Bis (2-ethylhexyl)phosphoric acid (HDEHP) is a renowned extractant, favored for its affinity to selectively remove uranium via its P=O groups. We previously synthesized HDEHP-functionalized mesoporous silica microspheres for solid-phase uranium adsorption. Herein, we investigated the kinetic and isothermal behavior of uranyl ion adsorption in mesoporous silica microspheres functionalized with phosphate groups. Adsorption experiments were conducted by equilibrating 20 mg of silica samples with 50 mL of uranium solutions, with concentrations ranging from 10 to 100 mgU L−1 for isotherms and 100 mgU L−1 for kinetics. Three distinct samples were prepared with varying HDEHP to TEOS molar ratios (x = 0.16 and 0.24) and underwent hydrothermal treatment at different temperatures, resulting in distinct textural properties. Contact times spanned from 1 to 120 hours. For x = 0.16 samples, it took around 50 and 11 hours to reach equilibrium for the hydrothermally treated samples at 343 K and 373 K, respectively. Adsorbed quantities were similar (99 and 101 mg g-1, respectively), indicating consistent functional group content. This suggests that the key factor influencing uranium adsorption kinetics is pore size of the silica. The sample treated at 373 K, with a larger pore size (22.7 nm) compared to 343 K (11.5 nm), experienced less steric hindrance, allowing uranium species to diffuse more easily through the mesopores. The data confirmed the excellent fit of pseudo-second-order kinetic model (R2 > 0.999) and closely matched the experimental value, suggesting that chemisorption governs the rate-controlling step. To gain further insights into uranium adsorption behavior, we conducted an adsorption isotherm analysis at various initial concentrations under a constant pH of 4. Both the Langmuir and Freundlich isotherm models were applied, with the Langmuir model providing a superior fit. The relatively high R2 value indicated its effectiveness in describing the adsorption process, suggesting homogenous sorbate adsorption on an energetically uniform adsorbent surface via a monolayer adsorption and constant adsorption site density, without any interaction between adsorbates on adjacent sites. Remarkably, differences in surface area did not significantly impact uranium removal efficiency. This observation strongly suggests that the adsorption capacity is primarily governed by the loading amount of HDEHP and the inner-sphere complexation with the phosphoryl group (O=P). Our silica composite exhibited an impressive adsorption capacity of 133 mg g-1, surpassing the results reported in the majority of other silica literature.

Transition metal chalcogenides are promising cathode materials for next-generation battery systems, particularly sodium-ion batteries. Ni3Co6S8-pitch-derived carbon composite microspheres with a yolk-shell structure (Ni3Co6S8@C-YS) were synthesized through a three-step process: spray pyrolysis, pitch coating, and post-heat treatment process. Ni3Co6S8@C-YS exhibited an impressive reversible capacity of 525.2 mA h g-1 at a current density of 0.5 A g-1 over 50 cycles when employed as an anode material for sodium-ion batteries. However, Ni3Co6S8 yolk shell nanopowder (Ni3Co6S8-YS) without pitch-derived carbon demonstrated a continuous decrease in capacity during charging and discharging. The superior sodium-ion storage properties of Ni3Co6S8@C-YS were attributed to the pitchderived carbon, which effectively adjusted the size and distribution of nanocrystals. The carbon-coated yolk-shell microspheres proposed here hold potential for various metal chalcogenide compounds and can be applied to various fields, including the energy storage field.

Probiotics are defined as advantageous microorganisms to human when they are ingested. However, without any protection, the viability of microbes and their adhesive ability to surface of colon decreases through acidic condition such as stomach and intestines. Therefore, many studies have been conducted to figure out to enhance not only the viability of probiotics, but also its adhesion for increasing effect of probiotics. In this study, extrusion method was conducted to encapsulate Enterococcus faecium. E. faecium-alginate solution was injected to CaCl2 solution with regular side air injection. To prevent coagulation of beads, stirring was conducted in CaCl2 solution and encapsulated alginate-Ca2+ microspheres were produced. For optimal encapsulation condition, air pressure was 100 mbar, flow rate of E. faecium solution was 0.02 ml/h and stirring rate was 200 rpm. For mucoadhesive ability, Monolayer of HT-29 cells used as a colon cell and encapsulated cells were inoculated and incubated in 37℃, 5% CO2/95% air atmosphere for 1 h. Encapsulation efficiency of the encapsulation method used in this study was 98.2%. For mucoadhesive test, the concentration of inoculated E. faecium was 9.9×108 CFU/ml and the concentration of adhered E. faecium was 1.6×106 CFU/ml. In conclusion, encapsulation efficiency of extrusion method was high enough to be accepted for this study, however, alginate-Ca2+ microspheres revealed lower adhesive ability compared to expectation. Therefore, it needs further studies to increase adhesive ability with other polymers.

SPG (Shirasu porous glass) 관형 막이 설치된 회분식 막유화 장치를 사용하여 단분산 칼슘 알지네이트 미립자를 제조하기 위한 막유화 공정변수의 최적조건을 결정하였다. 막유화의 공정변수로는 연속상에 대한 분산상의 비율, 알지네이트 농도, 유화제의 종류와 농도, 안정제 농도, 가교제 농도, 교반속도, 막간 압력차 및 SPG 막의 세공크기로 설정하고, 이들 변수가 제조된 알지네이트 미립자의 입자 크기와 분포에 미치는 영향을 검토하였다. 막유화의 공정변수들 중에서 연속상에 대한 분산상의 비율, 막간 압력차 그리고 알지네이트 농도가 증가할수록 미립자의 크기가 증가하였다. 반면 유화제의 농도, 교반속도 그리고 가교제의 농도가 증가할수록 미립자의 크기가 감소하였다. 세공 크기 2.9mum인 SPG막을 사용한 경우 막유화의 공정변수 조절을 통해 최종적으로 평균 입자 크기 6mum, 크기 분산도 1.1인 단분산 알지네이트 미립자의 제조가 가능하였다.

While carrying out a series of study for improving the durability of High Volume Admixture Concrete using the ERCO, we found that the resistance of freezing and thawing declined due to the decrease of air amount in concrete when using the ERCO. In order to solve the problem, we carried out an experiment using the DEM. As a result of that, it did not affect the basic characteristic of concrete, and the problem of decreasing air amount caused by using the ERCO is also considered to be solved by securing the target air amount.

For insulation to concrete, lightweight aggregate and the hollow microspheres were mixing to improve the insulation performance. Hollow microspheres according to the replacement method and the replacement ratio was to compare the degree of performance improvement.