VEPIKA KANDJOU; ANA MATILDE PEREZ-MAS; MIGUEL HERNAEZ; BEATRIZ ACEVEDO; ANDREW MAYES; SONIA MELENDI ESPINA
The augmenting and urgently impending water crisis calls in for the implementation and development of efficient strategic water purification materials. Graphene Oxide (GO) has been of great interest owing to its promising surface and chemical properties. Its 2-dimensionality together with its hydrophilicity offers an increased water flux possibility by several orders of magnitudes in comparison to conventional water-treatment polymer-membranes (Hageb, 2015). The major problem with graphene oxide membranes in water treatment, purification and desalination is the widening of the membrane pore-gap that lead to a poor stability in water media (Qiu, 2009). A potential approach is to investigate proper cross-linkers to enhance the stability of the membranes by fine-tuning the pore gap of the membranes. In this study p-Phenylenediamine (PPD) was used as a cross-linker due to its small size (<1nm) and to symmetrical functional amino groups that can interact with the epoxy group present in the GO and fix the pore-gap. The membranes were fabricated by a dip-assisted layer by layer assembly. The effectiveness of the pore-gap was tested with MgCl2 (hydrated diameter of 1.52nm) (Persson, 2010) solutions by a homemade nanofiltration system.
Link to source: https://www.researchgate.net/profile/Vepika-Kandjou/publication/327246633_THE_USE_OF_P-PHENYLENEDIAMINE_PPD_TO_CONTROL_GRAPHENE_OXIDE_MEMBRANE_PORE-GAP_AND_STABILITY_FOR_WATER_PURIFICATION/links/5b83f295299bf1d5a72b1095/THE-USE-OF-P-PHENYLENEDIAMINE-PPD-TO-CONTROL-GRAPHENE-OXIDE-MEMBRANE-PORE-GAP-AND-STABILITY-FOR-WATER-PURIFICATION.pdf
Materials and Methods
… The dispersion of the GO water suspensions and PPD were enhanced by a Sonicator (Ultrawave limited Cardiff CF2 1YY, Hz – (50-60)) and the membranes were fabricated with a rotary dip-coater device (Nadetech Innovations, Spain).