3种新型改性玉米秸秆生物炭对Cd~(2+)吸附特性的比较  

Comparison of the cadmium adsorption characteristics of three types of new modified corn straw biochars

作　　者：陈欣洁 叶燕清 杨浙湘 黄兴洲 周曦 张温尔 李荭荭 CHEN Xinjie;YE Yanqing;YANG Zhexiang;HUANG Xingzhou;ZHOU Xi;ZHANG Wener;LI Honghong(School of History and Geography,Minnan Normal University,Zhangzhou 363000;College of Resources and Environment,Fujian Agricultural and Forestry University,Fuzhou 350002)

机构地区：[1]闽南师范大学历史地理学院,漳州363000 [2]福建农林大学资源与环境学院,福州350002

出　　处：《安徽农业大学学报》2023年第6期1006-1012,共7页Journal of Anhui Agricultural University

基　　金：福建省自然科学基金(2021J05200)资助。

摘　　要：为比较3种新型改性生物炭对溶液中镉(Cd)的吸附行为,以玉米秸秆生物炭为原料,制备巯基改性生物炭(S-BC)、铁改性生物炭(Fe-BC)和氮掺杂生物炭(N-BC),分析改性前后生物炭的元素组成、比表面积、表面官能团等性质的变化,通过系统的吸附试验,比较3种改性生物炭对Cd的吸附性能和作用机理。结果表明:与未改性生物炭(BC)相比,N-BC和Fe-BC比表面积分别增加了6.3和9.0倍,总孔体积分别增加了2.68和4.08倍。S-BC因改性后表面光滑,使得生物炭比表面积减小,但其表面官能团变化明显,S-BC在2 977 cm^(-1)处出现新的吸收峰对应脂肪族(C-H)的伸缩振动,而且在1 089 cm^(-1)、1 044 cm^(-1)位置出现双特征吸收峰。3种生物炭对Cd^(2+)的吸附主要为化学吸附过程为主,且Langmuir吸附等温线模型所拟合的热力学吸附优于Freundlich吸附等温模型,推测N-BC、Fe-BC、S-BC 3种生物炭对Cd^(2+)的吸附过程为单分子层物理吸附。通过Langmuir模型计算可以得到几种生物炭对Cd^(2+)最大吸附量表现为Fe-BC (69.11 mg·g^(-1))>N-BC (61.92 mg·g^(-1))>S-BC (53.85 mg·g^(-1))>BC (40.34 mg·g^(-1))。In order to explore the adsorption behavior of Cd2+onto three types of new modified biochars,named as thiol-modified biochar(S-BC),FeSO_(4)/FeCl_(3) modified biochar(Fe-BC)and nitrogen-containing biochar(N-BC),which were prepared from corn straw biochar(BC),the changes in the elemental composition,specific surface area,surface functional groups and microstructure of the biochars before and after the modification were examined.Through laboratory-based adsorption experiments,the adsorption properties and mechanism of the modified biochar for Cd2+were compared.The results showed that compared with the unmodified biochar(BC),the specific surface area of N-BC and Fe-BC was increased by 6.3 and 9.0 times,respectively,and the total pore volume was increased by 2.68 and 4.08 times,respectively.Due to the smooth surface of S-BC,the specific sur-face area of S-BC was at a lower level than that of BC,while its surface functional groups changed significantly.Fourier transform infrared spectroscopy(FTIR)analysis revealed that a new absorption peak of S-BC was found at 2977 cm^(-1),and a double characteristic absorption peak appeared at 1089 cm^(-1) and 1044 cm^(-1).The adsorptive removal of Cd2+by the three modified biochars could be better simulated with the Langmuir adsorption isotherm model than the Freundlich adsorption isotherm model,suggesting a chemisorption process might participated in the Cd2+removal.In addition,Langmuir,the monolayer adsorption model,was better to explain the mechanism of Cd2+removal by the biochars.The maximum adsorption capacity of these biochars to Cd2+was listed in the order:Fe-BC(69.11 mg·g^(-1))>N-BC(61.92 mg·g^(-1))>S-BC(53.85 mg·g^(-1))>BC(40.34 mg·g^(-1)).

关 键 词：巯基改性生物炭 铁改性生物炭 微纳米含氮生物炭 镉 吸附行为 

分 类 号：X703.1[环境科学与工程—环境工程]