多场耦合作用下石墨烯纳米颗粒在填埋场GCL中的迁移机理及防控机制

With the extensive use of graphene, large number of graphene nanoparticle enter the municipal solid waste (MSW) landfills, and quickly spread to the landfill leachate. Whether Geosynthetic Clay Liner (GCL), which is the final seepage barrier in accordance with the current landfill design, can effectively block graphene nanoparticles to the surrounding environment of MSW landfill has become the key to waste disposal safety. For landfill widely distributed seepage pressure, temperature and concentration of pollutants coupled environment, (a) the stability and aggregation of graphene nanoparticles in the landfill leachate under different factors was firstly analyzed. (b)Then, the graphene nanoparticles transport in GCL under coupling action of seepage pressure, temperature and initial concentration was conducted by multifunctional permeameter, the transport behavior and influencing factors was analyzed.(c)Based on DLVO theory, interaction between graphene nanoparticles and GCL was analyzed. The barrier and interception of GCL and deposition mechanism of nanoparticles in GCL was investigated. (d)Based on Modified colloidal theory, the migration mechanism of graphene nano-particles under the multi-field coupling effect in the GCL was analyzed, and the prevention and transport model of graphene nano-particles under the multi-field coupling effect in the GCL was educed. The research results can provide a theoretical basis for transport prediction of graphene nanoparticles in SMW landfills and environmental pollution risk assessment.

随着石墨烯材料大量使用，大量石墨烯纳米颗粒废弃物进入垃圾填埋场，并快速扩散至填埋场渗滤液中。按照填埋场现行设计，作为最后一道防渗屏障的复合膨润土垫层（GCL），能否有效阻滞石墨烯纳米颗粒向填埋场周边环境泄露，已经成为垃圾处置安全的关键。针对垃圾填埋场中广泛存在的渗流压力、温度和污染物浓度等环境，首先，分析多因素作用下石墨烯纳米颗粒在填埋场渗滤液中的稳定性及团聚性；在此基础上，采用多功能渗滤仪，开展渗流压力、温度和初始浓度等耦合作用下石墨烯纳米颗粒在GCL中迁移试验，分析石墨烯纳米颗粒迁移行为与影响因素；然后，基于扩展的DLVO理论，研究石墨烯纳米颗粒与GCL相互作用，分析GCL的截留和纳米颗粒沉积作用机理；最后，基于改进的胶体理论，构建多场耦合作用下石墨烯纳米颗粒在GCL中的迁移模型，并提出防控机制。预期研究成果可为现有垃圾填埋场中，石墨烯纳米颗粒迁移预测与环境污染风险评估提供理论依据。

随着石墨烯材料大量使用，大量石墨烯纳米颗粒废弃物进入垃圾填埋场，并快速扩散至填埋场渗滤液中。按照填埋场现行设计，作为最后一道防渗屏障的复合膨润土垫层（GCL），能否有效阻滞石墨烯纳米颗粒向填埋场周边环境泄露，已经成为垃圾处置安全的关键。针对垃圾填埋场中广泛存在的渗流压力、温度和污染物浓度等环境，分析了不同因素作用下石墨烯纳米颗粒在填埋场渗滤液中的稳定性及团聚性；采用多功能渗滤仪，开展了渗透压力、温度、离子强度和有机质含量单因素作用和耦合作用下石墨烯纳米颗粒在GCL中迁移试验，分析了石墨烯纳米颗粒迁移行为与影响因素；基于扩展的DLVO理论，分析了GCL的截留和纳米颗粒沉积作用机理；基于改进的胶体理论，构建多场耦合作用下石墨烯纳米颗粒在GCL中的迁移模型，基于不同的初始浓度、GCL厚度、GCL针刺和改性膨润土，开展GONPs在GCL中的迁移实验，实验结果表明GCL对GONPs的防控作用受初始浓度、GCL厚度、GCL针刺和膨润土改性的影响，在分析不同条件下GCL对GONPs迁移的防控效果基础上，提出了防控机制。预期研究成果可为现有垃圾填埋场中，石墨烯纳米颗粒迁移预测与环境污染风险评估提供理论依据。