摘要
生物炭由于其富碳特性、高比表面积及强吸附特性而被广泛使用,其产生的微纳米颗粒对水环境中的养分元素和污染物行为具有重要影响,然而目前表面改性对生物炭纳米颗粒表面性质、悬液稳定性和迁移特性的影响尚不清楚。该文以苹果枝条为原料,通过浸渍法制备钾改性苹果枝条生物炭,采用球磨+高速离心法得到苹果枝条纳米生物炭(AB-NP)和钾改性苹果枝条纳米生物炭(KAB-NP)。首先对2种纳米生物炭进行性质表征,进而利用动态光散射仪测定其在常见电解质溶液中的悬液稳定性,最后采用石英砂柱法对比其迁移特征。结果表明,AB-NP和KAB-NP均为多孔结构,KAB-NP的芳香性、微孔面积和孔径变小,氧含量、亲水性、极性、比表面积、外表面积和zeta电位均增大。KAB-NP在NaCl和CaCl_(2)溶液中的临界聚沉浓度均大于AB-NP,在相同pH条件下,由于Ca^(2+)压缩双电子层的能力强于Na^(+),使Ca^(2+)溶液条件下的临界聚沉浓度更小;在同一种背景电解质溶液中,随着pH的增大,由于2种纳米生物炭表面具有更多的负电荷,使临界聚沉浓度增大。颗粒相互作用能计算表明,钾改性使得苹果枝条纳米颗粒的引力势能大幅降低而排斥势垒增加,因此其分散性更强。AB-NP的迁移率随着溶液浓度增大而降低,在相同背景电解质溶液条件下,AB-NP的迁移率随着pH的增大而增大,而KAB-NP的迁移率更低。研究结果可为精确评估生物炭胶体的环境行为提供科学依据。
Biochar is widely applied due to its high carbon content,large specific surface area,and strong adsorption proper⁃ties,and the micro-nanoparticles produced from it have a significant impact on the behavior of nutrient elements and pollut⁃ants in aquatic environments;however,it is yet unclear as to the effects of surface modification on the surface properties,suspension stability,and migration characteristics of biochar nanoparticles(NP).In this study,apple branches(AB)as raw materials were used to prepare potassium(KAB)-modified biochar by means of impregnation,and ball milling plus highspeed centrifugation to obtain apple branch biochar nanoparticle(AB-NP)and potassium-modified apple branch biochar nanoparticle(KAB-NP),and at first these two types of biochar NPs were characterized by modern analytical techniques,then their suspension stability in common electrolyte solutions was determined using dynamic light scattering apparatus,and finally their(AB-NP,KAB-NP)transportation characteristics were compared by the quartz sand column method.As a result,the study indicates that both of AB-NP and KAB-NP have porous structures,and as for KAB-NP,its aromaticity,microporous area and pore size become smaller,while its oxygen content,hydrophilicity,polarity,specific surface area,external surface area,and zeta potential increase;when KAB-NP being in both NaCl and CaCl_(2)solutions,its critical coagulation concentra⁃tions were larger than those of AB-NP,and at the same pH condition,CCC(critical coagulation concentration)becomes small⁃er in Ca^(2+)solution due to the stronger ability of Ca^(2+)that compresses the double electron layer than Na^(+);under same one back⁃ground,in the electrolyte solution,as the value of pH increased,the CCC increased due to more negative charges on the sur⁃face of both AB-NP and KAB-NP.Besides,the calculations regarding the particle interaction energy show that potassium modification enables the apple branch NPs become more dispersible as the van der Waals attractive potential energy decreases dramatically while the repulsive potential barrier increases.The mobility of AB-NP decreased with increasing solution con⁃centration;and in same background electrolyte solution,the mobility of AB-NP increases with an increase of pH value,while the mobility of KAB-NP becomes even lower.Consequently,the results drawn from the study could be used as a basis for ac⁃curate assessment of the environmental behavior of biochar colloids.
作者
唐尧
闫雨阳
杨琼芳
耿增超
杜伟
胡斐南
许晨阳
TANG Yao;YAN Yuyang;YANG Qiongfang;GENG Zengchao;DU Wei;HU Feinan;XU Chenyang(College of Natural Resources and Environment,Northwest A&F University,Yangling 712100,China;Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China,Ministry of Agriculture and Rural Affairs,Northwest A&F University,Yangling 712100,China;State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau,Northwest A&F University,Yangling 712100,China;Institute of Soil and Water Conservation,Chinese Academy of Sciences&Ministry of Water Resources,Yangling 712100,China)
出处
《环境科学与技术》
北大核心
2025年第8期115-125,共11页
Environmental Science & Technology
基金
陕西省自然科学基金面上项目(2023-JC-YB-263)
国家自然科学基金面上项目(42277311)。
关键词
纳米生物炭
改性生物炭
胶体稳定性
迁移
临界聚沉浓度
biochar nanoparticles
modified biochar
colloid stability
transport
critical coagulation concentration
