Non-Calorimetric Determination of the Adsorption Heat of Volatile Organic Compounds under Dynamic Conditions

Abstract

Avoiding strong chemical bonding, as indicated by lower heat of adsorption value, is among the selection criteria for Volatile Organic Compounds adsorbents. In this work, we highlight a non-calorimetric approach to estimating the energy of adsorption and desorption based on measurement of involved amounts, under dynamic conditions, with gaseous Fourier Transform Infrared spectroscopy. The collected data were used for obtaining adsorption heat values through the application of three different methods, namely, isosteric, temperature programmed desorption (TPD), and temperature-programmed adsorption equilibrium (TPAE). The resulting values were compared and discussed with the scope of turning determination of the heat of adsorption with non-calorimetric methods into a relevant decision making tool for designing cost-effective and safe operating of adsorption facilities.

Selective recovery of rare-earth elements from diluted aqueous streams using N- and O-coordination ligand–grafted organic–inorganic hybrid composites

“…Despite this, the apparent hysteresis loops were present between P/Po of 0.9 and 1, although they are common with type IV and V isotherm curves. Similar loops were also reported in other works assigned as "pseudo type II-b" [146,147]. This could reveal that the pores might be narrow slit-like forms, filled with internal voids of irregular shapes, the sizes of which spanned over a broad range [146].…”

Speeding Up Chemisorption Analysis by Direct IR-Heat-Release Measurements (Infrasorp Technology): A Screening Alternative to Breakthrough Measurements

“…In this manuscript, we will present a new tool that can help to answer this demand: Infrasorp technology (Figure , left). − This machine is based on optical detection of chemisorption heat in the IR range, allowing us to measure information on different materials aspects, such as the porosity of MOFs, the correlation of single-point BET-surface area, and the n -butane capacity (among other gases), with the possibility to use different types of gases (e.g., inert such as nitrogen or corrosive such as as H 2 S) quickly, easily, and with high accuracy. − The principle of measuring the heat of adsorption in order to evaluate catalytic activities has been used since the 1970s. − Also nowadays, adsorption calorimetry is used extensively in order to get deeper insights into the adsorption of, for example, CO, CO 2 , or volatile organic compounds on catalysts. − However, these measurements are laborious and especially difficult to conduct with corrosive gases such as H 2 S. In contrast to DSC measurements, the Infrasorp technique is based only on noncontact detection of the emitted infrared radiation coming from the temperature increase in the sample. Therefore, the technique allows for rapid screening tests and can also be conducted easily with corrosive gases.…”

Calculating adsorption isotherms using Lennard Jones particle density distributions

“…An experimentally equivalent to such a suggestion is the ability to measure an adsorption isotherm using instrumentation not specialised for adsorption. Yet, recent techniques, associated with vibrational spectroscopy, powder diffraction or calorim etry, actually report the same objective [43][44][45][46]. These tech niques explore the adsorption characteristics of a sample solid at a temperature programmed sequence.…”