The performance of Adsorbing and Removing gaseous acetic acid by activate carbon

Abstract

Currently, gaseous molecular contaminants (acetic acid) is one of the main factors that cause defects in semiconductors and wafers, reduce product yields in high-tech process plants. Propylene Glycol Monomethyl Ethyl Ether Acetate (PGMEA) is a versatile solvent with many applications. Solvents used in the solder mask process in the manufacture of printed circuit boards (PCBs). The diluent in photoresist and edge bead removers used in semiconductor and wafer fabrication is PGMEA, which forms acetate contaminants through an acid-catalyzed hydrolysis reaction. The concentration standard of acetic acid pollutants in clean rooms is 1ppb.In order to protect the expensive optical components, the acetic acid generated by PGMEA needs to be controlled.For this purpose, the activated carbon filter in the intake filter prevents acetic acid from contaminating the components and corroding the material. In this study, we used the commercially available activated carbon fabricated filter to adsorption of acetic acid. The effect of adsorption under different face velocity (0.03/0.06/0.09 m/s) and initial acetic acid concentrations (4/6/8/10 ppm) were measured according to the principle of ASHRAE 145.1standard. The experimental data are also evaluated for adsorption performance, adsorption capacity, kinetic model of acetic acid adsorption process, and isothermal model of acetic acid adsorption process.The results of the acetic acid adsorption experiment show that MM3000 activated carbon has the highest adsorption capacity and the longest adsorption saturation time than KPL activated carbon. The higher the inlet acetic acid concentration at a fixed wind speed, the shorter the saturation time and the higher the adsorption capacity; the faster the wind speed at a fixed acetic acid concentration, the shorter the saturation time and the higher the adsorption capacity.The Langmuir (R2) of the MM3000 sample is higher than the Freundlich’s coefficient of determination (R2), which indicates that the adsorption phenomenon of the MM3000 sample is more suitable to be described by the Langmuir isothermal adsorption mode, which is the adsorption of a single molecular layer on a homogeneous surface. The Freundlich R2 of the KPL sample is higher than the Langmuir’s coefficient of determination (R2), which means that the adsorption phenomenon of this KPL sample is more suitable to be described by the Freundlich isothermal adsorption mode, and it is a case of adsorption of multiple layers on an inhomogeneous surface. The adsorption of MM3000 activated carbon and KPL activated carbon is more suitable to be described by the proposed second-order adsorption kinetic model, which is a phenomenon of chemisorption.

Keywords

• acetic acid
• activated carbon
• adsorption
• filter