Synthesis of Biomass-Derived Mesoporous Carbon with Super Adsorption Performance by an Aqueous Cooperative Assemble Route

Exploring the suitable precursors that interact with the surfactant via hydrogen bonding is an important task for the green synthesis of mesoporous carbons (MCs). Boron-doped mesoporous carbon and its derived super adsorbent are synthesized by a reproducible and low-cost hydrothermal method. β-Cyclodextrins and boric acid were employed as the environmentally friendly carbon precursor and dopant, respectively, which give the mesoporous carbon a certain doping amount and super capture ability. This method not only permits the biomass-derived compounds to participate the self-assembly process but also reduces the potential industrial-scale production cost and avoids the employment of hazardous substances. Textural properties, mesostructured morphology, X-ray photoelectron spectroscopic and surface functional groups of products are characterized to describe synthetic mechanism. The obtained B-doped MCs show a developed mesostructure, a finite boron doping (around 2 wt %) and a high specific surface area (∼648.57 m2/g) as well as a considerable improved adsorption performance of methylene blue in a neutral aqueous solution. The product of removing boron showed the highest capture ability and the fastest absorption rate for methylene blue. The introduction of boron play important effects in the adjustments of the surface chemical properties and material structure. The method has great promising application in various fields

Influence of solids retention time on membrane fouling: characterization of extracellular polymeric substances and soluble microbial products

<div><p>The objective of this study was to investigate the influence of solids retention time (SRT) on membrane fouling and the characteristics of biomacromolecules. Four identical laboratory-scale membrane bioreactors (MBRs) were operated with SRTs for 10, 20, 40 and 80 days. The results indicated that membrane fouling occurred faster and more readily under short SRTs. Fouling resistance was the primary source of filtration resistance. The modified fouling index (MFI) results suggested that the more ready fouling at short SRTs could be attributed to higher concentrations of soluble microbial products (SMP). Fourier transform infrared (FTIR) spectra indicated that the SRT had a weak influence on the functional groups of the total extracellular polymeric substances (TEPS) and SMP. However, the MBR under a short SRT had more low-molecular-weight (MW) compounds (<1 kDa) and fewer high-MW compounds (>100 kDa). Aromatic protein and tryptophan protein-like substances were the dominant groups in the TEPS and SMP, respectively.</p></div

Assessing dissolved organic matter in the Johannesburg-Sulfur autotrophic denitrification system using excitation—emission matrix fluorescence spectroscopy with a parallel factor analysis

<p>A novel system integrating Johannesburg (JHB) and sulfur autotrophic denitrification (SAD) process was proposed with the purpose of efficient removal of organic matter and nitrogen when treating low COD/TN ratio municipal wastewater. The characteristics and fate of dissolved organic matter in the Johannesburg-Sulfur autotrophic denitrification (JHB-SAD) system were investigated using excitation–emission matrix fluorescence spectroscopy with a parallel factor analysis. Three components were identified including tryptophan-like (component <i>C</i>₁), tyrosine-like (component <i>C</i>₂), and fulvic-like (component <i>C</i>₃) materials. The tyrosine-like and tryptophan-like materials, which were more abundant than fulvic-like materials, were the dominant components of the raw municipal wastewater in Shenyang North Wastewater Treatment Plant. In the JHB-SAD system, the tyrosine-like and tryptophan-like materials were more efficiently removed than the fulvic-like materials, and the removal efficiencies of the three components were 80.8% (tryptophan-like materials), 72.5% (tyrosine-like materials), and 33.4% (fulvic-like materials), respectively. Furthermore, the removal performance of the three components varied in the different zones of the JHB-SAD system. The tryptophan-like and fulvic-like materials were removed in the pre-anoxic, anaerobic, and aerobic zones. The tyrosine-like materials were mainly degraded in the anoxic and aerobic zones; then, they were released by the bacteria in the SAD reactor. In addition, the tryptophan-like materials had a very significant positive linear correlation with the concentrations of soluble chemical oxygen demand.</p

Bacterial Community Structure in Geographically Distributed Biological Wastewater Treatment Reactors

Current knowledge of the microbial communities within biological wastewater treatment reactors is incomplete due to limitations of traditional culture-based techniques and despite the emergence of recently applied molecular techniques. Here we demonstrate the application of high-density microarrays targeting universal 16S rRNA genes to evaluate microbial community composition in five biological wastewater treatment reactors in China and the United States. Results suggest a surprisingly consistent composition of microbial community structure among all five reactors. All investigated communities contained a core of bacterial phyla (53−82% of 2119 taxa identified) with almost identical compositions (as determined by colinearity analysis). These core species were distributed widely in terms of abundance but their proportions were virtually the same in all samples. Proteobacteria was the largest phylum and Firmicutes, Actinobacteria, Bacteroidetes were the subdominant phyla. The diversity among the samples can be attributed solely to a group of operational taxonomic units (OTUs) that were detected only in specific samples. Typically, these organisms ranked somewhat lower in terms of abundance but a few were present is much higher proportions