Fast screening of adsorbents: from equilibrium and kinetics to bench scale process tests

在过去的几十年里，新型纳米多孔吸附剂和催化剂的开发急剧增加。其中最有前途的包括分子筛，从微孔沸石和碳分子筛开始，它们在上个世纪的最后十年之前一直主导着该领域。自20世纪90年代初以来，已经开发了一系列全新的其他纳米多孔材料，包括周期性介孔筛（PMS）、周期性介孔有机硅酸盐（PMO）、分级沸石、金属有机框架（MOF）以及这些材料的各种混合和官能化变体。由于这些材料中的一些材料的大量可能的化学组成和结构，例如，由于可以制造几乎无限数量的MOF，每种MOF都具有不同的性能特征，因此需要开发使用少量样品快速表征材料的技术，并允许容易地解释结果。吸附平衡、动力学和动态测量传统上通过重量法、体积法和填充柱流动技术进行。这些技术简单而准确，但它们耗时，需要相对大量的吸附剂样品（通常为颗粒状），并且不太适合吸附剂快速筛选研究，因为准确性不太重要。最初的零长度（ZLC）技术是由Eic和Ruthven在20世纪80年代后期引入的，用于研究吸附动力学。该技术将是开发一种新型ZLC系统的基础，该系统设计用于吸附剂的快速筛选，包括从平衡和动力学到动态（突破）表征的完整表征，这是该提案的主要目标。研究结果将用于从大量潜在吸附剂中选择性能最佳的材料，或者用于在实验室中对合成材料进行改性，以便为特定应用生产量身定制的吸附剂。所提出的研究的其他目标是：*1）合成吸附剂的合成和改性，特别是用于气体分离的新型纳米原纤化纤维素（NFC）吸附剂的合成。这一发展有可能为新兴的森林生物经济创造新的市场机会。由于将制备大量NFC样品，因此将通过本提案第一部分中开发的快速筛选方法表征合成/改性样品。* 2)将使用变压吸附（PSA）装置通过实验室规模工艺试验对所选样品的性能进行检测。这些测试将完成从合成和快速筛选到实验室规模操作的完整周期。* 本研究基于我们在吸附领域25年的工作。**

The last several decades have have seen a dramatic increase in the development of new nanoporous adsorbents and catalysts. The most promising among them include molecular sieves, starting with microporous zeolites and carbon molecular sieve, which dominated the field until the last decade of the last century. Since the early 1990's a whole new array of other nanoporous materials have been developed including periodic mesoporous sieves (PMS), periodic mesoporous organosilicates (PMO's), hierarchycal zeolites, metal organic frameworks (MOF's) and a variety of hybrid and functionalized variants of these materials. Due to the large number of possible chemical compositions and structures of some of these materials, e.g., a near infinite number of MOF's can be made- each with different performance characteristics, there is a requirement for developing techniques to characterize materials rapidly using small sample quantities and allowing easy interpretation of the results. Adsorption equilibrium, kinetics and dynamic measurements have traditionally been carried out by gravimetric, volumetric and packed column flow techniques. These techniques are straightforward and accurate, but they are time consuming and require relatively large amounts of adsorbent samples (often in pelleted form) and are not well-suited to adsorbent rapid screening studies, where accuracy is less critical.***The original zero length (ZLC) techique was introduced by Eic and Ruthven in late 1980's to study adsorption kinetics. This technique will be the basis for developing a novel ZLC system designed for the fast screening of adsorbents that would include complete characterization from equilibrium and kinetics to dynamic (breakthrough) characterizations, which is the main objective of this proposal. The results will be used either to select the best performing material from a larger selction of potential adsorbents or it will be used to modify synthesized material in lab in order to produce tailor-made adsorbent for specific application.***The other objectives of the proposed research are:***1) Synthesis and modifications of synthesized adsorbents, in particular, synthesis of novel nanofibrilated cellulose (NFC) adsorbents for gas separations. This development has the potential to create a new market opportunities for the emerging forest bioeconomy. Since a large number of NFC samples will be prepared the synthesized/modified samples will be characterized by the fast screening methods developed in the first part of this proposal.***2) Performance of the selected samples will be tested by bench scale process testing using pressure swing adsorption (PSA) apparatus. These tests will complete a full cycle from the synthesis and rapid screening to the bench scale operation. ***The research proposed here is built on 25 years of our work in the adsorption area. **