ABSTRACT:The active aromatic polyamide layers of thin film composite nanofiltration (NF-TFC) membranes were prepared via interfacial polymerization (IP) from three different types of polyamine: p-phenylenediamine (PPD), mphenylenediamine (MPD), or piperazine (PRP), and trimesoyl chloride (TMC) on polysulfone/sulfonated polysulfone (PSf/SPSf) alloy substrates. Chemical components, cross section structures, and thermal properties of the polyamide active layers and the bulk membranes, characterized by Fourier transfer IR spectroscopy and attenuated total reflection IR spectroscopy, scanning electron microscopy, and differential scanning calorimetry and thermogravimetry, respectively, revealed an interpenetrating layer between the polyamide active layer and the substrate. A ridge-valley structural active layer was formed on the PSf/SPSf substrate for the NF-TFC membrane with a thick polyacrylamide (PA) layer. Compared with the NF-TFC membranes on PSf substrates, those on PSf/SPSf alloy substrates had a higher permeability without losing the selectivity by introducing the hydrophilic SPSf into the hydrophobic PSf substrates. The binding between the modified substrate and the active PA layer was also improved. Good separation performances using these NF-TFC membranes were obtained in the polyvalent ion separation, the ground water softening, and the treatment of wastewater from adipic acid plants in a wide pH range.
Oxide crystals have been widely used in nonlinear optics (NLO) in the ultraviolet-visible and near-infrared regions.M ost traditional oxide crystals are restricted to the mid-infrared region due to their narrowtransmission window. Hence,a ttempting to extend infrared cutoff wavelength of oxides has attracted muchattention. Herein, we report two new tellurates Li 2 TiTeO 6 (LTT) and Li 2 SnTeO 6 (LST) with broad transparent regions of 0.38-6.72 and 0.38-6.86 mm, respectively,asexcellent candidates for mid-infrared NLO applications. Both LTTa nd LST crystallizei nt he orthorhombic space group Pnn2. The LTTcrystal exhibits intense powder secondorder generation efficiency (26 KDP) under the fundamental wavelength of 1064 nm. First-principles calculations and dipole moments were used to illustrate the results of the powder second-harmonic generations based on the crystal structures. Our results provide an ovel oxide NLO crystal with as trong SHG and wide transparency range.T hey also pave aw ay for the design of new oxide mid-IR NLO crystals.
Catalytic efficiency of two Schiff base manganese(III) complexes toward the hydrolysis of bis(p-nitrophenyl) phosphate (BNPP) was evaluated in a micellar media formed by bis(hexadecyldimethylammonium)hexane bromide (abbr.16-6-16, 2Br -) at 25°C. Effects of various reaction conditions on the hydrolysis of BNPP were systematically investigated. The observations obtained indicate that the two Mn(III) catalysts can efficiently promote hydrolysis of BNPP with a six order of magnitude rate enhancement relative to the background rate constant (k 0 ). Different structures of the two complexes lend to their distinguishing activities each other. Furthermore, rates of BNPP hydrolysis in Gemini 16-6-16 micellar medium are much higher than that in hexadecyltrimethylammonium bromide (CTAB) and nlauroylsarcosine sodium (LSS) micelles.
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