摘要
以大宗农业废弃物玉米秸秆为原料,借助高温焙烧制得了玉米秸秆生物炭,并通过对水中铅镉的吸附实验,考察了高热解温度生物炭的重金属脱除性能。结果显示:800℃焙烧所得玉米秸秆生物炭以块状及棒状形态为主,孔径以微孔居多,灰分中碱金属及碱土金属占比较大;在25℃、pH值4、960 min、Pb^(2+)、Cd^(2+)初始质量浓度分别为429.24和280.34 mg/L时,生物炭对Pb^(2+)和Cd^(2+)最大吸附量分别为94.79和24.47 mg/g;该去除过程满足准二级动力学方程、Freundlich等温线模型,在铅镉初始质量浓度均为150 mg/L时,所得平衡吸附容量可达69.0、24.4 mg/g;热力学分析显示,该去除过程为吸热熵增过程;而共存离子吸附实验显示,铅离子对镉离子存在明显的拮抗作用。高热解温度玉米秸秆生物炭对水中铅镉的去除过程是物理吸附与化学沉淀共同作用的结果。
Biochar was prepared by high-temperature pyrolysis with bulk agricultural waste corn straws as raw material,and the performance of biochar on heavy metal removal was investigated through the adsorption experiments of lead and cadmium in water.The results showed that the corn straw biochar obtained at 800℃was mainly in the form of block and rod,the pore structure was micropores,and the alkali metals and alkaline earth metals in the ash were dominated.The maximum adsorption capacities of Pb^(2+) and Cd^(2+) ere 94.79 and 24.47 mg/g,respectively,when the adsorption temperature was 25℃,pH value was 4,adsorption time was 960 min,and the mass concentrations of Pb^(2+) and Cd^(2+) were 429.24 and 280.34 mg/L.The removal process of lead and cadmium in water by biochar followed the pseudo-second-order kinetic equation and the Freundlich isotherm model.When the initial mass concentrations of lead and cadmium were all 150 mg/L,the obtained equilibrium adsorption capacities were 69.0 and 24.4 mg/g,respectively.Thermodynamic analysis showed that the process belongs to endothermic and entropy increasing.Additionally,Pb^(2+) could significantly antagonize the removal of Cd^(2+) in binary metal ion solution.The adsorption mechanism of corn straw biochar indicated that the removal of both metal ions was the combination of physical adsorption and chemical precipitation.
作者
赵建兵
朱俊波
庄长福
郑志锋
李双庆
李雪梅
ZHAO Jianbing;ZHU Junbo;ZHUANG Changfu;ZHENG Zhifeng;LI Shuangqing;LI Xuemei(National Joint Engineering Research Center for Highly-Efficient Utilization Technology of Forest Biomass Resources,School of Chemical Engineering,Southwest Forestry University,Kunming 650224,China;School of Material Science and Engineering,Southwest Forestry University,Kunming 650224,China;Fujian Engineering and Research Center of Clean and High-Valued Technologies for Biomass,College of Energy,Xiamen University,Xiamen 361102,China)
出处
《生物质化学工程》
CAS
2022年第4期15-24,共10页
Biomass Chemical Engineering
基金
云南省农业联合基金项目(2018FG001-058)
云南省教育厅教师类项目(2018JS332)
国家自然科学基金地区项目(31960296)
西南地区林业生物质资源高效利用国家林业和草原局重点实验室开放项目(2020-KF11)。
关键词
生物炭
重金属
吸附
动力学
热力学
biochar
heavy metals
adsorption
kinetics
thermodynamics