Iranian Journal of

---

Background and Objectives: The dyestuff manufacturing and textile industries consume a high volume of water and produce a great amount of wastewater containing various toxic substances. Different methods are used to remove dye compounds from wastewaters. Removal of dyes from water by adsorption processes received considerable attention and a number of studies focused on the adsorption of some dyes by non-conventional low cost and effective adsorbents. In this study, the suitability of the canola stalks for Acide orange 7 adsorption was assessed.
Materials and Methods: The dry canola stalks obtained from the research farm were milled and screened and the particles size ranged between 0.4-0.7mmwere used in all experiments. Acid orange 7 supplied by Alvan Sabet. Initially, the effects of initial dye concentration, pH and temperature on adsorption were examined. The kinetic and equilibrium data obtained for various concentrations of evaluated on the basis of Langmuir and Freundlich isotherms.
Results: The results showed that the absorption efficiency depended strongly on pH and slightly on the temperature. Absorption of acid orange 7 on the canola stalks was fairly rapid and more than 95% of adsorption occurred within the initial 5 minutes of the treatment. Both Langmuir and Freundlich models were applicable for the description of acid orange 7 dye adsorption by canola stalks.
Conclusion: According to the Langmuir model, the highest capacity of canola stalks for acid orange 7 adsorption was found 24.8 mg/g which was higher than the capacity of beech wood sawdust and soil mixture with fly ash.

---

A MicrosoftInternetExplorer4 Background and Objectives: Colored wastewaters are known as one of the most important sources of environmental pollutants. Having toxic chemicals and aesthetic problems has made treatment of these wastewaters very crucial. So far a number of methods such as electrochemical treatment, coagulation and flocculation, and adsorption have been used for treatment of textile industries wastewater. Hence,  the efficiency of zero-valent iron powder in the presence of UV light and hydrogen peroxide to remove Acid Orange 7 and Reactive Black 5 from the synthetic solutions was investigated.
Materials and Methods: Conducting all experiments in a batch reactor, we examined different parameters including initial concentration of the color (25, 50, 75 mg/L), contact time (30,  60, 120 min), pH (3, 7, 11), the amount of iron powder (0.6, 1.3,  2  g/l), and hydrogen peroxide concentration (10, 15, 20  ml/l).
Result: The results showed that dye removal efficiency was increased by increasing contact time, the amount of iron powder and hydrogen peroxide concentration. On the other hand, with the increasing pH and initial concentration of dye, removal efficiency decreased in both AO7and RB5 dyes.
Conclusion: We found that the integrated ZVI/UV/H₂O₂ method has  high efficiency in removing azo dyes Acid Orange 7 and Reactive Black 5.