담도 스텐트 삽입 및 제거 시술 과정에서 담도 주위 혈관에 손상을 주어 혈액 담즙이 유발되는 경우가 드물게 보고된다. 불안정한 활력 징후를 동반할 만큼 심각한 혈액 담즙증이 발생한 경우, 구조요법으로 피막형 팽창성 금속 스텐트를 삽입할 수 있다. 본 증례는 급성담관염을 동반한 총담관 담석 환자에게 기계적 쇄석술을 시도하던 과정에서 발생한 바스켓 장치 감돈을 해결하던 중 다량의 혈액 담즙증이 발생하였고, 피막형 팽창형 금속 스텐트 삽입을 통해 내시경적 지혈술에 성공하였으나 이후 경과 관찰 중에 스텐트가 원위부로 이탈 되면서 주위 혈관에 가성동맥류를 동반한 재출혈을 경험하였고 혈관 중재술과 추가적인 지혈술에도 불구하고 결국 사망에 이른 사례이다. 지혈을 위해 삽입한 스텐트가 적절한 위치에 삽입되더라도 지혈이 잘 안될 수 있고, 스텐트가 이탈하게 되면 혈액 담즙증이 악화될 수 있으므로 출혈이 다시 발생하는지를 면밀하게 살피며 주의를 기울여야 한다.

Uranium-contaminated soil can be effectively decontaminated through acid leaching; however, this process process generates significant amounts of radioactive wastewater. Therefore, developing efficient methods to remove uranium from wastewater is essential to minimize radioactive waste generation. This study investigates the applicability of various precipitation methods for uranium removal from acidic wastewater produced during soil-washing processes. Three methods were evaluated: metal hydroxide (M–OHx) co-precipitation, uranium peroxide (UO4) precipitation, and uranium phosphate (KUO2PO4) precipitation. The M–OHx precipitation method removes uranium by precipitating excess metal ions in wastewater by adjusting the pH. This method is easy to use and has a high removal efficiency. The UO4 and KUO2PO4 precipitation methods involve adding reagents to precipitate uranium in the mineral phase. They enable selective uranium separation and further volume reduction. In the results, M–OHx and KUO2PO4 precipitation methods remove uranium to less than 1 mg∙L−1 within 2 h, demonstrating superior capabilities compared to UO4 precipitation. The optimal method is different depended on the management strategy for the recovered uranium. The M–OHx precipitation method was suitable for permanent disposal, whereas KUO2PO4 could be recycled. Based on these findings, guidelines for the effective treatment of wastewater containing uranium from the soil-washing process can be established.

This study developed and evaluated a non-coagulant dredged sediment treatment system as an eco-friendly river dredging and management technology. From 2014 to 2023, heavy rain damage in South Korea amounted to approximately 2.8 trillion KRW, with a sharp increase since 2020. River dredging has been recognized as a crucial countermeasure, and this study aimed to minimize the environmental impact of conventional dredging methods by introducing a non-coagulant treatment system. The developed system utilizes a remotely operated vehicle (ROV) to suction dredged sediment, which is then processed through sedimentation and filtration to separate solids and discharge treated water. Field tests were conducted in Seohwa Stream, Okcheongun, Chungcheongbuk-do. Results showed that the turbidity increase within the ROV operation area was minimal at 3.8%, and the suspended solids (SS) removal rate was 100%. Additionally, the system is akinetes discharge concentration was confirmed to be 0 cells g-1, demonstrating its effectiveness in water quality restoration. These findings confirm that the non-coagulant dredged sediment treatment system reduces environmental impact while ensuring efficient dredging and water quality enhancement. The proposed technology is expected to serve as a sustainable solution for river dredging and management.

Korea is a major chestnut producer, and about half of its production is discarded as chestnut shells. This study aimed to manufacture an environmentally friendly adsorbent using these wastes. For this purpose, the optimum carbonization temperature of chestnut shells was derived through thermogravimetric analysis, with structural change confirmed through SEM analysis. The results showed that the sample that carbonized at 350oC for 60 min after phosphorylation had both the highest initial acetaldehyde removal rate and the longest duration compared to other samples. As a result, an eco-friendly adsorbent for acetaldehyde was produced from chestnut shell biomass. Through this research, it was confirmed that the adsorbent can be effectively used for acetaldehyde control while addressing the issue of recycling chestnut shell wastes.

Industries that use or produce radionuclides have unintentionally released these substances into surrounding soils and sediments. To address this problem, Beautiful Environmental Construction (BEC) Co. developed the BEC’s Radioactive Soil Decontamination (BERAD) system to remove contaminants and reduce the volume of radionuclide-contaminated soils. Owing to the limited availability of radioactive isotopes such as 60Co, 90Sr, 137Cs, and uranium-contaminated soil, naturally occurring elements in soil were used in this demonstration. The soil was divided into six size fractions via manual wet sieving and the BERAD system. Then, the concentrations of uranium, cobalt, strontium, cesium, and iron in each fraction were measured. The results of both separations showed that a considerable amount of each element is retained in the finer size fractions (<0.2 mm). After BERAD separation, the corresponding values yielded 53% uranium, 45% strontium, 66% cobalt, and 53% cesium in the fine size (<0.2 mm) fractions of 35% by weight. The study found that the concentrations of these elements increased as the particle sizes decreased. Iron and micaceous minerals played a significant role in retaining the elements. The pilot scale BERAD system yielded results that were similar to those obtained via laboratory wet-sieving and was successfully demonstrated as a soil washing technology.

이 연구의 목적은 염전에서 폐기되는 간수로 만든 담체의 비소 제거 특성을 연구한 것이다. 간수담체의 물리적 특성은 800 ~ 900℃에서 소성된 것을 사용하여 검토하였다. 비표면적과 흡수율은 각각 16.670 m2/g, 42.3%이었고 압축강도와 총 기공부피는 각각 28.3 kgf/cm2, 0.00818 cm2/g이었다. 간수담체의 화학적 조성은 SiO2가 55.3%이었고 특히, MgO가 19.2%로 매우 높은 농도로 존재하였다. 이런 결 과는 마그네슘 이온을 고농도로 포함하고 있는 간수의 영향을 받은 것으로 판단된다. 또한, X-Ray 회절 분석 결과, 간수담체는 Forsterite(Mg2SiO4)와 결정구조가 유사한 것으로 밝혀졌다. 간수담체는 제올라이트와 다양한 간수 용량으로 제조되었고 20% 간수로 만든 간수담체에서 비소 제거 효율이 최대화되었다. 또한, 수용액 중 간수담체의 용량이 40%일 때 90% 이상의 비소 제거 효율을 나타냈다. 간 수담체의 비소 제거 반응은 매우 빠르게 발생하였고 대부분의 비소 제거 반응이 수 시간 내에 끝났다. 회분식 실험을 통해서 간수담체의 비소 제거율에 미치는 pH 영향을 검토한 결과, 간수담체는 넓은 pH 범위(pH 5 ~ 10)에서도 높은 비소 제거 효율을 나타내었다.

본 실험에서는 실험실 규모의 혈액투석 장치를 구성하고 국내 의료기기 제조업체에서 제작한 혈액투석기의 특성을 확인하였다. 혈액투석기 제조에 사용된 혈액투석막은 일반적으로 약 0.01 μm에서 0.2 μm의 기공을 갖는 Polyethersulfone (PES) 소재의 중공사막을 사용하였으며 중공사막의 외경은 약 270 μm, 내경은 약 200 μm이다. 혈액투석기의 하우징은 polycarbonate 소재를 사용하였으며 약 9,600개에서 12,000개의 중공사막을 탑재시켜 제작하였다. 탑재된 혈액투석막의 개수에 따라 각기 다른 막 표면적을 가지는 3종류의 혈액투석기를 사용하여 각 혈액투석기의 구조적강도와 수투과특성, 그리고 주요 요독물질 중 하나인 urea (요소)의 제거 실험을 진행하였다. 제거된 urea의 농도는 총유기탄소(total organic carbon, TOC) 분 석을 이용하여 분석하였으며 가장 높은 1.8 m2의 막 표면적을 가지는 혈액투석막의 urea 제거 성능은 약 1시간 만에 98.3% 를 달성하였다.

In this paper, the commercial anion exchange resin (IRA900) was used to investigate the adsorption properties, comparing the anion selectivity of phosphate and sulfate in water. The phosphate removal efficiency was 29.6% less than sulfate in single condition, and significantly decreased from 44.8% to 3.47 in mixed conditions while sulfate removal efficiency remained unchanged, confirming a higher selectivity for sulfate over phosphate. In the pH effect, phosphate removal efficiency increased with increase of pH due to the increased HPO4 2- species. The total removal efficiency of phosphate and sulfate was obtained approximately 62% in mixed condition, regardless of solution pH, indicating that the total anion exchange capacity was not influenced in the pH. The values of qmL and bL derived from Langmuir isotherm equation were 11.5 and 8.10 times higher for sulfate than for phosphate in mixed conditions. In single condition, sulfate and phosphate reached to equilibrium at 6 and 3 h, respectively. In mixed condition, phosphate was desorbed by the sulfate after 1h and the time to equilibrium for sulfate was retarded to 6h. Furthermore, when comparing the separation factor (αP/S), increasing the initial concentration led to higher selectivity of phosphate.

The MBR process, which uses membrane to separate solids instead of secondary clarifier, has the advantage of maintaining high MLSS (Mixed Liquor Suspended Solids) concentration in bioreactors. In this study, three MBR processes combined with chemical phosphorus removal facility were studied: the phase-isolated MBR process with one recirculation pump, the A2O MBR process with two recirculation pumps, and the MBR process without a oxygen depletion reactor with three recirculation pumps. 116 simulations by EQPS (Effluent Quality Prediction System) were performed, under same design influent characteristics and hydraulic retention time, to see the effects of recirculation ratio changes on effluent water quality. The final effluent limits for total nitrogen and phosphorus were set to as 10 ㎎/L or less and 0.2 ㎎/L or less, respectively. AlCl3 was fed at MBR effluent to make 0.2 ㎎/L of total phosphorus precisely by PI (Proportional-Integral) controller in EQPS. This study showed that the phase isolated MBR process (R1 600%) had the highest nitrogen removal efficiency, with a final effluent T-N concentration of 6.765 mg/L. However, the A2O MBR process (R1 400%, R2 100%) required the lowest AlCl3 flow of 0.742 m3/day, which is approximately 59.1% lower than the average AlCl3 flow of the phase-isolated MBR process. It also produced 4,835 kg/day of sludge, the lowest among the studying MBR processes. It seems that A2O MBR process is the most economic method to treat studying wastewater to meet final effluent nutrient limit targets. However, carbon neutrality must be considered to select the best process to treat studying wastewater and it will be presented later.

In this study, in order to develop an eco-friendly filtration method that considers the health and safety of the aquatic ecosystem by differentiating it from chemical methods (coagulants, oxidants, etc.), which are mainly used as methods for managing the removal of algae in the algal bloom stage, an effective separation membrane for algae removal was reviewed, an appropriate technology was proposed through field application, and the effect of algae removal was evaluated. The membrane used was applied in the field by constructing an optimal technology through auxiliary facilities with an immersion tubular membrane and a pressurized tubular membrane resistant to adhesive pollutants and algae. As a result, the strong characteristics of Fouling (blocking) by adhesive algae were confirmed, and the effect of removing algae and particulate matter in the immersion type tubular membrane was 99% chlorophyll-a (Chl-a), 99.2% suspended solid (SS), and 96.7% of pressurized tubular membranes, showing excellent effects in removing algae and particulate organic matter. In addition, as a result of field application to eutrophic reservoirs where high-density algae are distributed, it was confirmed that stable operation of algae was possible during the process of filtering, separation, and concentration.

Building step-scheme (S-scheme) heterojunctions has recently emerged as a highly effective approach for developing superior photocatalysts for water purification. Herein, a C3N5/ Ag3PO4 (CA) S-scheme heterojunction was prepared by in situ growth of Ag3PO4 nanoparticles on 2D C3N5 nanosheets. Notably, under visible-light irridiation, CA exhibited significantly higher activity in the photodegradation of LEVO, which is about 28.38, 2.41, and 2.14 times higher than the rates for C3N5, Ag3PO4, and the mixture, respectively. Based on the radical scavenging experiments, the mechanism for enhanced photocatalytic performance has been analyzed, is attributed to improved interfacial charge separation, the elevated redox potential of photon-generated electrons and holes, and the increased generation of active species resulting from the S-scheme transfer of photoinduced carriers. Additionally, CA demonstrates greater stability than either C3N5 or Ag3PO4 alone in the photo-oxidation of LEVO and the photodegradation of RhB. In essence, this study not only deepens our comprehension of the photocatalytic mechanism of CA, but also pioneers a novel concept for the development of highly effective and stable S-type heterojunction photocatalysts.

This study evaluates the balance between cellular removal and extracellular matrix (ECM) preservation in cardiac tissue engineering by comparing chemical and physical decellularization methods. Cardiac tissues were treated with chemical agents (sodium dodecyl sulfate and Triton X-100) and physical methods (freeze-thawing and ultrasound). These methods were assessed based on residual cellular content, DNA quantification, ECM structural integrity, and preservation of key ECM components like collagen and glycosaminoglycan (GAG). The results revealed that while chemical methods, particularly SDS, achieved more complete cell removal, they significantly compromised ECM integrity. In contrast, physical methods, such as freeze-thawing, preserved ECM structure more effectively, despite moderate cellular removal. The findings underscore the importance of tailoring decellularization techniques to specific cardiac tissue engineering needs, with chemical methods excelling in cell removal and physical methods offering superior ECM preservation. Future research should aim to optimize these methods to achieve a better balance between decellularization efficiency and ECM integrity.

This study evaluates the potential of various coagulants to enhance the efficiency of total phosphorus removal facilities in a sewage treatment plant. After analyzing the existing water quality conditions of the sewage treatment plant, the coagulant of poly aluminium chloride was experimentally applied to measure its effectiveness. In this process, the use of poly aluminium chloride and polymers in various ratios was explored to identify the optimal combination of coagulants. The experimental results showed that the a coagulants combination demonstrated higher treatment efficiency compared to exclusive use of large amounts of poly aluminium chloride methods. Particularly, the appropriate combination of poly aluminium chloride and polymers played a significant role. The optimal coagulant combination derived from the experiments was applied in a micro flotation method of real sewage treatment plant to evaluate its effectiveness. This study presents a new methodology that can contribute to enhancing the efficiency of sewage treatment processes and reducing environmental pollution. This research is expected to make an important contribution to improving to phosphorus remove efficiency of similar wastewater treatment plant and reducing the ecological impact from using coagulants in the future.

Industrial activities that utilize nuclear technology can cause radioactive contamination in the ecosystems. In particular, cesium (Cs) has problems, such as neurological diseases, when it is exposed and accumulated in the bodies of animals, plants, and humans for a long time. Therefore, the development of simple and economical adsorbents for Cs removal is required. In this study, the surface of petroleum residue pitch was modified using NaClO and it was used to remove Cs from an aqueous solution. Batch experiments and characterization of the modified adsorbent were performed to determine the adsorption mechanism between the adsorbent and Cs. From these results, chemical and monolayer adsorption were found to occur at the carboxyl groups on the adsorbent surface, along with a cation exchange reaction occurred due to the sodium ions on the surface. Through this modification process, the total acidity, including phenolic, lactonic and carboxylic functional groups, was improved to 1.563 mmol/g and the maximum adsorption capacity of Cs for the modified adsorbent was 65.8 mg/g.

Although most strains of escherichia coli (E. coli) are harmless, some serotypes can cause serious food poisoning in humans. It is very difficult to eliminate E. coli from our lives. Here we show that E. coli can be eliminated by hydroxyapatite (HAp). Because HAp has a positive charge, the material and E. coli are attracted through electrostatic interactions. Additionally, because the surface of HAp is porous, it enters the pores of the HAp surface removing them from the environment. The amount of adsorption was observed to increase over time, and the zeta potential value of the material tended to be similar to that of E. coli. This phenomenon is thought to have zeta potential similar to that of E. coli as it is adsorbed onto the HAp surface over time. E. coli stained with crystal violet was spread on a glass slide and HAp porous sol powder was dropped to remove the E. coli. We expect that this analysis will open a new direction for antibacterial materials.