Advanced rotating-anode electrocoagulation for simultaneous arsenate and fluoride removal: Reaction kinetics, energy consumption, and techno-economic evaluation

Title : Advanced rotating-anode electrocoagulation for simultaneous arsenate and fluoride removal: Reaction kinetics, energy consumption, and techno-economic evaluation

Abstract:

This study introduces an advanced rotating-anode electrocoagulation (RA-EC) as an effective solution for simultaneous arsenate (As(V)) and fluoride (F⁻) removal. The impact of key operating parameters, including current density (CD), inter-electrode distance (IED), treatment time, and anode rotational speed (N), was systematically investigated using an advanced electrocoagulation (EC) reactor configured with aluminum (Al–Al) electrodes. The results demonstrate that for low contaminant levels (As(V) = 0.1 mg L⁻¹ and F⁻ = 3.0 mg L⁻¹), the EC achieves 98.20% As(V) and 91.46% F⁻ removal within 3 min under the optimal operating conditions (pH = 6.3–6.92, IED = 30 mm, CD = 21.66 mA cm⁻², and N = 100 rpm). In contrast, for higher contaminant levels (As(V) = 0.25 mg L⁻¹ and F⁻ = 12.0 mg L⁻¹), 97.4% As(V) and 91.80% F⁻ removal were achieved within 12 min under similar operating conditions, except for pH (6.78–9.57). Furthermore, kinetic analysis confirmed that the EC process follows pseudo-first-order kinetics. In addition, the effect of co-existing ions, including Ca²⁺, Mg²⁺, bicarbonate, sulfate, and phosphate, was investigated in both synthetic water and real water matrices. Among the tested ions, phosphate exhibited the strongest inhibitory effect on the EC performance. Under optimal operating conditions, energy consumption and operating costs were 1.87–5.73 kWh m⁻³ and 0.214–0.692 US$ m⁻³, respectively, for low and high contaminant concentrations. Additionally, FESEM, EDX mapping, XPS, and FTIR analyses confirmed the formation of aluminum-based phases and the effective removal of As(V) and F⁻. These findings demonstrate the system's potential for efficient, sustainable, large-scale multi-contaminant water treatment.

Biography:

Mukesh Bharti is a Ph.D. student in the Department of Chemical Engineering at the Indian Institute of Technology Guwahati. His research focuses on advanced electrocoagulation and rotating-electrode reactor systems for water and wastewater treatment, particularly removing arsenic, fluoride, and hardness. His research interests include reactor design, process optimization, reaction kinetics, and techno-economic assessment. He has published research and review articles in international journals and has co-authored a book and book chapters on electrocoagulation and environmental engineering.