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Crab Shell (crab + shell)

Distribution by Scientific Domains
Chemistry75%

Selected Abstracts

Effects on the removal of Pb2+ from aqueous solution by crab shell

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 11 2001
Dong Seog Kim
Abstract The effects of temperature, pH, chitin and chitosan on Pb2+ removal by crab shell were investigated. Pb2+ removal by crab shell was greater than that of chitin and chitosan, indicating that chitin did not contribute to Pb2+ removal by crab shell. The quantity and rate of Pb2+ removal increased as the pH value increased. The rate of Pb2+ removal increased with increased temperature, but the maximum amount of Pb2+ removal was constant irrespective of temperature. Metal ions (K+, Na+, Mg2+, Ca2+) were released from crab shell concomitant with Pb2+ removal by ion exchange. The amount of Ca2+ released was greater than any for other metal ions in both Pb2+ and Pb2+ -free solutions. The amount of Ca2+ released in Pb2+ solution was greater than that in Pb2+ -free solution, whereas CO32, release in Pb2+ solution was less than in Pb2+ -free solution. Pb2+ removal was mainly a consequence of dissolution of CaCO3(s) with consequence precipitation of Pb3(CO3)2(OH)2(s) and PbCO3(s). Pb2+ accelerated the dissolution of CaCO3(s) by ion exchange and the precipitation occurred both at the surface and in the inner part of the crab shell. © 2001 Society of Chemical Industry [source]

Modeling chromium (VI) biosorption by acid washed crab shells

AICHE JOURNAL, Issue 4 2007
Catherine Hui Niu
First page of article [source]

Successful removal of p -quinone with chitosan in an aqueous phase in relation to degree of deacetylation

BIOFACTORS, Issue 1-4 2004
Tomoki Takahashi
Abstract Phenol oxidant is successfully removed by using chitosan particles in the aqueous phase. Removal of p -quinone by chitosan from crab shells was investigated kinetically from molecular weight (MW) of chitosan, deacetylation degree (DD) and reaction temperature. The rate constant assuming first-ordered reaction on removal of p -quinone in aqueous phase primarily depended on the MW of chitosan, not on the DD. Quantities of chitosan exceeding 5 × 105 MW are able to obtain a sufficiently high rate constant (10,3 s,1). At higher temperatures, higher rate constants were obtained in the entire experimental MW and DD. The activation energy obtained was 43.8 kJ·mol,1. [source]