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The surface of gold nanorods is chemically charged by ascorbic acid; the charging effect results in not only the blue shift on their surface plasmon bands, but also the change of the deposition rate of silver on their surfaces. The rate was prominently accelerated at room temperature, but slightly slowed down at higher temperature. The shape of gold‐silver core‐shell nanoparticles could not be obviously affected. The Fermi level of gold nanorods begins to increase under the action of charging and alters the electrical double‐layer structure of gold nanorods, resulting in the different deposition rate of silver on gold. [ABSTRACT FROM AUTHOR]

Under the present investigation, removal capacities and influential factors of four heavy metals (HMs) (Cu, Pb, Cr, and Ni) by three wetland vegetations, i.e.Canna indica,Dracaena sanderiana,Cyperus alternifolius, were conducted to assess their feasibility and reliability to collocate into an ecological vegetation-activated sludge process (V-ASP) for HMs contained wastewater treatment. The maximum specific Cu, Pb, Cr, and Ni removal rate ofD. sanderiana,C. indica,C. indica, andC. alternifoliuswas 17.6, 6.39, 19.09, and 7.05 mg/kg WW-d, respectively. Co-existence of organic and nitrogenous pollutants and their content fluctuation affected significantly on Cu, Pb, and Ni removal efficiency, and moderately on Cr removal. A weak alkaline (7.5–8.0) in bulk favored Cu and Pb removal, while a weak acidic (~6.5) was beneficial to Ni elimination. Vegetation roots had a much higher HMs concentration than their stems and leaves, and continuous HMs accumulation within vegetation decreased its photosynthesis rates, and made various morphological changes, although which would be recovered under proper conditions. Evidences of stable HMs removal by proper vegetation collocation give direct guideline for V-ASP configuration, which have profound significance for its practical application. [ABSTRACT FROM PUBLISHER]

A submerged membrane bioreactor (MBR) employed for nitrobenzene-contain water resource treatment was operated for investigation of system effectiveness and for specification of nitrobenzene (NB) removal pathway. Two sludge retention times (2 and 25 d) that regulated biomass content in MBR were adopted to evaluate the importance of activated sludge for NB removal through biodegradation way. From a long-term examination, both of organic biodegradation by activated sludge and rejection by fresh and/or fouled membrane were the major ways to remove organic matters including NB. However, activated sludge played a rather significant role in NB removal. A lengthening solid retention time form 2 to 25 d in MBR resulted in a significantly improvement of removal efficiency in dissolved organic matters, ammonia-N and NB, due mainly to the continuous accumulation of biomass within bulk. Especially, the NB removal efficiency displayed an apparently positive correlation with the biomass content. After sludge acclimation process, the MBR was able to remove NB by a removal rate at 1.266 mg/(gMLSS h), equivalent to the NB removal efficiency up to 80%. In addition, by Fluorescence excitation-emission matrix observation, it was found that biomass growth and accumulation could also impact the effective removal of organic fractions, as that there were obvious selectivity of organic removal by biodegradation of activated sludge. The experimental results obtained herein are very useful to recognize the refractory organics removal pathway in MBR, and to understand the importance of activated sludge. [ABSTRACT FROM PUBLISHER]

A laboratory-scale flat-sheet membrane bioreactor (MBR) was employed to treat real micro-polluted surface water loaded with 2,4,6-trichlorophenol (2,4,6-TCP). MBR treatment performances were evaluated in terms of dissolved organic matters (DOM) degradation, target trace organic (2,4,6-TCP) removal, and effluent bio-stability improvement. The experimental results showed that the removal efficiency of DOM related closely with the biomass content in MBR. With continuous growth and accumulation of biomass under a long sludge retention time (SRT), stable DOM removal efficiency above 50% could be obtained, resulted in an effluent DOM kept below 2.0 mg TOC/L. Upon the steady state of MBR, more than 90% 2,4,6-TCP was removed by synergistic function of aeration volatilization, biological degradation, and activated sludge adsorption. The removal pathways of 2,4,6-TCP were specified by series of batch-scale trials, and corresponding contributions were estimated. It was revealed that fresh ultrafiltration rejection took a major responsible for 2,4,6-TCP removal in the start-up phase, which rejected about 15% 2,4,6-TCP. In comparison, for a steady state where had a high biomass content around 450 mg/L, biodegradation was the main pathway for 2,4,6-TCP removal, reflected by that above 300 μg/L 2,4,6-TCP was eliminated by microorganism degradation within no more than 1.2 h. The results herein claimed that MBR is a feasible way to treat micro-polluted water resource, and its removal pathway specification gave reliable guidance for MBR application. [ABSTRACT FROM PUBLISHER]

Simultaneous nitrogen and phosphorus removal by denitrifying phosphorus accumulating organisms (DPAO) from domestic wastewater with a low C/N was studied in a pilot-scale A2N/BAF process. Through long-term investigation for more than 820 d, it was evidenced that the A2N/BAF performed well on COD,-N and TP removals with efficiencies averaged at 84, 97 and 90%, respectively. Phosphorus removal in the system was mainly attributed to the function of DPAO through the analysis of phosphorus uptake and nitrate consumption, and the relative phosphorus uptake activity of DPAO/PAO was approximately 70.3%. Moreover, the microbial diversity and dominant bacterial community in the A2N/BAF was investigated with high-throughput sequencing. It was revealed that the A2N/BAF sludge had comparatively less diversity than seed sludge and shared several common dominant taxonomic bacteria with seed sludge, while long-term operation also shifted the microbial community. The A2N/BAF system was feasible for the treatment of low C/N wastewaters without any additional carbon source, which gave a new insight for efficient removal of organic and nutrients simultaneously. [ABSTRACT FROM AUTHOR]

The investigation of the mechanisms of plant adaptation to stressor action is one of the leading directions of current biological studies. To understand the mechanism of salt tolerance of seabuckthorn ( Hippophae rhamnoides L.) and identify its ability to cope with the salinity effect in the saline and extremely cold region of Qinghai, China, a test was conducted with two-year-old seedlings subjected to 0, 200, 400 and 600 mmol·L−1 NaCl solutions for 30 d. The results show that with an increase in salinity, the biomass of H. rhamnoides seedlings clearly decreased. Leaf water potential ( Ψw) and relative water content (RWC) were significantly reduced under salinity, with severe water shortages appearing in leaves. At the same time, the total chlorophyll content declined markedly. When salinity increased and stress time prolonged, the net CO2 assimilation rate ( A) significantly declined. Intercellular CO2 concentration ( Ci) declined at first and was then followed by an increase over the stress time. We conclude that H. rhamnoides grown in the extremely cold and saline region of Qinghai has a certain resistance to salt, which can be planted at appropriate salinity levels. [ABSTRACT FROM AUTHOR]