Fuel cell humidifiers play a crucial role in maintaining the optimal performance of proton exchange membrane (PEM) fuel cells by regulating the humidity levels of the incoming air stream.
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Dry air enters the humidifier through the dry air inlet while water enters the humidifier through the water inlet. Inside the humidifier, the dry air passes through a series of channels or a porous membrane. The membrane is selectively permeable, allowing water molecules to pass through and mix with the dry air. This process can occur through diffusion, where water vapor naturally moves from a region of higher concentration to a region of lower concentration, or through pressure-driven flow, where pressure differences drive the movement of water vapor. The now humidified air, containing the optimal level of moisture, exits the humidifier through the moist air outlet. This moist air is then directed towards the fuel cell stack.

Fuel cell humidifiers help maintain the proton conductivity of the PEM, thereby enhancing the efficiency and longevity of the fuel cell.

Liquid filtration is the process of separating particles, contaminants, or ions from a liquid using various filtration techniques. It is widely used in industries like water treatment, pharmaceuticals, and energy production. Two advanced filtration methods that rely on specialized membranes are:
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Nanofiltration uses a semi-permeable membrane with nanometer-sized pores. It allows water and small molecules to pass through while rejecting larger particles, dissolved salts, and organic molecules. The separation occurs due to size exclusion and slight charge interactions, making it ideal for softening water, removing certain solutes, and concentrating liquids.
Electrodialysis relies on ion-exchange membranes that allow charged ions to pass through while blocking neutral particles. Under an electric field, cations move through cation-exchange membranes, and anions pass through anion-exchange membranes, effectively separating salts and ions from the liquid. This method is efficient for desalination and ion removal.
In both methods, the membrane acts as a selective barrier, permitting specific substances to pass while retaining others, enabling purification or separation processes

A fuel cell is composed of an anode, cathode, and membrane electrode assembly (MEA). A typical fuel cell works by passing hydrogen through the anode of a fuel cell and oxygen through the cathode. At the anode site, a catalyst splits the hydrogen molecules into electrons and protons. The protons pass through the dense membrane, while the electrons are led through an external circuit where their energy is utilize, generating an electric current and excess heat. At the cathode, the protons, electrons, and oxygen combine to produce water molecules.  As there are no moving parts, fuel cells operate silently and with extremely high reliability.