The Construction And Application Of Three-dimensional Electrode Based On Graphene Aerogel Composites

Traditional organic wastewater treatment methods are suffered from the disadvantages of low treatment efficiency,incomplete degradation and secondary environmental pollution,etc.Developing new efficient water treatment technology is critical to solve the problem of water resource pollution.Due to the introduction of the particle electrodes,the three-dimensional electrode has many advantages,such as large specific surface area,ultra-high space utilization,fast mass transfer,without the need of auxiliary reagent and complete degradation of pollutants.Therefore,the preparation of particle electrode materials with high adsorbability,excellent electrocatalysis,good stability and recoverability has become the hot topics in recent years.As the basic unit of carbon nanomaterials,graphene has the advantages of large specific surface area,high electrical conductivity and excellent mechanical properties.Graphene aerogel composites assembled by graphene have demonstrated excellent performance in many fields such as environment protection,energy storage and electrocatalysis.In the present work,the graphene aerogel composites were prepared by the combination of hydrothermal and subsequent freeze drying and used as particle electrodes for the construction of a three-dimensional electrode reaction system to degrade organic wastewater.The main results are summarized as follows:（1）FeOOH and graphene aerogel composites（FeOOH/GA）were prepared by hydrothermal combined with freeze drying strategies,in which bubble and ice crystal act as dual templates,graphene oxide（GO）as precursor,sodium dodecyl sulfate（SDS）surfactant as template agent,Fe²⁺as reducing agent and cross-linking agent.The as-prepared graphene composites possess good mechanical property and abundant micron-scale pore structure,which provides a good channel for mass transfer of organic wastewater.FeOOH nanoparticles distributed uniformly on the nanosheets of graphene promote the occurrence of electro-Fenton reaction.Using FeOOH/GA as particle electrode for the construction of a three-dimensional electro-Fenton reaction system for methylene blue（MB）degradation(40 mg·L^-1),the degradation rate was up to 99.9%in 75 min under current density 3.0 m A·cm^-2,p H 4.0.（2）Graphene aerogel composites（Fe-Ni-S/GA）consisted of double active components were prepared by the combination of hydrothermal and freeze drying,using GO as precursor,nickel nitrate as nickel source,ferric nitrate as iron source,sodium sulfide as sulfur source and SDS as template agent.The as-prepared Fe-Ni-S/GA were used as particle electrode for the degradation of MB(40 mg·L^-1),which was degraded completely within 18 min.The performance of the Fe-Ni-S/GA as particle electrode surpassed those of Fe₂O₃/GA and Ni₃S₄/GA under the similar condition.The Fe-Ni-S/GA with well-developed porous structure and Fe-Ni bimetallic active components enhanced the degradation performance of organic wastewater in the three-dimensional electro-Fenton reaction system.