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Short Contact Time (short + contact_time)
Selected AbstractsAdsorption of Hg2+ on a novel chelating fiber prepared by preirradiation grafting and aminationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2009Ying Yang Abstract A novel chelating fiber was prepared by the irradiation-induced grafting copolymerization of glycidyl methacrylate on polypropylene fiber and consequent amination with diethylenetriamine. The effects of the reaction conditions, such as reaction time, temperature, and monomer concentration, on the degree of grafting were investigated. The optimal conditions for grafting were found to be 3 h, 100°C, and a 50% (v/v) glycidyl methacrylate concentration in tetrahydrofuran solution. This fiber showed good adsorption performance at different concentrations of Hg2+, in particular for trace Hg2+. Under the adsorption conditions of pH = 4, initial concentration = 1000 mg/L, and time = 20 h, the adsorption capacity of the chelating fiber for Hg2+ reached 785.28 mg/g. It completely adsorbed the Hg2+ ions in solution within a short contact time, showing a very high adsorption rate for Hg2+. Furthermore, the chelating fiber also had a high selectivity for mercury, whereas Cu2+ coexisted in different concentrations. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Millisecond catalytic wall reactors: I. Radiant burnerAICHE JOURNAL, Issue 5 2001J. M. Redenius Short-contact-time reactors have potential for high throughput in reactors much smaller than their traditional counterparts. While they operate adiabatically, heat can be exchanged at short contact time by integrating heat exchange into the reactor. Hot effluent of exothermic reaction systems can be redirected over feed gases to recuperate a portion of the sensible heat. Placing catalyst directly on reactor walls eliminates the resistance to heat transfer in the thermal boundary layer so that heat released by combustion can be effectively coupled to an emitter, such as in a radiant burner. A radiant heater was constructed, operated, and simulated incorporating short contact time, energy recuperation, and a catalytic wall. This burner operated stably for many hours at a firing rate from ,50 to > 160 kW/m2 at a radiant temperature of 950 to 1,150 K at a radiant efficiency of ,60% with a residence time in the reacting zone of ,10 ms. This reactor was modeled using 2-D Navier-Stokes equations including detailed models for chemistry and heat transport. Temperature and compositions predicted agreed well with experimental measurements. [source] Monolithic Ceramic Foams for Ultrafast Photocatalytic Inactivation of BacteriaJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 8 2009Pinggui Wu Palladium-modified nitrogen-doped titanium dioxide (TiON/PdO) foams were synthesized by a sol,gel process on a polyurethane foam template. The TiON/PdO foam was tested for microbial killing using Escherichia coli cells as a target. Under visible-light illumination, the TiON/PdO foam displayed a strong antimicrobial effect on the bacteria cells in water. The antimicrobial effect was found to be dependent on the palladium content and the calcination temperature. In a flow-through dynamic photoreactor, the new photocatalyst efficiently inactivated E. coli within a short contact time (<1 min), the shortest ever reported for the photocatalytic killing of bacteria. The strong antimicrobial functions of the TiON/PdO foam were related to charge trapping by PdO and the high contact efficiency of the foam structure. [source] High Rate Silicification of Peptide-Polymer Assemblies Toward Composite NanotapesMACROMOLECULAR RAPID COMMUNICATIONS, Issue 5 2008Stefanie Kessel Abstract Well-defined silica composite nanofibers are generated in a silicification process of self-assembled poly(ethylene oxide)-peptide nanotapes. Inspired by biological silica morphogenesis processes the nanotapes exhibit strong binding capabilities for silicic acid. Thus, pre-hydrolyzed tetramethoxysilane could be used as silica precursor. Very low concentrations (270 µM) and short contact times (10 s) are sufficient to form effectively integrated nano-composite tapes. [source] | ||||||||||