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Effect of calcium formate as an additive on desulfurization in power plants

Journal of Environmental Sciences 2018年第5期30卷 89-95页

作者： Zhenhua Li Chunfang Xie Jing Lv Ruiguo Zhai Key Laboratory for Green Chemical Technology of Ministry of Education School of Chemical Engineering and Technology Collaborative Innovation Center of Chemical Science and Engineering(Tianjin) Tianjin University Tianjin Zhongtian Science & Technology Co. Ltd.

SO2 in flue gas needs to be eliminated to alleviate air pollution. As the quality of coal decreases and environmental standard requirements become more stringent, the highefficiency desulfurization of flue gas faces more and more challenges. As an economical and environmentally friendly solution, the effect of calcium formate as an additive on desulfurization efficiency in the wet flue gas desulfurization（WFGD） process was studied for the first time. Improvement of the desulfurization efficiency was achieved with limited change in p H after calcium formate was added into the reactor, and it was found to work better than other additives tested. The positive effects were further verified in a power plant, which showed that adding calcium formate could promote the dissolution of calcium carbonate, accelerate the growth of gypsum crystals and improve the efficiency of desulfurization. Thus, calcium formate was proved to be an effective additive and can potentially be used to reduce the amount of limestone slurry required, as well as the energy consumption and operating costs in industrial desulfurization.

关键词： Calcium formate Desulfurization Lime-gypsum process Additive Power plant

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Designed synthesis of semi-embedded Pd over CeO₂-ZrO₂/Al₂O₃ as advanced three-way catalyst

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JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS 2018年 85卷 98-105页

作者： Lan, Li Yan, Chaoyang Chen, Shanhu Li, Hongmei Li, Dacheng Wang, Jinfeng Cheng, Yongxiang Chen, Yaoqiang Chengdu Univ Coll Pharm & Biol Engn Chengdu 610106 Sichuan Peoples R China Sichuan Chem Ind Res & Design Inst Chengdu 610041 Sichuan Peoples R China Sinocat Environm Technol Co Ltd Chengdu 611731 Sichuan Peoples R China Sichuan Univ Coll Chem Chengdu 610064 Sichuan Peoples R China

For catalytic system consists of Pd as active component and CeO2-ZrO2/Al2O3 (CZ/A) as support, the dispersion and oxidation state of Pd species, which are crucial to the catalytic performance, are closely related to the metal-support interaction. In this work, Pd species were introduced into CZ/A system at different thermal treating stages of the support, which brought about different Pd-CZ interaction. The characterization results reveal that when CZ/A support was thermal treated at 300 degrees C prior to the introduction of Pd species, a special Pd/CZ/A catalyst with Pd species semi-embedded in CZ/A was acquired, which exhibits excellent thermal stability owing to the appropriate Pd-CZ interaction. During thermal aging process, encapsulation and aggregation of Pd species are effectively inhibited for Pd/CZ/A with semi embedded structure. Thus, higher dispersion, more oxidative Pd2+ species and larger amount of oxygen vacancies are maintained after aging, which consequently lead to its superior three-way catalytic performance. (C) 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

关键词： Semi-embedded structure Pd-CZ interaction Three-way catalytic performance

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Enhancing the thermostability of fumarase C from Corynebacterium glutamicum via molecular modification

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ENZYME AND MICROBIAL techNOLOGY 2018年 115卷 45-51页

作者： Lin, Ling Wang, Ying Wu, Mianbin Zhu, Li Yang, Lirong Lin, Jianping Zhejiang Univ Key Lab Biomass Chem Engn Minist Educ Coll Chem & Biol Engn Hangzhou 310027 Zhejiang Peoples R China

Fumarases have been successfully applied in industry for the production of L-malate. However, the industrialization of fumarases is limited by their low thermostability. In this study, the thermostability of fumarase C from Corynebacterium glutamicum was enhanced through directed evolution, simulated mutagenesis, site-directed mutagenesis and saturated mutagenesis. Mutant 2G (A411V) was initially constructed through directed evolution. Its half-life at 50 degrees C (t(1/2), (50)(degrees C)) increased from 1 min to 2.2 min, and the T-50(15) (temperature at which the activity of enzyme decreased by 50% in 15 min) increased from 44.8 degrees C to 47.2 degrees C. Besides, several different mutants were obtained by site-directed mutation. Among them, mutant 3G (A227V) showed significant improvement in thermostability with a 3.3-fold improvement of t(1/2)(,)(50)(degrees C) and a 3.6 degrees C increase in T-50(15) compared to the wild-type enzyme. Then, 2/3G (A227V, A411V) was obtained by combining the mutant 2G with the mutant 3G, for which the t(1/2)(,50 degrees C) and T-50(15) increased to more than 768 min and 52.4 degrees C, respectively. Finally, site-saturated mutagenesis was employed on amino acid residues 175-Glu, 228-Gly, 297-Gly, 320-Lys and 464-Glu to maximize the thermostability of mutant 2/3G. The most thermostable mutant 175G with amino acid substitutions (A227V, A411V, E175K) was isolated. Its t(1/2,)(50)(degrees C) increased to more than 2700 min while that of wild-type enzyme was only 1 min and T-50(15) was 9.8 degrees C higher than the wild-type enzyme. The thermostable mutated enzymes generated without affecting the activity in this study would be an attractive candidate for industrial applications.

关键词： Fumarase Thermostability Directed evolution Site-directed mutagenesis Saturated mutagenesis

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New Insights into the Role of Nd in CeO₂-ZrO₂-Al₂O₃ Composite and Supported Pd Catalyst

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RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2018年第9期92卷 1689-1698页

作者： Lan, Li Li, Hongmei Chen, Shanhu Chen, Yaoqiang Chengdu Univ Coll Pharm & Biol Engn Chengdu 610106 Sichuan Peoples R China Sinocat Environm Protect Co Ltd Chengdu 611731 Sichuan Peoples R China Sichuan Univ Coll Chem Minist Educ Key Lab Green Chem & Technol Chengdu 610064 Sichuan Peoples R China

To improve the performance of CeO2-ZrO2-Al2O3 (CZA) composite, Nd was introduced and the role of Nd was deeply investigated. The characterization results revealed that introduction of appropriate amount of Nd (4 wt%) can effectively modify the textural and structural properties of CZA, in this case, Nd selectively combines with CZ and hardly interacts with Al2O3, which could incorporate into the lattice of CZ to form ternary CeO2-ZrO2-Nd2O3 (CZN) solid solution, thus more lattice defects and improved oxygen mobility are obtained. However, excessive doping amount of Nd (6-8 wt%) brings about formation of Nd0.5Ce0.5O1.75 and phase separation of CZ especially after thermal aging treatment. The XPS results demonstrate that the supported catalyst Pd/CZAN4 possesses higher surface Pd and Ce3+ concentrations compared with Pd/CZA, which consequently leads to improved reducibility and catalytic performance. Furthermore, higher thermal stability is obtained, after aging treatment, Pd/CZAN4a still exhibits enhanced reduction property along with superior three-way catalytic performance.

关键词： CeO2-ZrO2-Al2O3 Nd selectively combine CeO2-ZrO2-Nd2O3 solid solution three-way catalytic performance

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Removal of hard COD from biological effluent of coking wastewater using synchronized oxidation-adsorption technology: Performance, mechanism, and full-scale application

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WATER research 2020年 173卷 115517页

作者： Sun, Guangxi Zhang, Yu Gao, Yingxin Han, Xiaogang Yang, Min Chinese Acad Sci Univ Chinese Acad Sci Res Ctr Ecoenvironm Sci State Key Lab Environm Aquat Chem Beijing 100085 Peoples R China Chinese Acad Sci Univ Chinese Acad Sci Res Ctr Ecoenvironm Sci Key Lab Drinking Water Sci & Technol Beijing 100085 Peoples R China Chinese Acad Sci Res Ctr Ecoenvironm Sci Natl Engn Lab Ind Wastewater Treatment Beijing 100085 Peoples R China Univ Chinese Acad Sci Sino Danish Ctr Educ & Res SDC Beijing 100190 Peoples R China Wuhai Inst Ind Wastewater Treatment Technol Wuhai 016000 Peoples R China

Efficient removal of the non-biodegradable organics from the biological effluent of industrial wastewater is becoming more and more important with the increasing demand for stringent discharge regulation. In this study, a synchronized oxidation-adsorption (SOA) technology was proposed for the removal of hardly biodegradable COD (hard COD) from the biological effluent of coking wastewater, and its performance was verified in a full-scale coking industrial park wastewater treatment plant (Q = 5,000 m(3)/d). The SOA was performed by coupling oxidation by hydroxyl radical (molar ratio of Fe2+ to H2O2 of 1:1 and pH = 5.0 +/- 0.2) and adsorption by in-situ-formed nano hydrolyzed Fe3+ particles (nano-FeOOH). The nano hydrolyzed Fe3+ particles formed during the SOA exhibited a much higher specific surface area (22.83 m(2)/g) than the particles (10.87 m(2)/g) formed during the polyferric sulfate coagulation (PFSC). In comparison to PFSC, SOA performed better in terms of average COD removal (39% vs 18%) from the biological effluent. Wastewater fractionation result showed that SOA performed better in the removal of the hydrophobic acid matters, which was supported by the experiment using fulvic acid as the model organics. Mechanism studies using both biological effluent and fulvic acid solution showed that more carboxylic substances were adsorbed by the in-situ-formed nano-hydrolyzed Fe3+ particles formed by SOA than by PFSC, which was likely due to the generation of carboxylic substances by hydroxyl radical oxidation. In the full-scale, the COD was reduced from 118.5-198.0 mg/L in the PFSC-pretreated effluent to 61.5-104.0 mg/L through SOA treatment. The SOA treatment characterized with a mild pH condition (pH 5) and low molar ratio of Fe2+ to H2O2 (1:1) is particularly suitable for the polishing purpose to remove limited amount of organic pollutants from wastewater before discharge. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Tertiary treatment Industrial wastewater In-situ synchronized oxidation-adsorption Nano hydrolyzed Fe3+ particles Carboxyl compounds

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The speciation, transformation kinetics and saline groundwater

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JOURNAL OF CONTAMINANT HYDROLOGY 2019年 225卷 103505页

作者： Zhou, Xu Dang, Haijun Han, Xiaoyuan Li, Weiping Wang, Yu Wang, Weixian Chai, Nana Northwest Inst Nucl Technol Xian 710024 Shaanxi Peoples R China

The mobility of plutonium (Pu) in groundwater is dependent of its speciation distribution and transformation. The speciation and transformation kinetics of Pu(IV) and its colloids in highly saline groundwater have, however, been rarely studied. In the present study, groundwater (Ionic strength 1 M) from Dunhuang region, NW china, was collected for investigating the speciation, transformation kinetics and fate of spiked Pu (IV) with aging time. The results showed that similar to 99% of the spiked Pu (IV) (over initial concentration c(0) range 2.5 x 10(-10)-7.8 x 10(-7) mol.L-1) was easily associated with the natural colloids and transformed into relatively unstable Pu pseudo-colloids in 1 day, which then gradually deposited and/or adsorbed on the container walls with aging. The suspended Pu pseudo-colloids decreased in similar exponential models, with rate equations r(t) = -3.1 x 10(-10)e(-t/4) and -1.3 x 10(-8)e(-/3) for c(0) = 1.25 x 10(-9) mol.L(-1)and 4.17 x 10(-8) mol.L-1, respectively. The chemical speciation of the suspended colloidal Pu was dominated by "Fe/Mn Oxides" at the early time, while "Carbonates" with slower depositing rate (r(t) = -6.9 x 10(-12)e(-0.149t)) dominated it (similar to 82%) at equilibrium state. Whatever the c(0) was, the concentration of dissolved Pu (i.e., the apparent solubility of Pu) kept at 0.7 x 10(-11) mol.L-1 over aging. The valence of dissolved Pu was dominated by Pu(IV) at early time, while Pu(V + VI) would become dominant (similar to 95%) at equilibrium state with transformation rate of r(t) = -92.9e(-t/16.6) + 96.9. The equilibrium times of Pu deposition (and/or adsorption), speciation transformation of the suspended colloidal Pu, and valence change of the dissolved Pu were 30 d, 80 d and 120 d, respectively. The kinetic process for each Pu species could be well fitted with exponential model. These results suggest that the majority of released Pu(IV) into highly saline groundwater will be easily associated with natural aquat

关键词： Plutonium Speciation transformation Kinetics highly saline groundwater Nuclide migration

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Longitudinal in vivo intrinsic optical imaging of cortical blood perfusion and tissue damage in focal photothrombosis stroke model

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JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM 2019年第7期39卷 1381-1393页

作者： Yang, Shanshan Liu, Kezhou Ding, Huijie Gao, Huan Zheng, Xiaoxiang Ding, Zhihua Xu, Kedi Li, Peng Zhejiang Univ Coll Opt Sci & Engn State Key Lab Modern Opt Instrumentat Room 3113 Teaching Bldg38 Zheda Rd Hangzhou 310027 Zhejiang Peoples R China Zhejiang Univ Dept Biomed Engn Educ Minist Key Lab Biomed Engn 2 Old Biomed Engn Bldg38 Zheda Rd Hangzhou 310027 Peoples R China Hangzhou Dianzi Univ Coll Life Informat Sci & Instruments Engn Hangzhou Zhejiang Peoples R China Zhejiang Univ Qiushi Acad Adv Studies QAAS Hangzhou Zhejiang Peoples R China Zhejiang Univ Zhejiang Prov Key Lab Cardiocerebral Vasc Detect Hangzhou Zhejiang Peoples R China

A thorough understanding of the spatiotemporal dynamics of blood supply and tissue viability is of great importance in stroke researches. In the current study, vascular and cellular responses to focal ischemia were monitored with optical coherence tomography on chronic rat photothrombotic stroke model. The 3D mapping of blood perfusion and cellular scattering were achieved by analyzing the temporal dynamics and depth attenuation of intrinsic backscattered light respectively. Optical coherence tomography revealed that vessels of different types presented various spatial and temporal dynamics during the photothrombotic occlusion and the later recovery period. The large distal middle cerebral arteries presented a spontaneous recanalization and the small pial microvessels presented a reperfusion along with newly appeared vessels from the peripheral into the core area. The cortical capillary perfusion presented a weak recovery. Compared to the male group, the female rats showed a faster vascular recovery after photothrombotic. Moreover, the dynamic changes of the cellular scattering signal showed a high spatial and temporal correlation with the cortical capillary perfusion. Combined with well-designed photothrombotic stroke model and chronic optical window, optical coherence tomography imaging offers a unique approach to improve the understanding of stroke procedure and evaluate the treatment outcomes.

关键词： Optical coherence tomography photothrombotic stroke model focal cerebral ischemia blood perfusion scattering coefficient

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Optimized synthesis of highly thermal stable CeO₂-ZrO₂/Al₂O₃ composite for improved Pd-only three-way catalyst

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MATERIALS & DESIGN 2018年 147卷 191-199页

作者： Lan, Li Chen, Shanhu Li, Hongmei Wang, Jinfeng Li, Dacheng Chen, Yaoqiang Chengdu Univ Coll Pharm & Biol Engn Chengdu 610106 Sichuan Peoples R China Sinocat Environm Technol Co Ltd Chengdu 611731 Sichuan Peoples R China Sichuan Univ Coll Chem Chengdu 610064 Sichuan Peoples R China

As is well known, impregnation of precursors of Ce and Zr onto as-prepared Al2O3 powders is a commonly used approach to prepare CeO2-ZrO2/Al2O3 composite. In this work, a highly thermal stable CeO2-ZrO2/Al2O3 composite was synthesized by modifying the conventional preparation procedure, i.e., the precursor of Al2O3 thermal treated at comparatively lower temperature (200 degrees C) was applied to conduct the impregnation process. The characterization results of the supported Pd-only three-way catalysts reveal that in themodified sample, stronger interaction between CeO2-ZrO2 and Al2O3 is achieved, which consequently gives rise to higher thermal stability of the catalyst. Upon hydrothermal aging treatment, only slight aggregation of the CeO2-ZrO2 and Al2O3 particles takes place, meanwhile phase transformation of gamma-Al2O3 and phase separation of CeO2-ZrO2 component are successfully suppressed. As a consequence, Pd species supported on the modified CeO2-ZrO2/Al2O3 composite remain finely dispersed, and more oxidative PdO species are maintained owing to the intimate interaction between Pd and CeO2-ZrO2. Therefore, improved reduction capability and superior three-way catalytic performance are achieved for the modified Pd/CeO2-ZrO2/Al2O3 catalyst after aging treatment. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： CeO2-ZrO2/Al2O3 composite Stronger interaction higher thermal stability Three-way catalytic performance

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Structure analysis of the spinneret from Bombyx mori and its influence on silk qualities

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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES 2019年 126卷 1282-1287页

作者： Guo, Nangkuo Lu, Kunpeng Cheng, Lan Li, Zhi Wu, Chunman Liu, Zulan Liang, Shubo Chen, Sihao Chen, Wenhao Jiang, Chenlong Dai, Fangyin Southwest Univ Coll Biotechnol State Key Lab Silkworm Genome Biol Key Lab Sericultural Biol & Genet BreedingMinist Chongqing 400715 Peoples R China Southwest Univ Chongqing Engn Res Ctr Biomat Fiber & Modern Text Coll Text & Garment Chongqing 400715 Peoples R China

Silk is an excellent natural fiber, which has been widely used in versatile fields. Silk spinning is a complex process involving the larval spinneret. The spinneret is essential for silk spinning, but the sectional morphology of the spinneret that determines the silk monofilament, the muscular activities around the silk press as well as the relationships between the spinneret and the properties of the resulting silk remain poorly understood. We studied these factors by dissecting the spinneret and analyzing silk from different Bombyx mori strains. The sectional morphology of silk monofilament was found to be largely determined by the spinneret, especially by the silk press. Moreover, contractile activity of the muscles around the silk press is high, and the contraction frequency of the muscles was estimated to range from 11.42 to 50 HZ. A comparison of the fibroin filaments before they entered the common tube indicated that the spinneret determines both silk shape and silk size. This study provides insight into the silk spinning process, which may help develop bionic spinning in further studies and also provides a rationale to study the effect of the spinneret on silk fineness at the molecular level. (C) 2018 Published by Elsevier B.V.

关键词： Spinneret Silk press Morphology

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Vibration Signal Processing and Weak Information Extraction Method for high-Speed Shaft Fault of Wind Turbine in Wind Shear

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INTERNATIONAL JOURNAL OF PATTERN RECOGNITION AND ARTIFICIAL INTELLIGENCE 2020年第14期34卷

作者： Xu, Xiaoli Liu, Xiuli Beijing Informat Sci & Technol Univ Key Lab Modern Measurement & Control Technol Minist Educ 12 Xiaoying East Rd Beijing Peoples R China

Due to the influence of random wind shear in the atmospheric phenomenon, the random vibration of the main shaft of the wind turbine generator is generated. This vibration signal will be mixed with the misalignment signal of the high-speed shaft, which will cause interference to the fault diagnosis. Based on the analysis of the phenomenon of wind shear and the fault, the independent component analysis was carried out on the high-speed shaft mixed vibration signals on the basis of using rapid fixed point algorithm based on kurtosis, and the weak fault information is extracted successfully. At the same time, this method was compared with the weak information extraction method based on wavelet denoising, which proved the superiority of the proposed method. The experimental results show that the method has good field applicability and has a good application prospect in the field of weak information extraction for rotating machinery of wind power generation.

关键词： high-speed shaft of wind turbine vibration signal fault weak information fast fixed point algorithm based on kurtosis

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