Liquid crystal polaroid glass electrode from e-waste for synchronized removal/recovery of Cr+6 from wastewater by microbial fuel cell

• Disposed computer monitor is used as electrodes for the reduction/recovery of Cr+6.
• LCPGE shows an excellent electrochemical performance with distinct redox peaks.
• Functional groups and biocompatibility of LCPGE promotes bacterial attachment.
• Maximum current density of 110 mA/m2 (10 mW/m2) achieved with 100% Cr+6 removal.
• Nontoxic Cr2O3 was recovered and confirmed by FT-IR and XPS analysis.

This study demonstrates the use of Liquid Crystal coated Polaroid Glass Electrode (LCPGE) material collected from disposed liquid–crystal display (LCD) computer monitor as electrodes in microbial fuel cell (MFC) for the simultaneous reduction/recovery of Cr+6 from chromium wastewater. Fourier transform infrared spectrum (FT-IR) confirms the presence of NH2, CN, CO and OC and/or COC functional groups in LCPGE. An excellent electrochemical performance with distinct redox peaks were observed in cyclic voltammetry test (100 mV/s). The maximum current density of 110 mA/m2 (10 mW/m2) was achieved by operating MFC in batch mode. At the cathode LCPGE (10.5 cm2) interface, toxic Cr+6 ions readily accepted electrons and formed nontoxic Cr2O3 as confirmed by FT-IR and X-ray photoelectron spectroscopy analysis. Moreover, electrochemical impedance analysis shows that bacteria were readily attached to the surface of LCPGE (10.5 cm2) within 24 h in a Bioelectrochemical System (BES).

Figure optionsDownload as PowerPoint slide