摘要
生物炭因具有原料来源广泛、表面活性官能团含量丰富、性质稳定等特点,近年来,在环保领域作为重金属处理吸附剂受到越来越多的重视。使用松木屑在碳化温度为400℃条件下制备生物炭(简称AB400),并使用HNO3、H3PO4、NH3·H2O、Ca(OH)2对生物炭进行改性。借助SEM、FTIR、BET、Boehm滴定法和Zeta电位测定等方法对改性前后AB400表征,并进行Cr(Ⅵ)吸附实验。改性后生物炭结构呈半穿透至穿透状圆形塌陷,存在微孔。酸性改性条件下,HNO3改性生物炭(简称AB400HNO3)、H3PO4改性生物炭(简称AB400H3PO4)中酸性官能团含量均有所升高,且生物炭p H均减小,其对应p Hpzc增大,而碱改性的生物炭则反之。对于Cr(Ⅵ)的吸附,酸性改性生物炭在整体上的吸附效果优于碱性改性生物炭,其中AB400H3PO4吸附效果最佳,吸附容量从58.48 mg/g提高至101.82 mg/g。这是因为碱性改性生物炭表面为负电荷,与Cr(Ⅵ)的含氧阴离子相斥;而AB400HNO3微孔容积较小,圆形塌陷数量甚微,表面虽正电荷,但吸附性能不及AB400H3PO4。
Biochar attracted more and more attention as a processing adsorbent of heavy metals in the field of environmental protection,due to its wide source of raw materials,abundant active functional groups in surface,and stable physical and chemical properties.In this work,pine sawdust was used to synthesize biochar at a carbonization temperature of 400℃(AB400)by using HNO3,H3 PO4,NH3·H2 O,Ca(OH)2 as the modification agent of the biochar.SEM,FTIR,Boehm titration method and Zeta potential determination were adopted to characteriza Biochar AB400.And Cr(Ⅵ)adsorption experiment was conducted.After modification,the structure of biochar appeared semi-penetrating to penetrating round collapse with micropores.Under the conditions of acid modification,the content of intermediate acid functional groups of AB400HNO3 and AB400H3 PO4 increased,and the pH values of biochar decreased,corresponding to the increase in pHpzc value.As for the Cr(Ⅵ)adsorption,the overall adsorption performance of the acid modified biochar was better than that of alkaline modified biochar,and AB400H3 PO4 achieved the best adsorption performance with an adsorption capacity increased from 58.48 mg/g to 101.82 mg/g.This was probably because the surface of alkaline modified biochar was negatively charged and repulsive to the oxygen-containing anions of Cr(Ⅵ).AB400HNO3 had smaller volume of micropores and a smaller number of round collapses than AB400H3 PO4.Although the surface of AB400HNO3 was also positively charged,its adsorption performance was not as good as that of AB400H3 PO4.
作者
赵洁
贺宇宏
张晓明
李琦
杨卫春
ZHAO Jie;HE Yu-hong;ZHANG Xiao-ming;LI Qi;YANG Wei-chun(Chinese National Engineering Research Center for Control&Treatment of Heavy Metal Pollution,School of Metallurgy and Environment,Central South University,Changsha 410083,China)
出处
《环境工程》
CAS
CSCD
北大核心
2020年第6期28-34,共7页
Environmental Engineering
基金
国家重点研发计划项目(2018YFC1802204)。
关键词
生物炭
酸碱改性
Cr(Ⅵ)吸附
biochar
acidic-alkalic modification
Cr(Ⅵ)adsorption
作者简介
第一作者:赵洁(1994-),女,硕士,主要从事重金属废水及土壤的修复治理研究工作。1403831045@qq.com;通信作者:杨卫春(1982-),女,博士,教授,主要从事环境功能材料制备及水污染控制研究。yang220@csu.edu.cn。
