The search for safer and sustainable management of animal manure is a global and topical challenge, in particular for the reduction of nitrogen (N) content. The use of natural adsorbents as zeolite-rich tuffs is recognized as a valid method to recover N, in the form of ammonium (NH4+), from animal manure. While the scientific literature is rich in studies performed on synthetic solutions and using clinoptilolite zeolites as adsorbent, it lacks information concerning adsorption in real liquid manure and using other types of zeolite-rich tuffs (e.g., chabazite). This work aims at exploring the NH4+ adsorption process from raw liquid swine manure, using a chabazite-rich zeolite tuff as adsorbent. The effects of temperature, contact time, and grain size have been assessed. Isotherms, kinetic models, and thermodynamic parameters have been investigated. Harkins-Jura isotherm correlates well with the observed data, in accordance with the formation of an adsorption multilayer. Kinetic data have been explained by intraparticle diffusion and pseudo-second-order models. In conclusion, the natural chabazite tuff has proven to be a valid material for NH4+ adsorption from raw liquid swine manure. In particular, to reach the highest adsorption capacities and adsorption rates, it is recommended to use it at a fine particle size and with dosages < 6 %.

中文翻译：

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使用富含天然菱沸石沸石凝灰岩的原液粪中 NH4+ 吸附的等温线、动力学和热力学

寻求更安全和可持续的动物粪便管理是一项全球性的热门挑战，特别是在减少氮 (N) 含量方面。使用天然吸附剂作为富含沸石的凝灰岩被认为是从动物粪便中以铵 (NH4+) 形式回收 N 的有效方法。虽然科学文献中有大量关于合成溶液和使用斜发沸石沸石作为吸附剂的研究，但缺乏关于在真正液体粪便中吸附和使用其他类型富含沸石凝灰岩（例如菱沸石）的信息。本工作旨在探索使用富含菱沸石的凝灰岩作为吸附剂从原液猪粪中吸附 NH4+ 的过程。已经评估了温度、接触时间和晶粒尺寸的影响。已经研究了等温线、动力学模型和热力学参数。根据吸附多层的形成，Harkins-Jura 等温线与观察到的数据密切相关。动力学数据已通过粒子内扩散和伪二阶模型来解释。总之，天然菱沸石凝灰岩已被证明是一种有效的材料，可以从原液猪粪中吸附 NH4+。特别是，为了达到最高的吸附容量和吸附率，建议以细粒度和< 6 % 的剂量使用它。