In multiple fields such as food, medicine, and chemical engineering, organic acids like citric acid, lactic acid, and gluconic acid are indispensable core raw materials, widely used in scenarios such as beverage flavoring, drug synthesis, fine chemical product manufacturing, and food additives. However, the traditional organic acid production process has long been confronted with numerous bottlenecks. The advent of bipolar membrane electrodialysis technology has brought about a dual innovation of green production and efficient preparation to the industry.

The predicament of traditional craftsmanship: The problem of waste salt and the shackles of cost

The production of traditional organic acids (such as citric acid, lactic acid, and gluconic acid) requires complex steps like acid-base neutralization and crystallization to extract the products. In the neutralization process, to convert the organic acid salts in the fermentation broth into organic acids, a large amount of strong acids such as sulfuric acid and hydrochloric acid need to be added. This not only generates a large amount of waste acid but also produces waste salts with high impurity content and great difficulty in treatment. If these waste salts are directly discharged, they will cause serious environmental pollution. Enterprises will have to invest a large amount of money in environmental protection treatment, significantly increasing production costs. Meanwhile, the crystallization step of the traditional process relies on thermal evaporation for dehydration, which consumes extremely high energy. For heat-sensitive organic acids, high temperatures may also cause their decomposition and deterioration, affecting product quality and yield. In addition, the loose connection among various production links and the inability to recycle resources further restrict the improvement of production efficiency and economic benefits.

Bipolar membrane electrodialysis: The green magic of Closed-loop production

Bipolar membrane electrodialysis technology has opened up a brand-new path for the production of organic acids. It can directly convert organic acid salts (such as sodium citrate) in fermentation broth into high-purity organic acids and alkaline solutions without the need to add chemical reagents throughout the process, truly achieving green production. Its core working principle stems from the unique properties of bipolar membranes. Bipolar membranes are composed of a cation exchange layer, an intermediate catalytic layer and an anion exchange layer. Under the action of a direct current electric field, water molecules in the catalytic layer will dissociate into hydrogen ions (H?) and hydroxide ions (OH?). Among them, H? migrates through the cation exchange layer towards the cathode, and OH? migrates through the anion exchange layer towards the anode. When bipolar membranes are used in combination with unipolar membranes (cation exchange membranes, anion exchange membranes), specific compartments are formed: after the organic acid salts in the fermentation broth enter the salt chamber, the organic acid radical ions migrate through the anion exchange membrane to the acid chamber and combine with the H? dissociated by the bipolar membrane to form organic acids. The cations in the fermentation broth migrate to the alkali chamber through the cation exchange membrane and combine with OH? to form the alkali solution. More valuable is that the by-product alkaline liquid can be recycled for the front-end fermentation process. During the fermentation process, alkaline solution needs to be added to adjust the pH value to ensure the normal growth and metabolism of microorganisms. The alkaline solution produced by bipolar membrane electrodialysis technology has high purity and meets the process requirements. Thus, a closed-loop production system is established, significantly reducing raw material consumption and improving resource utilization efficiency.

Technical advantages: Dual guarantees of greenness and efficiency

The environmental friendliness has been significantly enhanced. Compared with traditional processes, the bipolar membrane electrodialysis technology does not require the use of strong acids, reducing the generation of waste acids from the source. At the same time, it avoids acid-base neutralization reactions and significantly reduces the discharge of waste salt. This not only alleviates the environmental protection pressure on enterprises but also saves funds for environmental treatment, helping enterprises fulfill their social responsibilities while achieving economic benefits. The core highlight of more efficient resource utilization is the recycling and reuse of by-product alkaline liquid. By reusing it for the front-end fermentation, a resource loop is achieved, reducing the amount of raw material procurement and lowering production costs. This model is in line with the concept of sustainable development and helps enterprises build green supply chains and enhance their market competitiveness. The purity of the product is superior. Relying on the precise regulation characteristics of membrane separation, organic acid radical ions can efficiently migrate to the acid chamber, while impurity ions are retained. The purity of the final obtained organic acid can reach food grade or pharmaceutical grade standards, meeting the strict quality requirements of different fields and providing support for the high-end upgrade of products. The energy consumption has been significantly optimized by adopting an electric drive mode to replace the traditional thermal evaporation process, resulting in a notable reduction in energy consumption. At the same time, it avoids the influence of high temperatures on heat-sensitive organic acids, ensures product quality and yield, conforms to the trend of energy conservation and emission reduction, and further helps enterprises reduce costs and increase efficiency.

Producer's Delight: Cost reduction and enhanced competitiveness

For producers, bipolar membrane electrodialysis technology not only realizes the greening of the production process but also brings tangible economic benefits. By reducing the discharge of waste acid and salt, lowering the cost of environmental protection treatment, and saving raw material and energy consumption at the same time, the comprehensive production cost of enterprises has dropped significantly. In addition, high-purity products can meet the demands of the high-end market, increase the added value of products, and enhance market competitiveness. In the current era when consumers are increasingly concerned about environmental protection and sustainable development, enterprises that adopt green production technologies are more likely to gain market recognition and trust, thereby expanding their market share and achieving long-term sustainable development.

Bipolar membrane electrodialysis technology, with its unique advantages and huge potential, has sparked a green and efficient industry revolution in organic acid production. With the continuous development and improvement of technology, its application in the field of organic acid production will become more in-depth, promoting the entire industry to steadily move towards a green, efficient and sustainable direction.