Anaerobic co-digestion of thermo-alkaline pretreated microalgae and sewage sludge: Methane potential and microbial community

To improve methane production from sewage sludge(SS),co-digestion of SS and microalgae(MA)was studied and the application of thermo-alkaline pretreatment to MA was evaluated.The results showed that thermo-alkaline pretreatment at 90℃ for 120 min on MA was the optimum pretreatment condition.Furthermore,when the volatile solids(VS)ratio of SS and MA was 1:2,the methane yield reached maximum(368.94 mL/g VS).Fourier transform infrared(FT-IR)and thermogravimetric analysis confirmed the synergetic effects of thermoalkaline pretreated MA on its co-digestion with SS.The analyses of microbial community indicated that Methanobacterium and Methanosarcina were the dominant methanogens during the co-digestion process.However,the relative abundance of Methanosarcina in thermoalkaline pretreated groups was higher compared to unpretreated groups.The microbial community structure might be affected by thermo-alkaline pretreatment rather than by the MA dosage in the co-digestion.

Roles of various Ni species on TiO2 in enhancing photocatalytic H2 evolution

Low-cost nickels can be used as cocatalyst to improve the performance of photocatalysts,which may be promising materials applied in the field of photocatalytic water splitting.In this study,different nickel species Ni,Ni(OH)2,NiO,NiOx,and NiS are used to modified titanium dioxide(P25)to investigate their roles on the photocatalytic hydrogen evolution activities.UV-visible,X-ray diffraction(XRD),Brunner-Emmet-Teller(BET)measurements,transmission electron microscopy(TEM),X-ray photoelectron spectroscopy(XPS)analysis etc.are employed to characterize the physical and chemical properties of catalysts.The results indicate that all the nickel species can improve the photocatalytic hydrogen production activity of P25.The P25 modified with NiOx and NiS has more superior photocatalytic hydrogen evolution activities than those modified with other nickel species.The reason for this is that NiOx and NiS can form p-n junctions with P25 respectively.In addition,NiOx can be selectively deposited on the active sites of P25 via in situ the photodeposition method and NiS is beneficial for H+reacting with photo-excited electrons.