Agro Waste Derived Activated Carbon as a Catalyst in Red-۲G Degradation Process Optimized by Definitive Screening Design Approach

Red-۲G is considered a non-biodegradable azo dye by United States Environmental Protection Agency (EPA) as it is resistant to biological degradation. Here, a new method is presented to prepare activated carbon (ACP-۸۵۰) using thermally treated pistachio nutshell and potassium oxalate as precursors to accelerate the dye degradation process with peroxymonosulfate (PMS) as an oxidation agent. Having a high surface area (۲۳۱۸ m۲/g) and low-cost precursors, and the achievement of recyclable, biodegradable, and agricultural solid wastes are among the benefits of the proposed method. Also, the definitive screening design approach is performed to evaluate the role of independent variables in the degradation efficiency of PMS/ACP-۸۵۰ system. Minitab response optimizer indicates the possibility of achieving a response value of ۱۰۰% through the use of a factorial blend of PMS=۳.۰ mM, pH=۳.۰, ACP=۱.۰ g/L, and time= ۸۰ min at room temperature for Red-۲G concentration of ۶۰ mg/L as optimum conditions. Furthermore, complete degradation of Red-۲G with a higher concentration (۱۷۰ mg/L) to H۲O and CO۲ as eco-friendly compounds occurs under following condition: PMS=۶.۰ mM, pH=۳.۰, ACP=۲.۰ g/L, and time= ۱۸۰ min at a temperature of ۵۵ °C,. Radical quenching experiments prove that sulfate anion radical (SO۴-•) and superoxide anion radical (O۲• -) play key roles as reactive species in the PMS/ACP-۸۵۰ system at acidic and basic conditions, respectively. Reusability investigation confirms that ACP-۸۵۰ can be frequently utilized to degrade dye from the contaminated solution. The LC/MS/MS and UV-VIS spectrometry analysis results along with mineralization rate demonstrate the effective possibility of decomposing Red-۲G by the PMS/ACP-۸۵۰ system.

کلیدواژه ها:

Design of experiment ، High surface area activated carbon ، Peroxymonosulfate ، Pistachio nutshell ، Potassium oxalate ، Red-۲G