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- Philip, JosephYN, et al.
(författare)
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Preparation of molecularly imprinted polymers using anacardic acid monomers derived from cashew nut shell liquid
- 2007
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Ingår i: Journal of Agricultural and Food Chemistry. - : American Chemical Society (ACS). - 0021-8561 .- 1520-5118. ; 55:22, s. 8870-8876
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this work was to use monomers from cashew (Anacardium occidentale L.) nut shells to develop molecularly imprinted polymers. Cashew nut shell liquid (CNSL) is a cheap and renewable agro byproduct consisting of versatile monomers. Solvent-extracted CNSL contains over 80% anacardic acid (AnAc) with more than 90% degree of unsaturation in its C-15 side chain. From AnAc monomer, anacardanyl acrylate (AnAcr) and anacardanyl methacrylate (AnMcr) monomers were synthesized and their chemical structures were characterized by Fourier transform IR and NMR. Different imprinted bulk polymers based on AnAc, AnAcr, and AnMcr functional monomers have been prepared. In the present study, each functional monomer was separately copolymerized in toluene with ethylene glycol dimethacrylate and divinylbenzene as cross-linkers, using racemic propranolol as a model template. While the AnAc based polymer revealed a meager rebinding ability, the imprinted polymers made from AnAcr and AnMcr displayed highly specific propranolol binding. At a polymer concentration of 2 mg/mL, AnAcr and AnMcr based imprinted polymers were able to bind over 50% of trace propranolol (initial concentration 1.2 nM). Under the same condition propranolol uptake by the two nonimprinted control polymers was less than 20%. Chiral recognition properties of these polymers were further confirmed using tritium-labeled (S)-propranolol as a tracer in displacement experiments, suggesting that the apparent affinity of the imprinted chiral sites for the correct enantiomer is at least 10 times that of the mismatched (R)-propranolol. Moreover, cross reactivity studies of these polymers showed that the (S)-imprinted sites have higher cross-reactivity toward (R,S)metoprolol than (R)-propranolol and (R)-timolol.
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- Ye, Guozhu, et al.
(författare)
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Elimination of zinc ferrite for hydrometallurgical recovery of zinc from EAF dust
- 2006
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Ingår i: 2006 TMS Fall Extraction and Processing Division: Sohn International Symposium. - 0873396332 - 9780873396332 ; , s. 397-411
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Konferensbidrag (refereegranskat)abstract
- Hydrometallurgical zinc recovery from EAF dust has several advantages compared to pyrometallurgical alternatives in terms of low temperature operation, lower energy consumption and higher flexibility. Many hydrometallurgical processes have been suggested and tested over the years without success. The main reasons are: - Low leaching yield of zinc due to the fact that a high fraction of ZnO in the EAF dust exists in the zinc ferrite structure which makes selective leaching of ZnO not possible - Many of the proposals could not handle the halide in the EAF dust To eliminate these two disadvantages, two zinc ferrite elimination concepts have been tested and developed in the REZIN project of the EU 5 th Framework Programme. The two concepts for zinc ferrite elimination could be shortly described by the following chemical reactions: A. ZnOFe 2O 3 + 2CaO = Ca 2Fe 2O 5 + ZnO free B. ZnOFe 2O 3 + C = Fe met + CO/CO 2 + ZnO free These two concepts were investigated in details in combination with a subsequent leaching step using the novel EZINC process for recovery of zinc from EAF dust. Leaching of pretreated samples has shown great increases of a zinc recovery yield. A zinc recovery of over 90 % could be reached, as compared to about 50 % for no-pretreated samples. This paper will describe the two concepts in details.
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