فهرست مطالب ar rahmani

Electroproxone process is a combination of ozonation process and electrolysis in which the production of hydroxyl radical and ultimately degradation of a pollutant occurs. The aim of this study was to estimate the E-Proxone process in removing ceftriaxone from a synthetic solution.

In this experimental study, a semi-continuous reactor equipped with four graphene electrodes having 2 × 10 cm dimension and 3 mm thickness was used. The effect of pH (3-11), concentration of ozone gas (1-5 mg/min), direct electric current (1-3 A), initial concentration of ceftriaxone (5-50 mg/L) and radical scavenger dose (tertbutanol = 20 mmol/L) was studied in a 0-60 minutes reaction time. The Ceftriaxone concentration was measured by HPLC, COD was measured with spectrophotometer (DR6000) and TOC with a TOC analyzer.

The results of this study indicated that this process had sufficient performance in the degradation of the antibiotic and diminishing of COD and TOC. The excellent condition was pH = 3, the electric current of 3 A, the ozone concentration of 5 mg/min, and the sodium sulfate as an electrolyte was 50 mmole/L. The ceftriaxone concentration was 5 mg/L in the duration of the 30 minutes experiment. 99.39% of the Ceftriaxone was destroyed. The process efficiency in COD and TOC removal was highest at 90 minutes. The presence of tertbutanol reduced the process efficiency to 83%.

The E-Proxone process, as one of the advanced oxidation processes, has the ability to reduce the pollution load of pharmaceutical industry, especially the ceftriaxone in this wastewater. This process is considered an environmentally friendly process.

Dyes are one of the most important existing pollutants of textile industry wastewater. They are often toxic, carcinogenic, teratogenic, and non-biodegredable. This study was conducted to evaluate efficiency of Steel/Pb/PbO2 electrode in the removal of Reactive Blue 29 and Reactive Red 198 Azo dyes from aqueous solutions using Electrochmical Process.
Concentration of colors was measured before and after Electrochemical Process. Moreover, the intensity of the electric current, the reaction time, the pH, and the initial dye concentration were measured on the efficiency of the removal process and the amount of electrical energy consumed.
The results of the experiments showed that the process efficiency increased by increasing reaction time and electrical current intensity. It was also decreased by increasing pH and initial concentration of color. Under constant operating conditions (pH=4, electric current intensity of 0.5 mA cm2, reaction time of 60 minutes and color concentration of 150 mg/l), the efficiency of this process were 94% and 88% in the removal of Reactive Red 198 and Reactive Blue 29, respectively.
According to our findings, the Electrochemical Process with Steel/Pb/PbO2 was very efficient and economic process in removing color from wastewater.

Main sources of 4-Chlorophenol wastewater are petroleum industry, coal, paper and resin production. The aim of this study was to compare the performance of raw and cationic surfactant modified nanoclay in removal of 4-Chlorophenol from aqueous solutions.
The influence of contact time, initial pH of solution, adsorbent dosage and 4-Chlorophenol concentration as effective parameters in adsorption process and the influence of modification solution pH and surfactant loading rates were investigated. The modified nanoclay was characterized by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) spectroscopy. Finally, the isotherm and adsorption kinetics were investigated.
The removal efficiency of 4-Chlorophenol was increased by increasing the initial pH from 3 to 11, so that after of 120 min, the absorption efficiency at an initial 4-Chlorophenol concentration of 100 mg/L and 0.25 g adsorbate was 26 and 95.5 % at pH 3 and 11, respectively. Under the same conditions the removal efficiency for the raw nanoclay was 2 and 9% at pH 3 and 11, respectively. The FTIR and XRD analyses revealed that the nanoclay structural changed from hydrophilic to hydrophobic and the interlayer spacing was increased. The adsorption of 4-Chlorophenol on raw and modified nanoclay was consistent with Langmuir and pseudo-second-order kinetics. The maximum absorption capacity of raw and modified nanoclay was 0.5 and 25.77 mg/g, respectively
The modification of nanoclay with cationic surfactant increased the adsorption efficiency of 4-Chlorophenol.

The chromium compounds could be hazardous to human’s health. The aim of this study was to compare the Performance of Electro- Fenton and Fenton process in the removal of chromium in presence of cyanide as an Intermediate in aqueous.
Material & In this experimental study, a reactor with 1 liter useful volume was used. Four electrodes made of iron were used in EF. Parameters of study including pH, Voltage, initial concentration of chromium, H2O2 and cyanide as an intermediate in EF process and pH, concentration of Fe ions, initial concentration of chromium, H2O2 and cyanide as an intermediate in F process were examined.
The results showed that efficiency of EF process in pH=3, Voltag = 20V in 100 mg/lit chromium, was 97%. Also in F process in optimum condition with pH=3, Fe ions = 500mg/lit, H2O2 = 50ml/lit and chromium concentration = 100 mg/L efficiency was 90%. By cyanide addition reactor efficiency was decreased.
EF process outperformed Fenton process in removal of chromium compounds.

Chlorophenols, commonly found in most industrial waste products are persistent compounds in the environment. The purpose of this study was to investigate performance of modified Na-MMT nanoclay using cationic surfactant tetradecyltrimethyl ammonium bromide in the removal of 4-chlorophenol from aqueous solutions. This study was implemented under laboratory scale and in a batch flow adsorption reactor. The influence of various parameters such as modification in different pH conditions, initial pH of solution, loading rates of the surfactant, adsorbate concentration, 4-chlorophenol concentration, contact time were evaluated, the raw and modified nanoclay structure was investigated using XRD and FTIR spectrum.The experimental data were evaluated with the Langmuir and Freundlich isotherm models and pseudo-first-order and pseudo-second-order adsorption kinetic. The results showed that removal of 4-chlorophenol increased by increasing the pH of solution from 3 to 11, as the maximum absorption of 4-chlorophenol was achieved at initial solution pH of 11 and for modified nanoclay in acidic conditions pH was4.5.Onthese conditions and after 120 min, the removal efficiency was obtained by 94.5%.Removal efficiency of 4-chlorophenol increased from 69.25% to 94.5% as surfactant loading increased from 0.25 to 2 CEC of the nanoclay, while increased loading surfactant from 3 to 4decreasedremoval efficiency. With increasing concentrations of 4-chlorophenol and adsorbent dose the removal efficiency, respectively, decreased and increased. Absorption of 4-chlorophenol on cationic modified nanoclay was consistent with Langmuir model and pseudo-second-order kinetics. Maximum absorption capacity (qm) was obtained 25.77 mg/g FTIR analysis revealed that the modification was successfully achieved due to the bands at 2919, 2851 and 1469 cm−1. After modification, XRD results showed that basal spacing value increase from 17 Ao to 24 Ao Cationic surfactant-modified nanoclay with tetradecyltrimethyl ammonium bromide by changing the properties of the adsorbent from hydrophilic to hydrophobic leads to increased efficiency of the absorbent in the absorption of 4-chlorophenol in aqueous environments.

Chromium is an extremely important heavy metal which is used in different industries. It can be found in water resources due to insufficient treatment of industrial wastewater. The goal of this study was to survey the feasibility of application of hexavalent chromium reduction using granular magnesium as reducing agent and to investigate the affects of various operational parameters. In this experimental study, zero-valent magnesium was used for the removal of hexavalent chromium from aqueous solution. Synthetic solution of chromium was prepared from dionized water. Several experimental steps was done in 250 ml glass beakers in a shaker incubator device and different operational parameters such as pH of solution, initial concentration of chromium, temperature, contact times, magnesium dose and intercurrent factors were investigated. Concentration changes of chromium were determined with spectrophotometer at an absorbance wavelength of 540 nm. The results indicated that chromium removal efficiency, using zero-valent magnesium, increases with contact times, magnesium dose, initial concentration of chromium and temperature. However, chromium removal efficiency decreased with increasing pH of solution. The highest removal efficiency was achieved in pH 3, initial concentration of chromium at 150 mg/L and magnesium at dose of 0.7 g/L, respectively. In addition, the presence of humic acid, hardness and alkalinity in solution extensively decreased the chromium removal efficiency. The results showed that zero-valent magnesium, due to high oxidation and reduction potential, can be extensively effective for removing hexavalent chromium in aqueous solution.

One of the important factor for development in each region is the availability of appropriate water resources. In addition to water quantity quality is also of great importance. The aim of this study is to medel the qualitative indices (BOD, DO) of river water using multi-layer perceptron neural network. In this paper, the information and data from Morad Beik river of hamadan including 10 monthly parameters of water quality in a one-year period and at six stations were used to predict biological exygen demand (BOD) and dissolved oxygen (DO), as indices affecting water quality. Efficiency of the neural network model was evaluated by some statistical criteria including correlation coefficient (R), root mean square error (RMSE) and mean absolute error (MAE). In the optimum structure of neural network the correlations coefficient for BOD and DO were 0.986 and 0.969, and root mean square errors were 8.42 and 0.84 respectively. The results indicated the ability of multi-layers perceptron neural network as a suitable technique for simulating changes in BOD and DO indices.