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규산마그네슘 복합화를 통한 할로이사이트 기반 튜브형 담체의 메틸렌 블루 및 중금속 흡착능 향상 연구
전준영,전종록,신승구,이윤기 대한환경공학회 2023 대한환경공학회지 Vol.45 No.1
Objectives: Thermal stability of the halloysite and magnesium silicate is discussed in terms of microstructure and adsorption behavior to optimize their composite as an absorbent for methylene blue (MB) and heavy metal ions removal from an aqueous solution. Methods: Halloysite/magnesium silicate tubular composites with high adsorption capacity of methylene blue and heavy metal ions were prepared with extrusion and consequent firing. To define the firing temperature of the tubular media, The microstructure and the adsorption equilibrium characterized the thermal stability of the halloysite and the magnesium silicate Results and Discussion: The magnesium silicate used in this study shows broad peaks in x-ray diffraction; however, the treatment of 750℃ induces its crystallization. The specific surface area of the magnesium silicate is also gradually decreased along with the firing temperature increase. No significant degradation in methylene blue adsorption capacity for magnesium silicate is observed until 500℃-treatment. However, the higher firing temperature reduces the capacity: 14.0%P, 26.1%P, and 96.3%P decrease for 600℃, 700℃, and 750℃, respectively. Regardless of heat treatment, the Langmuir isotherm equation represents the adsorption equilibria well compared to the Freundlich model. The tubular media of the halloysite – 30 wt.% of magnesium silicate fired at 600℃ exhibits a high specific surface area of 115 m2 g-1 and a relative porosity of 43.5%. Compared to the halloysite-only tubular media, the adsorption capacity of the composites is significantly improved with the incorporation of magnesium silicate. The adsorption capacity of 168h for methylene blue is more than tripled, 29.8 mg g-1, and the adsorption capacity of Cr(III), Cu(II), and Zn(II) is also greatly enhanced by more than 4.8 times. Conclusions: Thermal stability of magnesium silicate is investigated for use as an additive adsorbent in terms of the microstructure and the adsorption capacity. Even at 600℃ of the firing temperature, magnesium silicate shows a higher specific surface area and higher adsorption capacity of MB compared to those of the halloysite; the adsorption fits well into Langmuir behavior. The addition of magnesium silicate into the halloysite media significantly enhances its adsorption capacity for MB and heavy metal ions such as Cr(III), Cu(II), and Zn(II). 목적: 본 연구는 향상된 메틸렌 블루 및 중금속 이온 제거 흡착능을 지닌 규산마그네슘-할로이사이트 복합 담체 제조를 위해 소재 및 담체의 열적 안정성 및 흡착 거동을 평가하였다. 규산마그네슘-할로이사이트 복합 담체를 제조하여 수용액으로부터 메틸렌 블루 및 중금속 이온 제거를 위한 흡착제로 활용하기 위해 소재의 열적 안정성 및 흡착능을 평가하였다. 방법: 메틸렌블루 및 중금속에 대해 높은 흡착능을 지닌 할로이사이트/규산마그네슘 관형 복합 담체가 압출 및 소성 공정을 통해 제조되었다. 미세구조 및 흡착 평형 분석을 통해 할로이사이트 및 규산마그네슘의 열적 안정성을 평가하였으며, 결과를 통해 관형 담체의 소성 온도를 결정하였다. 결과 및 토의: 규산마그네슘은 750℃ 소성 시 결정화가 진행되었으며, 비표면적은 소성 온도가 증가함에 따라 저감되었다. 저감된 규산마그네슘의 흡착능은 500℃ 소성까지는 유의미한 변화가 없었으나, 600℃, 700℃ 및 750℃ 열처리 시 각각 14.0%P, 26.1%P, 및 96.3%P 감소되었다. 열처리와 무관하게, 할로이사이트 및 규산마그네슘의 등온 흡착 데이터는 Langmuir 등온흡착식에 가장 잘 맞았다. 600℃소성된 할로이사이트-30 wt.% 규산마그네슘 복합 관형 담체는 115 m2 g-1 의 높은 비표면적 및 43.5%의 기공율을 나타내었으며, 168시간 메틸렌블루 흡착능이 29.8 mg g-1 을 나타내었다. 이는 할로이사이트 관형 담체 대비 3배 이상 증가한 값이며, Cr(III), Cu(II), 및 Zn(II)의 흡착능도 모두 4.8배 이상 향상되었다. 결론: 미세구조 및 흡착능의 관점에서 흡착제로서의 규산마그네슘의 열적 안정성이 평가되었다. 600℃열처리 후에도 규산마그네슘은 할로이사이트 대비 높은 비표면적 및 흡착능을 보여주었으며, 흡착은 Langmuir 거동을 보였다. 할로이사이트 담체의 규산마그네슘 복합화를 통해 메틸렌 블루 및 Cr(III), Cu(II), and Zn(II)흡착능이 대폭 향상되었다.
Humic Acid Confers HIGH-AFFINITY K+ TRANSPORTER 1-Mediated Salinity Stress Tolerance in Arabidopsis
Laila Khaleda,박희진,윤대진,전종록,김민갑,차준영,김외연 한국분자세포생물학회 2017 Molecules and cells Vol.40 No.12
Excessive salt disrupts intracellular ion homeostasis and inhibits plant growth, which poses a serious threat to global food security. Plants have adapted various strategies to survive in unfavorable saline soil conditions. Here, we show that humic acid (HA) is a good soil amendment that can be used to help overcome salinity stress because it markedly reduces the adverse effects of salinity on Arabidopsis thaliana seedlings. To identify the molecular mechanisms of HA-induced salt stress tolerance in Arabidopsis, we examined possible roles of a sodium influx transporter HIGH-AFFINITY K+ TRANSPORTER 1 (HKT1). Salt-induced root growth inhibition in HKT1 overexpressor transgenic plants (HKT1-OX) was rescued by application of HA, but not in wild-type and other plants. Moreover, salt-induced degradation of HKT1 protein was blocked by HA treatment. In addition, the application of HA to HKT1-OX seedlings led to increased distribution of Na+ in roots up to the elongation zone and caused the reabsorption of Na+ by xylem and parenchyma cells. Both the influx of the secondary messenger calcium and its cytosolic release appear to func-tion in the destabilization of HKT1 protein under salt stress. Taken together, these results suggest that HA could be applied to the field to enhance plant growth and salt stress tolerance via post-transcriptional control of the HKT1 transporter gene under saline conditions.
이익의 품질과 자본시장의 이례현상 : 수익-비용 대응의 원칙과 주가표류현상
최국현 ( Kuk-hyun Choe ),전종록 ( Jong-rok Jeon ) 한국생산성학회 2016 生産性論集 Vol.30 No.3
The matching principle in conventional accrual basis accounting, rather than cash basis accounting, recognizes accounting income by recording related expenses at the period when revenues are recognized. Accounting methods with high level of matching principle can be defined as neutrality in accounting in the sense that an impartial point of view is maintained in revenue and expense recognition. According to previous studies, it has been reported that the higher the level of matching principle is, the higher the quality of accounting income becomes. Thus, by analyzing the effects of the level of matching principle on the firm specific stock returns, post-earnings-announcement drift, this study examines earnings quality of matching principle is attributable to post-earnings-announcement drift. Previous studies find that earnings quality of earnings persistence is positively correlated with post-earnings-announcement drift. Thus, another estimate of earnings quality, the degree of matching revenues to expenses, is hypothesized to have the positive effect on post-earnings-announcement drift. Our results are generally consistent with the hypothesis. Findings show that firms with higher degree of revenue-expense matching have abnormal stock returns 10 days post-earnings announcement. Whereas over 10 days post-earnings announcement fail to show excessive stock returns. Some caveats can be attributable to these findings. The way we measure the degree of matching principle by the adjusted R² from revenue to expenses may not be adequate, and random walk model to estimate expected earnings may capture the properties with considerable errors. Nonetheless, over 2,000 observations in the period of 8 years can alleviate such errors in our results.
이수임,박종환,김성헌,강세원,조주식,전종록,이용복,서동철 한국응용생명화학회 2019 Applied Biological Chemistry (Appl Biol Chem) Vol.62 No.-
The objective of this study was to evaluate the adsorption characteristics of malachite green (MG) on pristine lignin as a dye adsorbent. The adsorption capacity of MG on lignin (31.2 mg/g) was described by Langmuir isotherm and pseudo second order models, and were higher than humic acid (6.4 mg/g). The adsorption of MG by lignin was rapid occurring within 15 min of the reaction, and then equilibrium was reached. The adsorption of MG by lignin based on an intraparticle diffusion model indicated that it was dominated by external boundary. Removal of MG by lignin can be applied at a wide range of pH’s (2–5), and optimal lignin dosage for MG removal was 3 g/L. In addition, the desorption efficiency of MG adsorbed on lignin was highest in methanol + acetic acid (95:5%, v/v) mixture of all solutions tested. The peaks attributed to the hydrogen-bonded stretching vibrations and sulphonyl groups in lignin before MG adsorption, were assigned at about 3400 and 620 cm−1, while the peaks in lignin after MG adsorption were attenuated or reduced. This result indicates that the adsorption of MG by lignin is closely related to the O–H and S–O bonds. Finally, this study suggests that pure lignin, which excludes active processes, can also be used as an adsorbent for dyes. However, in order to utilize the dye-adsorbed lignin repeatedly, further studies will be needed.