| CO2气氛热解与硝酸改性的生物炭Pb2+吸附性能对比 |
| 摘要点击 773 全文点击 243 投稿时间：2023-02-08 修订日期：2023-04-04 |
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| 中文关键词 生物炭 二氧化碳（CO2） HNO3改性 重金属 吸附 矿物 |
| 英文关键词 biochars carbon dioxide（CO2） HNO3-modification heavy metal sorption mineral |
| 作者 | 单位 | E-mail | | 江豪 | 昆明理工大学环境科学与工程学院, 云南省土壤固碳与污染控制重点实验室, 昆明 650092 | 1312608722@qq.com | | 陈瑞芝 | 昆明理工大学环境科学与工程学院, 云南省土壤固碳与污染控制重点实验室, 昆明 650092 | | | 朱自洋 | 昆明理工大学环境科学与工程学院, 云南省土壤固碳与污染控制重点实验室, 昆明 650092 | | | 王琳 | 昆明理工大学环境科学与工程学院, 云南省土壤固碳与污染控制重点实验室, 昆明 650092 | | | 段文焱 | 昆明理工大学环境科学与工程学院, 云南省土壤固碳与污染控制重点实验室, 昆明 650092 | duanwenyan0405@qq.com | | 陈芳媛 | 昆明理工大学环境科学与工程学院, 云南省土壤固碳与污染控制重点实验室, 昆明 650092 | |
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| 中文摘要 |
| 酸改性处理常被用于生物炭的改性过程,但也存在酸消耗量大、废液处理难和成本高等问题.利用热解过程直接改性提高生物炭重金属的去除效果、降低改性成本,是未来实现改性生物炭广泛使用的重要前提.为评估CO2气氛热解法在生物炭制备和应用方面的优势和潜力,对CO2气氛热解与HNO3改性生物炭对Pb2+的去除性能进行对比分析.采用元素分析、傅里叶红外光谱（FTIR）和X射线光电子能谱（XPS）对生物炭的元素组成和结构特性进行表征.结果表明,500℃热解条件下,HNO3改性的生物炭产生了较多的C=O和O=C—O—等羧基类官能团,并引入了—NO2（asy）和—NO2（sym）基团,提高了生物炭的表面活性和络合能力.CO2气氛制备生物炭中含有较多的金属碳酸盐,可通过离子交换和共沉淀作用吸附去除Pb2+.此外,CO2改性生物炭具有较大的比表面积和更优的微孔结构,有利于Pb2+传质扩散,促进表面吸附,W500CO2和W700CO2对Pb2+的吸附容量提升显著,达到60.14 mg·g-1和71.69 mg·g-1.而HNO3改性生物炭W500N2-A和W700N2-A对Pb2+的最大吸附容量较低,分别为42.26 mg·g-1和68.3 mg·g-1.CO2改性生物炭吸附容量优于HNO3改性生物炭,是由于比表面积和官能团的双重作用.因此,CO2气氛直接热解相比于HNO3改性生物炭具有成本低、环境友好和重金属去除效率高等优点,是一种值得推广应用的生物炭改性方法. |
| 英文摘要 |
| Acid modification has been widely used to modify the structural properties of biochars. However, acid modification led to the large consumption of acid, increased difficulty of waste effluent disposal, and a high application cost. To evaluate the advantages and application potential of biochars prepared under CO2, utilizing pyrolysis to directly modify biochars to improve heavy metal removal efficiency and reduce production cost, would be an important prerequisite for the broad application of biochars. The sorption performance of Pb2+ with CO2-modified biochars was compared with that of HNO3-modified biochar. The elemental compositions and structural properties of biochars were characterized through elemental analysis, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The results revealed that for biochars produced at 500℃, HNO3 modification produced abundant carboxylic groups and -NO2 (asy) and -NO2 (sym) groups, promoting the surface activities and complexing abilities of biochars. The CO2-modified biochars contained abundant carbonate minerals, which could remove Pb2+ by electrostatic ion exchange and coprecipitation or complex. In addition, compared to that of HNO3-modified biochars, CO2-modified biochars had the larger specific surface area and better microporous structures, which were beneficial to the diffusion of Pb2+ and further promoted surface sorption. CO2 modification increased the maximum Pb2+ sorption capacity of W500CO2 and W700CO2, which were 60.14 mg·g-1 and 71.69 mg·g-1. By contrast, HNO3-modified biochars W500N2-A and W700N2-A showed the lower Pb2+ sorption capacities, which were 42.26 mg·g-1 and 68.3 mg·g-1, respectively. The increasing of the specific surface area and functional groups simultaneously promoted the sorption capacity of CO2-modified biochars. Consequently, the CO2-modified biochar had the advantages of low cost, environmental friendliness, and high heavy metal removal efficiency, which is a modification method worthy of promotion and application. |
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