraction time, type and volume of the eluent, sample volume, and sorption capacity. In the selected conditions, it was observed that the limits of detection were 0.11 ng mL−1 for Cd(II) and the maximum sorption capacity of this suggested magnetic nanosorbent was 120mg/g. Finally, the suggested procedure was applied for determination of cadmium (II) at trace levels in different water samples with satisfactory results.

Nanostructured Mn2Sb2O7 powders were synthesized via stoichiometric1:1 Mn:Sb molar ratio solid state reaction at different reactions temperatures for 8 h using MnSO4.H2O and Sb2O3 as raw materials. The synthesized materials were characterized by powder X-ray diffraction (PXRD) technique. Structural analyses were performed by the FullProf program employing profile matching with constant scale factors. The results showed that the patterns had a main monoclinic Mn2Sb2O7 crystal structure with space group P21. The morphologies of the synthesized materials were studied by field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM) which showed that the Mn2Sb2O7 samples had flower like and spherical particles morphologies. Ultraviolet – Visible spectroscopy (UV-Vis) showed that the band gap was about 2.85 eV. The most pure sample (S6) was used as catalyst in the one-pot synthesis of the heterocyclic compounds 3,4-dihydropyrimidin-2(1H)-ones (DHPMs) in Biginelli reactions. Experimental design was used to find the optimized reaction conditions.