Reaction kinetics on treatment of food industry wastewaters by electrochemical oxidation

Abstract

Reaction kinetics during electrochemical treatment of deproteinated whey wastewater (DWW) and fruit juice factory wastewater (FJW) was investigated in a stirred batch electrochemical reactor under reaction conditions of 100% wastewater concentration and 11.29 V applied voltage at room temperature using cost-effective iron electrodes. Reaction mediums for electrochemical treatment of DWW and FJW were supplemented with 19.87 and 5.95 g L⁻¹ NaCl as supporting electrolyte, respectively. Kinetic investigations denoted that reaction orders (n) of both reactions were 0.6. Specific reaction rate constants (k) at 25°C of electrochemical DWW and FJW treatment reactions were 0.04 and 1.21 mg^0.6 L^−0.6 min⁻¹. Activation energies (E_a) and Arrhenius constants (A) were calculated as 41.60–9.59 kJ mol⁻¹ and 740.93–61.82 mg^0.6 L⁻⁰⁶ min⁻¹ for DWW and FJW, respectively. In our study, relatively fast reaction kinetics values were obtained compared to the data previously reported for electrochemical wastewater treatment in the literature. These results support the applicability of electrochemical treatment to the deproteinated whey and fruit juice factory wastewaters as an advanced post-treatment method providing further research.

Keywords:

• Deproteinated whey wastewater
• Electrochemical wastewater treatment
• Fruit juice factory wastewater
• Reaction kinetics

Acknowledgment

Support of Akdeniz University Project Management Unit is gratefully acknowledged. The authors acknowledge the technical help of Mr. Koray Özdemir in some preliminary measurements.