Parameters Influencing Power Generation in Eco-friendly Microbial Fuel Cells

Pulp and papermaking industries generate high volumes of carbohydrate-rich effluents. Microbial fuel cell(MFC) technology is based on organic materials' consumption and efficient power production. Using a classical two-chamber lab-scale MFC design with an external resistance of2000 W, we investigated the effects of anode chamber biofilm adaptation(ACBA) and cathode chamber redox solutions(CCRS) on the operation efficiency of MFC when treating wastewater. In ACBA studies, biofilm growth activation showed an increase in the power density to 20.48, 35.18, and36.98 mW/m^2 when the acetate feeding concentrations were 3, 6, and 12 g/L,respectively. Improvement by biofilm adhesion on granular activated carbon(GAC) was examined by scanning electron microscopy(SEM). The obtained power density increased to 25.47, 33.42, and 40.39 mW/m^2 when the GAC particles concentrations were 0, 50, and 100 g/L, respectively. The generated power densities were 51.26 and 40.39 mW/m^2 as well as the obtained voltages were 0.41 and 0.72 V when the electrode area increased from 16 to 64 cm^2,respectively. Using the MFC optimized parameters, CCRS studies carried out using five different cathodic redox solutions. The results revealed that the use of manganese dioxide dissolved in hydrochloric acid generated the maximum power density of 112.6 mW/m^2, current density of 0.094 A/m^2, and voltage of1.20 V with a successful organic removal efficiency of 86.0% after 264 h of operation.

Facile Approach for Preparation of Xylan-based Double-network Hydrogels

In this study,xylan-based double-network(DN)hydrogels(xylanbased DN gels)with excellent mechanical properties were prepared using acrylic acid and acrylamide(AM)based on a DN approach.The first layer network was obtained by grafting and crosslinking polyacrylic acid(PAA)molecular chains onto xylan with ammonium persulfate(APS)as the initiator and N,N'-methylenebisacrylamide(MBA)as the crosslinking agent;this network was subsequently immersed into an aqueous AM monomer in the presence of APS and MBA for the preparation of the second layer network.The results showed that the double networks were crosslinked by covalent bonds and that the mechanical properties of the xylan-based DN gels were enhanced.Thus,the xylan-based DN gels exhibited a maximum compression stress of 24.9 MPa.The xylan-based DN gels could also recover 97%of their original height after 15 repeated compression cycles;this indicates that the xylan-based DN gels possessed high resistance to friction and wear.Therefore,the prepared xylan-based DN gels have considerable potential for tissue engineering applications.