Inocula selection in microbial fuel cells based on anodic biofilm abundance of Geobacter sulfurreducens

Microbial fuel cells(MFCs)rely on microbial conversion of organic substrates to electricity.The optimal performance depends on the establishment of a microbial community rich in electrogenic bacteria.Usually this microbial community is established from inoculation of the MFC anode chamber with naturally occurring mixed inocula.In this study,the electrochemical performance of MFCs and microbial community evolution were evaluated for three inocula including domestic wastewater(DW),lake sediment(LS)and biogas sludge(BS)with varying substrate loading(L_(sub))and external resistance(R_(ext))on the MFC.The electrogenic bacterium Geobacter sulfurreducens was identified in all inocula and its abundance during MFC operation was positively linked to the MFC performance.The LS inoculated MFCs showed highest abundance(18% ± 1%)of G.sulfurreducens,maximum current density [I_(max)=(690 ± 30)m A·m^(-2)] and coulombic efficiency(CE = 29% ± 1%)with acetate as the substrate.Imaxand CE increased to(1780 ± 30)m A·m^(-2)and 58% ± 1%,respectively,after decreasing the R_(ext) from 1000 Ω to 200 Ω,which also correlated to a higher abundance of G.sulfurreducens(21% ± 0.7%)on the MFC anodic biofilm.The data obtained contribute to understanding the microbial community response to Lsub and R_(ext)for optimizing electricity generation in MFCs.

Lanthanide-doped heterostructured nanocomposites toward advanced optical anti-counterfeiting and information storage

The continuously growing importance of information storage,transmission,and authentication impose many new demands and challenges for modern nano-photonic materials and information storage technologies,both in security and storage capacity.Recently,luminescent lanthanide-doped nanomaterials have drawn much attention in this field because of their photostability,multimodal/multicolor/narrowband emissions,and long luminescence lifetime.Here,we report a multimodal nanocomposite composed of lanthanide-doped upconverting nanoparticle and EuSe semiconductor,which was constructed by utilizing a cation exchange strategy.The nanocomposite can emit blue and white light under 365 and 394 nm excitation,respectively.Meanwhile,the nanocomposites show different colors under 980 nm laser excitation when the content of Tb3+ions is changed in the upconversion nanoparticles.Moreover,the time-gating technology is used to filter the upconversion emission of a long lifetime from Tb3+or Eu3+,and the possibilities for modulating the emission color of the nanocomposites are further expanded.Based on the advantage of multiple tunable luminescence,the nanocomposites are designed as optical modules to load optical information.This work enables multi-dimensional storage of information and provides new insights into the design and fabrication of next-generation storage materials.

Effects of different heating patterns on the decomposition behavior of white pine wood during slow pyrolysis

This study investigated the effect of different heating rates on the pyrolysis behavior of the white pine wood residues.The raw materials were tested via two heating patterns with variable heating rates and compared with three other heating patterns with constant heating rates.The yields and characteristics of products such as char,pyrolysis oil and non-condensable gases under different heating rates were also determined.The gas,liquid,and solid phase yields of the products via heating with decreasing heating rates were similar to the yields obtained from constant heating rate at 2.3℃/min.The pyrolysis process by decreasing heating rates resulted in 30.04% char,44.53% bio-oil,and 25.43% non-condensable gases,which displayed higher char yield and pyrolysis gas than the other heating patterns.The results of thermo-gravimetric analysis showed that variable heating rate significantly changed the weight loss profiles during pyrolysis.It was observed during gas chromatography test that CO and CO_(2) were released earlier than CH_(4) and H_(2).The analysis of the chemical components confirmed that the bio-oil produced by heating process with decreasing rates contains less macromolecular organic matter content than the other patterns.

Effect of exogenous additives on heavy metal passivation and nitrogen retention in pig manure composting

The widespread use of feed additives in intensive and large-scale pig farming has resulted in high levels of heavy metals in pig manure.The long-term application of organic fertilizers containing high levels of heavy metals leads to the accumulation of heavy metals in the soil,which not only causes heavy metal pollution in the soil,and also affect food safety and endanger human health.Composting is an economical and effective technical measures to achieve environmentally-sustainable treatment of pig manure and is a practical method to reduce the problem of heavy metals and to improve the resource value of pig manure.The composting process is accompanied by high temperatures and the production and emission of gases,and also lead to changes in the nitrogen content of the compost and provide opportunity for heavy metal passivation additives.This paper summarizes the forms and types of heavy metals present in pig manure and reviews the progress of research as well as the techniques and problems of in the composting process,and provides recommendations for research on heavy metal passivation and nitrogen retention in pig manure composting.