  This study investigates the prospect of using reduced graphene oxide
encapsulated between thin wood membranes as a composite filter for water
filtration. Graphene oxide (GO) with a volume range of 0.2 to 0.5 mL was
deposited on a 95 mm2 area of thin sheets of Balsa wood with a thickness range
of 2.20 - 3.50 mm. The dried GO deposits were laser treated in reduced oxygen
environment to prepare a reduced graphene oxide-wood composite (rGO-wood). The
rGO substrate of the composite was sandwiched between 2 wood sheets which were
glued using polydimethylsiloxane (PDMS) to give a stable membrane. Fabricated
membranes improved the Allura red rejection from 8.29 $\pm$ 0.69% in the
controls (sandwiched wood sheets without rGO) to 93.14 $\pm$ 1.31% in the 1 mL
total rGO composites. The ratio of percentage permeance drop of the treatments
over the controls ranged from 62.8 $\pm$ 4.3 to 85.4 $\pm$ 5.2% from the 0.4 to
1 mL rGO composites respectively. The correlation coefficient (r) between the
GO volume and rejection was 0.94 suggesting that the GO treatments provided
some control over the transport of molecules through the membrane. The
correlation coefficient between wood thickness, and Allura red rejection shows
that the wood sheets did not influence the rejection. The permeance was weakly
affected by the membrane thickness (r = -0.46). An 93% improvement in rejection
performance of the composite membranes over the controls was observed. The
overall data suggests that the wood-rGO composite has potential for water
filtration applications.
