Removal of Reactive Red 74 Dye from Textile Industrial Waste using Zinc Oxide Nanoparticle

Global population growth and industrial activities in recent decades has been caused to enter excessive amount of pollutants to water resources. Industrial textile dyes are an important class of the pollutants in the sewage system. Disposal of the dyes in precious water resources must be avoided, however, and for that various treatment technologies are in use. Considering the toxicity of the pollutants, their removal from water resources is necessary. In this research, removal of reactive red 74, RR47, from aqueous solution by zinc oxide nanoparticles was investigated and the affecting parameters such as pH, contact time and adsorbent mass on removal efficiency were determined. Langmuir and Freundlich isotherms were studied and the results indicated that the adsorption process obey the Langmuir and Freundlich isotherms. The experimental results also showed that the pseudo-second order kinetic equation could nicely describe the sorption kinetics

Synthesis of nickel ferrite nanoparticles as an efficient magnetic sorbent for removal of an azo-dye: Response surface methodology and neural network modeling

In this research, nickel ferrite (NiFe2O4) nanoparticles (NFNs) are prepared through coprecipitation method, and applied for adsorption removal of a model organic pollutant, methyl orange (MO). The characterization of the prepared NFNs was performed using scanning electron microscopy (SEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and transmission electron microscopy (TEM). Optimization and modeling of the removal of MO applying NFNs were performed via central composite design (CCD) and the influential parameters including nano-sorbent amount, dye initial concentration, contact time and pH were considered as input variables for CCD. A dye removal percentage of 99 % was achieved under the optimum condition established for MO removal that was in agreeing with the predicted value. Additionally, multi-layer artificial neural network (ML-ANN) was applied to acquire a predictive model of MO removal. The isothermal investigation of MO adsorption was performed by developing Langmuir, Freundlich and Temkin models, and results showed that experimental data were best fit in Freundlich model. Based on the adsorption kinetics studies, the pseudo-second-order kinetic model was the best model to describe the adsorption mechanism of MO onto NFNs

Determination of Trace Amount of Cadmium in Real Water And Baby Food Samples By Microinjection Flame Atomic Absorption Spectrometry After Cloud Point Extraction Using Selective Synthesis Ligand

A cloud point extraction procedure was used for preconcentration and determination of trace amount of cadmium ion in real water and baby food samples by microinjection flame atomic absorption spectrometry and with using new synthesis dithiocarbamate ligand. The method is based on cloud point extraction of cadmium using triton X-114 as nonionic surfactant. A certain amount of ligand (Complexing Agent) and surfactant was added to samples and after pH adjustment; the sample was heated in a water bath. A hydrophobic complex was formed between cadmium and [N-(2-phenylethyl) dithiocarbamate] ligand and followed by its extraction into triton X-114 surfactant-rich phase.The surfactant-rich phase was diluted with suitable solvent and was separated with using centrifugation, and then measurements were performed with a micro-injection flame atomic absorption spectrometry. Extraction conditions such as pH, amount of Ligand (Complexing Agent) and Surfactant, equilibrium temperature and time, diluent volume and type were optimized. Also ionic strength effect and limit of interferences were studied. Under the optimum conditions, the limit of detection (3Sb/m) of 0.2 µg L-1, an enhancement factor of 116 and the relative standard deviation (5 µg L-1, n=5) of 4.5% were obtained. The calibration curve was linear for the concentration range of 0.5 to 20 µg L-1 with correlation coefficient of 0.9992. The proposed method was applied to determination of cadmium ion in water samples including tap water, mineral water, river water and sea water also baby food samples including infant formula powder (milk-based) and infant cereal Powder (wheat and milk-based).Â

Magnetic Solid Phase Extraction of Au(III) using Fe3O4 Nanoparticles Prior to its Flame Atomic Absorption Spectrometric Determination

A simple solid phase extraction procedure has been proposed for determination of Au(III) based on separation and preconcentration using magnetite nanoparticles (MNPs) prior to its determination by flame atomic absorption spectrometry. The influences of experimental parameters including sample pH, sorbent mass, contact time, volume and type of eluent, and interference of some ions with extraction of Au(III) ions were investigated using batch procedure. The maximum adsorption capacity of the sorbent for Au(III) was found to be 45.0 mg g-1. The sorption of Au(III) ions was quantitative in the pH range of 4.0–5.0 and quantitative desorption was achieved using 10 mL of thiourea (0.5 mol L-1)/hydrochloric acid (1 mol L-1) solution. In the initial solution, the calibration curve was linear in the range of 8.8 - 666.0 μg L-1 with R2 = 0.9994 (n = 8), the detection limit (3Sb, n = 8) was 6.2 μg L-1, relative standard deviation (R.S.D) of 20 μg mL-1 of Au(III) was 3.9% (n = 8), and the preconcentration factor was 30. The proposed method has been applied to the determination of Au(III) in water and wastewater samples with good recoveries in the range of 95% –103%