With the rapid development of the electroplating industry, wastewater treatment has become a key problem hindering the sustainable development of the industry. Traditional treatment methods such as chemical precipitation and ion exchange, although they can alleviate pollution problems to a certain extent, have obvious drawbacks such as high resource consumption, high risk of secondary pollution, and persistently high operating costs. Electrodialysis technology, with its unique physical separation properties and efficient resource recovery capabilities, is gradually becoming the core technical choice for the electroplating industry to achieve the "zero discharge" goal.
I. Industry Predicament of Electroplating Wastewater Treatment: Inherent Shortcomings of Traditional Technologies
Electroplating wastewater is complex in composition, containing heavy metal ions such as chromium, nickel and copper, cyanide, organic additives and high-concentration salts. Its treatment difficulty is much higher than that of ordinary industrial wastewater. Traditional processing technologies mainly face three core contradictions:

The imbalance between efficiency and cost: The chemical precipitation method requires the addition of a large amount of chemicals, resulting in a significant increase in sludge production. Ion exchange resins need to be regenerated frequently, and the resulting cost of chemical agents accounts for more than 40% of the total operating cost of the enterprise.
The disconnection between resource recycling and pollution control: Traditional processes only focus on the removal of pollutants but neglect the recycling and utilization of high-value heavy metals such as nickel and chromium, resulting in the waste of tens of thousands of tons of strategic resources every year.
The disconnection between end-of-pipe treatment and full-process control: A single end-of-pipe treatment model is difficult to meet increasingly strict environmental protection standards. The industry urgently needs to start from the production source and optimize the overall process flow.
Ii. Principle of Electrodialysis Technology: The physical separation logic of directional ion migration

Electrodialysis technology uses a direct current electric field as its power source and relies on the selective permeability of ion-exchange membranes to achieve the directional migration of cations and anions in the solution. Its core mechanism is mainly reflected in two aspects:

Electric field drive effect: Under the action of a direct current electric field, charged ions such as Ni²? and CrO?²? will move towards electrodes of opposite polarity. Among them, cations pass through the cation membrane into the concentration chamber, while anions pass through the anion membrane into the adjacent concentration chamber.
Membrane separation screening function: Ion-exchange membranes (including cation membranes, anion membranes and bipolar membranes) form selective barriers, allowing only specific ions to pass through while blocking other substances, thereby achieving the simultaneous process of solution desalination and concentration.
This physical separation process does not require the addition of chemical agents, fundamentally avoiding the generation of secondary pollution. Moreover, the treatment scale can be flexibly adjusted through modular design to meet the actual needs of different enterprises.

Iii. Innovative Application Scenarios of Electrodialysis in the Electroplating Industry
The core component of the zero-discharge system for electroplating wastewater
In the zero-emission process system of "physical and chemical pretreatment + membrane concentration + evaporation crystallization", electrodialysis, as the key equipment in the membrane concentration stage, can replace the traditional reverse osmosis (RO) technology to achieve higher concentration rates. Its core advantages are as follows:

Stronger anti-pollution ability: It has a higher tolerance for suspended solids, oils and other pollutants contained in the influent water, effectively simplifying the process of the pretreatment stage.
Superior concentration efficiency: Through a multi-stage series design, the salt content of electroplating wastewater can be concentrated to over 20%, significantly reducing the energy consumption in the subsequent evaporation and crystallization processes.
Resource recovery in advance: During the concentration process, the enrichment of heavy metal ions is achieved simultaneously, providing a high-concentration raw material liquid for the subsequent metal recovery.
2. A brand-new model for the resource recovery of heavy metals
The innovative process that combines electrodialysis technology with coordination chemistry has opened up a new path for heavy metal recovery:

Nickel recovery process: For nickel plating wastewater, a membrane stack design with alternating cation and anion membranes is adopted. In the concentration chamber, a nickel sulfate concentrate with a nickel ion concentration of up to 80g/L can be obtained. This concentrate can be directly reused in the plating tank, achieving a "closed-loop circulation".
Chromic acid recovery system: By using bipolar membrane electrodialysis technology, Cr (VI) in chromium-containing wastewater is converted into Cr (III), while generating sulfuric acid and sodium hydroxide. This not only achieves self-sufficiency in acid and alkali but also reaches the goal of chromium resource recovery, realizing dual benefits.
3. Specialized solutions for the treatment of special wastewater
Cyanide-containing wastewater treatment: By using oxidation-resistant ion-exchange membranes, efficient separation of cyanide ions (CN?) from metal ions is achieved under the action of an electric field. After treatment, the cyanide content in the wastewater can be reduced to below 0.1mg/L.
Complexed wastewater treatment: By adjusting the electric field intensity and membrane stack voltage, the stable structure between metals and complexing agents is disrupted, thereby achieving efficient removal of complexed metal ions such as copper and zinc.
Iv. Technological Upgrade: The Iterative Development Direction of Electrodialysis
To meet the strict process requirements of the electroplating industry, electrodialysis technology is constantly evolving in the following directions:

Membrane material innovation: Develop new types of ion-exchange membranes with high-temperature resistance, anti-pollution, and high selectivity, such as graphene-modified membranes and nanocomposite membranes, to extend the membrane's service life to over five years.
Process integration and optimization: Promote the coupled application of electrodialysis technology with electrodeposition, membrane distillation and other technologies, and build an "electrodialyst-electrodeposition" combined process to achieve energy cascade utilization in the metal recovery and wastewater treatment processes.
Intelligent control system upgrade: AI algorithms are introduced to monitor key parameters such as the voltage and current density of the membrane stack in real time, and dynamically adjust the operating conditions to ensure that the system is always in the optimal processing state.
V. Industry Impact: From end-of-pipe Treatment to Green Upgrading of the Entire Industrial Chain
The promotion and application of electrodialysis technology are driving the electroplating industry to transform from the traditional "end-of-pipe treatment" model to a "resource recycling" model.

The economic benefits have been significantly enhanced: After a large electroplating enterprise applied this technology, it saved over 3 million yuan in chemical agent costs annually and generated a value of 8 million yuan from metal recovery.
Environmental risks have been effectively reduced: The reuse rate of wastewater has increased to over 95%, and the generation of hazardous waste has decreased by 70%, significantly lowering the environmental compliance costs for enterprises.
The industrial competitiveness has been continuously enhanced: By building a differentiated competitive advantage through resource recycling, it helps enterprises break through international green trade barriers.
Electrodialysis - The green revolution engine of the electroplating industry
Under the dual impetus of the "dual carbon" goals and environmental protection policies, electrodialysis technology, with its core advantages of high efficiency, low carbon and resource utilization, has become a key technical support for the transformation and upgrading of the electroplating industry. From a "resource extractor" for heavy metal recovery to a "core engine" for zero wastewater discharge, electrodialysis technology is redefining the value chain of electroplating production. With the continuous breakthroughs in membrane material science and intelligent control technology, this separation technology, which was born in the middle of the 20th century, is bound to radiate new vitality in the green manufacturing wave of the 21st century.