Selective and efficient tripodal receptors for competitive solvent extraction and bulk liquid membrane transport of Hg2+.
ABSTRACT A series of tripodal receptors that are different from each other in their end groups were synthesized. The extraction ability and the transport rate of these receptors were evaluated for transition metal ions (Fe(3+), Ni(2+), Cu(2+), Zn(2+) and Hg(2+)). The receptor bearing pyridyl nitrogens extracted Hg(2+) from a buffered aqueous medium containing a mixture of metal ions and transported it into an organic phase with a complete selectivity over the other metal ions. This receptor was effectively used for transporting Hg(2+) from aqueous buffered source phase to aqueous receiving phase through a chloroform membrane.
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Conference Paper: Partial interference subspace rejection in CDMA systems[Show abstract] [Hide abstract]
ABSTRACT: Previously presented interference subspace rejection (ISR) proposed a family of new efficient multiuser detectors for CDMA. We reconsider in this paper the modes of ISR using decision feedback (DF). DF modes share similarities with parallel interference cancellation (PIC) but attempt to cancel interference by nulling rather than subtraction. However like the PIC they are prone to wrong tentative decisions. We propose a modification to DF modes that performs partial ISR instead of complete interference cancellation. When tentative decisions are correct, interference is therefore not perfectly rejected anymore. This drawback is compensated by improved robustness to wrong tentative decisions. We show that in hard handoff systems, partial ISR can only provide negligible performance improvements in high loaded systems outside the region of interest due to out-sector interference. In situations where both in-sector and out-sector interferences are cancelled, as may occur in soft handoff situations, BER performance may improve by more than I dBVehicular Technology Conference, 2001. VTC 2001 Spring. IEEE VTS 53rd; 02/2001
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ABSTRACT: Kinetic study of Cu(II) transport through a soybean oil-based bulk liquid membrane (BLM) containing di-2-ethylhexylphosphoric acid (carrier) and tributylphosphate (phase modifier) diluted in soybean oil (diluent) was conducted. Effects of initial Cu(II) concentration in the feed phase and temperature were investigated and their kinetic parameters were determined from the kinetic models of two consecutive irreversible first-order reactions. Various initial Cu(II) concentrations in the feed phase (50–500mg/L (0.788–7.88mM)) and temperatures (27–43°C) were found not to affect the rate of extraction process significantly, but enhanced the rate of stripping process with decreasing initial Cu(II) concentration in the feed phase and increasing temperature. The rate-controlling steps of both extraction (diffusion-controlled) and stripping (chemical reaction-controlled) processes were determined and a plausible transport mechanism was proposed. The kinetics of Cu(II) transport through soybean oil-based BLM was then compared with that of a similar kerosene-based BLM and their extraction (k1) and stripping (k2) rate constants (soybean oil-based BLM: k1=1.94h−1, k2=0.11h−1; kerosene-based BLM: k1=1.73h−1, k2=0.13h−1) were determined. Application of soybean oil-based BLM in real industrial wastewater was also studied.Chemical Engineering Journal - CHEM ENG J. 01/2011; 173(2):352-360.
- European Journal of Pain Supplements 01/2011; 5(1):135-136.