Glycerin-based adsorbents for the separation of ethane and ethylene

The separation of ethane from a mixture of ethane/ethylene is a large scale process. Therefore, if adsorption is to be considered for this separation, besides the amounts adsorbed and selectivity type and values, the adsorbent also needs to have a relatively low cost. Considering the large volume of glycerol coming from biodiesel production it is also important to find new applications for this substance. With this goal, we synthesized a series of glycerin-activated carbons via a two-step procedure involving carbonization followed by chemical activation. The prepared adsorbents presented high surface areas, ranging from 1166 to 2150 m2 g-1 and have pore volumes between 0.63 and 1.03 cm3g- 1. The glycerin-activated carbons were evaluated as adsorbents for adsorptionseparation of ethane and ethylene. All the adsorbents showed to be ethane selective, that is to say, the materials exhibited higher adsorption capacity of ethane than ethylene. This is a key factor, related with the nature of the materials surface, for their application in the separation of ethylene from a mixture of ethane/ethylene. Ethane adsorption capacity was in the range 8.92-14.81 mmol g-1. Therefore, a low-cost by-product of biodiesel production - glycerin - can be transformed in a material that has promising properties for adsorption-separation of C2H6/C2H4.

Automated summary

The research demonstrated that glycerin-activated carbons prepared via chemical activation exhibit high selectivity in adsorption-separation of ethane and ethylene, showing a higher adsorption capacity for ethane. This serves as a successful example of utilizing glycerin, a low-cost by-product, to produce promising adsorbents for gas separation.