Effects of low molecular weight organic acids on aggregation behavior of biochar colloids at acid and neutral conditions
低分子量有机酸对酸性和中性条件下生物炭胶体聚集行为的影响
酸性および中性条件でのバイオ炭コロイドの凝集挙動に及ぼす低分子量有機酸の影響
산성 및 중성 조건에서 바이오 숯 콜로이드의 응집 거동에 대한 저분자량 유기산의 영향
Efectos de los ácidos orgánicos de bajo peso molecular sobre el comportamiento de agregación de coloides de biocarbón en condiciones ácidas y neutras
Effets des acides organiques de faible poids moléculaire sur le comportement d'agrégation des colloïdes de biochar dans des conditions acides et neutres
Влияние низкомолекулярных органических кислот на агрегационное поведение коллоидов биоугля в кислых и нейтральных условиях
Yang Wang 王洋 ¹, Changxi Wang ¹, Jiayi Xiong ¹, Qianru Zhang 张倩茹 ², Jianying Shang 商建英 ¹
¹ College of Land Science and Technology, China Agricultural University, Key Laboratory of Plant-Soil Interactions, Ministry of Education, Key Laboratory of Arable Land Conservation (North China), Ministry of Agriculture, Beijing, 100193, China
中国 北京 中国农业大学土地科学与技术学院 植物-土壤相互作用教育部重点实验室 农业部华北都市农业重点实验室
² Key Laboratory of Nonpoint Source Pollution Control, Ministry of Agriculture and Rural Affairs, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China
中国 北京 中国农业科学院农业资源与农业区划研究所 农业农村部面源污染控制重点实验室
Low molecular weight organic acids (LMWOAs), as active components in the rhizosphere carbon cycling, may influence the environmental behaviors of biochar colloids. This study selected the pine-wood and wheat-straw biochars (PB and WB) as two typical biochars.
The effects of typical LMWOAs (oxalic acid, citric acid, and malic acid) on aggregation kinetics of PB and WB colloids were investigated under pH 4 and 6 conditions. Critical coagulation concentrations (CCCs) of both PB and WB colloids were decreased with the LMWOAs regardless of the types of biochar and the solution pH, and the most significant effect occurred in pH 4 due to more LMWOAs sorption on the biochar colloids. The different types of LMWOAs caused various CCCs changes. For example, the CCC values of PB colloids decreased from 75 mM to 56, 52, and 47 mM in the pH 4 NaCl solutions when 1 mM oxalic acid, citric acid, and malic acid were present in the suspensions, respectively.
The chemical structure (functional groups) and molecular weight of LMWOAs, solution pH, and the electrophoretic mobility (EPM) of biochar co-influence the interactions between biochar colloids and LMWOAs, thus affecting the stability of biochar colloids in the presence of LMWOAs. The presence of LMWOAs accelerated the aggregation of colloidal biochar by increasing the interaction of surface bridging bonds (hydrogen bonding) and decreasing the repulsive force between colloidal biochar particles.
This study showed that LMWOAs could accelerate the aggregation of biochar colloids in acidic or neutral environments and reduce the mobility of biochar colloids in soil rhizosphere.
