Algae cathode microbial fuel cells for cadmium removal with simultaneous electricity production using nickel foam/graphene electrode.

Graphical abstract Highlights • Chlorella was introduced into MFC for Cd(II) removal in the biocathode. • Simultaneous high power generation and metal removal efficiencies can be achieved. • NF-rGO enhanced power generation (36.4 mW m−2) and Cd(II) removal (115 g m−2). • NF-rGO improve the maximum tolerable concentrations of Cd(II) for algal biocathode. • Cadmium were removed mainly through hydroxide precipitation and biosorption. Abstract Microalgae ( Chlorella sp. QB-102) was introduced into microbial fuel cell (MFC) as the cathode for Cd(II) removal using nickel foam/graphene (NF/rGO) as electrodes. It was found that graphene enhanced the power generation and decreased the internal resistance in the algal-cathode MFC. The start-up time was shortened and the maximum power density obtained by using NF/rGO (36.4 mW m−2) was eight times higher against bare NF. Graphene further improve the maximum tolerable concentrations of Cd(II) in the algal-cathode, which estimated to be 50 ppm. Using NF/rGO electrode, the algal-cathode MFC achieved a high Cd(II) removal efficiency of almost 95% and a maximum adsorption amount of 115 g m−2. It was found that hydroxide precipitation and biosorption are the major mechanisms for the Cd removal in the biocathode self-sustained MFC. The results suggested that photoautographic MFC is feasible and effective for heavy metal removal in the algal-cathode and graphene modification in the electrodes is recommended. [ABSTRACT FROM AUTHOR]