Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
583980 | Journal of Hazardous Materials | 2008 | 7 Pages |
Abstract
The removal of Cr(VI) from aqueous solution by rice straw, a surplus agricultural byproduct was investigated. The optimal pH was 2.0 and Cr(VI) removal rate increased with decreased Cr(VI) concentration and with increased temperature. Decrease in straw particle size led to an increase in Cr(VI) removal. Equilibrium was achieved in about 48Â h under standard conditions, and Cr(III), which appeared in the solution and remained stable thereafter, indicating that both reduction and adsorption played a part in the Cr(VI) removal. The increase of the solution pH suggested that protons were needed for the Cr(VI) removal. A relatively high level of NO3â notably restrained the reduction of Cr(VI) to Cr(III), while high level of SO42â supported it. The promotion of the tartaric acid modified rice straw (TARS) and the slight inhibition of the esterified rice straw (ERS) on Cr(VI) removal indicated that carboxyl groups present on the biomass played an important role in chromium remediation even though were not fully responsible for it. Isotherm tests showed that equilibrium sorption data were better represented by Langmuir model and the sorption capacity of rice straw was found to be 3.15Â mg/g.
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Authors
Hui Gao, Yunguo Liu, Guangming Zeng, Weihua Xu, Ting Li, Wenbin Xia,