水葫芦促进农田灌溉水中悬浮态镉沉降性能研究  

Enhanced Removal of Suspended Cadmium from Farmland Irrigation Water by Water Hyacinth(Eichhornia crassipes)

作　　者：郑明扬 陈邵柠 宋慧娟[1] 彭亮[1] ZHENG Ming-yang;CHEN Shao-ning;SONG Hui-juan;PENG Liang(College of Resource and Environment,Hunan Agricultural University,Changsha 410128,PRC)

机构地区：[1]湖南农业大学资源环境学院,湖南长沙410128

出　　处：《湖南农业科学》2020年第9期42-46,共5页Hunan Agricultural Sciences

基　　金：国家重点研究发展计划(SQ2017YFNC060064);湖南省教育厅重点项目(18A095)。

摘　　要：基于灌溉水的特点以及镉的形态,利用水葫芦和磷肥协同的方法,以浏阳河湖南农业大学段河水和校内生长水葫芦的池塘水为样本,设置快速絮凝去除悬浮态镉试验,研究水葫芦和磷肥对灌溉水中重金属镉的去除效果及机制。结果显示:水葫芦根系分泌物与磷肥能有效提高水体中镉的去除速率;在根系分泌物存在条件下镉去除速率是河水的12倍;而再添加磷肥至磷浓度为0.15 g/L后镉的去除速率是河水的36倍,仅需2 h即可将40μg/L的镉浓度降低到5μg/L,远低于国家农田灌溉水标准10.0μg/L;通过Zeta电位分析发现,根系分泌物及磷肥都能降低固体悬浮物(SS)电势,并促进SS粒径增大,加速沉降;通过自动电位滴定和物质分析发现,根系分泌物质含有大量的氨基多糖物质,能起到中和SS负电荷和絮凝的作用。研究表明,在待净化区养殖水葫芦,并适当地添加磷肥能快速有效地净化含镉的农田灌溉水。It is vitally meaningful to quickly purify farmland irrigation water containing heavy metals.Based on the characteristics of irrigation water and cadmium phase,a rapid flocculation method of removing suspended cadmium was adopted to study the removal effect and mechanism of heavy metal cadmium in irrigation water by the synergistic action of water hyacinth(Eichhornia crassipes)and phosphate fertilizer.Water samples were from the Liuyang River at Hunan Agricultural University section and from the campus pond where water hyacinth was growing.The results showed that the removal rate of cadmium in irrigation water could be effectively improved by water hyacinth root exudates and phosphate fertilizer.Under the condition that the root exudates were added,the removal rate of cadmium was 12 times that of the control(river water CKH);furthermore,after adding phosphate fertilizer to the concentration of 0.15 g/L,the removal rate of cadmium was 36 times that of CKH,i.e.,it only took 2 hours to reduce the concentration of cadmium from 40μg/L to 5μg/L which was much lower than 10.0μg/L of cadmium content in the national farmland irrigation water standard.The Zeta potential analysis shows that both root exudates and phosphate fertilizer can reduce the electric potential of suspended solid(SS),promote the increase of SS particle size and accelerate settlement.Through automatic potentiometric titration and substance analysis,it is found that the root exudates contain large amounts of glycosaminoglycan that can play the role of flocculation and neutralizing the negative charge of SS.This study shows that after water hyacinth is cultivated in the area waiting for purification,adding proper amount of phosphate fertilizer can quickly and effectively purify the irrigation water containing cadmium.

关 键 词：灌溉水 悬浮态镉 絮凝 水葫芦 重金属 农田 

分 类 号：S555.5[农业科学—作物学]