Effects of tourmaline on nitrogen removal performance and biofilm structures in the sequencing batch biofilm reactor

The effects of tourmaline on nitrogen removal performance and biofilm structures were comparatively investigated in two identical laboratory-scale sequencing batch biofilm reactors（SBBRs）（denoted SBBR1 and SBBR2） at different nitrogen loading rates（NLRs） varying from（0.24 ± 0.01） to（1.26 ± 0.02） g N/（L·day）. SBBR1 was operated in parallel with SBBR2, but SBBR1 was filled with polyurethane foam loaded tourmaline（TPU） carriers and another（SBBR2） filled with polyurethane foam（PU） carriers. Results obtained from this study showed that the excellent and stable performance of SBBR1 was obtained. Ammonia nitrogen removal and total nitrogen removal were higher in SBBR1 than that in SBBR2 with increase of NLR. At an NLR of（0.24 ± 0.01） g N/（L·day）, the majority of the spherical and elliptical bacteria were surrounded by the extracellular polymeric substance（EPS） and bacillus or filamentous bacteria in two SBBRs biofilms. When NLR increased to（1.26 ± 0.02） g N/（L·day）, the clusters were more obvious in the SBBR1 biofilm than that in the SBBR2 biofilm. Bacteria in SBBR1 were inclined to synthesis more EPS, and the formed EPS could protect the bacteria from free ammonia（FA） under extreme condition NLR（1.26 ± 0.02） g N/（L·day）. The results of polymerase chain reaction-denaturing gradient gel electrophoresis analysis showed that the microbial community similarity in SBBR2 decreased more obviously than that in SBBR1 with the increase of NLR, which the microbial community in SBBR1 was relatively stable.

Three-dimensional porous photo-thermal fiber felt with salt-resistant property for high efficient solar distillation

The urgent need for fresh water resource is a public issue facing the world.Solar distillation for seawater desalination is a promising freshwater production method.Interfacial solar evaporation systems based on 2 D photo-thermal membranes have been widely studied,but salt pollution is one of the main challenges for solar distillation.In order to solve this problem,a hydrophilic three-dimensional(3 D)porous photo-thermal fiber felt(PFF)was obtained by one-step method,through a simple polydopamine(PDA)coating method with hydrophobic graphite felt as a substrate.The PFF had a good evaporation rate of 1.48 kg m^(-2)h^(-1)and its corresponding light-vapor conversion efficiency reached 87.4%.In addition,the PFF exhibited an excellent salt-resistant ability when applied to photo-thermal evaporation of highsalinity seawater with 10 wt%NaCl,owing to its intrinsic 3 D macroporous structure for the migration circulation of salt ions.The development of the PFF offers a new route for the exploration of salt-re sistant photo-thermal materials and is promising for the practical application of solar distillation.