科研之友
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摘要
In this study, four types of biomasses originating in loess areas (flax straw, rape straw, flaxseed tailing and rapeseed tailing) were collected and converted into biochars through pyrolysis. The biomasses pyrolyzed from flax straw at 600 degrees C (FS600), rape straw at 600 degrees C (RS600), flaxseed tailing at 400 degrees C (FT400) and rapeseed tailing at 400 degrees C (RT400) were selected and characterized. The adsorptive performance of Cr(VI) onto the four types of biochars was investigated using the batch equilibrium method. The effects of solution pH, temperature, contact time, and initial Cr(VI) concentration on Cr(VI) adsorption were tested. The results showed that Cr(VI) adsorption by the biochars was highly pH-dependent, and the Cr(VI) adsorption capacity decreased with increasing pH values. The adsorption kinetics followed the pseudo-second-order equation. The adsorption data were well described by the Langmuir isotherm. The maximum adsorptive capacities of Cr(VI) were 26.7, 30.8, 33.0 and 29.2 mg/g by FS600, RS600, FT400 and RT400, respectively. The adsorptive capacity increased with increasing temperature, indicating that the adsorption processes were mostly endothermic chemical processes. According to FTIR, the differences in the surface structures and functional groups from before and after Cr(VI) adsorption showed that the mechanisms of Cr(VI) adsorption onto the biochars primarily included chemical bonding and electrostatic attraction.
- 出版日期2016
- 单位兰州交通大学
