【摘要】 为增强秸秆炭对水体中铬(Ⅵ)的吸附能力,利用FeCl3溶液,把氧化铁引入其孔隙中,通过响应面实验方法优化制备过程。得到最优氧化铁改性秸秆炭(以最优改性炭表示)的制备条件为炭化温度400℃,铁与炭质量比0.85。最优改性炭和未改性炭特性通过元素分析、BET比表面积、扫描电镜、红外光谱和X射线衍射等表征测定,结果表明:最优改性炭表面粗糙,比表面积和孔隙体积增大,孔隙中含有多种氧化铁成分。最优改性炭吸附铬性能表明:Langmuir理论最大铬吸附量为30.96 mg·g-1;吸附过程符合准二级动力学模型;随溶液pH值的增大,铬吸附量减小;随炭用量的增加,铬去除率增大。研究表明:改性秸秆炭的铬(Ⅵ)吸附能力得到显著提升,可用于水体中铬(Ⅵ)的吸附去除,这也为高效利用农作物秸秆提供新途径。更多还原

【Abstract】 To enhance the adsorption capacity of chromium(Ⅵ)from water by wheat straw biochar, FeCl3 solution was used to introduce iron oxide into the biochar pores; the preparation process was optimized using response surface methodology(RSM). A carbonization temperature of 400 ℃ and iron/biochar mass ratio of 0.85 were the optimum conditions for the preparation of iron oxide-modified straw biochar(expressed as optimal modified biochar). The optimal modified biochar and the straw biochar samples were characterized by elemental analysis, BET specific surface area, scanning electron microscopy, infrared spectroscopy, and X-ray diffraction. The surface of the optimal modified biochar was rough, the specific surface area and pore volume increased, and a large amount of iron oxide was introduced into the biochar pores. The chromium adsorption performance results showed that the maximum chromium adsorption capacity was 30.96 mg?g-1,based on Langmuir theory. Kinetic studies showed that a pseudo second-order rate equation fit the experimental data well. Chromium adsorption decreased with an increase in pH. With an increase in straw biochar content, the removal rate of chromium increased. The adsorption ability of wheat straw biochar was significantly improved with iron oxide coating, which can be used for the adsorption removal of Cr(Ⅵ)from water, providing a new way to use crop straw efficiently.更多还原