浒苔生物炭的特征及其对Cr(Ⅵ)的吸附特点和吸附机制  

Characteristics of Enteromorpha prolifera Biochars and Their Adsorption Performance and Mechanisms for Cr(Ⅵ)

作　　者：陈友媛[1,2] 惠红霞[1] 卢爽[1] 王报英 王志婕 王楠 

机构地区：[1]中国海洋大学环境科学与工程学院,青岛266100 [2]中国海洋大学海洋环境与生态教育部重点实验室,山东省海洋环境地质工程重点实验室,青岛266100

出　　处：《环境科学》2017年第9期3953-3961,共9页Environmental Science

基　　金：青岛市政府采购项目(T-20150205-018)

摘　　要：为使浒苔得到资源化利用,本研究采用慢速热解技术于不同温度下制备浒苔生物炭,并对其理化性质进行表征.结果表明,400℃时,浒苔裂解已达较高程度.浒苔生物炭产率及灰分含量与热解温度呈负相关,碳含量与热解温度呈正相关,其表面呈蜂窝状多孔结构,比表面积为44.54~317.82 m^2·g^(-1),表面含有丰富的羟基(—OH)和羧基(—COOH)等含氧官能团.吸附实验显示,浒苔生物炭对Cr(Ⅵ)的吸附符合准二级动力学方程和Langmuir等温吸附模型.表明浒苔生物炭对Cr(Ⅵ)的吸附为单分子层化学吸附,主要受快速反应过程控制.浒苔生物炭吸附Cr(Ⅵ)的最适p H为2,吸附容量表现为BC400>BC700>BC600>BC500>BC300,其中BC400的吸附量为4.79 mg·g^(-1).浒苔生物炭对Cr(Ⅵ)的吸附机制主要包括生物炭与HCr O-4和Cr2O_2-7等阴离子之间的静电作用,以及生物炭表面—OH和—COOH等含氧官能团的络合作用.This study aims to understand the recycling process of Enteromorpha prolifera by using the slow pyrolysis technology to prepare biochars under different temperatures and by characterizing the physicochemical properties of biochars. The results showed that a relatively high level pyrolysis of Enteromorpha prolifera could be reached when the temperature was up to 400℃. The yield rate and the ash content of biochars were negatively correlated with the pyrolysis temperature,while the carbon content was positively correlated.The specific surface area of Enteromorpha prolifera biochars was in the range of 44. 54-317. 82 m^2·g^-1. The biochar surface was in the shape of a honeycomb and rich in oxygen-containing functional groups,such as hydroxyl（ —OH） and carboxyl（ —COOH） groups.The adsorption experiments revealed that the adsorption of Cr（ Ⅵ） onto Enteromorpha prolifera biochars followed the pseudo-secondorder kinetics equation and Langmuir isotherm,indicating that the adsorption process was controlled by the fast reaction process and governed by monomolecular and chemical adsorption. The optimal p H for Cr（ Ⅵ） adsorption onto Enteromorpha prolifera biochars was2 and their adsorption capabilities were in the order of BC400 〉BC700〉 BC600〉 BC500 〉BC300（ the adsorption capacity of BC400 was 4. 79 mg·g^-1）. The adsorption mechanism included the electrostatic interactions between biochar and anions（ HCr O4^- and Cr2O7^2-） and the complexation of oxygen-containing functional groups.

关 键 词：浒苔 生物炭 吸附 Cr(Ⅵ) 机制 

分 类 号：X131[环境科学与工程—环境科学]