Nordentoftbarnett4856

A complex mechanism involving monovalent cation stimulation of proteins; ionic strength impacts on exopolysaccharides and morphology; solution density influence on sludge density and settling; and tonicity impacts on cell viability and treatment is described.Solvent extraction desalination (SED) is one of the liquid-liquid separation techniques that selectively uptake freshwater from high saline water, and then separate the absorbed freshwater from the solvent through temperature swing. DA-3003-10 This study evaluated the desalination performance of seven different amine solvents. Among these solvents, dipropylamine (DPA) was selected as the best solvent for SED, with higher potential of water recovery and salt removal efficiency in batch screening experiment. A continuous SED process was operated using DPA as the solvent, and its desalination performance, i.e. water recovery and salt removal efficiency, was investigated under varied retention time, mixing intensity, and separation temperature. Increase in mixing time, mixing intensity, and separation temperature led to better efficiency of water recovery. On the other hand, salt removal efficiency tended to depend on the inherent characteristics of the solvent, rather than the operating conditions. When the retention time, mixing intensity, and separation temperature were 30 min, 600 rpm, and 80 °C, respectively, the continuous SED process showed 11.05% of water recovery, and 95.5% of salt removal efficiency. Under these conditions, the total thermal energy consumption was estimated at 5.0-6.9 kW h/m3, which is significantly lower than the evaporation process 14.1-27.3 kW h/m3, and comparable to the membrane process 4.0-6.0 kW h/m3.Geopolymer has received increasing amounts of attention recently due to its potential utilization of industrial and urban wastes. However, the variability of source materials and the complexity of mixture design hinder geopolymer applications derived from various waste streams. There is a need for a practical and quick scanning tool for material evaluation and mixture design optimization. Six types of industrial and urban wastes, two types of reagents, and two curing temperatures were employed in this study to systematically evaluate the feasibility of using isothermal calorimetry to optimize the geopolymer mixture design and predict the three-day strength. Test results show that isothermal calorimetry has the potential to quantify the compositional differences between source materials, identify the different kinetics of geopolymers, and determine the mechanical properties of final products. For the source materials with similar microstructure and fineness, fairly strong correlations between heat and strength could be found with R2 = 0.91 for the NaOH solution and R2 = 0.90 for the composite solution.Pyrolysis is a promising technology for recycling organic materials from waste printed circuit boards (WPCBs). Nevertheless, the generated organic bromides are toxic and urgently needed to be removed. The coexisting copper (Cu) of WPCBs has potential performance on debromination. However, the catalytic effect and mechanism of Cu on pyrolysis process and products were still unclear. To clarify the in-situ catalysis of Cu, the analysis on kinetics and pyrolysis products was performed. The results showed that Cu can change the mechanism function of pyrolysis, which reduced the apparent activation energy (Ea). The mechanism function of Cu-coated WPCBs was obtained by Šesták-Berggren model and expressed as dαdt=1.65×107×1-α-1.30α6.09-ln1-α-6.03exp⁡-202.45KJ/molRT. Product analysis suggested that Cu promoted the conversion of organic bromides to Br2 and HBr. During the process of pyrolysis, bromide atoms interacted with Cu to form coordination compound, which can weaken the strength of C-Br bond and generate bromide free radical (Br*). Besides, Cu can promote the conversion of aromatic-Br to Br2 as the catalyst for Ullmann cross-coupling reaction. Therefore, the presence of Cu was beneficial to pyrolysis. This work provided the theoretical basis for the improvement and application of pyrolysis technology.Treating the organic fraction of municipal solid waste (OFMSW) can be performed by coupling the anaerobic digestion (AD) and partial nitritation-anammox (PN-AMX) processes for organic matter and nitrogen removal, respectively. Besides, an ammonia stripping (AS) step before the AD benefit the removal of organic matter. In the present study, the operation of two PN-AMX sequencing batch reactors with and without AS pre-treated OFMSW digestate (AS-SBR and nAS-SBR, respectively) was assessed. The specific anammox activity decreased by 90 % for increasing proportions of fed OFMSW in both cases, indicating no differences over the anammox activity whether the AS pre-treatment is implemented or not. For 100 % OFMSW proportion, the AS-SBR achieved better effluent quality than the nAS-SBR (127 ± 88 vs. 1050 ± 23 mg N/L) but with lower nitrogen removal rates (58 ± 8 vs. 687 ± 32 g N/(L·d)). Still, the latter required successive re-inoculations to obtain higher removal rates. Changes in the microbial communities were mainly correlated to sCOD/N ratios in the OFMSW, being Candidatus Brocadia the dominant anamnmox species. The results proved the AS to be a suitable pre-treatment, despite the higher sCOD/N ratios in the OFMSW digestate, achieving good synergy between the PN-AMX and heterotrophic denitrification processes.Photo-transformation dominates the fate of graphene oxide (GO) in the environment. However, the photo-transformation mechanisms of GO under different UV bands remain unclear. Our results showed that UV bands played a crucial role in sunlight-induced GO transformation. UVA and UVB induced significant photo-reduction of GO as indicated by decreasing surface O/C ratio, which could be explained by an O2-independent electron-hole pair-mediated mechanism (Mechanism I), and an O2-dependent reactive oxygen species (ROS)-mediated reduction mechanism (Mechanism II). Mechanism II accounted for 62.7 % and 33.3 % of total GO photo-transformation under UVA and UVB, respectively. Different from UVA and UVB, UVC led to GO reduction under anaerobic condition via Mechanism I and Mechanism III (direct decarboxylation). However, under aerobic condition, UVC caused significant oxidation of GO, which was the combined effect of Mechanisms I-III and the oxidation of graphitic structure on GO with the assistance of O2 (Mechanism IV).