Activated Carbon Modified by Ester Hydrolysis of Ethyl Acetate for Water Vapor Adsorption Enhancement

Abstract

To improve water vapor adsorption, this study employed oxalic acid–ethyl acetate acidic hydrolysis to modify honeycomb activated carbon and introduce hydrophilic functional groups. Scanning electron microscopy (SEM), Boehm titration, Fourier transform infrared spectroscopy (FT-IR), and an automatic surface area analyzer (BET) were used to characterize the microscopic morphology, surface functional groups, specific surface area, and pore size changes. The results showed that, when the concentration of oxalic acid is 0.0006 mol/cm3, the specific surface area is 179.06 m2/g. After hydrolysis with ethyl acetate, the original functional groups became more abundant, while the number of total acidic functional groups on the surface grew from 0.497 mmol/g to 1.437 mmol/g. The static water vapor adsorption experiments were conducted on modified activated carbon under constant temperature and humidity conditions. Compared with unmodified activated carbon, the activated carbon modified with 0.0006 mol/cm3 oxalic acid increased the adsorption capacity of water vapor by 15.7%. The adsorption capacity of activated carbon after being combined with 0.0006 mol/cm3 oxalic acid and ester hydrolysis modification increased by 37.1%. At the same temperature, the adsorption capacity increased with a higher relative humidity. At the same relative humidity, the adsorption capacity decreased as the temperature rose. Therefore, this modification method may provide clues for the application of enhancing the hygroscopic ability of activated carbon.

Effect of HCl Treatment on Acidity of Pd/TiO2 for Furfural Hydrogenation

“…When the pore cavity size distribution is wider than the neck size distribution, type H2(a) hysteresis with a steep desorption step occurs, and in the opposite case, type H2(b) hysteresis occurs [31]. Studies have reported that the size and shape of pores tend to change with acid treatment [32,33]. Therefore, it was considered that the pore size changed due to acid treatment, which affected the BET results.…”

Preparation of High Specific Surface Area Activated Carbon from Petroleum Coke by KOH Activation in a Rotary Kiln

“…High specific surface area activated carbon (AC) is widely used as an adsorbent for gas storage, a catalyst support and an electrode of electrochemical capacitors because of its high surface area and well-developed microporous structure [1][2][3][4]. It is generally produced from raw materials with high carbon content, such as petroleum coke (PC) and anthracite, by alkaline hydroxides such as NaOH and KOH activation.…”