15 January 2019
Focused filtering for gas-based fuels
Published online 31 October 2018
A porous solid-state material that can filter unwanted contaminants from natural gas could transform the production of gas-based fuels.
Natural gas is cheaper, more abundant, and more environmentally friendly than gasoline and diesel. However, transforming methane, biogas and gas by-products into safe, usable fuels requires the removal of contaminants such as carbon dioxide (CO2) and hydrogen sulfide (H2S). These acid gases quickly corrode pipework, and piped gases must pass stringent quality standards. Previous attempts to remove CO2 and H2S have had limited success, and removing both simultaneously from a gas flow requires complex strategies and equipment.
Now, Mohamed Eddaoudi, Youssef Belmabkhout and their team at King Abdullah University of Science and Technology (KAUST) in Saudi Arabia, together with scientists in France and the US, have designed and fabricated a fluorinated metal–organic framework (MOF) capable of filtering out both acid gases from natural gas, regardless of its composition and impurity concentrations.
MOFs are synthetic, solid-state materials constructed from networks of metal ions connected by organic linkers. Their structures are manipulated to fulfil specific tasks. When natural gas passes through the MOF constructed by Eddaoudi’s team, the CO2 and H2S molecules are attracted to and trapped by different nanoscale structures within its framework. The MOF performed effectively, removing the contaminants from natural gas streams at different pressures and temperatures.
Other MOF designs by the same team can single out contaminants for removal, offering multiple further applications.
“Recent advances in MOF chemistry by our KAUST team have permitted the design and construction of various MOF platforms appropriate for energy-intensive separations, such as natural gas upgrading,” says Eddaoudi.
Belmabkhout, Y. et al. Natural gas upgrading using a fluorinated MOF with tuned H2S and CO2 absorption selectivity. Nat. Energy http://dx.doi.org/10.1038/s41560-018-0267-0 (2018).