Automated device for the purification of graphene oxide dispersions: integration of cross-flow filtration and dialysis

Abstract

Graphene oxide (GO) dispersions require extensive purification to remove contaminants from synthesis. Conventional methods, such as dialysis, filtration and centrifugation are effective, but also labor-intensive, time-consuming, and challenging to automate. These approaches consume large volumes of water and energy, and limited efficiency in removing residues can compromise the properties of GO. We present a fully automated device integrating cross-flow filtration and dialysis using polyethersulfone (PES) membrane. Real-time conductivity monitoring enables optimal water exchange and resource use. The optimized system reduced conductivity from ~70 to < 0.5 mS cm−1 in under 16 h for 1.0 L dispersion at 1 mg mL−1. Chemical analysis showed effective removal of ions (93% Cl−, 97% Mn2+, 92% SO42−), outperforming commercial samples. GO morphology and lateral dimensions were preserved, as verified by comprehensive characterization. This scalable platform enables high-throughput, application-ready GO purification, providing a practical solution for laboratories and industry seeking consistent, high-purity nanomaterials.