摘要
物理和化学改性方法会引起生物炭理化性质和微观结构的改变,从而影响其对污染物的吸附.通过对玉米粒进行微波膨化制备出膨化生物炭,再用氢氧化钠和磷酸分别对膨化生物炭进行改性制备膨化活性生物炭.利用SEM、BET、FT-IR和XRD等手段对生物炭材料进行表征.通过吸附试验探究了膨化和活化过程对生物炭吸附双酚A(BPA)的影响.结果发现,膨化后炭材料比表面积增大,吸附量增加.膨化结合酸活化的生物炭比表面积最大(856.34 m^(2)·g^(−1)),对双酚A的吸附量也最大(220.73 mg·g^(−1)),吸附量较未经膨化和活化的生物炭提升了7倍.膨化结合碱活化的生物炭孔结构更加发达,平均孔径为6种材料中最大(2.25 nm).Langmuir模型能够较好地拟合6种生物炭对BPA的吸附等温线,说明吸附过程以单层吸附为主.吸附位点能量分析表明,BPA在低浓度时优先占据碳材料表面的高能位点,高浓度时转为占据较低能量的位点.内扩散模型分析说明膨化和活化均能提高扩散过程速率.
The physicochemical properties and microstructure of biochar could be changed by physical and chemical modification,thus affecting the adsorption of pollutants.Puffed biochar was prepared by microwave puffing of corn kernels.Then the puffed biochar was modified with sodium hydroxide or phosphoric acid to prepare puffed activated biochar.The biochars were characterized by SEM,BET,FT-IR and XRD.The effects of puffing and activation processes on the adsorption of bisphenol A(BPA)by biochar were investigated via adsorption experiments.The results showed that the specific surface area(SSA)and the adsorption capacity of the puffed biochar increased.The SSA of puffed biochar combined with acid activation was the largest,reaching 856.34 m^(2)·g^(−1),leading to the highest adsorption capacity of BPA,up to 220.73 mg·g^(−1),which was 7 times higher than that of the biochar derived from raw corn kernels.The pore structure of the puffed biochar combined with alkali activation was more developed and the average pore size is the largest of the six materials(2.25 nm).The adsorption isotherm was fitted better by Langmuir model than Freundlich model,which indicates the adsorption process was mainly monolayer absorption.Based on the site energy distribution analysis,it was found that BPA occupied the high-energy sites at lower concentration,and converted to occupying the low-energy sites at higher concentration.The intra-particle diffusion model shows that the diffusion rate could be increased by both puffing and acid or base modification.
作者
许珈玮
尹梦楠
石林
张凰
XU Jiawei;YIN Mengnan;SHI Lin;ZHANG Huang(Faculty of Environmental Science and Engineering,Kunming University of Science and Technology,Kunming,650500,China;Faculty of Agriculture and Food,Kunming University of Science and Technology,Kunming,650500,China;Yunnan Provincial Key Lab of Soil Carbon Sequestration and Pollution Control,Kunming,650093,China)
出处
《环境化学》
CAS
CSCD
北大核心
2023年第1期253-263,共11页
Environmental Chemistry
基金
国家自然科学基金(42167030)
云南省中青年学术技术带头人后备人才(2018HB008)
云南省万人计划青年拔尖人才(YNWR-QNBJ-2018-336)
云南省土壤科学和生态安全创新团队项目(2019HC008)资助.
关键词
膨化生物炭
酸活化
碱活化
双酚
A
吸附.
puffed biochar
acid activation
base activation
bisphenol A
adsorption.
