Fabrication of MWCNTs/PDMS mixed matrix membranes for recovery of volatile aromatic compounds from brewed black tea

A novel multiwall carbon nanotube (MWCNTs)/polydimethylsiloxane (PDMS) mixed matrix pervaporation membrane with a dipping amount of 2% was successfully fabricated and characterized. The presence of MWCNTs provided two more transport channels in PV process, greatly improving the separation performance of the membrane for aromatic compounds. The maximum permeation fluxes in MWCNTs/PDMS of methyl salicylate (MetSa), linalool and beta-Ionone were1.25, 1.28 and 0.075 g.m(-2).h(-1), respectively, at 30 degrees C in an aromaticaqueous model system, which were 19.04%, 23.07% and 50% higher than those in a pure PDMS membrane. The pervaporation of MetSa and linalool was improved by the presence of beta-Ionone ; however, that of MetSa was competitively weakened by linalool. Furthermore, the performance of MWCNTs/PDMS for recovery of VOCs from real brewed tea was investigated. The recovery rates of linalool, MetSa and beta-Ionone were 85.80%, 90.84% and 83.40%, after treatment at 30 degrees C for 6 h, and the concentrations on the permeation side were as high as 3.53 mg.L-1, 4.47 mg.L-1 and 72.41 mg.L-1, which showed good application prospects of MWCNTs/PDMS membrane in aroma recovery by pervaporation technology.

Automated summary

The novel MWCNTs/PDMS mixed matrix membrane shows excellent separation performance for aromatic compounds in PV process, improving permeation fluxes for MetSa, linalool, and beta-Ionone. Additionally, the membrane demonstrates promising results in recovering VOCs from brewed tea.