Treatment of dye wastewater by bentonite adsorption and catalysis

The methylene blue dye wastewater was treated by various amount of hydroxyl Fe modified bentonite, then, the dye was oxidized by the bentonite with the Fe catalysis. As a result the modified bentonite was regenerated and could be recycled in adsorption. Ultrasound and hydrogen peroxide have synergistic action on degradation of methylene blue for OH-Fe-bentonites' regeneration. The adsorption of dye and the influencing factors had been investigated, such as the amount of hydrogen peroxide and ferrous percentage of OH-Fe-bentonites. The results showed that the removal efficiency is more than 90% when 0.4 g/L OH-Fe-bentonites was added. The 60% cationic exchange capacity (CEC) hydroxyl Fe modifited bentonite had nearly 80 percent regeneration ability under the following condition: the concentration of hydrogen peroxide is 0.5 mol/L, pH= 3.5, the power of ultrasound is 90 W in 3 hours. OH-Fe-bentonites keep good adsorption ability after six times regeneration. On the other hand, the sedimentation speed of the adsorbent was accelerated. The results showed the modified bentonite excellent application potential.