非溶解性有机质对沿岸带土壤铜吸附及老化的影响  

Influence of non-dissolved organic matter on the adsorption and aging of copper in riverbank soil

作　　者：陈凌源 何海霞 赵幼琳 何鸿庆 陈双莉 李文斌 邓红艳 任兆刚 CHEN Lingyuan;HE Haixia;ZHAO Youlin;HE Hongqing;CHEN Shuangli;LI Wenbin;DENG Hongyan;REN Zhaogang(College of Environmental Science and Engineering,China West Normal University,Nanchong 637009,China)

机构地区：[1]西华师范大学环境科学与工程学院,四川南充637009

出　　处：《农业环境科学学报》2021年第8期1696-1706,共11页Journal of Agro-Environment Science

基　　金：四川省教育厅项目(18ZB0576);国家自然科学基金项目(41271244);西华师范大学基本科研业务费资金(17E057,18B023)。

摘　　要：河流沿岸带土壤是阻滞径流污染进入河流水体的最后屏障。为了探索川渝地区常见残渣中非溶解性有机质(NDOM)对流域土壤铜吸附及老化的影响,以嘉陵江(川渝段)内广元、南部、南充和合川沿岸土壤为研究对象,分别将空心莲子草、柠檬果渣和污泥NDOM以10%的比例添加到各沿岸土壤中,研究不同环境条件下NDOM改良土壤对铜的等温吸附,并分析铜在不同NDOM改良土壤中老化特征。结果显示:相比于柠檬果渣和空心莲子草,污泥NDOM改良土壤对Cu^(2+)吸附效果更好。不同NDOM改良土壤对Cu^(2+)的吸附能力与土壤阳离子交换量和比表面积成正比。Langmuir模型比Freundlich模型更适宜描述NDOM改良土壤对Cu^(2+)的吸附过程。温度的升高可以促进Cu^(2+)的吸附,且Cu^(2+)吸附过程是一个自发、吸热和熵增的过程。各NDOM改良土壤对Cu^(2+)的吸附量随离子强度的增大先升高后降低(0.1 mol·L^(-1)时最大),而随pH值的升高持续增加。随着老化时间的增加,各NDOM改良沿岸土中的离子交换态和碳酸盐结合态铜含量降低,而铁锰氧化物结合态和有机结合态铜含量升高。相比原始土壤,各NDOM改良土壤中的Cu^(2+)迁移能力整体降低。残渣中NDOM可以增强河流沿岸土壤对Cu^(2+)吸附能力,土壤温度和pH越高,Cu^(2+)老化时间越长,改良土壤对Cu^(2+)的吸附阻滞效果越好。Riverbank soil is the last barrier blocking runoff pollution into the river water body.To explore the effect of non-dissolved organic matter(NDOM)on copper adsorption and aging in watershed soils,soils along Guangyuan,Nanbu,Nanchong,and Hechuan from the Jialing River(Sichuan-Chongqing section)were chosen as the research object.Alternanthera philoxeroides,lemon pomace,and sludge NDOM were added to the riverbank soils in a 10%ratio to study the isotherm adsorption of copper(Cu^(2+))by NDOM-amended soil under different environmental conditions.The aging characteristics of Cu^(2+) in the different NDOM-amended soil treatments were analyzed.The results showed that:compared with lemon pomace and A.philoxeroides,the sludge NDOM-amended soil exhibited a better adsorption effect on Cu^(2+).The Cu^(2+) adsorption amount on different NDOM-amended soil samples was proportional to the cation exchange capacity and specific surface area of the soil.The Langmuir model was better suited to describing the Cu^(2+)adsorption process on the NDOM-amended soil than the Freundlich model.An increase in temperature promoted Cu^(2+) adsorption,which is a spontaneous,endothermic,and entropy-adding process.The amount of Cu^(2+) adsorbed by each NDOM-amended soil sample first increased and then decreased with an increase in ionic strength(maximum at 0.1 mol·L^(-1)),and continued to increase with an increase in pH.With the increased aging time,the exchangeable and carbonate form Cu^(2+) content in the NDOM-amended soil decreased,whereas the iron-manganese oxide bound form and organic bound form Cu^(2+) content increased.Overall,Cu^(2+) mobility in each NDOM-amended soil sample was lower than that of the original soil.Sludge NDOM enhanced Cu^(2+) adsorption in the riverbank soil.The higher the soil temperature and pH,the longer the Cu^(2+) aging time,and the better the Cu^(2+) adsorption and blocking effect on the NDOM-amended soil.

关 键 词：非溶解性有机质 沿岸土壤 铜 吸附量 老化 

分 类 号：X53[环境科学与工程—环境工程]