Breakthrough analysis has widely been explored for the dynamic separation of gaseous mixtures in porous materials. In general, breakthrough experiments measure the components of a flowing gas when a gaseous mixture is injected into a column filled with an adsorbent material. In this paper, we report on the design and fabrication of a breakthrough curve measurement device to study the dynamic adsorptive separation of hydrogen isotopologues in porous materials. Using the designed system, an experiment was conducted involving a 1:1 mixture of hydrogen and deuterium passed through a column filled with zeolite 13X (1 g). At room temperature, both hydrogen and deuterium were adsorbed in negligible amounts; however, at a temperature of 77 K, deuterium was preferentially adsorbed over hydrogen. The selectivity was different from that in the existing literature due to the different sample shapes, measurement methods, and column structures, but was at a similar level to that of cryogenic distillation (1.5).

Non-face-to-face online education which suddenly began with COVID-19, was an opportunity to expand to university education sites. This study presents online classes based on the Tandem learning method as examples and examines the class operation, learning content, and learner satisfaction according to the actual type of flip learning classes and real-time video classes. By converting Tandem classes operated by B University in Busan into online classes, the existing e-Tandem classes were expanded using flip learning and ZOOM. The first Flip learning class allows self-directed learning, and the free form of learning through pre-learning becomes an advantage of the online class type. However, while professors participate in the small conference room and feedback, there is a need to be supplemented with the ability to feedback directly to other teams. Furthermore, as a result of the learner satisfaction survey, there were complaints about prior learning and the amount of tasks, so studies on specific tasks and the content and methods of prior learning are also needed. The second real-time video class allows interaction between professors and learners, learners and learners. The biggest feature of this class type is that it can solve the absence of communication, which was a disadvantage of non-face-to-face classes. However, the ability of a professor is needed to conduct a real-time video class like this. Unlike learners who are familiar with digital technology, only when they understand and learn various online content and functions will their online classes become as natural as face-to-face classes.

In order to prove that perchlorate-laden resins could be bio-regenerated through direct contact with anaerobic microorganisms, two bio-regeneration systems, internal and external, were tested. Anaerobic digestion was demonstrated to be very efficient in degrading perchlorate that had been adsorbed onto A520E resin. The internal bio-regeneration test showed that the fully exhausted resins recovered about 80% of the perchlorate-exchange capacity after 4 weeks of bio-treatment in the anaerobic digester. The bio-regeneration efficiency of the external system increased with the amount of flow passed through the column. Comparison of two perchlorate breakthrough curves obtained from column test, one with virgin resin and the other with bio-regenerated resin, proved that the bio-regenerated resin could be used repeatedly to treat perchlorate in spent or waste brine. The A520E resin was very stable in the anaerobic digester and its perchlorate-exchange capacity was barely changed during 26 weeks of incubation. The most significant contribution of this research is to develop the concept of direct bio-regeneration of exhausted resins by combining physicochemical ion-exchange and biological reduction technology, especially for the removal of perchlorate.

A zeolite material with a Si/Al molar ratio of 1.2 was synthesized by changing the NaOH/CFA ratio of coal fly ash (CFA) via a fusion/hydrothermal reaction in the HD thermal power plant. The change in the crystal structure of the zeolite was confirmed using XRD and SEM, and the ammonia adsorption capacities of the synthesized zeolitic materials and a commercial zeolite (Na-A zeolite) were analyzed via an ammonia temperature-programmed desorption (NH3-TPD) process. The SEM and XRD results revealed out the zeolitic materials from the coal fly ash maintained a hexagonal Linde-type crystal structure similar to that of Na-A zeolite, but the crystallinity of the synthesized zeolitic material was reduced due to impurities. The NH3 adsorption capacity, determined from the NH3-TPD analysis of was 1.122 mmol/g of the synthesized zeolitic material, which was lower than the NH3 adsorption capacity of the Na-A zeolite.

The adsorption experiments of lithium ions were conducted in the fixed bed column packed with activated carbon modified with nitric acid. Effect of inlet concentration, bed hight and flow rate on the removal of lithium ions was investigated. The experimental results showed that the removal and the adsorption capacity of lithium ions increased with increasing inlet concentration, and decreased with increasing flow rate. When the bed height increased, the removal and the adsorption capacity increased. The breakthrough curves gave a good fit to Bohart-Adams model. Adsorption capacity and breakthrough time calculated from Bohart-Adams model, these results were remarkably consistent with the experimental values. The adsorption capacity was not changed in the case of 3 times repetitive use of adsorbent.

Adsorption of phenol on activated carbon in a fixed bed was studied. The effects of fixed-bed length, superficial velocity (flow rate) and particle size of adsorbent on fixed-bed performance were investigated. Some characteristic parameters such as the breakthrough time (t0.05), saturation time (t0.95), length of mass transfer zone (LMTZ), adsorptive capacity (W), and adsorption rate constant (Ka) were derived from the breakthrough curves. Adsorbent particle sizes significantly affected the shape of the breakthrough curve. Larger particle sizes resulted in an earlier breakthrough, a longer LMTZ and a lower adsorption rate. Superficial velocity was a critical factor for the external mass transfer during fixed-bed adsorption process. The external mass transfer resistance was dominant as increasing superficial velocity.