Porous graphene membranes hold great promise for high-selectivity separation. Moreover, their practical application is limited by the lack of a simple and efficient method for the synthesis of porous graphene. Here, a rapid and scalable method is developed for the synthesis of porous graphene via partial combustion of graphene oxide imperfectly covered by hydrotalcite. This method is not only less energy-and time-intensive than existing ones, but also allows precise control of pore size. Remarkably, the resulting membrane of porous graphene exhibits high selectivity for K + and Na + (α = 3.84) separation. Hence, this facile route for preparing membranes of porous graphene oxide might direct application membranes in environmental, energy, desalination, and biomedical fields.

Rare earth elements (REEs) are used widely in devices of many fields, but it is still a troublesome task to achieve their selective separation and purification. Metal–organic frameworks (MOFs) as an emerging porous crystalline material have been used for selective separation of REEs using the size-selective crystallization properties. However, so far, almost all MOFs cannot be used directly for selective separation of REEs in strong acid via solid-state adsorption. Herein, a zinc-trimesic acid (Zn-BTC) MOF is grown by solid synthesis in situ on ZnO nanoparticles covering nanoporous graphene for preparing Zn-BTC MOF/nanoporous graphene composites with strong acid resistance. The adsorption capacity of the resulting composites to REEs is highly sensitive to the ionic radius, which may be attributed to the fact that the REE ions coordinate with O to form a stable structure. The selectivity of Ce/Lu is ≈10,000, and it is extremely important that the selectivity between adjacent REEs (e.g., Nd/Pr) is as high as ≈9.8, so the composite exhibits the best separation performance so far. This work provides a green, facile, scale, and effective synthesis strategy of Zn-BTC MOF/nanoporous graphene, which is hopefully applied directly in the separation industries of REEs.

Chiral materials are usually the key to the separation of chiral membranes. In this work, we propose a new strategy that chiral porous graphene membrane can be fabricated from nonchiral porous graphene by mechanical stirring to induce vortex structure. Porous graphene with controlled, nanosized pores was synthesized by a newly designed, one-pot process directly from graphite as opposed to graphene oxide. Then porous graphene was immobilized on ultrafiltration membrane through filtering while stirring to form porous graphene membrane, which was applied for enantioselective separation toward DL-amino acids: for example, the separation factor of L-/D-phenylalanine reached 4.76. Interestingly, we first observed that the front and back sides of the porous graphene membrane exhibited opposite optical activities.