A novel membrane-free electrochemical separation-filtering crystallization coupling process for treating circulating...

Area of Science:

• Electrochemistry
• Water Treatment Technology
• Materials Science

Background:

• Traditional electrochemical descaling suffers from low hydroxide ion utilization, limited cathode area, and slow precipitation.
• These limitations hinder efficient scale removal in circulating cooling water systems.

Purpose of the Study:

• To introduce and evaluate a novel membrane-free electrochemical separation-filtering crystallization (MFES-FC) coupling process for circulating cooling water treatment.
• To overcome the drawbacks of conventional electrochemical descaling methods.

Main Methods:

• A membrane-free electrochemical separation (MFES) system rapidly extracts hydroxide ions via pump suction, increasing pH and enhancing Ca2+ and Mg2+ removal.
• The MFES system is coupled with a filtration crystallization (FC) system using activated carbon to capture scale particles and accelerate precipitation.

Main Results:

• The MFES-FC process achieved high single-pass removal rates: 92% total hardness, 97% Ca2+ hardness, 64% Mg2+ hardness, and 67% alkalinity.
• Effluent turbidity was reduced to 3 NTU with a current efficiency of 86.6% and energy consumption of 7.19 kWh·kg−1 CaCO3.

Conclusions:

• The MFES-FC coupling process offers an effective and cost-efficient method for removing hardness and alkalinity from circulating cooling water.
• This technology provides a new reference for advancing electrochemical descaling.