零价纳米铁-壳聚糖改性生物炭对土壤结构体分布和Cd形态的影响  

Effects of zero-valent iron-chitosan modified biochar on soil Cd morphology and soil structural distribution

作　　者：汤文轲 王锐[1] 王亚麒 姬强 TANG Wen-ke;WANG Rui;WANG Ya-qi;JI Qiang(School of Agriculture,Ningxia University,Yinchuan Ningxia 750021)

机构地区：[1]宁夏大学农学院,宁夏银川750021

出　　处：《中国土壤与肥料》2023年第8期42-49,共8页Soil and Fertilizer Sciences in China

基　　金：宁夏自然科学基金(2020AAC02015);国家自然科学基金(31960638);宁夏高校一流学科建设项目(030900002104);宁夏大学生创新创业训练计划(S202110749066)。

摘　　要：为明确土壤结构体分布和Cd赋存形态对零价纳米铁-壳聚糖改性生物炭的响应,以黄绵土为试验对象,枸杞枝条制备改性生物炭,以不添加改性生物炭土壤为对照,研究不同浓度CdCl_(2)溶液污染条件下,1%~3%改性生物炭输入处理对土壤pH值、有机碳(SOC)、阳离子交换量(CEC)、水稳性团聚体及不同Cd形态含量的影响。结果表明:经过300 d沉化,相对于对照处理,添加改性生物炭后,土壤pH、CEC、SOC分别平均显著增加8.30%、17.23%、68.48%;土壤大颗粒团聚体(>0.25 mm)含量增加7.69%,有效态Cd含量中弱酸提取态、可还原态和可氧化态各占比都有所减少,分别减少12.61%、5.52%和1.21%,无效态Cd含量(残渣态)增加19.34%。路径分析表明,土壤pH和SOC含量直接影响有效态Cd的含量且存在因果关系,SOC含量直接影响土壤小颗粒团聚体(<0.25 mm)的形成,且土壤小颗粒团聚体形成和CEC与有效态Cd存在因果关系。从路径分析的结果来看,土壤CEC和土壤团聚体是土壤Cd有效性的关键作用因子。在本试验条件下,对于高浓度Cd污染土壤,零价纳米铁-壳聚糖改性生物炭对Cd固定有较好的效果。In order to clarify the response of soil structural distribution and Cd fugacity to zero-valent iron nanoparticleschitosan modified biochar,this study was conducted to investigate the effects of 1%-3%modified biochar input treatment on soil pH,organic carbon(SOC),cationic exchange capacity(CEC),water-stable agglomerates and different Cd forms under different concentrations of CdCl_(2) solution contamination conditions.The results showed that after 300 d of sedimentation,the soil pH,CEC and SOC were increased significantly by 8.30%,17.23%and 68.48%,respectively,compared with those of the CK.The content of large agglomerates(>0.25 mm)was increased by 7.69%,and the effective Cd content was decreased in the weakly acid-extracted,reducible and oxidizable states.The effective Cd content were decreased by 12.61%,5.52%and 1.21%,respectively,and the ineffective Cd content(residual state)was increased by 19.34%.The path analysis showed that soil pH and SOC content directly affected the content of effective Cd and there was a causal relationship between the content of SOC and the formation of soil small particle agglomerates(<0.25 mm),and there was a causal relationship between the formation of soil small particle agglomerates and CEC content and effective Cd.From the results of the pathway analysis,soil CEC and soil agglomerates were the key role factors of soil Cd effectiveness.Under the present experimental conditions,the zero-valent iron nanoparticle-chitosan modified biochar was more effective on Cd fixation for soil with high Cd concentration.

关 键 词：改性生物炭 镉 有机碳 水稳性团聚体 赋存形态 

分 类 号：S152.4[农业科学—土壤学]