芦苇生物质炭对镉的吸附及机制

郭琳颖; 王凯男; 王梦寒; 仇祯; 张秋卓

文章摘要

芦苇生物质炭对镉的吸附及机制

Adsorption mechanisms of cadmium onto reed-derived biochar

投稿时间：2018-12-04

DOI：10.13254/j.jare.2018.0347

中文关键词: 芦苇，生物炭，镉，吸附机制

英文关键词: reed, biochar, cadmium, adsorption mechanism

基金项目:崇明生态研究院自由项目（ECNU-IEC-201901）；上海市科委科技基金项目（17295810603，17DZ1202804，18295810400）

作者	单位	E-mail
郭琳颖	华东师范大学生态与环境科学学院, 上海市城市化生态过程与生态恢复重点实验室, 上海 200241
王凯男	华东师范大学生态与环境科学学院, 上海市城市化生态过程与生态恢复重点实验室, 上海 200241
王梦寒	华东师范大学生态与环境科学学院, 上海市城市化生态过程与生态恢复重点实验室, 上海 200241
仇祯	华东师范大学生态与环境科学学院, 上海市城市化生态过程与生态恢复重点实验室, 上海 200241
张秋卓	华东师范大学生态与环境科学学院, 上海市城市化生态过程与生态恢复重点实验室, 上海 200241 崇明生态研究院, 上海 200062	qzhzhang@des.ecnu.edu.cn

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中文摘要:

为解决重金属废水处理问题，寻求芦苇的新型资源化利用途径，采用限氧热解方法在不同温度下制备芦苇生物质炭（RBC）。在对芦苇生物质炭进行元素分析的基础上，进行吸附动力学实验和等温吸附实验，并通过扫描电镜（SEM）、傅立叶变换红外光谱（FTIR）和X射线衍射（XRD）等表征方法，探究不同热解温度对RBC吸附Cd²⁺的影响及吸附机制。结果表明： RBC对Cd²⁺的吸附过程更符合准二级吸附动力学方程，Langmuir等温吸附模型能更好描述RBC对Cd²⁺的吸附；500℃下制备得到的RBC产率较高，Cd²⁺吸附量最大，理论吸附量可达39.05 mg·g^-1；吸附Cd²⁺后，RBC表面生成粒状结构，XRD谱图出现CdCO₃和CdSiO₃晶型的峰，推断Cd²⁺分别能与CO₃^2-与SiO₃^2-形成沉淀。研究表明，芦苇生物质炭的最优热解温度为500℃，此温度下产率最高，对Cd²⁺的吸附能力最强，吸附Cd²⁺的机制可能为阳离子交换、沉淀吸附、络合和Cd²⁺-π金属键合共同作用。

英文摘要:

In order to solve the problem of heavy metal-contaminated wastewater and to find a novel application for reeds, reed-derived biochar(RBC) was synthesized at different pyrolysis temperatures under limited oxygen conditions. Elemental analysis, adsorption kinetics, and isothermal models were used to explore the adsorption mechanism. The effects of different pyrolysis temperatures on the adsorption of Cd²⁺ onto RBC were investigated by SEM-EDS, FTIR, and XRD. The results showed that the adsorption of Cd²⁺ fitted a pseudo-second-order model, but could be better described by Langmuir models. RBC synthesized at 500℃ had a high yield and the largest theoretical Cd²⁺ adsorption capacity, which was as high as 39.05 mg·g^-1. SEM images showed a granular structure on the surface of RBC after adsorption and, according to the XRD spectra, peaks of CdCO₃ and CdSiO₃ crystalline forms appeared. It was, therefore, inferred that Cd²⁺ could precipitate with CO₃^2- and SiO₃^2- respectively. In this study, the adsorption mechanism of Cd²⁺ onto reed biochar was systematically described as the common result of cation exchange, precipitation adsorption, complexation, and Cd-π metal bonding interaction.

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