ramazan ali diyanati tilaki

The presence of phenol in water and wastewater, due to its toxic threat to human life and environment, is a major concern. The purpose of this study was to investigate the rate of phenol adsorption by modified Azolla and Canola. This study was conducted at laboratory scale. In this study the effect of various parameters on adsorption performance was investigated and isotherms and kenitics adsorption were determined. In order to measure the specific surface area of absorbents the BET isotherm technique was carried out. The concentration of phenol in samples was measured by HPLC instrument. Removal efficiency increased with increase of adsorbent dose and contact time and decrease of the initial concentration of phenol. Optimal phenol removal was obtained at pH =3, adsorbent dose of 10 g/L and contact time of 90 and 120 min for Azolla and Canola biomass respectively. Coefficients showed that the best isotherms for Azolla and Canola adsorbents are Langmuier and Freundlich respectively. The reaction rate for both adsorbents agrees with the pseudo-second order kenitics model. Based on the Langmuier model, the maximum adsorption capacities were calculated to be 11.2 and 9.4 mg/g for Azolla and Canola biomasses respectively. According to the obtained results, Azolla and Canola biomass can be used as efficient and cost-effective adsorbents for treatment of industrial effluents.

Background and dye is widely used in industries such as cosmetic, leather, paper and textile and release to the environment via their effluents. The purpose of this study was to compare the efficiency of low-cost adsorbents in acid orang 7 dyes removal from water. The Rice Stem biomass was sun dried, crushed and sieved to particle sizes in range of 1-2 mm. Then treated with 2.0 mol/L nitric acid for a period of 1 h followed by washing with distilled water and finally washed Stem was dried at 105◦ in oven. The residues concentration of acid orang 7 dyes was measured by spectrophotometer in λmax of 452 nm. The effect of pH, contact time and initial AO7 dye concentration, kinetic and isotherm models were studied. Then data interpreted and analyzed by Excel 16 software. The pH value of 3, contact time of 75 min, adsorbent dosage of 8 g/L and dye concentration were 10 mg/l determined as optimum conditions for adsorbents. The most acid orang 7 dyes removal efficiency of 98% was obtained for modified Rice Stem in optimum conditions. The equilibrium data is best fitted on Langmuir isotherm and the adsorption kinetic model follows pseudo-second model. Based on data obtained in this study, it can be concluded that adsorption by modified Rice Stem