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

在过去的几十年里，新的纳米孔吸附剂和催化剂的开发有了戏剧性的增长。其中最有希望的包括分子筛，从微孔沸石和碳分子筛开始，它们一直主导着该领域，直到上个世纪的最后十年。自20世纪90年代初以来，S开发了一系列新的纳米孔材料，包括周期性介孔分子筛(PMS)、周期性介孔有机硅酸盐(PMO)、层状沸石、金属有机骨架(MOF)以及这些材料的各种杂化和功能化变体。由于这些材料中有大量可能的化学成分和结构，例如，可以制造几乎无限数量的MOF--每种材料都具有不同的性能特征，因此需要开发技术来使用小样本量快速表征材料并允许容易地解释结果。传统上，吸附平衡、动力学和动态测量都是通过重量法、容积法和填充柱流技术进行的。这些技术简单而准确，但它们耗时较长，需要相对大量的吸附样品(通常是颗粒状的)，不适合于对准确性不那么重要的吸附剂快速筛选研究。*最初的零长度技术是由EIC和Ruthven在1980年末的S引入的，用于研究吸附动力学。这项技术将是开发一种新的ZLC系统的基础，该系统旨在快速筛选吸附剂，包括从平衡和动力学到动态(突破)表征的完整表征，这是本提案的主要目标。研究结果将用于从更多的潜在吸附剂中选择性能最好的材料，或者用于在实验室对合成材料进行改性，以生产特定应用的定制吸附剂。*拟议研究的其他目标是：*1)合成吸附剂的合成和改性，特别是合成用于气体分离的新型纳米纤维纤维素(NFC)吸附剂。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，合成/改性样品将通过本建议第一部分中开发的快速筛选方法进行表征。*2)所选样品的性能将通过使用变压吸附(PSA)装置的小规模过程测试进行测试。这些试验将完成从合成、快速筛选到小试运行的完整周期。*这里提出的研究是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. **