Sequential recovery of copper and nickel from wastewater without net energy input

In situ synthesis of polypyrrole on graphite felt as bio-anode to enhance the start-up performance of microbial fuel cells

This study introduces an effective method to deposit polypyrrole (PPy) on graphite felt (GF) as anode to improve the start-up performance of microbial fuel cells (MFCs). The results of scanning electron microscope (SEM) and electrochemical testing reveal that polypyrrole is able to improve the electrical conductivity and surface roughness, which is beneficial to the microorganism attachment and growth. It shows that microorganisms grow faster on polypyrrole-modified anode than on unmodified anode. It takes ca. 5 days for polypyrrole-modified anode to reach a reproducible voltage platform, while it takes 11 days for unmodified anode. Moreover, the maximum power density of microbial fuel cells with polypyrrole-modified anode was 919 mW m^-2, which were 2.3 times of that with unmodified anode. This research revealed that polypyrrole modification can improve the start-up performance of microbial fuel cells. It is considered as a feasible, economical and sustainable anode.

Assessment of cathode materials for Ni(ii) reduction in microbial electrolysis cells

Four cathode materials including stainless steel mesh (SSM), copper sheet (CS), graphite plate (GP) and carbon cloth (CC) were evaluated for nickel recovery in a MEC. We found that MEC with CS cathode exhibited the best electrochemical performance.