Open AccessA Study on the Removal of Chromium(VI) from Waste Solutions by Adsorption on to Sawdust in Stirred Vessels
Author(s) -
Mahmoud A. Zarraa
Publication year - 1995
Publication title -
adsorption science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.682
H-Index - 36
eISSN - 2048-4038
pISSN - 0263-6174
DOI - 10.1177/026361749501200205
Subject(s) - sawdust , chromium , chemistry , adsorption , freundlich equation , mass transfer , impeller , langmuir , rotational speed , mass transfer coefficient , particle size , nuclear chemistry , chromatography , analytical chemistry (journal) , thermodynamics , organic chemistry , physics , quantum mechanics
The ability of sawdust to adsorb chromium(VI) from waste solutions has been studied in a batch reactor under forced convection conditions. Variables investigated were the rotational speed of the impeller, the initial concentration of chromium(VI) in solution and the weight and particle diameter of the sawdust. Increasing both the rotational speed of the impeller and the initial concentration of chromium(VI) in solution led to an increase in the volumetric mass transfer coefficient (k) according to the relationships k ∝ ω) 0.71 and k ∝ C 0.26 , where ω is the rotational speed of the impeller (rev./min) and C 0 is the initial concentration of chromium(VI) in solution (mg/dm 3 ). On the other hand, the volumetric mass transfer coefficient was found to decrease with increasing particle diameter of sawdust (d p ) according to the relationship k ∝ d p −0.87 . The removal of chromium(VI) was also found to be significantly dependent on the weight of sawdust. Analysis of the equilibrium isotherm data has been undertaken using the Freundlich and Langmuir equations. The maximum adsorption capacity of sawdust for chromium(VI) was found to be 4.44 mg/g.