In this study, the hydrogen sulfide removal performance of materials that can be used instead of NaOH was evaluated to reduce the amount of NaOH, a harmful substance used in chemical cleaning methods. Three alternative chemical agents were evaluated: commercially available chemical-based CB, enzyme-based EB, and natural substance-based NB. The hydrogen sulfide removal performance evaluation consisted of three lab tests: the EL608 method, a method using a bag, a method using a sensor and a chamber, and a field test conducted on a scrubber in operation in the actual field. As a result of evaluation by the EL608 Method, CB was 92.3% (±2.9%), EB 60.5% (±5.8%), and NB 88.3% (±3.6%), similar or somewhat similar to NaOH (5%) 99.8% (0.1%). In the evaluation of the hydrogen sulfide removal performance using Bag, the Michaelis-Menten coefficient was CB 4.30 and EB 5.30, lower than NaOH 6.60, and the affinity for hydrogen sulfide was evaluated to be stronger. Even in the method using the sensor and chamber, CB and EB showed similar hydrogen sulfide removal performance of NaOH, but NB showed low treatment performance. In the evaluation using the scrubber in the actual field, the treatment efficiency of CB and EB was higher than that of NaOH under all hydrogen sulfide inlet concentration conditions. If microorganisms grow on the packing material filled inside the scrubber, treatment efficiency may decrease. In order to prevent this phenomenon, the microbial growth inhibitory function of alternative materials was evaluated, and CB, EB, and NB were all superior to NaOH. As a result of this study, it was shown that CB and EB can replace NaOH because they have excellent performance in removing hydrogen sulfide and inhibiting microbial growth.

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.

먼지 필터 막은 인간의 건강, 안전 및 환경 보호의 몇 가지 중요한 측면에 기여하기 때문에 인간의 삶과 다양한 산업에서 중요한 역할을 한다. 이 연구는 고온 조건에 대한 우수한 열안정성과 접착 특성을 가진 polysulfone@polyphenylene sulfide/polytetrafluoroethylene (PSf@PPS/ePTFE) 복합 먼지 필터 막의 개발을 제시한다. FT-IR 분석은 PSF 접착제가 PPS 직 물에 성공적으로 함침되고 ePTFE 지지체와의 상호 작용을 확인한다. FE-SEM 이미지는 향상된 섬유 상호 연결 및 PSf 농도 와 함께 접착력을 보여준다. PSf@PPS/ePTFE-5는 가장 적합한 다공성 구조를 보여준다. 복합 막은 400°C까지 예외적인 열 안정성을 보여준다. 박리 저항 테스트는 먼지 여과에 대한 충분한 접착력을 보여 공기 투과성을 희생시키지 않고 힘든 고온 조건에서 신뢰할 수 있는 성능을 보장한다. 이 막은 산업 응용 분야에서 유망한 잠재력을 제공한다. 더 나아가 최적화 및 응 용 가능성을 탐구할 수 있다.

The germination process is critical for plant growth and development and it is largely affected by environmental stress, especially salinity. Recently, hydrogen sulfide (H2S) is well known to act as a signaling molecule in a defense mechanism against stress conditions but poorly understood regulating seed germination. In this study, the effects of NaHS (the H2S donor) pretreatment on various biochemical (hydrogen peroxide (H2O2) content and amylase and protease activity) and physiological properties (germination rate) during seed germination of oilseed rape (Brassica napus L. cv. Mosa) were examined under salt stress. The seed germination and seedling growth of oilseed rape were inhibited by NaCl treatment but it was alleviated by NaHS pretreatment. The NaCl treatment increased H2O2 content leading to oxidative stress, but NaHS pre-treatments maintained much lower levels of H2O2 in germinating seeds under salt stress. Amylase activity, a starch degradation enzyme, significantly increased over 2-fold in control, NaHS pretreatment, and NaHS pretreatment under NaCl during seed germination compared to NaCl treatment. Protease activity was highly induced in NaHS-pretreated seeds compared to NaCl treatment, accompanied by a decrease in protein content. These results indicate that NaHS pretreatment could improve seed germination under salt stress conditions by decreasing H2O2 accumulation and activating the degradation of protein and starch to support seedling growth.

Sulfide concentrations critically affect worker safety and the integrities of underground facilities, such as deep geological repositories for spent nuclear fuel. Sulfide is highly sensitive to oxygen, which can oxidize sulfide to sulfate. This can hinder precise measurement of the sulfide concentration. Hence, a literature review was conducted, which revealed that two methods are commonly used: the methylene blue and sulfide ion-selective electrode (ISE) methods. Inductively coupled plasma optical emission spectroscopy (ICP-OES) was used for comparison with the two methods. The sulfide ISE method was found to be superior as it yielded results with a higher degree of accuracy and involved fewer procedures for quantification of the sulfide concentration in solution. ICP-OES results can be distorted significantly when sulfide is present in solution owing to the formation of H2S gas in the ICP-OES nebulizer. Therefore, the ICP-OES must be used with caution when quantifying underground water to prevent any distortion in the measured results. The results also suggest important measures to avoid problems when using ICP-OES for site selection. Furthermore, the sulfide ISE method is useful in determining sulfide concentrations in the field to predict the lifetime of disposal canisters of spent nuclear fuel in deep geological repositories and other industries.

The major concern in the deep geological disposal of spent nuclear fuels include sulfide-induced corrosion and stress corrosion cracking of copper canisters. Sulfur diffusion into copper canisters may induce copper embrittlement by causing Cu2S particle formation along grain boundaries; these sulfide particles can act as crack initiation sites and eventually cause embrittlement. To prevent the formation of Cu2S along grain boundaries and sulfur-induced copper embrittlement, copper alloys are designed in this study. Alloying elements that can act as chemical anchors to suppress sulfur diffusion and the formation of Cu2S along grain boundaries are investigated based on the understanding of the microscopic mechanism of sulfur diffusion and Cu2S precipitation along grain boundaries. Copper alloy ingots are experimentally manufactured to validate the alloying elements. Microstructural analysis using scanning electron microscopy with energy dispersive spectroscopy demonstrates that Cu2S particles are not formed at grain boundaries but randomly distributed within grains in all the vacuum arc-melted Cu alloys (Cu-Si, Cu-Ag, and Cu-Zr). Further studies will be conducted to evaluate the mechanical and corrosion properties of the developed Cu alloys.

Lead sulfide ( PbS ) nanocrystals anchored on nitrogen-doped multiwalled carbon nanotubes ( CNx ) have been synthesized employing an environmentally friendly and inexpensive wet chemistry process. CNx∕PbS composites have been examined by scanning electron microscopy, X-ray diffraction and Raman spectroscopy. Theorical ab initio calculations have been developed to determine the samples structural, morphological and optical properties to explain the experimental evidences. The PbS nanoparticles exhibit of 4 nm to 27 nm particle size with a face-centered cubic crystal structure and are homogeneously distributed along the carbon nanotubes. The nitrogen-doped CNTs acts as binding sites for the PbS clusters as ab initio theoretical study suggests.

Public complaints arising from centralized animal manure treatment plants are increasing due to the odors produced during animal manure treatment. Various physico chemical and biological methods are used to mitigate such odors. Still, many problems exist, such as a lack of fundamental data on odor generation characteristics and design standards for odor mitigation facilities. Therefore, this study evaluated the characteristics of NH3 and H2S gas produced from a centralized animal manure treatment plant. The centralized animal manure treatment plant selected in this study has a treatment capacity of 150 tons (animal manure and food waste) per day. The composting matrix was mechanically turned from 9:00 am to 6:00 pm on weekdays and not turned all day on weekends. The NH3 concentrations measured during the day on weekdays (96.4 ± 7.8 ppmv) were about 14% higher than on weekends (84.9 ± 15.9 ppmv). During the week, the ammonia concentration during the day was about 15% higher than at night, but there was no difference between day and night on weekends. The hydrogen sulfide concentration during the day (4,729 ± 3,687 ppbv) on a weekday was about 4.7 times higher than at night (1,007 ± 466 ppbv). The results of this study provide valuable information that is necessary for the operation of odor mitigation facilities. It is expected that the results will contribute to establishing an operational strategy that can reduce the energy required to collect exhaust gas.

This study evaluated the odor mitigation effect of rice husk biochar addition to the bedded pack dairy barn floor using lab-scale reactors for five days. Rice husk biochar mixed with dairy manure and sawdust mixture at different ratios (5%-addition test unit: adding biochar by 5% of the total solid weight of the mixture, 10%-addition test unit: adding biochar by 10% of the total solid weight of the mixture). Cumulative NH3 and H2S emissions of 10%-addition test unit were reduced by 26% (p< 0.05) and 46% (p = 0.0655), respectively, compared with control. However, 5%-addition test unit did not show NH3 and H2S emission reduction. Further research is needed to determine the appropriate level of biochar addition between 5 and 10%, and to evaluate applicability in the field through economic analysis.

Tin-antimony sulfide nanocomposites were prepared via hydrothermal synthesis and a N2 reduction process for use as a negative electrode in a sodium ion battery. The electrochemical energy storage performance of the battery was analyzed according to the tin-antimony composition. The optimized sulfides exhibited superior charge/discharge capacity (770 mAh g-1 at a current density of 100 mA g-1) and stable lifespan characteristics (71.2 % after 200 cycles at a current density of 500 mA g-1). It exhibited a reversible characteristic, continuously participating in the charge-discharge process. The improved electrochemical energy storage performance and cycle stability was attributed to the small particle size, by controlling the composition of the tin-antimony sulfide. By optimizing the tin-antimony ratio during the synthesis process, it did not deviate from the solubility limit. Graphene oxide also acts to suppress volume expansion during reversible electrochemical reaction. Based on these results, tin-antimony sulfide is considered a promising anode material for a sodium ion battery used as a medium-to-large energy storage source.

Odor is a type of sensory pollution that can stimulate the human sense of smell when it occurs, causing discomfort and making it difficult to create a pleasant environment. For this reason, there is a high possibility of complaints regarding odors if odors occur in pigsties near residential properties, and the number of such complaints is also increasing. In addition, odors emanating from pigsties around military installations can cause physical and psychological harm, not only to the soldiers living in these type of facilities but also to the families belonging to military personnel living there as well. Because the concentration of odors varies due to diverse factors such as temperature, humidity, wind direction, wind speed, and interaction between causative materials, predicting odors based on only one factor is not proper or appropriate. Therefore, in this work, we sought to construct models that are based on several regression techniques of machine learning using data collected in field. And we selected and utilized the model that has the highest-accuracy in order to notify and warn residents of odors in advance. In this work, 3672 data items were used to train and test the model. The several machine learning algorithms to build the models are polynomial regression, ridge regression, K-nearest neighbor regression (KNN Regression), and random forest. Comparing the performance of models based on each algorithm, the study found that KNN Regression was the most suitable model, and the result obtained from KNN regression was significant.

Two lab-scale trickle-bed type biofilters with a single fungal species (Aspergillus fumigatus, Acidomyces acidophilus, respectively) have been studied to investigate the simultaneous removal of inorganic (hydrogen sulfide) and organic (butyl acetate) compounds. The biofilter with Aspergillus fumigatus treated simultaneously two different compounds with removal capacity of 1,511 mgS/m3/hr and 6,324 mgC/m3/hr; and the biofilter inoculated with Acidomyces acidophilus had the removal capacity of 1,254 mgS/m3/hr and 6,045 mgC/m3/hr. Stable operational performance was observed in both biofilters under an acidic condition of pH 2 to 4. Based on pseudo-first-order removal rates as a function of depth in the biofilter, Aspergillus fumigatus showed a twice faster rate of hydrogen sulfide removal than Acidomyces acidophilus, 15.9% (Aspergillus fumigatus) and 17.9% (Acidomyces acidophilus) of total sulfur removed were oxidized to produce sulfates, and 77.8% (Aspergillus fumigatus) and 79.4% (Acidomyces acidophilus) were accumulated in the form of S0 through the bed in both biofilters, respectively.

Sulfide dissolved in wastewater is a potential source of hydrogen sulfide. Hydrogen sulfide is an odorous substance that causes civil complaints and is a dangerous substance that threatens the corrosion of structures and the safety and health of workers. The removal efficiencies of the chemical oxidant and the coagulants were compared to evaluate the removal of dissolved sulfide. Since the effectiveness may vary depending on the characteristics of the wastewater, water was used as a control, and 5 mg/L of dissolved sulfide was dissolved in water and sewage wastewater. When oxidant was used, the results showed a high sulfide removal rate in sewage wastewater than water, and the removal efficiency was enhanced with increasing oxidant concentration. Sulfide removal efficiencies after one hour after injecting oxidants H2O2, NaOCl, NaClO2 to sewage wastewater were 70%, 90%, and 100%, respectively. After the oxidants were administered four times, the removal was 90%, 100%, and 100%, respectively. In the case of sulfide removal with the oxidizing agent, the removal efficiency was NaClO2, NaOCl, H2O2 (highest - lowest). NaClO2 showed 100% removal efficiency within 10 minutes under all conditions (A condition, B condition), making it the most sewage effective agent in this study. In the case of the coagulants, 100% of the sulfides dissolved in water were removed in the first 10 minutes under all conditions. In sewage wastewater, FeCl2 and FeSO4 also showed 100% removal efficiency under all conditions after one hour, and FeCl3 showed 90% and 99% removal rates under A and B conditions, respectively. That is, the monovalent iron coagulants (FeCl2, FeSO4) were found to be somewhat more effective in the removal of sulfides in sewage wastewater than the divalent iron (FeCl3) coagulants. When the sulfides were removed with coagulants, FeCl2 had the highest removal efficiency followed by FeSO4 and FeCl3. Moreover, it was found that NaClO2 has the best reaction efficiency at the minimum reaction time and the reaction concentration.