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Effect of wastewater composition on the calcium carbonate precipitation in upflow anaerobic sludge blanket

Shucheng YANG, Yanling HE, Charles CHOU, Pengxiang ZHANG, Dongqi WANG, Yonghong LIU,

《环境科学与工程前沿（英文）》 2010年 第4卷 第2期   页码 142-149 doi: 10.1007/s11783-010-0026-3

摘要： Calcium carbonate often precipitates in anaerobic reactors treating wastewater with high calcium content. The aim of this paper is to study the effect of wastewater composition on calcium carbonate precipitation in upflow anaerobic sludge blanket (UASB) reactors. Two laboratory-scale UASB reactors were operated with calcium-containing influents using acetate and carbohydrate as substrate, respectively. There was an obvious accumulation of inorganic precipitate observed in the biogranules. Observations via scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) showed that the acclimated biogranules in the two reactors differed in microstructure. Calcium carbonate was found to have precipitated on the surface of acetate-degrading biogranules, but precipitated at the core of the carbohydrate-degrading biogranules. The results indicated that substrates had significant influence on the location of calcium carbonate precipitation in anaerobic granular sludge, which was expected due to the different methanogens distribution and pH gradient within the granular sludge degrading various substrates. Moreover, the location of calcium carbonate precipitation substantially affected the specific methanogenic activity (SMA) of the granular sludge. The SMA of the acetate-degrading biogranules dropped from 1.96 gCOD·gVSS·d to 0.61 gCOD·gVSS·d after 180-d of operation in the reactor. However, the SMA of the carbohydrate-degrading biogranules was not adversely affected by calcium carbonate precipitation.

关键词： calcium carbonate     precipitation     anaerobic granular sludge     wastewater composition     microstructure     upflow anaerobic sludge blanket (UASB)    

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Preparation of ultrafine α-AlO using precipitation-azeotropic distillation method

XIAO Jin, QIN Qi, ZHOU Feng, CHEN Yanbin, WAN Ye

《机械工程前沿（英文）》 2008年 第3卷 第2期   页码 226-231 doi: 10.1007/s11465-008-0029-y

摘要： Ammonium aluminum carbonate hydroxide (AACH) was prepared by a precipitation-azeotropic distillation method, which uses aluminum sulfate as the Al source and ammonium carbonate as the precipitant. Then, AACH was calcined into ultrafine ?-AlO powder. The factors that influence the dispersion property of ultrafine ?-AlO powder are discussed in this paper, such as the methods of adding materials, surfactant, and drying methods. The changes of the structure and property of ultrafine alumina in the thermal treatment process are also studied. The morphological structure and properties of AACH are characterized by DTA/TGA, SEM, XRD, and ICP measurements. The results show that ultrafine ?-AlO powder with a uniform particle size and well-distributed property can be synthesized only after aluminum sulfate atomizes into ammonium carbonate, proper amount of PEG1000 is added as the dispersant, and the product is treated by azeotropic distillation. The phase transformation of alumina during the calcination process can be described as amorphous AlO → ?-AlO → ?-AlO → ?-AlO. The crystal grain size and density of ultrafine alumina powder increase with the increase of the calcination temperature. After AACH has been calcined at 1200°C for 2 h, the ultrafine ?-AlO with uniform particle size, spherical shape, and more than 99.97% purity is obtained and its powder is well dispersed.

关键词： calcination temperature     spherical     AACH     carbonate hydroxide     ammonium carbonate    

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of vanadium and manganese from high-manganese containing vanadium wastewater by a solvent extraction-precipitation

Zishuai Liu, Yimin Zhang, Zilin Dai, Jing Huang, Cong Liu

《化学科学与工程前沿（英文）》 2020年 第14卷 第5期   页码 902-912 doi: 10.1007/s11705-019-1887-z

摘要： High-manganese containing vanadium wastewater (HMVW) is commonly produced during the vanadium extraction process from vanadium titano-magnetite. HMVW cannot be reused and discharged directly, and is harmful to the environment and affect product quality due to heavy metals in the wastewater. The wastewater is usually treated by lime neutralization, but valuable metals (especially V and Mn) cannot be recovered. In this study, an efficient and environmentally friendly method was developed to recover valuable metals by using a solvent extraction-precipitation process. In the solvent extraction process, 98.15% of vanadium was recovered, and the V O product, with a purity of 98.60%, was obtained under optimal conditions. For the precipitation process, 91.05% of manganese was recovered as MnCO which meets the III grade standard of HG/T 2836-2011. Thermodynamic simulation analysis indicated that MnCO was selectively precipitated at pH 6.5 while Mg and Ca could hardly be precipitated. The results of X-ray diffraction and scanning electron microscopy demonstrated that the obtained V O and MnCO displayed a good degree of crystallinity. The treated wastewater can be returned for leaching, and resources (V and Mn) in the wastewater were utilized efficiently in an environmentally friendly way. Therefore, this study provides a novel method for the coextraction of V and Mn from HMVW.

关键词： high-manganese containing vanadium wastewater     solvent extraction     carbonate precipitation     vanadium titano-magnetite     valuable metal recovery    

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Polyethylene glycol-supported ionic liquid as a highly efficient catalyst for the synthesis of propylene carbonate

Rui YAO, Hua WANG, Jinyu HAN

《化学科学与工程前沿（英文）》 2012年 第6卷 第3期   页码 239-245 doi: 10.1007/s11705-012-1297-y

摘要： The coupling reaction of propylene and CO to form propylene carbonate (PC) was promoted by an ionic liquid (IL) covalently bound to polyethylene glycol (PEG). The supported ionic liquid, which has both acidic and basic components, proved to be an active catalyst for PC synthesis under mild conditions. The effects of different cations and anions, reaction temperature, CO pressure, and reaction time were investigated. It was demonstrated that the acid group in the catalyst plays an important role in the reaction. With this system, a high PC yield (95%) was achieved under mild conditions (3.0 MPa, 120°C and 4 h) without a co-solvent. In addition, the catalyst was readily recovered and reused. Based on the experimental results, a plausible mechanism for the catalyst was proposed.

关键词： ionic liquid     PEG-supported ionic liquid     carbon dioxide     propylene carbonate    

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Modeling radiative effects of haze on summer-time convective precipitation over North China: a case study

Xuying WANG, Bin ZHANG

《环境科学与工程前沿（英文）》 2016年 第10卷 第4期 doi: 10.1007/s11783-016-0840-3

摘要： We modeled the impact of haze radiative effects on precipitation in North China. Shortwave heating induced by haze radiative effects would reduce heavy rainfalls. Convection was the key factor that whether precipitation was enhanced or suppressed. Precipitation was often suppressed where CAPE, RH and updraft velocities were high. The impact of haze radiative effect on summertime 24-h convective precipitation over North China was investigated using WRF model (version 3.3) through model sensitivity studies between scenarios with and without aerosol radiative effects. The haze radiative effect was represented by incorporating an idealized aerosol optical profile, with AOD values around 1, derived from the aircraft measurement into the WRF shortwave scheme. We found that the shortwave heating induced by aerosol radiative effects would significantly reduce heavy rainfalls, although its effect on the post-frontal localized thunderstorm precipitation was more diverse. To capture the key factors that determine whether precipitation is enhanced or suppressed, model grids with 24-h precipitation difference between the two scenarios exceeding certain threshold (>30 mm or<-30 mm) were separated into two sets. Analyses of key meteorological variables between the enhanced and suppressed regimes suggested that atmospheric convection was the most important factor that determined whether precipitation was enhanced or suppressed during summertime over North China. The convection was stronger over places with precipitation enhancement over 30 mm. Haze weakened the convection over places with precipitation suppression exceeding 30 mm and caused less water vapor to rise to a higher level and thus further suppressed precipitation. The suppression of precipitation was often accompanied with relatively high convective available potential energy (CAPE), relative humidity (RH) and updraft velocities.

关键词： Haze     Aerosol radiative effects     Convective precipitation    

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Changes in hourly precipitation may explain the sharp reduction of discharge in the middle reach of the

Lin LUO, Zhongjing WANG

《环境科学与工程前沿（英文）》 2013年 第7卷 第5期   页码 756-768 doi: 10.1007/s11783-013-0563-7

摘要： The Hekou-Longmen reach, together with local floods, is the main source area for coarse sedimentations into the Yellow River. When total rainfall slightly increased in the area, discharge dramatically decreased by 40%–70% after the year of 2000, and attracting extensive attention in the context of global climate change. High temporal resolution precipitation (timescales between 1 and 4 h) data from the June to September period from 270 rain gauges over the past three decades was mined in order to help explain the phenomenon. Each rainfall event was classified as light/moderate rain, large rain, heavy rain or rainstorm by the event’s rainfall amount, and further classified as low intensity rain, medium intensity rain and high intensity rain by the event’s rainfall intensity. The Mann-Kendall trend test was applied to detect the presence and significance of monotonic trends, and to find the change points in the mean and variance of the precipitation characteristics series, including the amount, intensity, frequency and duration of each rainfall category. Results show that although the total amount of precipitation has slightly increased, the average rainfall intensity has significantly decreased. The larger change happened in light/moderate rain events and low/medium intensity rain events, and the intensity changes have a great extent occurred around the threshold of Non-Runoff Rainfall regime, which was proposed for the approximate calculation of initial losses. Changes in rainfall distribution between different classes of the Runoff Rainfall regime in the 2000s could lead to 0.9 mm less runoff depth (17.3% of the total reduction) than the 1980–1999 period. The study indicates that changes in hourly precipitation may be responsible for the sharp reduction of discharge.

关键词： precipitation intensity     Mann-Kendall rank statistic     spatial and temporal distribution     climatic change    

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Novel eco-efficient reactive distillation process for dimethyl carbonate production by indirect alcoholysis

Iulian Patraşcu, Costin S. Bîldea, Anton A. Kiss

《化学科学与工程前沿（英文）》 2022年 第16卷 第2期   页码 316-331 doi: 10.1007/s11705-021-2047-9

摘要： Dimethyl carbonate is an eco-friendly essential chemical that can be sustainably produced from CO , which is available from carbon capture activities or can even be captured from the air. The rapid increase in dimethyl carbonate demand is driven by the fast growth of polycarbonates, solvent, pharmaceutical, and lithium-ion battery industries. Dimethyl carbonate can be produced from CO through various chemical pathways, but the most convenient route reported is the indirect alcoholysis of urea. Previous research used techniques such as heat integration and reactive distillation to reduce the energy use and costs, but the use of an excess of methanol in the trans-esterification step led to an energy intensive extractive distillation required to break the dimethyl carbonate-methanol azeotrope. This work shows that the production of dimethyl carbonate by indirect alcoholysis of urea can be improved by using an excess of propylene carbonate (instead of an excess of methanol), a neat feat that we showed it requires only 2.64 kW·h·kg dimethyl carbonate in a reaction-separation-recycle process, and a reactive distillation column that effectively replaces two conventional distillation columns and the reactor for dimethyl carbonate synthesis. Therefore, less equipment is required, the methanol-dimethyl carbonate azeotrope does not need to be recycled, and the overall savings are higher. Moreover, we propose the use of a reactive distillation column in a heat integrated process to obtain high purity dimethyl carbonate (>99.8 wt-%). The energy requirement is reduced by heat integration to just 1.25 kW·h·kg dimethyl carbonate, which is about 52% lower than the reaction-separation-recycle process. To benefit from the energy savings, the dynamics and control of the process are provided for ±10% changes in the nominal rate of 32 ktpy dimethyl carbonate, and for uncertainties in reaction kinetics.

关键词： dimethyl carbonate     reactive distillation     process design     plantwide control    

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地下水碳酸平衡检查系统

刘建刚,郑克勋,傅伟宁,吴顺华

《中国工程科学》 2003年 第5卷 第9期   页码 61-64

摘要：

文章主要研究地下水在不同温度和CO2分压条件下碳酸三种存在形式与pH值的关系，以便更有效地对地下水水质资料进行可靠性检查。分析认为HCO3-出现峰值的分界pH0值，纯水在CO2分压1～105Pa，温度0～30℃时的变化范围为7.92～8.60，碳酸盐岩地下水的变化范围为8.28～8.57。pH0值随温度的升高而降低。石灰岩和白云岩的pH0十分接近，碳酸盐岩地区的平衡特性将取决于方解石成分。

关键词： 碳酸盐岩     地下水     碳酸平衡     pH值    

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Multi-objective optimization of molten carbonate fuel cell system for reducing CO

Ramin ROSHANDEL,Majid ASTANEH,Farzin GOLZAR

《能源前沿（英文）》 2015年 第9卷 第1期   页码 106-114 doi: 10.1007/s11708-014-0341-7

摘要： The aim of this paper is to investigate the implementation of a molten carbonate fuel cell (MCFC) as a CO separator. By applying multi-objective optimization (MOO) using the genetic algorithm, the optimal values of operating load and the corresponding values of objective functions are obtained. Objective functions are minimization of the cost of electricity (COE) and minimization of CO emission rate. CO tax that is accounted as the pollution-related cost, transforming the environmental objective to the cost function. The results show that the MCFC stack which is fed by the syngas and gas turbine exhaust, not only reduces CO emission rate, but also produces electricity and reduces environmental cost of the system.

关键词： molten carbonate fuel cell (MCFC)     multi-objective optimization (MOO)     Pareto curve     genetic algorithm     CO2 separation    

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Effect of potassium carbonate on catalytic synthesis of calcium carbide at moderate temperature

Dejun SHI, Ke QIAO, Zifeng YAN

《化学科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 372-375 doi: 10.1007/s11705-010-0570-1

摘要： Calcium carbide was successfully synthesized by carbothermal reduction of lime with coke at 1973 K for 1.5 h. The effect of potassium carbonate as additive on the composition and morphology of the product was investigated using X-ray diffraction and scanning electron microscope. Addition of potassium carbonate increased the yield of calcium carbide. The sample in the presence of potassium carbonate generated acetylene gas of 168.3 L/kg, which was 10% higher than that in the absence of potassium carbonate. This result confirmed the catalytic effect of potassium carbonate on the synthesis of calcium carbide. A possible mechanism of the above effects was that the additive, which was melted at the reduction temperature, dissolved CaO and so promoted the contact between CaO and carbon, which was essential for the solid-solid reaction to form calcium carbide.

关键词： calcium carbide     synthesis     catalysis    

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Influence of crystalline phase of Li-Al-O oxides on the activity of Wacker-type catalysts in dimethyl carbonate

Yadong GE, Yuanyuan DONG, Shengping WANG, Yujun ZHAO, Jing LV, Xinbin MA

《化学科学与工程前沿（英文）》 2012年 第6卷 第4期   页码 415-422 doi: 10.1007/s11705-012-1214-4

摘要： The catalysts supported on LiAl O (spinel) for vapor phase synthesis of dimethyl carbonate (DMC) from methyl nitrite (MN) have been studied. Their catalytic activities on supports prepared by different methods were evaluated in a continuous reactor. The samples were characterized by powder X-ray diffraction, N adsorption-desorption isotherms, fourier transform infrared spectroscopy and temperature-programmed reduction of H . Li/Al molar ratio and calcination temperature greatly influence the structure of crystalline phase of Li-Al-O oxides. Desirable LiAl O (spinel) was formed at 800°C, while LiAl O (primitive cube) formed at 900°C is undesirable for the reaction. A high Li/Al molar ratio, which was related with LiAlO , also slowed the reaction rate. The electron transfer ability and the interaction with active component are the important properties of the spinel-based supports. The CuCl -PdCl /LiAl O (spinel) with better electron transfer ability and low Pd reduction temperature exhibited a better catalytic ability.

关键词： Wacker-type catalyst     dimethyl carbonate     methyl nitrite     spinel    

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Direct synthesis of diphenyl carbonate over heterogeneous catalyst: effects of structure of substituted

WU Guangwen, JIN Fang, WU Yuxin, ZHANG Guangxu, LI Dinghuo, WANG Cunwen, MA Peisheng

《化学科学与工程前沿（英文）》 2007年 第1卷 第1期   页码 59-64 doi: 10.1007/s11705-007-0012-x

摘要： The perovskite-type compound LaMnO was substituted for the part of La in position A and for the part of Mn in position B by citrate method. The phases were detected by X-ray diffraction. Powder morphologies were scanned by scanning electron microscopy. The valence of atoms was determined by X-ray photoelectron spectroscopy. It was found that the perovskite can form crystal defect and increase the proportion of high valence B element by doping. Active component Pd was loaded on various perovskite supports for synthesis of diphenyl carbonate. The results showed that the activities of catalysts in which supports have crystal defect by substitution were higher. It can be concluded that perovskite with defect structure by doping could lead to the formation of oxygen vacancy where the lattice oxygen became exchangeable with the oxygen gas. Also, this improved the redox process of the carrier by transferring electrons and activities of catalysts.

关键词： photoelectron spectroscopy     diphenyl carbonate     proportion     diffraction     perovskite    

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Evaluation of precipitation behavior of zirconium molybdate hydrate

Liang ZHANG, Masayuki TAKEUCHI, Tsutomu KOIZUMI, Izumi HIRASAWA

《化学科学与工程前沿（英文）》 2013年 第7卷 第1期   页码 65-71 doi: 10.1007/s11705-013-1314-9

摘要： In the dissolution step of spent nuclear fuel, there is a world-concern problem that zirconium molybdate hydrate precipitates as a byproduct, and accumulates in some reprocessing equipments. In order to prevent this accumulation, we have developed a new method based on the controlled reaction crystallization of zirconium molybdate hydrate (ZMH) in the reprocessing solution, followed by solid liquid separation. In order to measure the particle size of ZMH, batch crystallization experiments were conducted by varying nitric acid concentration and operating temperature. In result, almost all particle sizes scatter around 1 μm on average, despite the higher concentration of nitric aid and operating temperature, and then small particles grow up as an aggregate sticking to the crystallizer. Moreover, polymorph and color changing were observed by varying the concentration of nitric acid and reaction time. These results suggest that crystal color and adhesiveness are closely related to the particle size of ZMH. And the control of nitric acid concentration and small particle growth would be the useful technique to prevent the ZMH sticking.

关键词： spent nuclear fuel     zirconium molybdate hydrate     cleaning method     accumulation    

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碱硅酸反应与碱碳酸盐反应

唐明述

《中国工程科学》 2000年 第2卷 第1期   页码 34-40

摘要：

碱集料反应（AAR）可分为两类，即碱硅酸反应（ASR）与碱碳酸盐反应（ACR）。二者的共同点是与碱发生的化学反应可导致混凝土中集料的体积增大，从而可能使混凝土甚至整个建筑物或构筑物发生膨胀开裂。文章着重从膨胀过程和机理以及岩石的结构特征探讨二者的特性与差异。ASR类型岩石具有碱活性的前提条件是较低的二氧化硅结晶完整度。只有隐晶质、微晶质、玻璃质或发生过应变的二氧化硅才会具有较高的化学活性，导致混凝土破坏。通过系统研究证实，对碱碳酸盐反应，虽然结晶的完整程度以及白云石（CaCO3·MgCO3）分子式中Ca/Mg比也将影响其与碱反应的速率，但起决定作用的是白云石晶体的尺寸及其在岩石中的分布状态和被基质包围的紧密程度。从微观结构得出的这些特征将有助于加深对碱集料反应膨胀机理的认识。文中还介绍了形成活性白云石的地质环境和碱硅酸反应与碱碳酸盐反应的区分方法。

关键词： 碱     集料     硅酸     碳酸盐     混凝土开裂     机理    

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LiFePO/C cathode materials synthesized by co-precipitation and microwave heating

XU Yunlong, TAO Lili, MA Hongyan, HUANG Huaqing

《化学科学与工程前沿（英文）》 2008年 第2卷 第4期   页码 422-427 doi: 10.1007/s11705-008-0082-4

摘要： LiFePO/C cathode materials were synthesized by a combination of co-precipitation and microwave heating using polyethylene glycol (PEG) as a carbon resource and the influence of microwave heating time on the structure and electrochemical performance of the materials was also discussed. The samples were characterized by X-ray diffraction (XRD), TEM, particle-size analysis and constant current charge-discharge experiment. The results show that the LiFePO/C heated for 9 min has a pure olive-type phase and excellent electrochemical performance. The initial discharge capacities of this sample are 154.3, 139.7, 123.9 mAh/g at the rates 0.1C, 0.2C, 1C at room temperature, respectively, and after 20 cycles remain 152.3, 134.3, 118.5 mAh/g, respectively.

关键词： polyethylene     electrochemical performance     combination     co-precipitation     diffraction    

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标题 作者 时间 类型 操作

Effect of wastewater composition on the calcium carbonate precipitation in upflow anaerobic sludge blanket

Shucheng YANG, Yanling HE, Charles CHOU, Pengxiang ZHANG, Dongqi WANG, Yonghong LIU,

期刊论文

Preparation of ultrafine α-AlO using precipitation-azeotropic distillation method

XIAO Jin, QIN Qi, ZHOU Feng, CHEN Yanbin, WAN Ye

期刊论文

of vanadium and manganese from high-manganese containing vanadium wastewater by a solvent extraction-precipitation

Zishuai Liu, Yimin Zhang, Zilin Dai, Jing Huang, Cong Liu

期刊论文

Polyethylene glycol-supported ionic liquid as a highly efficient catalyst for the synthesis of propylene carbonate

Rui YAO, Hua WANG, Jinyu HAN

期刊论文

Modeling radiative effects of haze on summer-time convective precipitation over North China: a case study

Xuying WANG, Bin ZHANG

期刊论文

Changes in hourly precipitation may explain the sharp reduction of discharge in the middle reach of the

Lin LUO, Zhongjing WANG

期刊论文

Novel eco-efficient reactive distillation process for dimethyl carbonate production by indirect alcoholysis

Iulian Patraşcu, Costin S. Bîldea, Anton A. Kiss

期刊论文

地下水碳酸平衡检查系统

刘建刚,郑克勋,傅伟宁,吴顺华

期刊论文

Multi-objective optimization of molten carbonate fuel cell system for reducing CO

Ramin ROSHANDEL,Majid ASTANEH,Farzin GOLZAR

期刊论文

Effect of potassium carbonate on catalytic synthesis of calcium carbide at moderate temperature

Dejun SHI, Ke QIAO, Zifeng YAN

期刊论文

Influence of crystalline phase of Li-Al-O oxides on the activity of Wacker-type catalysts in dimethyl carbonate

Yadong GE, Yuanyuan DONG, Shengping WANG, Yujun ZHAO, Jing LV, Xinbin MA

期刊论文

Direct synthesis of diphenyl carbonate over heterogeneous catalyst: effects of structure of substituted

WU Guangwen, JIN Fang, WU Yuxin, ZHANG Guangxu, LI Dinghuo, WANG Cunwen, MA Peisheng

期刊论文

Evaluation of precipitation behavior of zirconium molybdate hydrate

Liang ZHANG, Masayuki TAKEUCHI, Tsutomu KOIZUMI, Izumi HIRASAWA

期刊论文

碱硅酸反应与碱碳酸盐反应

唐明述

期刊论文

LiFePO/C cathode materials synthesized by co-precipitation and microwave heating

XU Yunlong, TAO Lili, MA Hongyan, HUANG Huaqing

期刊论文