磁致自辅热沸石控温载体构建及其氨氮吸附再生调控机制

Preparation of a magnetically-induced self-heating zeolite carrier and the corresponding regulation mechanism on ammonia adsorption and regeneration

为解决常规沸石再生过程药耗较高的问题,满足当下双碳目标的要求,构建了结构化磁致自辅热沸石控温载体,利用磁热效应实现沸石氨氮原位吸附过程调控,避免再生过程中的药剂消耗。在优化筛选磁场条件与发热内核构型基础上,应用Langmuir、Freundlich模型、动力学模型及粒子内扩散模型考察了局部自辅热对沸石氨氮原位吸附及解吸过程的影响。结果表明,局部自辅热使沸石氨氮吸附行为更满足Freundlich模型,以物理吸附为主,动力学过程为准二级动力学模型,以粒子内扩散和液膜扩散为主。同时,局部自辅热使沸石氨氮12 h解吸率提升约29%,动力学拟合更满足准二级动力学模型,为化学解吸过程,扩散方式以以粒子外部扩散为主。最终证实,磁致自辅热可以有效调控沸石氨氮吸附解吸过程,可为沸石可控再生提供一种低耗高效途径。

In order to resolve the problems of high reagent-consuming in conventional regeneration of zeolite and meet the current global trends of emission peak and carbon neutrality,a layered-structure magneticallyinduced self-heating zeolite carrier was built to regulate the in-situ ammonia adsorption/desorption process and avoid the extra reagents consumption for material regeneration.Langmuir model,Freundlich model,chemical kinetics,and intraparticle diffusion model were used to study the effect of local self-heating on the mechanism of in-situ ammonia adsorption/desorption process on zeolite.The result showed that local self-heating led to a better fit of ammonia adsorption behavior on the self-heating zeolite carrier by Freundlich model than others,which was dominated by physical adsorption process.The adsorption kinetics could be well fitted by pseudosecond-order dynamic model which is dominated by intraparticle and liquid-film diffusion.Meanwhile,the desorption capacity of the self-heating zeolite carrier increased by 29%within 12 h compared to the common zeolite carrier,the former could be better fitted by pseudo-second-order dynamic model,and the chemical desorption process was promoted,which implied that an elevated desorption process was controlled by external particle diffusion.In general,the self-heating zeolite carrier could effectively regulate in-situ ammonia adsorption/desorption process,provide a controllable regeneration approach with low-carbon and costeffectiveness for zeolite.