Chemical Filters for Industrial Cleanrooms: An Overview

Physical adsorption: an adsorbent's enormous specific surface area attracts gaseous pollutant molecules through van der Waals forces and other intermolecular forces, causing them to adhere to its surface. Activated carbon is a common physical adsorbent and performs well against many volatile organic compounds, or VOCs, and large gas molecules.

Chemical adsorption: contaminant gases react with chemical ingredients in the filter medium. Toxic and harmful gaseous pollutants are neutralized or oxidized into harmless solid salts and other products, thereby removing them from the air. For example, activated carbon or a porous carrier impregnated with an alkaline substance can remove acidic gases, while material impregnated with an acidic substance can remove alkaline gases.

Common Types

Panel chemical filter: this composite filter efficiently removes both particulate and gaseous molecular contaminants. It is mainly used with fan filter units, or FFUs, and can also serve as a chemical-filtration component at a supply- or return-air outlet.

Industrial cleanroom panel chemical filter

W-shaped chemical filter: another composite filter widely used in ventilation systems for the semiconductor industry, data rooms and similar facilities. Its distinctive W-shaped structure increases the contact area and improves utilization of the filter medium.

Industrial cleanroom W-shaped chemical filter

Box chemical filter: commonly used where pollutant concentrations are relatively high and installed with an air-handling unit. Different media can be fitted to remove different airborne molecular contaminants, or AMCs. The large quantity of filter medium provides a long service life.

Industrial cleanroom box chemical filter

Cylindrical chemical-filter module: suitable for relatively high pollutant concentrations and used with an air-handling unit. Different media can be installed to remove different AMCs. Its large media volume allows it to effectively remove both particulate and gaseous molecular contaminants from the air.

V-shaped chemical-filter module: designed to hold various dry filter media. The V-shaped module increases both the contact area and contact time between gaseous pollutants and the medium. Its streamlined intake grille also lets air enter more easily, greatly reducing resistance.

Performance Parameters

Filtration efficiency: an important measure of a chemical filter's ability to remove gaseous molecular contaminants. Higher efficiency means better pollutant removal.

Rated airflow: indicates the filter's air-handling capacity. A higher rated airflow normally requires a larger filter and correspondingly more installation space.

Face velocity: directly affects adsorption. A lower velocity keeps air in the adsorbent bed longer and improves adsorption efficiency, but practical applications must balance velocity against the required supply-air volume.

Filter resistance: a key operating-cost indicator. At a fixed airflow, a lower pressure drop across the filter means lower energy consumption.

Adsorption capacity: the total quantity of pollutants the chemical filter medium can adsorb while maintaining its rated efficiency. It depends on the filter area, the properties of the adsorbent and other factors.

Applications

Electronics and semiconductor manufacturing: critical processes such as photolithography and etching have extremely strict environmental requirements. Chemical filters remove AMCs, prevent wafer-surface contamination and corrosion, and protect chip yield and performance.

Pharmaceutical manufacturing: chemical filters control airborne contaminants in cleanrooms, helping microbial and chemical contamination remain within standards during production and safeguarding medicine quality and safety.

Data centers: filters remove acidic gases, volatile organic compounds and other pollutants, preventing corrosion of servers and other equipment, extending equipment life and supporting stable data-center operation.

Laboratories and research facilities: chemical filters effectively remove chemical gases generated by laboratory reagents, providing a stable, clean environment and helping ensure accurate experimental results.