本文主要研究内容
作者赵立芳(2019)在《腐植酸、水铁矿及其共沉物对土壤镉的钝化效果研究》一文中研究指出:随着工农业的快速发展,土壤重金属污染已成为全球性的环境问题,原位钝化修复是目前最具有应用潜力的重金属污染农田土壤修复技术之一。腐植酸和水铁矿广泛存在于土壤环境中,两者可以通过吸附、共沉淀、絮凝和螯合等作用形成具有更高表面活性和氧化还原能力的共沉物,该共沉物在调控土壤重金属迁移和转化中起着重要作用。因此,探究腐植酸、水铁矿及其共沉物对农田土壤中重金属的固定作用对我国农产品安全和人体健康具有重要意义。本文以甘肃省白银市靖远县高湾乡农田土壤为研究对象,通过土培实验模拟不同浓度的Cd污染土壤;同时,通过共沉淀法合成了水铁矿和不同C/Fe比的水铁矿-腐植酸共沉物(碳铁共沉物),采用FTIR、SEM-EDS、XRD和N2吸脱附实验对腐植酸、水铁矿及其共沉物的官能团结构、表面形貌、结晶程度和比表面积进行分析,并采用改进BCR连续提取法研究腐植酸、水铁矿及其共沉物添加后土壤Cd形态随时间的变化。主要结论如下:(1)碳铁共沉物主要通过腐植酸上的羧基与水铁矿表面的羟基发生配位交换而结合,共沉淀下来的腐植酸未改变水铁矿原有的晶体结构,改变了水铁矿的表面形貌和结构性质。随着C/Fe比增加,颗粒表面凹凸程度增加,孔径增大,比表面积和孔容减小。(2)外源性Cd进入土壤后,改变了原状土壤中Cd的赋存形态,增加了土壤中Cd的活性和迁移性。原状土壤中Cd赋存形态的分配关系为:弱酸可溶态>残渣态>可还原态>可氧化态。添加外源性Cd后,土壤中Cd赋存形态的分配关系为:弱酸可溶态>可还原态>残渣态>可氧化态。随着外源性Cd含量的增加,土壤中非残渣态Cd所占比例逐渐增加,残渣态Cd所占比例逐渐降低。(3)Cd污染土壤中单独添加5%的腐植酸、水铁矿15 d、30 d和60 d后,均促使土壤中弱酸可溶态Cd向可还原态和残渣态转化,从而降低了土壤中Cd的活性和迁移性。当添加时间为30 d时,土壤中残渣态Cd所占比例最大,钝化效果最佳。此时,通过对比发现,腐植酸对轻微Cd污染土壤的修复效果较佳,使轻微Cd污染土壤中残渣态Cd含量比对照组增加24.81%;水铁矿对中度、重度Cd污染土壤的修复效果较佳,使中度、重度Cd污染土壤中残渣态Cd含量分别比对照组增加23.64%和41.69%。(4)5%的碳铁共沉物添加至Cd污染土壤15 d、30 d和60 d后,改变了土壤中Cd的赋存形态。当钝化时间为15 d和30 d时,碳铁共沉物的添加使容易被植物吸收的弱酸可溶态转化为植物难以吸收的可还原态和残渣态;当钝化时间为60 d时,碳铁共沉物的添加使容易被植物吸收的弱酸可溶态转化为植物难以吸收的可还原态、可氧化态和残渣态,从而有效地降低了土壤中Cd的活性和迁移性。(5)碳铁比为0.5、1.0、1.5、2.0和2.5的共沉物中,C/Fe=2.0的共沉物钝化效果最佳,轻微、中度Cd污染土壤在15 d时的钝化效果最佳,而重度Cd污染土壤在30 d时的钝化效果最佳。此时,轻微、中度和重度Cd污染土壤中残渣态Cd含量比对照组分别增加30.34%、37.86%和54.54%。(6)对比腐植酸、水铁矿及其共沉物(C/Fe=2.0)在其最佳钝化时间下对不同浓度Cd污染土壤的钝化效果,发现轻微Cd污染土壤的钝化效果依次为:碳铁共沉物(C/Fe=2.0)>腐植酸>水铁矿,中度和重度Cd污染土壤中的钝化效果依次为:碳铁共沉物(C/Fe=2.0)>水铁矿>腐植酸。
Abstract
sui zhao gong nong ye de kuai su fa zhan ,tu rang chong jin shu wu ran yi cheng wei quan qiu xing de huan jing wen ti ,yuan wei dun hua xiu fu shi mu qian zui ju you ying yong qian li de chong jin shu wu ran nong tian tu rang xiu fu ji shu zhi yi 。fu zhi suan he shui tie kuang an fan cun zai yu tu rang huan jing zhong ,liang zhe ke yi tong guo xi fu 、gong chen dian 、xu ning he ao ge deng zuo yong xing cheng ju you geng gao biao mian huo xing he yang hua hai yuan neng li de gong chen wu ,gai gong chen wu zai diao kong tu rang chong jin shu qian yi he zhuai hua zhong qi zhao chong yao zuo yong 。yin ci ,tan jiu fu zhi suan 、shui tie kuang ji ji gong chen wu dui nong tian tu rang zhong chong jin shu de gu ding zuo yong dui wo guo nong chan pin an quan he ren ti jian kang ju you chong yao yi yi 。ben wen yi gan su sheng bai yin shi jing yuan xian gao wan xiang nong tian tu rang wei yan jiu dui xiang ,tong guo tu pei shi yan mo ni bu tong nong du de Cdwu ran tu rang ;tong shi ,tong guo gong chen dian fa ge cheng le shui tie kuang he bu tong C/Febi de shui tie kuang -fu zhi suan gong chen wu (tan tie gong chen wu ),cai yong FTIR、SEM-EDS、XRDhe N2xi tuo fu shi yan dui fu zhi suan 、shui tie kuang ji ji gong chen wu de guan neng tuan jie gou 、biao mian xing mao 、jie jing cheng du he bi biao mian ji jin hang fen xi ,bing cai yong gai jin BCRlian xu di qu fa yan jiu fu zhi suan 、shui tie kuang ji ji gong chen wu tian jia hou tu rang Cdxing tai sui shi jian de bian hua 。zhu yao jie lun ru xia :(1)tan tie gong chen wu zhu yao tong guo fu zhi suan shang de suo ji yu shui tie kuang biao mian de qiang ji fa sheng pei wei jiao huan er jie ge ,gong chen dian xia lai de fu zhi suan wei gai bian shui tie kuang yuan you de jing ti jie gou ,gai bian le shui tie kuang de biao mian xing mao he jie gou xing zhi 。sui zhao C/Febi zeng jia ,ke li biao mian ao tu cheng du zeng jia ,kong jing zeng da ,bi biao mian ji he kong rong jian xiao 。(2)wai yuan xing Cdjin ru tu rang hou ,gai bian le yuan zhuang tu rang zhong Cdde fu cun xing tai ,zeng jia le tu rang zhong Cdde huo xing he qian yi xing 。yuan zhuang tu rang zhong Cdfu cun xing tai de fen pei guan ji wei :ruo suan ke rong tai >can zha tai >ke hai yuan tai >ke yang hua tai 。tian jia wai yuan xing Cdhou ,tu rang zhong Cdfu cun xing tai de fen pei guan ji wei :ruo suan ke rong tai >ke hai yuan tai >can zha tai >ke yang hua tai 。sui zhao wai yuan xing Cdhan liang de zeng jia ,tu rang zhong fei can zha tai Cdsuo zhan bi li zhu jian zeng jia ,can zha tai Cdsuo zhan bi li zhu jian jiang di 。(3)Cdwu ran tu rang zhong chan du tian jia 5%de fu zhi suan 、shui tie kuang 15 d、30 dhe 60 dhou ,jun cu shi tu rang zhong ruo suan ke rong tai Cdxiang ke hai yuan tai he can zha tai zhuai hua ,cong er jiang di le tu rang zhong Cdde huo xing he qian yi xing 。dang tian jia shi jian wei 30 dshi ,tu rang zhong can zha tai Cdsuo zhan bi li zui da ,dun hua xiao guo zui jia 。ci shi ,tong guo dui bi fa xian ,fu zhi suan dui qing wei Cdwu ran tu rang de xiu fu xiao guo jiao jia ,shi qing wei Cdwu ran tu rang zhong can zha tai Cdhan liang bi dui zhao zu zeng jia 24.81%;shui tie kuang dui zhong du 、chong du Cdwu ran tu rang de xiu fu xiao guo jiao jia ,shi zhong du 、chong du Cdwu ran tu rang zhong can zha tai Cdhan liang fen bie bi dui zhao zu zeng jia 23.64%he 41.69%。(4)5%de tan tie gong chen wu tian jia zhi Cdwu ran tu rang 15 d、30 dhe 60 dhou ,gai bian le tu rang zhong Cdde fu cun xing tai 。dang dun hua shi jian wei 15 dhe 30 dshi ,tan tie gong chen wu de tian jia shi rong yi bei zhi wu xi shou de ruo suan ke rong tai zhuai hua wei zhi wu nan yi xi shou de ke hai yuan tai he can zha tai ;dang dun hua shi jian wei 60 dshi ,tan tie gong chen wu de tian jia shi rong yi bei zhi wu xi shou de ruo suan ke rong tai zhuai hua wei zhi wu nan yi xi shou de ke hai yuan tai 、ke yang hua tai he can zha tai ,cong er you xiao de jiang di le tu rang zhong Cdde huo xing he qian yi xing 。(5)tan tie bi wei 0.5、1.0、1.5、2.0he 2.5de gong chen wu zhong ,C/Fe=2.0de gong chen wu dun hua xiao guo zui jia ,qing wei 、zhong du Cdwu ran tu rang zai 15 dshi de dun hua xiao guo zui jia ,er chong du Cdwu ran tu rang zai 30 dshi de dun hua xiao guo zui jia 。ci shi ,qing wei 、zhong du he chong du Cdwu ran tu rang zhong can zha tai Cdhan liang bi dui zhao zu fen bie zeng jia 30.34%、37.86%he 54.54%。(6)dui bi fu zhi suan 、shui tie kuang ji ji gong chen wu (C/Fe=2.0)zai ji zui jia dun hua shi jian xia dui bu tong nong du Cdwu ran tu rang de dun hua xiao guo ,fa xian qing wei Cdwu ran tu rang de dun hua xiao guo yi ci wei :tan tie gong chen wu (C/Fe=2.0)>fu zhi suan >shui tie kuang ,zhong du he chong du Cdwu ran tu rang zhong de dun hua xiao guo yi ci wei :tan tie gong chen wu (C/Fe=2.0)>shui tie kuang >fu zhi suan 。
论文参考文献
论文详细介绍
论文作者分别是来自兰州大学的赵立芳,发表于刊物兰州大学2019-07-29论文,是一篇关于水铁矿论文,腐植酸论文,碳铁共沉物论文,赋存形态论文,兰州大学2019-07-29论文的文章。本文可供学术参考使用,各位学者可以免费参考阅读下载,文章观点不代表本站观点,资料来自兰州大学2019-07-29论文网站,若本站收录的文献无意侵犯了您的著作版权,请联系我们删除。
标签:水铁矿论文; 腐植酸论文; 碳铁共沉物论文; 赋存形态论文; 兰州大学2019-07-29论文;