Modification of Resin-Type Adsorbents for Ethane/Ethylene Separation

Abstract

Modified adsorbents, Ag+-exchanged resins, have been prepared and studied for ethane/ethylene separation by adsorption. On Ag+-exchanged Amberlyst 35 (36.5% exchange) at 25 °C and 1 atm, the equilibrium adsorbed amount for C2H4 is 1.48 mmol/g, and the equilibrium adsorption ratio for C2H4/C2H6 is 6.4. The adsorption capacity is completely restored at 100−105 °C, although small residual amounts exist after desorption at 25 °C and 75 °C. For the adsorption encompassing both physical adsorption and π-complexation with energy heterogeneity, the equilibrium data are correlated with an equilibrium isotherm equation employing two fitting parameters. The fitted results agree well with the experimental data. Furthermore, the isosteric heats of adsorption and the diffusion time constants are calculated from experimental data. Considering all adsorption characteristics, these adsorbents show potential for application employing cyclic adsorption processes.

Spent tea leaves: A new non-conventional and low-cost biosorbent for ethylene removal

“…Moreover, FTIR spectral analysis of the regenerated MSTLP revealed that it had the same chemical nature as did MSTLP. Table 3 presents the comparative ethylene adsorption capacities of MSTLP and of some other economical adsorbents as obtained from a literature review (Wu et al, 1997;Wills and Warton, 2004;Kima et al, 2005;Liu et al, 2006;Albunia et al, 2008). Generally, zeolites and carbon-based materials are used as absorbents for the removal of ethylene.…”

Adsorption of C2H4, C2H6 and CO2 on Cation-exchanged Clinoptilolite

“…The similar adsorption uptakes at equilibrium could be due to a compensatory energetic effect, as a result of the specific interactions of the quadrupole moment (δ) and the polarizability (α) of the (Table 4): δ(CO 2 ) > δ(C 2 H 4 ) and α(C 2 H 4 ) > α(CO 2 ). Hence, the adsorption separation of this gaseous mixture using Cp may be achieved by virtue of the differences in the diffusion rates of these molecules (Yang 1997) observed at short adsorbent-adsorbate contact time, t < 10 s. However, Cp-H cannot be recommended for the separation of CO 2 /C 2 H 4 mixtures since its capacity for adsorbing CO 2 and C 2 H 4 is respectively lower and higher than that of the other samples studied (see Figure 9). The low irreversible adsorption of C 2 H 4 ( Figure 5) and the considerable reversible adsorption of CO 2 onto Cp-Na detected at 0 ºC enable this sample to be recommended as a suitable adsorbent for the good separation of a CO 2 /C 2 H 4 mixture at 0 ºC.…”

“…The search for a suitable adsorbent has been relentless; thus, Ackley and Yang (1991a,b) have modified natural zeolites chemically to improve their adsorption properties. It has been reported by Wu et al (1997) that the application of resin-type materials modified by Ag + ion-exchange leads to the complete restoration of the adsorption capacity towards ethylene at 100-105 ºC. Padin and Yang (2000) reported that new adsorbents for ethane/ethylene and propane/propylene separations could be prepared by dispersing AgNO 3 over γ-Al 2 O 3 , SiO 2 and MCM-41 substrates.…”

Nano-sized carbon hollow spheres for abatement of ethylene

“…Various metals ions especially Ag [7][8][9], Cu [10,11] and Pd [12], alone are mixed [13] and supported on porous inorganic and organic materials have been used as renewable and safer way for ethylene removal even at very low concentrations. Inorganic solids viz., zeolites [14], zirconia [15], clays [16], silicas [17], alumina [18] and organic materials viz., resins [19,20], polymers [21] and activated carbons [22] have been extensively used as support for the above-mentioned metal ions.…”