| 腐殖酸对生物炭去除水中Cr(Ⅵ)的影响机制研究 |
| 摘要点击 2396 全文点击 1364 投稿时间：2012-01-15 修订日期：2012-04-08 |
| 查看HTML全文
查看全文 查看/发表评论 下载PDF阅读器 |
| 中文关键词 生物炭 六价铬 腐殖酸 吸附 还原作用 重金属 污泥 |
| 英文关键词 biochar hexavalent chromium humic acid adsorption reduction heavy metal sludge |
| 作者 | 单位 | E-mail | | 丁文川 | 西南大学资源环境学院,重庆 400715
重庆大学三峡库区生态环境教育部重点实验室, 重庆 400045 | dingwenchuan@cqu.edu.cn | | 田秀美 | 西南大学资源环境学院,重庆 400715
重庆大学三峡库区生态环境教育部重点实验室, 重庆 400045 | | | 王定勇 | 西南大学资源环境学院,重庆 400715 | | | 曾晓岚 | 西南大学资源环境学院,重庆 400715
重庆大学三峡库区生态环境教育部重点实验室, 重庆 400045 | | | 徐茜 | 西南大学资源环境学院,重庆 400715
重庆大学三峡库区生态环境教育部重点实验室, 重庆 400045 | | | 陈健康 | 西南大学资源环境学院,重庆 400715
重庆大学三峡库区生态环境教育部重点实验室, 重庆 400045 | | | 艾小雨 | 西南大学资源环境学院,重庆 400715
重庆大学三峡库区生态环境教育部重点实验室, 重庆 400045 | |
|
| 中文摘要 |
| 以污泥生物炭作吸附剂处理水中Cr(Ⅵ),研究了共存腐殖酸对生物炭吸附性能影响. 结果表明, 腐殖酸能显著促进生物炭对Cr(Ⅵ)的吸附,大幅提高吸附量以及缩短吸附平衡时间,生物炭吸附过程符合准二级动力学模型. 在溶液初始pH 4.0,生物炭浓度20 g·L-1,Cr(Ⅵ)初始浓度在50~800 mg·L-1范围下,Langmuir模型比Freundlich模型更好地描述等温吸附行为. 加入腐殖酸(20 mg·L-1)后拟合得到的理论饱和吸附量达10.10 mg·g-1,较未加入腐殖酸的吸附量5.56 mg·g-1提高近1倍. 在pH 2.0~8.0范围内,吸附量随溶液初始pH值升高而减小. 腐殖酸浓度上升,生物炭吸附能力进一步提高. 红外光谱显示,生物炭表面的羟基、羧基、酯基、芳香环上C—H和环状结构上的C=C等化学活性官能团与Cr(Ⅵ)的吸附有关. 结合XPS分析结果,推断腐殖酸共存促进生物炭吸附的机制是: 腐殖酸提高了Cr(Ⅵ)在生物炭表面聚集浓度,有利于生物炭对Cr(Ⅵ)的直接吸附和还原,而腐殖酸本身具有的吸附能力增加了对溶液中Cr(Ⅵ)和Cr(Ⅲ)的去除. |
| 英文摘要 |
| Biochar derived from excess sludge was used for hexavalent chromium［Cr(Ⅵ)］ removal from water as a sorbent, and impacts of co-existing humic acid on performance of Cr(Ⅵ) sorption onto biochar were studied. The experimental results indicated that humic acid facilitated biochar adsorption of Cr(Ⅵ), which enhanced capacity of Cr sorption and shortened reaction time reaching equilibrium remarkably. The sorption kinetic process could be described with the pseudo second order model. On the condition of initial pH 4.0, biochar concentration 20 g·L-1,initial concentration of Cr(Ⅵ) in the range of 50-800 mg·L-1, the Langmuir model fitted adsorption isotherm better than the Freudlich model. The Langmuir Q0 values of biochar with and without existing humic acid were 10.10 mg·g-1 and 5.56 mg·g-1, respectively. In the pH range of 2.0-8.0, sorption capacity of all sorbents decreased with increasing initial pH value. Ascending concentration of humic acid in solution promoted sorption capacity of biochar. Fourier transform infrared spectroscopy (FTIR) analysis showed that hydroxyl, carboxyl, ester, aromatic C—H stretch and ring C=C on the biochar were responsible for Cr(Ⅵ) sorption. Combined with X-ray photoelectron spectroscopy (XPS) analysis, mechanism of promoting Cr(Ⅵ) sorption onto biochar was speculated that humic acid enhanced concentration of Cr(Ⅵ) ions aggregating on the surface of biochar and benefited Cr(Ⅵ) adsorption coupled with subsequent reduction by biochar functional groups. Meanwhile, humic acid also increased amount of Cr(Ⅵ) and Cr(Ⅲ) removal from aqueous solution. |
|
|
|
