فهرست مطالب yosef pour eshgh

Electro-Ozonation process (EOP) has a good potential for the removal of persistent organic pollutants. This process is a combination of ozonation process and electricity for producing hydroxyl radical and removal of pollutants. The purpose of this study was to evaluate the EOP for SDBS degradation in aqueous media. In this experimental study, a semi-batch reactor with four graphite electrodes of 120 cm2 area was used. The effects of pH (3-11), the inlet of ozone (6-30 mM / s), current density (16-85 mA/cm2), the initial concentration of SDBS (0.02-0.3 mM/L) and radical scavenger dose (0.2 mM/L) were studied.SDBS concentration measured by spectrophotometer (DR5000) by instructions provided in the standard method book. The results indicate the high efficiency of this process in the removal of SBDS and COD. In optimum conditions of pH = 3, current 85 mA/cm2, ozone flow rate 30 mM/s and initial SDBS concentration 0.02 mM/L, more than 99% removal was observed in 50 min. By changing the parameters of the optimum conditions, the process performance was decreased. High efficiency of COD removal in this process was obtained in 80 min. Influence of TBA in solution was the efficiency decrease of process to 80 %. Electro-ozonation process as an advanced oxidation process can reduce organic pollution industry and can be considered as an environmentally friendly process.

The effluent of textile industries is high dyefully and this is one of most problems for environmental health engineers. Two Azo dyes biosorption، direct black 19 and direct red 23، on Cystoseira indica، an invasive macroalga in Iran، has been investigated using visible absorption spectroscopy. Pre-treatment and chemical cross-linking with CaCl2، have been conducted in order to improve the stability as well as the biosorption capacity of the algal biomass. All measurements were conducted by UV-Visible Spectrophotometer. The effects of operating parameters such as contact time، pH، initial dye concentration and amount of biosorbent on the dye removal efficiency were investigated. The biosorption has been described in terms of isotherm and kinetic models; from the maximum adsorption capacity values، an estimation of the algal specific surface area was made. It has been found that biosorption kinetics can be described according to the pseudo second order model and biosorption equilibrated for 120 min (89. 3% of direct red 23 and 69. 02% of direct black 19 removed). Maximum biosorption found at pH 5 (2. 4mg/g). It also observed increasing initial dye concentration and decreasing biomass dosage would reduce dye removal. Isotherm studies also revealed the dye biosorption on algal biomass followed from Freundlich model. Biosorption of selected Azo dyes onto algal biomass، Cystoseira indica was fast and more dye is eliminated in the first hour. So، by determining the optimum conditions of contact time، pH، initial dye concentration and biosorbent dosage، Cystoseira indica can be used as an inexpensive sorbent for removal of Azo dyes from aqueous solutions.