Production and characterization of activated carbon derived from brewer’s yeast

Longzhe Cui,Guiping Wu,Tae-seop Jeong,Chan-Hee Won 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.5

Activated carbon (AC) was produced from brewer’s yeast with K2CO3 activation. The effects of K2CO3/yeast ratio and activation temperature on the yield and adsorption properties of the AC were investigated. The results indicate that the optimum conditions were as follows: ratio of K2CO3/yeast=2 and activation temperature 800 oC. The AC produced under the optimum conditions has BET surface area of 1,603 m2/g, pore volume of 1.43 cm2/g and average pore diameter of 3.5 nm. Adsorption of phenol onto the AC was determined by batch test at solution pH of 7. The effects of contact time and initial phenol concentration were investigated. The adsorption process was found to follow pseudosecond-order kinetics. The rate of phenol adsorption onto the AC produced was rapid with the adsorption equilibrium reached within 5 min. The experimental data fitted well with the Langmuir isotherm model. The maximum phenol uptake by the AC was estimated to be 513.5 mg/g.

中国跨境电子商务征税问题及征管建议

崔?哲(CUI LONGZHE),?宇梁(JIN YULIANG) 동아대학교 법학연구소 2021 國際去來와 法 Vol.- No.35

Since 2014, Chinas cross-border e-commerce has ushered in explosive development, constantly going deep into all aspects of peoples daily life and providing convenience for peoples life. When China sees the contribution of cross-border e-commerce to economic development, it should also pay attention to the tax problems brought by cross-border e-commerce. This problem mainly includes: in cross-border e-commerce transactions, enterprises set up virtual business institutions and places, resulting in unclear judgment standards for tax subjects; In cross-border e-commerce transactions, due to the trend of digitization and virtualization of goods, the qualitative classification standard of enterprise income is not clear, and it is difficult to classify enterprise income qualitatively; And because cross-border e-commerce is a new thing, the original tax management model lags behind. By combining the relevant legal provisions of Chinas enterprise income tax law and the tax collection and administration law, and analyzing the characteristics of Chinas cross-border e-commerce at present, this paper puts forward relevant suggestions on the tax problems of cross-border e-commerce: in view of the unclear judgment standard of tax subject, it is necessary to introduce the concept of real or virtual subject into the enterprise income tax law, Broaden the identification scope of enterprise institutions and places; In view of the unclear qualitative classification standard of enterprise income, it should be judged on the basis of the traditional qualitative classification standard of income, supplemented by the standards of contract type and transaction purpose; In view of the lag of the tax collection management mode, the tax registration system applicable to cross-border e-commerce should be stipulated and improved in the tax collection management law, the tax declaration system should be improved, and the legal liability should be strengthened.

Comparison of catalytic ozonation of phenol by activated carbon and manganese-supported activated carbon prepared from brewing yeast

Guiping Wu,Longzhe Cui,정태섭,원찬희 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.1

Activated carbon (AC) was prepared using brewing yeast as precursor by chemical activation and manganese was supported on activated carbon (Mn/AC) by adsorption-activation method. The characterizations of prepared AC and Mn/AC and their performance as ozonation catalysts was tested. The results indicated that the crystalline phase of supported manganese was MnO. The total BET surface areas of prepared AC and Mn/AC were found to be 1603.0m2/g and 598.9 m2/g, with total pore volumes of 1.43 and 0.49 cm3/g, respectively. The average pore diameters of AC and Mn/AC were found to be 3.5 nm and 3.3 nm. Adsorption capacities of phenol onto the produced AC and Mn/AC were determined by batch test, at 25 oC and pH 7. Langmuir and Freundlich isotherm models were used to fit the isotherm experimental data, and the Langmuir isotherm model fitted these two adsorption systems well. The maximum uptakes of phenol by AC and Mn/AC were estimated to be 513.5 mg/g and 128.2 mg/g. The presence of AC prepared from brewing yeast was advantageous for TOC reduction of phenol solution compared with single ozonation, and the greatest TOC removal efficiency was obtained in the presence of Mn/AC. All ozonation reactions followed the pseudofirst-order kinetics model well, the degradation rate of phenol was enhanced in the presence of catalysts, and the more pronounced degradation rate was achieved in O3/Mn/AC system. The rate constants were determined to be 2.16×10−2min−1 for O3 alone, 5.70×10−2 min−1 for O3/AC and 6.82×10−2 min−1 for O3/Mn/AC.

Degradation of methylene blue in aqueous solution by ozone-based processes

Jie Zhang,Longzhe Cui,Tae-seop Jeong,이경환 한국공업화학회 2009 Journal of Industrial and Engineering Chemistry Vol.15 No.2

The aim of this study was to compare the efficiency of conventional ozonation and catalytic ozonation (ozone/activated carbon (O3/AC) and ozone/TiO2/activated carbon (O3/TiO2/AC)) in the degradation of methylene blue (MB) component from MB aqueous solution. The removal rates of color and chemical oxygen demand (CODCr) were assessed to screen the most appropriate oxidative process of MB treatment. In this experiment conditions, the color was completely disappeared in the presence of TiO2/AC catalyst, after 40 min of reaction time. However, only ozone system still existed 11.8%MB in aqueous solution, while in case of O3/AC system MB of 4.6% was not removed. In the COD removal experiment, the catalytic ozonation process showed a superior performance, compared to that of the conventional ozonation. COD removal efficiency was significantly promoted in the presence of catalysts such as AC and TiO2. O3/TiO2/AC was found to be the most effective approach to eliminating the color and enhancing COD removal efficiency. The catalyst of TiO2/AC was characterized by using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS).

Iron-doped chitosan microsphere for As(III) adsorption in aqueous solution: Kinetic, isotherm and thermodynamic studies

Xiaoyu Lin,Leli Wang,Shi Jiang,Longzhe Cui,Gui-Ping Wu 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.7

Iron-doped chitosan microsphere was prepared successfully and employed for effective adsorption of As(III). The results showed that the adsorption capacity benefited from the increase of iron content, and the maximum adsorption capacity was achieved at pH=8. According to the study of adsorption kinetics, adsorption rate was controlled by liquid film diffusion at a lower rotational speed, while it was controlled by chemical reaction rate at a higher rotational speed. The Freundlich and Temkin models exhibited a better fit to adsorption isotherm data, which indicated the adsorption of As(III) on iron-doped chitosan microsphere was chemisorption and the active sites of adsorbents were non-uniform distributed. Adsorption process was a spontaneous exothermic reaction because its ΔG and ΔH were negative. In presence of cations (Cd2+, Pb2+ or Zn2+) in solution, the iron-doped chitosan microsphere also showed the significant removal of As(III). However, the existence of anions (NO3 , SO4 2 or PO4 3) inhibited the As(III) removal at different level. PO4 3 showed the most significant side effects on the removal of As(III) by iron-doped chitosan microsphere. The used iron-doped chitosan adsorbent can be effectively regenerated using 1.0mol·L1 NaOH solution, and the adsorption efficiency decreased only 15.69% after being reused three times. The results of XPS, FT-IR showed that the adsorption was mainly achieved by the coordination interaction between As (III) and doped Fe in adsorbent.

Catalytic ozonation of methylene blue in aqueous solution by loading transition metal(Co/Cu/Fe/Mn) on carbon

Fu-Huang Lin,Minghan Luo,Longzhe Cui,Gui-Ping Wu 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.2

Activated carbon(AC) was prepared using brewing yeast as a precursor by chemical activation; meanwhile,cobalt, copper, ferrum and manganese supported on activated carbon(Co/AC, Cu/AC, Fe/AC, Mn/AC) were preparedby adsorption-activation method. The characterizations of prepared AC, Co/AC, Cu/AC, Fe/AC, Mn/AC and theirperformance as ozonation catalysts were tested. The total BET surface areas of prepared AC, Co/AC, Cu/AC, Fe/AC,Mn/AC were found to be 957.7, 789.7, 485.3, 486.1 and 529.8m2/g. Absorption capacities of methylene blue (MB) weredetermined to 407.77, 206.52, 121.25, 123.01, 170.94mg/g, respectively. The presence of AC was advantageous for TOCreduction of MB compared with UV/O3 system, and metal Co, Cu, Fe, Mn play an important role in the degradationprocess. The greatest TOC removal efficiency was obtained in the presence of Co/AC.

활성탄 및 TiO₂가 담지된 활성탄을 이용한 Methylene Blue 의 흡착 연구

장걸 ( Zhang Jie ),얜요 ( Yan Yao ),정태섭 ( Jeong Tae Seop ),최용철 ( Cui Longzhe ) 한국환경기술학회 2008 한국환경기술학회지 Vol.9 No.1

본 연구에서는 활성탄을 이용하여 수용액중의 Methylene Blue 제거 실험을 수행하였다. 등온흡착 곡선과 동력학 방정식을 구하기 위하여 Batch실험을 하였는데 실험결과 동력학 방정식은 first-order Model과 일치하였고 등온흡착곡선은 Langmuir isotherm model에 부합되었다. 동시에 일반 활성탄과 TiO₂를 첨가한 활성탄의 최대 흡착량을 비교 분석하였다. The feasibility of activated carbon to remove Methylene Blue from aqueous solutions was investigated. Batch experiments were carried out to study the isotherm and kinetics with differen initial concentration of Methylene blue. The kinetic data were fitted to first-order Model, Second-order Model and it was found to follow closely the Second-order Model model. Equilibrium data were fitted to Langmuir and Freundlich isotherm models. The equilibrium data were best represented by the Langmuir isotherm model. Also the maximum adsorption capacity was compared in the equilibrium experiment using activated carbon and TiO₂-coated activated carbon.

Performance evaluation and prediction of activated carbon for VOCs via experiments and LFER methods

Yufeng Zhao,Mengxi Zhang,Chen Yang,Ruyi Xiang,Xudong Yang,Longzhe Cui 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.116 No.-

Due to the diversity and fluidity of volatile organic compounds (VOCs), it is difficult to conduct experimentalstudies on activated carbon (AC) used to capture VOCs in industry. Therefore, predicting theadsorption capacity of AC for VOCs is of great significance for evaluating the adsorption performanceof AC and developing its promising applications. Herein, based on the experimental data of dynamicadsorption, the poly parameter linear free energy relationship (pp-LFER) model was developed to quantifythe interactions between VOCs and AC. Through the dynamic adsorption curves of 25 VOCs on a fixedbed packed with the AC, the partition coefficient (PC) and adsorption capacity (q) of AC for VOCs werecalculated, and the pp-LFER equations used to predict them were established. For the PC values, thepp-LFER model consists of the excess molar refractive index (E), molar polarizability (S), hydrogenbondacidity (A), and logarithmic hexadecane-air partition coefficient (L), and the R2 of it was 0.86. Forthe ln q values, the developed model can predict it in R2 of 0.83, and the increased adsorption capacitywas predominantly attributed to the dispersive interaction (lL). Finally, the internal and external validationresults confirmed that the developed models have reliability, robustness, and predictability.

UV와 오존을 이용한 톨루엔의 분해반응과 현장적용에 관한 연구

정태섭 ( Tae-seop Jeong ),신철호 ( Chol-ho Shin ),김종선 ( Jong-seon Kim ),최용철 ( Cui Longzhe ) 한국환경기술학회 2007 한국환경기술학회지 Vol.8 No.1

본 연구는 UV, 오존, UV/오존 및 UV/오존/촉매 공정을 이용한 톨루엔의 제거 특성을 연구하였으며, 반응부산물로는 biphenyl, 벤즈알데히드 및 벤질알콜 등이 검출되었다. 이와 같은 결과를 토대로, UV/오존/촉매의 혼성공정을 이용하여 현장실험을 수행하였고, 그 결과는 다음과 같다. 1. 상대적으로 UV, 오존 및 UV/오존에 의한 톨루엔(100ppm)의 실험실적인 분해효율은 4.7-7.4%, 7.9-19.3% 및 15.1-29.2%로 나타났다. 2. 고농도 톨루엔(700ppm)의 분해효율은 UV/오존/촉매>오존/촉매>UV/촉매의 순으로 나타났다. 3. 초기 VOC 농도가 700-1,000ppm인 현장실험의 VOC 제거효율은 85-95%로 나타났다. 4. AOP 반응의 부산물로는 소량의 벤젠, 벤즈알데히드 및 벤질알콜 등의 화합물이 검출됐다. This study was carried out to determinate the removal efficiency of toluene in air using of UV, ozone, UV/ozone and UV/ozone/catalyst processes. The by-product of this reaction was analyzed to be the biphenyl, benzaldehyde and benzyl alcohol compounds. Based on the results mentioned above, we conducted the pilot test by using UV/ozone/catalyst hybrid system. The followings are the conclusions derived from this study. 1. In the laboratory experiments, the degradation efficiencies of toluene(100ppm) in the UV, ozone and UV/ozone process are 4.7-7.4%, 7.9-19.3% and 15.1-29.2% respectively. 2. The order of the degradation efficiency at a high concentration of toluene(700ppm) is like follows : UV/ozone/catalyst>ozone/catalyst>UV/catalyst. 3. At the pilot test(initial concentration of VOC:700-1,000ppm), the removal efficiency of VOCs was 85-93%. 4. A little amount of benzene, benzaldehyde and benzyl alcohol was detected in the by-products of these AOP reacions.

UV,오존 및 촉매를 이용한 벤젠과 자일렌의 처리에 관한 연구

정태섭 ( Tae-seop Jeong ),신철호 ( Chol-ho Shin ),김종선 ( Jong-seon Kim ),최용철 ( Cui Longzhe ) 한국환경기술학회 2007 한국환경기술학회지 Vol.8 No.1

본 연구는 고급산화공정인 UV, 오존, UV/오존 및 UV/오존/촉매 공정을 이용하여 벤젠과 자일렌의 제거특성를 결정하기 위해 수행하였으며, 반응 부산물은 GC/MS 및 HPLC를 이용하여 분석하였다. 비교적 낮은농도의 벤젠과 자일렌(150mg/㎥)의 전환 효율은 UV/O₃>O₃>UV순으로 관찰되었다. AOP 공정의 반응 부산물은 많은 양의 CO₂, CO 가 검출됐으며 벤즈알데하이드, 벤질 알콜, 페놀 및 벤조익산도 검출되었다. Ozone/UV/Catalyst의 혼성공정에 의한 상대적으로 높은 농도에서의 벤젠과 자일렌(500mg/㎥)의 변환 효율은 88.1~94.7%로 나타났다. This study was performed to determinate the removal benzene and xylene in air using of UV, ozone, UV/ozone and UV/ozone/catalyst. The by-products of this reaction were analyzed by GC/MS and HPLC. The conversion efficiencies of benzene and xylene were observed in the order of UV/O₃>O₃>UV at relatively low concentration of benzene and xylene(150mg/㎥). By products of these AOP processes were detected a lot of CO₂, CO and benzaldehyde, benzyl alcohol, phenol and benzoic acid. At relatively high concentration of benzene and xylene(500mg/㎥), conversion efficiencies of Ozone/UV/Catalyst hybrid processes were in the range of 88.1 to 94.7%.