Table 1. Performance Indicators (performance evaluation metrics)^a.

index	metric class	screening metric	definition	reference
1	ISMM	pore volume
2	ISMM	porosity
3	ISMM	surface area
4	ISMM	pore limiting diameter
5	IFMM	enthalpy of adsorption
6	IFMM	diffusivity
7	IFMM	Henry selectivity		Bae and Snurr, 201195
8	IFMM	adsorption selectivity		Bae and Snurr, 201195
9	IFMM	working capacity	WC = qads,1 – qdes,1	Bae and Snurr, 201195
10	IFMM	regenerability		Bae and Snurr, 201195
11	HMM	adsorbent figure of merit		Baksh and Notaro, 199880
12	HMM	sorbent selection parameterb		Rege and Yang, 200181
13	HMM	separation factor		Pirngruber et al., 201282
14	HMM	adsorbent performance indicator		Wiersum et al., 201383
15	HMM	adsorbent performance score	APS = WC1 × α1,2	Chung et al., 201684
16	HMM	separation performance parameter (SPP)		Braun et al., 201685
17	HMM	parasitic energy (PE)	PE = (0.75ηTfinal × Q) + Wcomp	Lin et al., 201286
18	PLM	purity in PSA/VSA		Rajagopalan et al., 201616
19	PLM	recovery in PSA/VSA		Rajagopalan et al., 201616
20	PLM	specific energy in PSA/VSA		Rajagopalan et al., 201616
21	PLM	productivity in PSA/VSA		Rajagopalan et al., 201616
22	GEM	general evaluation metric		Leperi et al., 201993

^aSubscripts 1 and 2 always denote stronger and weaker adsorbing components, respectively. For evaluation metrics 1–16, WC, α, β, C, K_H, and ΔH represent working capacity, adsorption selectivity, ideal selectivity, concentration, Henry’s constant, and enthalpy of adsorption. For SPP, M_ads, M_i,k, and E denote mass of adsorbent, moles of species i in stream k, and total energy required for separation.⁸⁵ For PE, Q, η, and W_comp are the thermal energy requirement, Carnot efficiency, and compressor work, respectively. For GEM, ΔH_N2 and WC_mod stand for enthalpy of adsorption for nitrogen and the modified working capacity as defined in ref (93).

^bFor Langmuir isotherms. For non-Langmuir systems, .⁹⁵