Adsorption–Desorption Behaviors of Methanol and Ethyl Acetate on Silica Gel: Modeling and Experimental Tests

Abstract

Methanol and ethyl acetate are typical oxygen-containing volatile organic compounds which are widely used in industry, often leading to serious pollution. Herein, the adsorption−desorption hybrid process has been applied to recover and recycle the methanol and ethyl acetate waste gases using micro−mesoporous silica gel. Results show that compared with commercial activated carbons, the silica gels perform better (85%) in adsorbing the methanol and ethyl acetate due to their stronger affinity. Further tests show that competitive adsorption happens between them. The silica gel shows stronger affinity to ethyl acetate than to methanol. It is also found that an increase in the flow rate and concentration could facilitate the mass transfer of the substances in the pores of the silica gels. Based on the tests, an adsorption process simulation method with ideal adsorption solution theory and the linear driving force model has been applied to simulate the overshoot behaviors of breakthrough curves for the dynamic adsorption of this binary mixture on silica gels (error in ±7%). In this way, the concentration distribution of each adsorbed component on the solid phase in the adsorption bed has also been visualized and analyzed, which was validated by experimental tests. A dynamic adsorption model has been proposed to describe the adsorbed multicomponents on the solid phase for the adsorption of mixture. Finally, according to the adsorption and desorption profiles, a temperature swing−pressure swing combined process is proposed to desorb the adsorbed methanol−ethyl acetate mixture.

Preparation and Adsorption Performance Study of Graphene Quantum Dots@ZIF-8 Composites for Highly Efficient Removal of Volatile Organic Compounds

“…Figure 12. Comparison between previous works and this work on the adsorption properties ofGQDs@ZIF-8 composites for toluene (a)[44][45][46][47][48][49][50][51] and ethyl acetate (b)[52][53][54][55][56][57][58][59].…”

“…These structures not only possess a high specific surface area, but also maintain high cycle stability, as shown in Figure 11, which make the GQDs@ZIF-8 composite an ideal candidate for the highly efficient removal of VOCs. The adsorption capacity and adsorption rate of previous adsorbents for toluene and ethyl acetate are shown in Figure 12 [44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59]. Compared with other adsorbents, the GQDs@ZIF-8 composites exhibit excellent performance both in adsorption capacity and in removal percentage due to their unique nano-micro hierarchical pore structures generated from the optimized matching of GQDs and ZIF-8.…”

Review of the Pressure Swing Adsorption Process for the Production of Biofuels and Medical Oxygen: Separation and Purification Technology

“…The cyclical nature of the PSA process and its operating conditions determine the type of model to use. For example, a separation process for producing pure oxygen from air From all this analysis, a general mathematical model of the PSA process is established, this involves most of the equations necessary to determine the important dynamics that characterize the PSA process, this detailed general model is shown in the following: 6 PDE Consider adsorption isotherms No pressure gradient [23] 3 PDE Does not present adsorption isotherms Consider pressure gradient [39] 6 PDE Consider adsorption isotherms Consider pressure gradient [40] 3 PDE Does not present adsorption isotherms Consider pressure gradient Table 5: Governing equations and simplifications for production and purification of bioethanol.…”

Converting lignocellulosic biomass into mesoporous carbons for the assessment of single adsorption equilibrium: the competing role of moisture and temperature on gaseous benzene adsorption

“…Materials are referred to as adsorbents and range in composition, structure, texture and their application. Some widespread examples of adsorbents are biochar [21], activated carbons (ACs) [22], silica gel [23], polymers [24], carbon composite [25], zeolites [26], and resins [27]. Among them, activated carbon (AC) is commonly recognized as an efficient adsorbent for VOC remediation due to its relatively higher surface area, permeability, and sorption capability [28,29].…”