不同地膜源微塑料对土壤中镉的吸附-解吸行为的影响研究  

Study on the Effects of Different Mulch Film-derived Microplastics on the Adsorption-Desorption Behavior of Cadmium in Soil

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作  者:姚倩 李存前 石纯玮 王博雅 YAO Qian;LI Cunqian;SHI Chunwei;WANG Boya(School of Biological and Environmental Engineering,Xi’an University,Xi’an 710065,China;Xi’an Key Laboratory of Plant Stress Physiology and Ecological Remediation Technology,College of Biological and Environmental Engineering,Xi’an University,Xi’an 710065,China)

机构地区:[1]西安文理学院生物与环境工程学院,陕西西安710065 [2]西安文理学院生物与环境工程学院,西安市植物逆境生理与生态修复重点实验室,陕西西安710065

出  处:《环境科学与技术》2024年第10期143-150,共8页Environmental Science & Technology

基  金:西安文理学院服务地方专项(22FWDF05)。

摘  要:微塑料(MPs)作为一类新兴污染物,广泛存在于土壤环境中。MPs的存在不仅会导致土壤的理化性质、生物活性发生变化,还会对其共存污染物的环境行为及生物有效性产生影响。该研究通过向土壤中添加3种不同类型的地膜源MPs——新添加聚乙烯地膜源MPs(新添加MPs)、老化聚乙烯地膜源MPs(老化MPs)以及可降解的聚己二酸-对苯二甲酸丁二酯地膜源MPs(可降解MPs),分析比较不同类型、不同使用程度的地膜源MPs处理下土壤对镉的吸附-解吸行为差异。结果表明:Cd在土壤中的理论最大吸附容量和解吸量分别为0.59 mg/kg和0.072 mg/kg。地膜源MPs的添加增加了土壤对Cd的吸附、解吸能力,其中Cd在老化MPs处理下的土壤中的理论最大吸附容量和解吸量最大,分别为2.93 mg/kg和0.50 mg/kg,其次是新添加MPs和可降解MPs处理下的土壤样本,其最大吸附容量分别为2.14 mg/kg和1.79 mg/kg,对应的解吸量分别为0.29 mg/kg和0.22 mg/kg。Cd在土壤中吸附动力学符合准一级动力学模型,而在不同类型地膜源MPs处理下的土壤中的吸附动力学符合准二级动力学模型。Langmuir模型能够较好地拟合Cd在土壤和不同MPs处理组中吸附等温过程。较大的吸附容量虽然会减少重金属的迁移,却会延长其在土壤中的存在时间,并有被解吸出来的风险,对土壤生态环境构成潜在威胁。该研究将为塑料地膜-重金属复合污染农田的修复提供参考。Microplastics(MPs),identified as emerging contaminants,are pervasive in soil environments.Their presence not only modifies the physicochemical properties and biological activities of soil but also influences the environmental behavior and bioavailability of co-existing pollutants.This study evaluated the adsorption-desorption behavior of cadmium(Cd)in soils amended with three different types of mulch film-derived MPs:newly added polyethylene-derived MPs(new MPs),aged polyethylene-derived MPs(aged MPs),and degradable poly(hexamethylene adipate-co-terephthalate)-derived MPs(degradable MPs).The findings indicate that the theoretical maximum adsorption capacity of Cd in the soil reached 0.59 mg/kg,with a corresponding desorption amount of 0.072 mg/kg.The addition of MPs increased both the adsorption and desorption capacities of Cd.Notably,soils treated with aged MPs exhibited the highest capacities,achieving maximum adsorption and desorption rates of 2.93 mg/kg and 0.50 mg/kg,respectively.This was followed by soils amended with new MPs and degrad⁃able MPs,which showed maximum adsorption capacities of 2.14 mg/kg and 1.79 mg/kg,respectively,and desorption capaci⁃ties of 0.29 mg/kg and 0.22 mg/kg.Adsorption kinetics of Cd adhered to a pseudo-first-order model,while the presence of MPs shifted this to a pseudo-second-order kinetic model.The Langmuir model aptly described the adsorption isotherm processes in both untreated and MP-treated soils.Importantly,while increased adsorption capacity reduces heavy metal mobility,it may prolong their presence in soil and elevate desorption risks,potentially threatening soil ecological health.This research underscores the need for strategic management of plastic mulch film-heavy metal contamination in agricultural Environmental Science&Technology settings and highlights the critical interplay between MPs and heavy metals in soil environments.

关 键 词:地膜源微塑料 土壤  吸附-解吸 吸附动力学 

分 类 号:X53[环境科学与工程—环境工程]

 

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