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| The properties and mechanism of Cu2+ and Zn2+ sorption by MnOx-loaded biochar |
| Received:December 07, 2017 |
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| KeyWord:modified biochar;potassium permanganate;Cu;Zn;sorption mechanism |
| Author Name | Affiliation | E-mail | | LU Man-man | School of Resources and Environmental Engineering, Anhui University, Heifei 230601, China | | | MA Jie-cheng | School of Resources and Environmental Engineering, Anhui University, Heifei 230601, China | | | ZHANG Xue-sheng | School of Resources and Environmental Engineering, Anhui University, Heifei 230601, China | | | LI Yu-cheng | School of Resources and Environmental Engineering, Anhui University, Heifei 230601, China | | | WANG Ning | School of Resources and Environmental Engineering, Anhui University, Heifei 230601, China | ningwang0001@163.com |
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| Abstract: |
| Biochar has a large surface and may be used to adsorb heavy metals from aqueous solution. In this study, the properties and mechanism of Cu2+ and Zn2+ sorption from aqueous solution by MRBC (MnOx-loaded rice-straw-derived biochar) was investigated. Rice straw was used to produce biochar at a pyrolysis temperature of 600℃ for 3 h. In order to increase the Cu2+ and Zn2+ sorption capacity of the biochar derived from rice straw, MnOx-loaded biochar was prepared using raw biochar modified with potassium permanganate (KMnO4). In this work, the characteristics and mechanism of Cu2+ and Zn2+ sorption by 50% MRBC was studied. Batch sorption experiments showed that contact time, initial concentrations of Cu2+ and Zn2+, modified biochar dosage, and initial solution pH affected the removal of the heavy metals. The biochars before and after sorption were characterized using Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Results suggested that with an increase of KMnO4 concentrations, the MnOx-loaded biochar showed a better removal effect of Cu2+ and Zn2+, which could be attributed to the increase in sorption sites on the surface of the MnOx-loaded biochar owing to the presence of manganese oxides. The sorption kinetics fit the pseudo-second-order kinetics model, and sorption equilibrium was reached after 240 min. The sorption isotherm conformed to the Langmuir model, and the maximum sorption capacities of copper and zinc were 107.53 and 96.15 mg·g-1, respectively. The sorption mechanism was speculated as follows:(1) surface complexation between oxygen-containing functional groups and heavy metal ions, (2) the cationic-π effect of metal ions and π electrons, and (3) the mineral crystals formed by inorganic mineral elements exchange ions with metal ions in aqueous solutions. |
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