rashin andayesh

Bio-absorbent palm fiber was applied for removal of cationic violet methyl dye from water solution. For this purpose, a solid phase extraction method combined with the artificial neural network (ANN) was used for preconcentration and determination of removal level of violet methyl dye. This method is influenced by factors such as pH, the contact time, the rotation speed, and the adsorbent dosage. In order to find a suitable model of parameters and calculate the desired output, two radial basis function (RBF) and multi-layer perceptron (MLP) non-recursive functions, which are among widely used artificial neural networks, were used for training the input data. The performance of this method is tested by common statistical parameters including RMSE, MAE, and CE. The results show that the artificial neural network algorithm has a good performance in simulating and predicting the removal of violet methyl dye.

Dissolved Thiocyanate in drinking water is a source of global health concern. The purpose of the present study was to remove aqueous Thiocyanate anions by using the titanium dioxide nanoparticles (TiO2 NPs). Titanium dioxide is inexpensive and non-toxic, making it an attractive choice for drinking water purification. Thiocyanate was adsorbed by the surface of nanoparticles into Fe-SCN complex and a filter was used for removing the nanoparticles. The effect of different parameters such as pH, buffer, time of stirring, the number of nanoparticles, concentration of the aqueous iron, and concentration of the electrolyte and its optimal amounts were investigated. Removal of the aqueous SCN- showed the best performance at the pH of 9, 0.5 mL of buffer, stirring for 15 min, and 0.5 g of TiO2. It was analyzed by means of spectrophotometry at ƛ=456.8 nm. Langmuir adsorption isotherm and Freundlich adsorption isotherm explained the best correlation between the Thiocyanate adsorption and equilibrium data. Langmuir adsorption isotherm showed more adaptability and the its sorption capacity was 11.6 mg/g-1 for nanoparticles. This method was tested for removing Thiocyanate from some real samples including tape water, Karoon River water, and water from petrochemical wastewater. Majority of the TiO2 NPs revealed an acceptable sorption capacity and reuse-ability in Thiocyanate anions removal in water solution.

Via Box-Behnken method, we evaluated the influence of various factors on absorption, including the amount of absorbent, the speed of stirring the solution and absorbent, pH of solution, time of contact, and various concentrations of violet methyl colour, to obtain optimum conditions. The maximum extent of violet methyl removal was found at 100 mg/L concentration, pH = 4.6, contact time = 50 minutes, 120 rotation speed, and absorbent dose = 1.488 g/L (0.0744 gram in 50 millilitre). In order to determine the reaction mechanism, two kinetic models were used, namely pseudo-first-order and pseudo-second kinetics models. The adsorption kinetics followed pseudo-second order model, and the mechanism of chemical reaction was the rate-limiting step. Furthermore, the Langmuir and Freundlich Isotherms were considered for absorbing the violet methyl on the palm fiber absorbent. The adsorption isotherms showed a balanced relationship between the materials adsorbed on the adsorbent (qe) and a balanced concentration in the solution (Ce) at a constant temperature. This method was used to remove the violet methyl colour from real samples such as industrial sewage, tap and river water.

A new sorbent was provided and exerted for separation and preconcentration of Pb (II) before the determination of lead ions by flame atomic absorption spectrometry. The normative studies on extraction, separation and preconcetration of Pb (II) were represented in the present work. This novel method was based on new sorbent by adding diethylenetriamine to sawdust and increasing incidence exterior. The effect of different parameters were studied; such as pH, ligand concentration and sample volume, type and volume of eluent and ligand effect. The optimum pH and preconcentration factor and limit of detection for Pb (II) were 4, 100 and 0.48 µg/L, respectively. Furthermore, in this approach calibration curve was linear in the range of 0.05-100 mg mL-1 with R2 = 0.995. The vertical and horizontal confines of calibration diagrams in 500 mL solution were calculated about 0-0.5 mg L-1 and 0-0.6. The results of applying the present  method to determinate the separated lead ions in water samples were prosperous and harmonious. Precision of the method was investigated by comparing them with observations from previous similar researches.