摘要
[目的]利用浸提试验研究不同粒径组成的砂土中吸附的铵氮存在形态,为了解铵在包气带中的迁移转化提供参考。[方法]首先用不同初始浓度的NH4Cl溶液浸泡采集于某垃圾填埋场背景区的砂土以及从此砂土中筛分出的粗砂和细砂,再用3种不同浸提能力的浸提剂———水、KCl、CaCl2浸提吸附于土样上的不同形态的铵。[结果]不同浸提剂的浸提能力为:水<KCl<CaCl2;当溶液中铵浓度低时,铵优先吸附在矿物的可交换点位,此时铵主要以交换态存在,随着溶液中铵浓度的升高,具备了与矿物内部足够的浓度差驱动力,铵才开始进入2∶1型黏土矿物(如伊利石)内部被固定,成为固定态;在粗砂土样中几乎没有固定态铵,即固定态铵主要存在于具有很强吸附能力的2∶1型黏土矿物中。[结论]砂土中铵的存在形态与土壤矿物组成和铵的初始浓度密切相关。
[Objective] The reference for the migration and transformation of the ammonium was researched through the experiment in its form,which was absorbed in the different sizes of sand.[Method] The sand soil in landfill was collected after it was soaked with the different initial concentrations of NH4Cl solution,then,the different sizes of sand particulars were screened from the sand soil,and finally,the ammonia with different forms in the sands was extracted with three kinds of extractant such as H2O,KCl and CaCl2.[Result] The results showed that the capacity of the extractant was H2OKClCaCl2.While the concentration of ammonia in solution was low,the ammonium preferred to occupy the exchangeable sites of mineral,at which moment,the ammonia was mainly in the exchangeable form.With the increment of the ammonia concentration in solution,which internal was with the sufficient driving force in the difference of the concentration of mineral,the ammonium would start to be fixed in the interlayer of 2：1 type of clay mineral,which was the fixed form.There was no clay-fixed ammonium in coarse sand,which meant the ammonia of fixed form was mainly in 2：1 type of clay mineral,which had strong absorption capacity of ammonium.[Conclusion] The form of ammonium was closely related to the mineral content in sand soil and the initial ammonium concentration.
出处
《安徽农业科学》
CAS
北大核心
2011年第3期1705-1707,1761,共4页
Journal of Anhui Agricultural Sciences
基金
水体污染控制与治理科技重大专项(2009ZX07424-002)
关键词
砂土
浸提
铵氮
Sand soil
Extraction
Ammonium nitrogen
