Enhancement of Elecrtrokinetic Power Generation by Surface Treatment on a Porous Glass

A direct energy conversion technology based on electrokinetic (EK) phenomenon has attracted an increasing attention during recent years. However, an external driving source (e.g. hydrostatic pressure) is needed to produce an EK flow in microchannels. We recently have developed a novel hybrid energy conversion technique using combined principles of EK and forward osmosis (FO) which directly converts the salinity gradient energy into the electric energy without need of external pressure input. In order to further enhance the power generation efficiency of the FO-EK system, an experimental study is conducted on surface treatment of porous glass (PG) that offers microchannels for EK flow to pass through. The results show that, ultrasonic treatment gives rises to more consistent potential difference and streaming current. SDS surface treatment on PG pretreated by ultrasonic can further enhance EK power generation. In particular, PG treated by ultrasonic and SDS 12 mM yields the best power generation performance with a power density of 3.08 W/m 3 , an increment of 27.3 % compared to PG without any surface treatment. In addition, the generated potential difference and streaming current linearly increase with the increasing flow rate. Finally, increasing the flow rate gives rise to higher power density increment.