摘要
作为典型的黑炭,近年来生物炭的应用发展受到人们广泛关注。由于生物炭施加在土壤中,在表生地球化学长期作用下,会有部分逐渐破碎变小,直至微米、纳米级别,在土壤或水体中迁移,因此,对生物炭、特别是活性更强的纳米级生物炭的迁移性研究具有十分重要的意义,而关于纳米级生物炭的迁移性研究目前十分匮乏。通过石英砂柱中纳米生物炭的柱迁移实验,获得天然有机质和不同pH值(4、7、10)条件下的穿透曲线和空间滞留曲线,研究影响作用机制。结果表明:天然有机质(腐殖酸)能增强纳米生物炭的迁移性,中碱性pH环境也有助于其迁移。一方面纳米炭的分散性得到改善,另一方面腐殖酸和碱性环境有助于增加纳米炭和石英砂介质的颗粒表面负电荷,增大Zeta电位值(负值),从而使颗粒间静电排斥力增强,有助于纳米炭的迁移。研究结果对深入理解生物炭在自然界中地球化学迁移行为及其吸附污染物后的潜在迁移风险具有重要意义。
Biochar,a kind of typical black carbon,has attracted attention for its application development in recent years. Since biochar is applied into the soils,some would gradually become fragmented into micro or nano sized biochar particles under the long term supergene geochemical process. It is very important to investigate the transport of biochar,specially,more reactive nanobiochar. Whereas,such research is few up to now. Hence,the column experiments were conducted on the transport of nanobiochar in quartz sand column to explore the breakthrough curve and retention curve. The aim of the present study is to elucidate the mechanism of the effects of natural organic matter( NOM) and different pH values( pH = 4,7,10) on nanobiochar transport behavior.The results showed that humic acid( HA,a model NOM) enhanced the mobility of nanobiochar,and neutral oralkaline aqueous medium favored nanobiochar transport. One reason is that the dispersibility of nanobiochar was improved. The other is due to net negative charge of biochar and quartz particles increased in the presence of HA and alkaline environment. So,the Zeta potential of particles increased and electrostatic repulsion force strengthened,which was beneficial to the transport of nanobiochar. This work is of importance to understand the geochemical transport behavior of nanobiochar and the potential risk of contaminant adsorption onto nanobiochar transported in the environment.
出处
《现代地质》
CAS
CSCD
北大核心
2018年第1期113-120,共8页
Geoscience
基金
国家自然科学基金面上项目(41472232
41272061)
中央高校基本科研业务费项目(2652015113
2652017234)
关键词
纳米生物炭
迁移
柱实验
腐殖酸
环境pH值
nanobiochar
transport
column experiment
humic acid
pH value in the environment
