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This study investigates the efficacy of sand coated with calcium / aluminum (Ca/Al)-layered double hydroxide (LDH) in the elimination of methyl orange dye from simulated groundwater using method of permeable reactive barrier. For green (sustainable) manufacturing of this sand, aluminum prepared from dissolution of alum (cheap coagulant) can be interacted chemically with calcium extracted from cement kiln dust byproduct to create nanoparticles of Ca and Al that precipitate on the filter sand. Sorption measurements for interaction of methyl orange dye and coated sand was well formulated by Langmuir model with highest value of correlation (determination coefficient= 0.999) and lowest errors (sum of squared errors= 0.0122). Also, the maximum capacity of adsorption was valued of 0.9453 mg/g and the sorption curve can classify as “favorable” type. According to desorption measurements, little percentage of dye (0.91%) can desorb from exhausted coated sand through washing with water due to strength of bonding between sorbent and dye molecules. Also, the exhausted sorbent can regenerate with efficiency not less than 85% after eight of regeneration cycles. Finally, measurements of breakthrough curves in the continuous mode operation using column setup proved that the propagation of dye front (and consequently the longevity of barrier) would increase significantly with thicker barrier and lowest values of influent concentration and flow rate. COMSOL (computer solution) package can use effectively in the simulation of these curves.

The degradation and mineralization of 4-chlorophenol (4-CP) by advanced oxidation processes (AOPs) was investigated in this work, using both of UV/H2O2 and photo-Fenton UV/H2O2/Fe+3 systems.The reaction was influenced by the input concentration of H2O2, the amount of the iron catalyst, the type of iron salt, the pH and the concentration of 4-CP. A colored solution of benzoquinon can be observed through the first 5 minutes of irradiation time for UV/H2O2 system when low concentration (0.01mol/L) of H2O2 was used. The colored solution of benzoquinon could also be observed through the first 5 minutes for the UV/H2O2/Fe+3 system at high concentration (100ppm) of 4-CP. The results have shown that adding Fe+3 to the UV/H2O2 system enhanced the rate of 4-CP oxidation at a molar ratio of H2O2/Fe+3/4-CP equals to 13/0.4/1 by a factor of 7. This reduced the consumption of H2O2 by a factor of 6 and the irradiation time required for complete degradation was reduced by a factor of 6. The experimental results have shown that the optimum reagents for a complete degradation of 4-CP(50ppm) were H2O2.=0.005mol/L, Fe+3=0.16*10-3 mol/L under acidic condition (pH=3) and irradiation time of 15 min for the UV/H2O2/Fe+3 system with a molar ratio of H2O2/Fe+3/4-CP equals to 13/0.4/1.