# Mitigating Global Methane Emissions Using Metal-Organic Framework Adsorbents
## 3 Results  
To investigate the effectiveness of MOFs as adsorbents for global methane mitigation, methane uptakes were determined from experiments. The textural properties and methane uptakes of MOFs at various conditions including 298 K and 1 bar are provided in Table 1.  
ATC-Cu exhibited the best methane uptake of 2.8 mmol g\({}^{-1}\) at 298 K and 1 bar. This is followed by Cu-**tbo**-MOF-5 which exhibited a methane uptake of 1.29 mmol g\({}^{-1}\) at 298 K and 1 bar and HKUST-1 which had an uptake of 1.0 mmol g\({}^{-1}\) at 298 K and 1 bar. In comparison, the methane uptake of carbonaceous materials such as KUA41751, KUA31751, KUA21751, and KUA51751 were less than 1.5 mmol g \({}^{-1}\) at 1 bar and 298 K (Table 2) [52]. HSAC-19, HSAC-21, HSAC-23, and HSAC 30, which are high surface area activated carbons reported to have high methane uptakes at low pressure, possessed methane uptakes of less than 2.7 wt.% at 298 K and 1 bar [53]. This corresponds to less than 1.7 mmol g\({}^{-1}\) of methane adsorbed. Poly(_p_-DCX) porous coordination polymer exhibited a methane uptake of less than 1 mmol g\({}^{-1}\) at 298 K and 1 bar [54]. Zeolites such as NaX and CaX exhibited a methane uptake of less than 0.75 mmol g\({}^{-1}\) at 303 K and 1 bar [55]. Based on these results, MOFs exhibited the best methane uptakes at 1 bar and 298 K from the materials investigated and are effective adsorbents. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**MOF**} & **Vr** & **BET Surface** & **Lang Surface** & **T (k)** & **P (bar)** & **Methane Uptake** & **Qu (d) mol\({}^{-1}\)** & **Ref.** \\  & **(cm\({}^{2}\) g\({}^{-1}\))** & **Area (cm\({}^{2}\) g\({}^{-1}\))** & **Area (cm\({}^{2}\) g\({}^{-1}\))** & **T (k)** & **P (bar)** & **Methane Uptake** & **Qu (d) mol\({}^{-1}\)** & **Ref.** \\ \hline UTSA-110a & 1.263 & 241 & - & 275.15 & 1 & - & 14.5 & [54] \\ HKUST-1 & 0.78 & 1850 & - & 298 & 1 & 1.0\({}^{<}\) & 17 & [57] \\ ATC-Cu & 0.23 & 600 & - & 298 & 1 & 2.8\({}^{<}\) & 26.8 & [35] \\ NU-1501-A1 & - & 7310 & - & 270 & 1 & - & - & [58] \\ Al-node-MOF-1 & 2.3 & 5585 & - & 298 & 1 & 0.33\({}^{<}\) & 10.5 & [59] \\ PCN-14 & 0.85 & 2170 & - & 298 & 1 & - & 17.6 & [32] \\ NJU-84 & 1.22 & 3090 & - & 298 & 1 & 0.20\({}^{<}\) & 14.45 & [60] \\ PCN-61 & 1.36 & 3000 & - & 298 & 1 & - & - & [44] \\ MOF-950 & 1.3 & 3440 & - & 298 & 1 & 0.38\({}^{<}\) & 11.9 & [61] \\ NJU-84 & 1.07 & 2830 & - & 298 & 1 & 0.80\({}^{<}\) & 14.49 & [60] \\ FethylO & - & - & - & - & 298 & 1 & 0.1\({}^{<}\) & - & [62] \\ NU-135 & 1.02 & 2530 & - & 298 & 1 & 0.9\({}^{<}\) & 16.6 & [63] \\ NU-125 & 1.29 & 3120 & - & 298 & 1 & - & 15.5 & [64] \\ ZU-25 & 1.183 & 2124 & - & 300 & 1 & - & 15.1 & [64] \\ MOF-519 & 0.938 & 2400 & - & 298 & 1 & 0.49\({}^{<}\) & 14.6 & [65] \\ MOF-5 & 1.4 & - & 298 & 1 & - & 12.3 & [66] \\ NJU-81 & 1.063 & 2803 & - & 298 & 1 & 0.85\({}^{<}\) & 14.8 & [67] \\ Cu-u6-MOF-5 & 0.595 & 3971 & - & 298 & 1 & 1.29\({}^{<}\) & 20.4 & [68] \\ MOF-905-A2 & - & - & - & 298 & 1 & 0.47\({}^{>}\) & - & [61] \\ MOF-905 & 1.34 & 3490 & 3770 & 298 & 1 & 0.33\({}^{>}\) & 11.7 & [61] \\ MOF-95-N2 & 1.25 & 3310 & 3540 & 298 & 1 & 0.45\({}^{>}\) & 11.3 & [61] \\ MOF-905-N2 & 1.29 & 3380 & 3600 & 298 & 1 & 0.403\({}^{>}\) & 10.7 & [61] \\ NJU-841 & 0.92 & 2370 & - & 298 & 1 & 0.96\({}^{<}\) & 17.77 & [60] \\ Al(_p_(b)ccx /M-120 & 0.11 & 308 & 432 & 303 & 10 & 1.7\({}^{>}\) & 27 & [69] \\ Cu\({}_{2}\)(d) [_P_(b)cm\({}^{2}\))-26] & 0.84 & 1854 & 2545 & 298 & 1.07 & 1.1\({}^{<}\) & - & [70] \\ Cu\({}_{2}\)(e_(b)chtc) & - & 1852 & 2844 & 273 & 1 & 0.6\({}^{<}\) & - & [71] \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Pore volume, BET surface area, Qst, and methane uptake of selected metal-organic frameworks (MOFs). Entropies of adsorption on MOFs were determined. Particular emphasis was paid to quantify the effect of methane confinement in MOFs. Some MOFs were investigated for this application were HKUST-1, NU-125, PCN-46, PCN-61, SNU-30, SNU-50, UTSA-20, MOF-5, MOF-905, and MOF-519 [40, 61, 64, 65].