Electrolytic degradation of polyacrylamide in aqueous solution using a three-dimensional electrode reactor

ABSTRACT

In this study, electrochemical treatment of a synthetic solution containing 2,000 mg/L of polyacrylamide (PAM) was studied using a three-dimensional electrode reactor, which received granular activated carbon (GAC) as particle electrodes. Air and ferrous salt were introduced into the system to electrogenerate hydrogen peroxide and Fenton’s reactions. The effect of operating conditions such as solution pH, current density, ferrous concentration and GAC amount on the efficacy of the process was investigated. The experimental results showed that the effluent with a satisfied chemical oxygen demand removal efficiency (84%) was obtained after 60 min of electrolysis when the initial pH was 3.0, current density was 40 mA/cm², air flow = 1.5 L/min, pH = 3, [Fe²⁺] = 1.5 mM, and temperature = 28°C. The analyses of five-day biochemical oxygen demand and Microtox® toxicity indicated that the optimum electrolysis duration was 30 min, at which satisfied biodegradability of wastewater was achieved. The three-dimensional electrode method can be selected as an effective alternative to PAM wastewater pretreatment before subjected to the biological process.

Keywords:

• Fenton’s reaction
• Ferrous salt
• Nitrate
• Microtox® toxicity