Abstract
In this study, regeneration of spent granular activated carbon (GAC) with reactive dye by hydroxyl and sulfate radical based advanced oxidation processes (Microwave (MW) + Persulfate (PS)), (Fe(II) + PS), and (O3 + H2O2) were evaluated. The adsorption of the dye to the GAC surface was characterized by chemisorption and Langmuir isotherm. Regeneration processes have been optimized by the Response Surface Methodology to determine the operating conditions that will provide the highest adsorptive capacity. The optimum conditions of (MW + PS), (Fe (II) + PS), and (O3 + H2O2) processes were (process PS anion of 45.52 g/L, pH of 11.4, MW power of 126 W, duration of 14.56 min), ( Fe (II) of 3.58 g/L, PS anion of 73.5 g/L, duration of 59.8 min, pH of 10.9) and (H2O2 of 2.8 mole/L, ozone dose of 98%, duration of 32.8 min, pH of 5.3), respectively. For (MW + PS), (Fe (II) + PS), and (O3 + H2O2) processes, the adsorptive capacity under optimum conditions were found as 4.36, 8.89 and 8.12 mg dye / g GAC respectively. For (Fe (II) + PS) and (O3 + H2O2) processes these values are approximately equal to the adsorptive capacity of raw GAC (8.01 mg dye / g GAC). The predicted values of the adsorption capacities by the obtained models were in good agreement with the actual experimental results. PROMETHEE approach was used in the preference of the appropriate regeneration process. The adsorptive capacity of regenerated GAC, operating cost of the regeneration process, change in the adsorptive capacity during the regeneration cycle and carbon mass loss criteria were taken into account. The order of preference of regeneration processes was determined as (Fe (II) + PS)> (MW + PS)> (O3 + H2O2) considering all criteria.
Optimization of the Spent Activated Carbon Regeneration with the Radical Based Advanced Oxidation Processes: Preference of the Most Suitable Process by PROMETHEE Approach
