Preparation Of Sodium Polystyrene Sulfonate Grafted Polysulfone FO Membrane And Its Applications In OsMFCs

Forward Osmosis Membrane and Forward Osmosis technology is a novel water separation technology which has lower costs and less pollution than Reverse Osmosis.It’s promising in many areas like water reuse,food industries,pharmacy purifications and energy industries.The new OsMFCs combined MFCs with FO membrane has been investigated for only 6 years,which enhanced the power generation of MFCs and water purification abilities.However the lack of novel membrane materials hindered its widely applications due to its severe internal concentration polarization（ICP）in the support layer of Forward Osmosis Membranes.Focusing on the severe ICP,a novel TFC membrane was fabricated using chemical grafting method based on suspension polymerization.With the sulfonated group grafted onto PSF molecular chain,the influence of the hydrophilicity of support membranes on its ICP was studied.Then a new Osmotic Microbial Fuel Cell setup was operated using grafted TFC membrane as separator,following by sequences of power generation and water purification tests.As a result,three different molecular weight SPS were successfully grafted onto PSF chain as is proved by the 1040cm^-1 peak in Infrared Spectroscopy and enhanced hydrophilicity of the fabricated support membranes in a Drop Shape Analyzer using Sessile Drop Method.Low molecular weight SPS with MW70000 is proved to be more active in suspension polymerization,result in optimal hydrophilicity with average Water Contact Angle of 55.40^o.And the water flux of TFC membranes fabricated by SPS7w-g-PSF reached a high 17.2LMH with a salt flux merely 4.3gMH under FO mode（Feed:DI water;Draw:0.5M NaCl）.In order to improve its mechanical property,PET meshes were embedded into TFC membranes’support layer.The ultimate mechanical property was reached,with its Elongation at Break of 59.32%,Tensile Strength of38.67N/cm²,which reinforced the foundation of the applications of TFC membrane.In the OsMFCs and MFCs,the power generation of both MFCs and the water purification abilities of OsMFCs were tested,which turn out that TFC membranes especially the grafted membranes possess higher performance over Nafion Proton Exchange Membranes,possibly because of the water flux enhanced the proton flux and the concentrated solution at the surface of TFC membrane active layer lowered the resistance of TFC membranes and the total resistance OsMFCs.Among four different TFC membranes,the SPS7w-g-PSF membranes with a higher FO water flux exhibit highest Current Density 1.06A/m² and Power Density 0.169W/m²,which is twice of MFCs with Nafion PEM as separators.Furthermore,OsMFCs using SPS7w-g-PSF as separator reached a high water flux of 11LMH in semi-continues mode,and the water flux of TFC membranes in FO test using 35g/L NaCl as Draw solution only declined between 11.3%¹2.6%,meanwhile the salt flux was declined too.As the water osmosed from anode cells to cathode cells,Dissolved Oxygen transportation from cathode cells to anode cells was inhibited,which maintained the DO of anode cells under anaerobic circμmstance.