Acid treated RHWBAC electrode performance for Cr(VI) removal by capacitive deionization and CFD analysis study

Area of Science:

• Environmental Science
• Materials Science
• Electrochemistry

Background:

• Chromium(VI) contamination poses significant risks to aquatic ecosystems and human health.
• Developing cost-effective and sustainable materials for heavy metal removal is crucial.

Purpose of the Study:

• To develop and evaluate acid-treated rice husk waste biomass activated carbon (RHWBAC) as an electrode material for capacitive deionization (CDI).
• To investigate the electrosorption performance of RHWBAC for Cr(VI) removal from aqueous solutions.
• To analyze the electrosorption mechanism and fluid dynamics of the CDI cell.

Main Methods:

• Rice husk biomass was treated with acid to produce activated carbon.
• RHWBAC was utilized as an electrode material in a capacitive deionization (CDI) cell.
• Electrosorption experiments were conducted to determine Cr(VI) removal capacity and kinetics.
• Adsorption isotherm and kinetic models (Redlich Peterson, Langmuir, Pseudo-first order) were applied.
• Computational fluid dynamics (CFD) was used to analyze CDI cell hydrodynamics.

Main Results:

• The RHWBAC electrode demonstrated a maximum electrosorption capacity of 2.8316 mg g⁻¹ for Cr(VI) at an initial concentration of 100 mg L⁻¹ and 1.2 V.
• The electrosorption process followed Redlich Peterson and Langmuir isotherm models, and Pseudo-first order kinetics.
• CFD analysis indicated that increasing feed flow rate reduces stagnant regions within the CDI cell.

Conclusions:

• Acid-treated rice husk biomass activated carbon is a viable and sustainable electrode material for Cr(VI) removal via CDI.
• The RHWBAC electrode is particularly effective for treating low-concentration Cr(VI) aqueous feeds.
• Optimizing flow rates in CDI systems can enhance contaminant removal efficiency.