摘要
针对农田受重金属污染严重的现状,设计了利用水生植物净化灌溉水中镉的综合性实验。实验内容包括净化实验的设置、水体悬浮物等基本指标测定、水体镉测定、植物样品消解、原子吸收分光光度计使用等。实验结果表明,水生植物能显著强化灌溉水中镉和悬浮物的去除,水葫芦、苦草和黑藻对镉的去除率高达90%以上,其中苦草和黑藻对镉具有较强的吸收积累能力。该教学实验内容与现实环境问题相结合,具有综合性、研究性和应用性特点,有助于培养学生综合运用专业知识解决实际问题的能力,同时激发他们的实验学习兴趣,提高实践能力。
[Objective]The farmland in China is seriously polluted by heavy metals,and irrigation water is one of the main input ways of heavy metals.The purification of irrigation water is a key link for alleviating cadmium pollution in farmland and guaranteeing the quality of agricultural products.In view of this severe situation,a comprehensive experiment of cadmium removal from irrigation water using aquatic plants was designed to screen aquatic plants with excellent purification ability toward cadmium-contaminated irrigation water and further provide the preferred experimental materials and solutions for water purification.[Methods]The dried sediment was mixed with river water,and then a cadmium solution was added to reach the final concentration of 1.0 mg/L for preparing the cadmium-contaminated irrigation water.The gathered living aquatic plants were washed,particularly at the roots,and placed into a tank containing the prepared irrigation water.Liquid water samples were taken at time intervals from the central of the tank at 1/2 depth for analyzing the cadmium and suspended substance concentrations to evaluate the purification performance of different aquatic plants.After the purification process,the aquatic plants were collected,washed,dried,crushed,and digested to analyze the accumulated cadmium content.The experiment includes the identification and gathering of aquatic plants,the experimental setup,the determination of the suspended substance and other regular water-quality indexes,the determination of cadmium concentration,the digestion of plant samples,and the use of an atomic absorption spectrophotometer.[Results]The results showed that aquatic plants promoted the removal of suspended substances from irrigation water significantly.The removal process fitted the pseudo-second-order kinetic model with the correlation coefficient R2>0.999 for all tested plants.The highest removal rate for suspended substances was observed at 96.6%for Hydrilla verticillata(L.f.)Royle.Other plants also significantly enhanced the removal of cadmium from irrigation water.Higher cadmium removal rates from irrigation water were observed with the addition of Eichhornia crassipes(Mart.)Solms(98.57%),Vallisneria natans(Lour.)H.Hara(98.16%),and H.verticillata(L.f.)Royle(91.85%).The cadmium removal process in irrigation water also fitted the pseudo-second-order kinetic model well with the correlation coefficient R2>0.999 or even up to 1.000 for all tested plants.Moreover,V.natans(Lour.)H.Hara and H.verticillata(L.f.)Royle showed good accumulation capacity for cadmium,with the cadmium content accumulated up to 513 and 444 mg/kg,respectively.[Conclusions]Aquatic plants with excellent cadmium removal ability from irrigation water were successfully screened in this experiment.In the practical application process,factors including the ability of the aquatic plants to accumulate cadmium and promote its precipitation,the biomass of the aquatic plants,and the further treatment of the accumulated cadmium or deposited cadmium should be all taken into account comprehensively for selecting suitable aquatic plants or their collocations to obtain satisfied purification effects for irrigation water.This teaching experiment is combined with current and realistic environmental problems,which reflects the comprehensiveness,research-oriented approach,and practicality of the content.This experiment is not only beneficial for cultivating the students’ability to comprehensively use professional knowledge to solve practical problems,but also stimulating their interest in experimental learning and promoting practical skills.
作者
尚翠
周细红
胡方凡
彭亮
陈安伟
SHANG Cui;ZHOU Xihong;HU Fangfan;PENG Liang;CHEN Anwei(College of Environment&Ecology,Hunan Agricultural University,Changsha 410128,China;Practical Teaching Center of Resource and Environment,Hunan Province,Changsha 410128,China)
出处
《实验技术与管理》
CAS
北大核心
2024年第11期95-99,共5页
Experimental Technology and Management
基金
湖南省普通高等学校教学改革研究项目(202401000674)。
关键词
综合实验
镉
灌溉水
水生植物
修复
comprehensive experiment
cadmium
irrigation water
aquatic plants
remediation
作者简介
尚翠(1988-),女,湖北襄阳,硕士,实验师,研究方向为本科实验教学与管理、环境污染物检测与修复治理,C.Shang@hunau.edu.cn。;通信作者:陈安伟(1987-),男,湖南衡阳,博士,教授,研究方向为环境污染修复与生态毒理,A.Chen@hunau.edu.cn。
