Self-assembled dendrimer polyamide nanofilms with enhanced effective pore area for ion separation.

Membrane technology using well-defined pore structure can achieve high ion purity and recovery. However, fine-tuning the inner pore structure of the separation nanofilm to be uniform and enhance the effective pore area is still challenging. Here, we report dendrimers with different peripheral groups that preferentially self-assemble in aqueous-phase amine solution to facilitate the formation of polyamide nanofilms with a well-defined effective pore range and uniform pore structure. The high permeabilities are maintained by forming asymmetric hollow nanostripe nanofilms, and their well-designed ion effective separation pore ranges show an enhancement, rationalized by molecular simulation. The self-assembled dendrimer polyamide membrane provides Cl-/SO42- selectivity more than 17 times that of its pristine polyamide counterparts, increasing from 167.9 to 2883.0. Furthermore, the designed membranes achieve higher Li purity and Li recovery compared to current state-of-the-art membranes. Such an approach provides a scalable strategy to fine-tune subnanometre structures in ion separation nanofilms.

[Analysis of oxygen atmospheric band in dielectric barrier discharge at atmospheric pressure].

The emission spectra of pure oxygen in dielectric barrier discharge at atmospheric pressure were observed. Comparison between experimental and fitting spectra of oxygen A band (b 1Sigmag(+) --> X 3Sigmag(-)) (0, 0) was used to determine the gas temperature, and the electronic temperature was calculated from O I lines. The causation of oxygen A band in atmospheric dielectric barrier discharge was discussed by means of analysis of producing and quenching approaches. The result showed that the electronic temperature, (11,800+/-400) K, was much higher than the gas temperature, (650+/-20) K. The emission from a 1Deltag or A 3Sigmau(+) was not been observed, but atmospheric band with its resoluble rotational structure was measured.

Experimental and mechanism research of SO(2) removal by cast iron scraps in a magnetically fixed bed.

Sulfur dioxide can be effectively removed by cast iron scraps corrosion process in a DC magnetically fixed bed, and iron sulfate compounds are gained as an available byproduct. At approximate 50 degrees C, when magnetic field intensity was at 15 mT and height of scraps was about 25 mm, the SO(2) removal efficiency can be kept above 80%. As the deposited rusts accumulated, the corrosion rate and desulfurization efficiency gradually decreased. The results show SO(2) removal efficiency depends on corrosion rate, and it can be obviously enhanced by DC magnetic field. With the XRD and SEM research, it can be found that DC magnetic field cannot change the crystal structure of rusts, but can make the surface morphologies on the surface of scraps looser which means easily to be removed. Consequently, the corrosion resistance can be lessened and SO(2) removal efficiency is improved significantly.

Effects of nutrients on Microcystis growth more easily forming bloom.

Different nutrient media experimentally were N, P and Fe-limited conditions and a serial of diluted BG11 media. The cell change of morphology and life history, cell number, cell color and cell area of Microcystis were analyzed quantitatively. First, the effects of nitrogen, phosphorus and iron depletion were distinctively different. Phosphorus and iron depletion caused more special division cells, slowly growth increasing, the easier change of bigger cell area. Second, the nitrogen and iron depletion could make the color of alga from green to brown. Finally, according to the resource competition and Monod equation, Microcystis kinetics of phosphorus and iron were also examined. K(s) and micro(max) of phosphorus absorption were 0.0352 micromol/L, 0.493 d(-1) respectively; iron absorption: 0.00323 micromol/L, 0.483 d(-1). In a word, some evidences of the Microcystis bloom dominance in certain nutrient conditions were indicated in the experiments. The dominances were determined as the reviving under the adverse circumstances through the special division, the various nitrogen resources, and the lower kinetics of phosphorus and iron than that of most of other algae. The conclusions provided the scientific basis for preventing and managing Microcystis bloom in freshwater.