低分子量有机酸对茶园土壤团聚体吸附Cu<sup>2+</sup>的影响

李欣雨; 夏建国; 李琳佳; 宋承远

文章摘要

李欣雨,夏建国,李琳佳,宋承远.低分子量有机酸对茶园土壤团聚体吸附Cu²⁺的影响[J].农业环境科学学报,2017,36(2):272-278.

低分子量有机酸对茶园土壤团聚体吸附Cu²⁺的影响

Cu²⁺ adsorption of tea plantation soil micro-aggregates with low molecular weight organic acids

投稿时间：2016-08-30

DOI：10.11654/jaes.2016-1119

中文关键词: 低分子量有机酸土壤团聚体 Cu²⁺ 吸附

英文关键词: low molecular weight organic acids soil aggregates Cu²⁺ adsorption

基金项目:四川省学术和技术带头人培养基金项目（2014）；四川农业大学学科建设双支计划项目（2016）

作者	单位	E-mail
李欣雨	四川农业大学环境学院, 成都 611130
夏建国	四川农业大学资源学院, 成都 611130	xiajianguo@126.com
李琳佳	四川农业大学资源学院, 成都 611130
宋承远	四川农业大学资源学院, 成都 611130

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中文摘要:

为探讨低分子量有机酸对茶园土壤团聚体吸附Cu²⁺的影响，探明蒙山茶园土壤中铜的环境化学行为，以蒙山茶园土壤为对象，通过超声波分散法、沉降-虹吸法等提取土壤团聚体，采用批实验法研究了低分子量有机酸（柠檬酸、苹果酸、草酸）对土壤团聚体吸附Cu²⁺的影响。结果表明：茶园土壤原土及各粒径土壤团聚体对Cu²⁺的吸附量均随着Cu²⁺浓度的增加而增加，而随低分子量有机酸加入浓度的增加呈现先增加后降低的趋势，受到土壤团聚体比表面积、游离氧化铁、阳离子交换量以及有机质等的影响，吸附量大小顺序为（<0.002 mm）粒径组 > 0.053~0.002 mm粒径组 > 原土 > 2~0.25 mm粒径组 > 0.25~0.053 mm粒径组；应用Langmuir、Freundlich、Temkin三种方程对其等温吸附过程的拟合均达到了显著水平（P<0.05），其中Langmuir方程的拟合效果最佳；低分子量有机酸对土壤吸附Cu²⁺的影响先表现为促进作用，随着加入量的增加转为抑制作用，柠檬酸、苹果酸浓度在0~1 mmol·L^-1，草酸浓度在0~0.1 mmol·L^-1能促进土壤团聚体对Cu²⁺的吸附，而柠檬酸、苹果酸浓度 > 1 mmol·L^-1，草酸浓度 > 0.1 mmol·L^-1时却抑制其吸附，柠檬酸、苹果酸为0.5 mmol·L^-1时吸附量达到最大。综上可知，低分子量有机酸对土壤团聚体吸附Cu²⁺的影响受有机酸种类、浓度及土壤团聚体大小的综合作用。

英文摘要:

The effect of different low molecular weight organic acids(citric, malic, and oxalic acid) on copper(Cu²⁺) adsorption in soil aggregates from a tea plantation in Mengshan was determined. Results indicate that the Cu²⁺ adsorption capacity of regular and of different-sized fractions of soil aggregates increased as Cu²⁺ concentration increased. However, this effect was limited and eventually decreased as the amount of low molecular weight organic acids added went beyond a maximum effective amount. Factors such as surface area, ferric oxide availability, cation exchange capacity, and presence of organic matter influence Cu²⁺ adsorption. Cu²⁺ adsorption is also affected by soil aggregate size wherein adsorption diminished as soil aggregate size increased:(<0.002 mm) > 0.053~0.002 mm > original soil > 2~0.25 mm > 0.25~0.053 mm. The isothermal adsorption process was fitted to three equations, namely, Langmuir, Freundlich, and Temkin. The equations were used to fit, resulting in a significant level(P<0.05), with the Langmuir equation showing the best fit. Low molecular weight organic acids not only have a promoting effect but also an inhibitory effect on Cu²⁺ soil adsorption. Cu²⁺ adsorption is promoted at a concentration of 0~1 mmol·L^-1 for citric acid and malic acid and 0~0.1 mmol·L^-1 for oxalic acid. However, at a concentration of > 1 mmol·L^-1 for citric acid and malic acid and > 0.1 mmol·L^-1 for oxalic acid, Cu²⁺ adsorption is inhibited. Adsorption capacity reached maximum when the concentration of citric acid and malic acid was 0.5 mmol·L^-1. Different organic acids with different concentrations, as well as soil aggregate size, affect the Cu²⁺ adsorption of soil aggregates.

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