摘要
我国土壤重金属污染严重,尤以镉砷污染最为突出。镉砷复合污染土壤中各元素间表现为拮抗和协同等作用,其有效态含量受土壤pH变化和氧化还原电位等的影响,增加了镉砷复合污染土壤的修复难度,严重威胁我国粮食安全。综述了常见的镉砷复合污染土壤钝化修复材料的优缺点及其对镉砷复合污染土壤钝化修复效果和机理。常见的钝化材料有生物质炭类、磷酸盐类、金属及其氧化物类、含硅类材料、黏土矿物类、有机肥类和新型材料等。有大量研究表明生物质炭材料对镉有良好的吸附效果,为了同时钝化镉砷,通常使用改性生物质炭或与其他材料配合施用,常见的改性/配施材料有金属及其氧化物、黏土矿物、家禽粪便、复合肥等,其钝化反应机制包括离子交换、共沉淀和表面络合等;磷酸盐类主要与铁盐或铁粉配施,通过吸附和同晶替代钝化镉、点位竞争机制钝化砷;金属及其氧化物类多与生物质炭、石灰和黏土矿物等配施,通过专性吸附和共沉淀钝化镉、氧化还原和络合作用等钝化砷;铁硅肥、硅钙肥、硅钾肥等通过共沉淀钝化镉、专性吸附和点位竞争机制钝化砷;黏土矿物中多施用海泡石,主要与金属氧化物和钙镁磷肥等配施,通过离子交换、沉淀和络合反应钝化镉砷;污泥和动物粪便中含有腐殖化程度较高的有机质,主要通过吸附、氧化还原和有机络合以及微生物作用钝化镉砷;此外,富含巯基和氨基、谷聚多以及富含硫和硒的物质也可有效钝化镉砷。本文对镉砷复合污染土壤钝化修复材料进行总结,归纳了镉砷钝化材料特性,以期为镉砷复合污染土壤修复提供一定的指导。
In China,heavy metal pollution in soils is very serious,especially cadmium(Cd)and arsenic(As)pollution.In Cd and As(Cd-As)co-contaminated soils,the two elements Cd and As act either antagonistically or synergically,and their effective concentrations are affected by soil pH,redox potential,and some other soil environmental factors,which makes it more difficult to remediate the Cd-As co-contaminated soil and seriously threatens food security in our country.In this paper,a review is presented to show the advantages and disadvantages of the passivation materials for Cd-As soil co-contamination,as well as their effects and mechanisms.Common passivating materials include biochar,phosphates,metals and their oxides,silicon-containing materials,clay minerals,organic fertilizers and some other new materials.Recently,a large amount of studies have demonstrated that biochar is a good adsorbent for Cd,but modified biochar is usually used in combination with other materials,like metals or their oxides,clay minerals,poultry manure,compound fertilizer,etc.to passivate Cd and As simultaneously.The mechanism of modified biochar to passivate Cd and As was ion exchange,coprecipitation and surface complexation.Phosphate is mainly applied together with iron salt or iron powder to passivate Cd by adsorption and isomorphic substitution,and to passivate As by site-competition;metals and their oxides are mostly combined with biochar,lime or clay minerals to passivate Cd through specific adsorption and coprecipitation,and to passivate As through redox and complexation.Iron silicon fertilizer,silicon calcium fertilizer or silicon potassium fertilizer is used to passivate Cd via coprecipitation,and to passivate As through specific adsorption and site competition mechanism.In clay minerals,sepiolite is widely used,mainly combined with metal oxide,calcium magnesium phosphate fertilizer,etc.,to passivate Cd and As through ion exchange,precipitation and complexation.Sludge and animal manure,which contain organic matter with high degree of humifi
作者
李英
商建英
黄益宗
王农
LI Ying;SHANG Jianying;HUANG Yizong;WANG Nong(College of Land Science and Technology,China Agricultural University,Beijing 100193,China;Key Laboratory of Plant-Soil Interactions,Ministry of Education,Beijing 100193,China;Key Laboratory of Arable Land Conservation(North China),Ministry of Agriculture,Beijing 100193,China;Agro-Environmental Protection Institute,Ministry of Agriculture and Rural Affairs,Tianjin 300191,China)
出处
《土壤学报》
CAS
CSCD
北大核心
2021年第4期837-850,共14页
Acta Pedologica Sinica
基金
国家重点研发计划项目(2017YFD0801503)资助。
关键词
重金属
复合污染
钝化材料
钝化机制
Heavy metal
Co-contaminated
Passivation materials
Passivation mechanisms
