FUEL
·
2021
·
IF 6.609
Yong Wei,Guijian Liu,Biao Fu,Yuan Liu,Xuan Xue
Fine particulate matter (PM) emitted from coal-fired power plants (CFPPs) has aroused widespread environmental and human health concerns. Cadmium (Cd), as one of the prime toxic air pollutants, which exists in fine PM intensifies its toxicity. In this research, three particle sizes of PM (PM 1 , PM 2.5 , and PM 10 ) at the outlet of electrostatic precipitator (ESP), along with feed coal, bottom ash, and ESP ash, were collected from a 300-MW pulverized CFPP. Results showed that Cd was more enriched in the fly ash than in bottom ash. With the PM diameter decreasing, the relative enrichment index (REI) value of Cd increases from 2.30 to 7.84. The concentration of Cd was found to be intimately related to Ti in the PM. Abundant Ti-rich particles were identified in the PM 1 , having quite different chemical compositions as compared to particles larger than 2.5 μm. The major processes governing the formation of Ti-rich particles included melting of silicate-bound Ti and heterogeneous condensation of gaseous Ti from the decomposition of organic-associated Ti in coal. The transformation behavior of Cd to PM in a coal combustion process was discussed based on its occurrence mode in coal, thermodynamic property, and the possible interactions with ash particle compositions. The retention of Cd (g) by Ti-rich particle were probably dominated by chemisorption at high temperature; at lower temperature, physical adsorption or condensation may be the primary mechanisms for capturing CdCl 2 (g).
研究领域:
环境科学
·
化学
✓ 已验证
DOI
高影响因子
FUEL
·
2017
·
IF 4.601
Yiquan Guo,Junying Zhang,Yongchun Zhao,Shaolong Wang,Cheng Jiang,Chuguang Zheng
Fly ash fine particles emitted from coal-fired power plants are the primary atmospheric pollutant in China. The pressure, temperature, and velocity distribution of the flow field in a chamber was simulated to evaluate chemical agglomeration. The effect on the removal efficiency of composition, concentration, pH, K + content, and zeta potential of the chemical agglomeration solutions as well as surfactant and flue gas temperature were evaluated. The results suggested that suitable solutions could significantly improve the removal efficiency of fine particles. Among these, kappa-carrageenan performed best and achieved a removal efficiency of 47.1%. Synergism was detected as two different chemical agglomeration solutions were mixed together: a mixture of kappa-carrageenan and konjac glucomannan attained a removal efficiency of 59.3%, higher than their individual values. The efficiency improved initially and then decreased as the solution K + concentration increased. Also surfactants affected agglomeration: cationic and non-ionic surfactants enlarged the removal efficiency by 9.0% and 3.7%, respectively, whereas anionic surfactants lessened average removal efficiency by 5.6%. Zeta potential influenced the removal efficiency as well: it peaked as the zeta potential was around 0 mV.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Cleaner Production
·
2021
·
IF 9.297
Yong Wei,Guijian Liu,Biao Fu,Ruwei Wang,Yuan Liu,Xuan Xue,Mei Sun
Inhalable fine particulate matter (PM), which is rich in Pb and other pollutants from coal-fired power plants, can cause air pollution and severe health problems. To facilitate the development of efficient techniques for controlling fine particulate Pb emissions, in this study, various types of size-resolved fine PM (<10.0 μm) were collected from the outlets of fabric filter units (FFs) at an industrial circulating fluidized bed (CFB) power plant to assess the distribution and partitioning behavior of Pb. The results showed that the mass particle size distribution (PSD) of the collected fine PM followed unimodal distribution, peaking at 5.8–4.7 μm, which might be caused by the fragmentation of limestone additives and new-formed CaSO 4 . However, the mass PSD of Pb for size-fractionated PM displayed different distribution pattern. Two peaks were observed in the size ranges of 5.8–4.7 μm and 1.1–0.7 μm. The mechanism of Pb enrichment in the supermicron particles was mainly controlled by the surface adsorption reaction, which could be explained by 1/d p dependence and be improved using excess active CaO produced by the injected limestone. For submicron particles, gas-film transfer or heterogenous condensation (mass transfer) might represent the deposition mechanism . Besides Pb enrichment, it was found that the submicron particles (<0.7 μm) mainly consisted of Si-rich and Si–Al phases. The emission of those fine SiO 2 -bearing particles should be limited as they can be inhaled and can damage the respiratory system.
研究领域:
环境科学
·
公共卫生
✓ 已验证
DOI
高影响因子
Petroleum Science
·
2024
·
IF 6
Wei-Feng Yuan,Yu-Long Yang,Lu Yuan,Ji-Rui Hou
Fine particle detachment and subsequent migration can lead to severe pore plugging and consequent permeability decline. Therefore, it is crucial to quantify the critical condition when fine particle detachment occurs. The frequently observed deviations or even contradictions between experimental results and theoretical predictions of fines detachment arise from an insufficient understanding of adhesion force that can be highly influenced by salinity and temperature. To clarify the intrinsic influence of salinity and temperature on fines detachment, adhesion forces between carboxyl microspheres and hydrophilic silica substrates in an aqueous medium were measured at various salinities and temperatures using atomic force microscopy (AFM). The AFM-measured adhesion force decreases with increasing salinity or temperature. Trends of mean measured adhesion forces with temperature and salinity were compared with the DLVO and XDLVO theories. DLVO theory captured the trend with temperature via the impact of temperature on electric double layer interactions, whereas XDLVO theory captured the observed trend with salinity via the impact of salinity on the repulsive hydration force. Our results highlight the significance of hydration force in accurately predicting the fate of fines in porous media.
研究领域:
石油工程
·
表面科学
·
胶体化学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2016
·
IF 4.803
Pengfei Wang,Hui Liu,Yuxing Xu,Yunfa Chen,Jun Yang,Qiangqiang Tan
Reducing the particle size is a straightforward way to increase the specific surface area of ruthenium oxide, which usually translates to the high specific capacitance for a supercapacitor. Herein, we report a facile strategy to fabricate ultrafine ruthenium oxides supported on various carbon-based substrates (carbon powders, carbon nanotubes, or reduced graphene oxides) as excellent electrode materials for a supercapacitor. The novelty of this work lies in its synthetic approach, which involves an aqueous synthesis of ruthenium nanoclusters under the control of pH value, and an air oxidation-based conversion process. In particular, owing to their ultrafine particle size, the as-prepared carbon-, carbon nanotube-, or reduced graphene oxide-supported ruthenium oxides exhibit specific capacitance as high as 879.1 F g −1 , 966.8 F g −1 and 1099.6 F g −1 , respectively, for a supercapacitor at a current density of 0.5 A g −1 . The specific capacitance maintains 98.4% (for carbon supports), 98.0% (for carbon nanotube supports) and 98.4% (for reduced graphene oxide supports) at current density of 1 A g −1 with good cycling stability. The remarkable simplicity and environmental friendliness of this synthesis may provide a liable quantity production route to produce ruthenium oxides as highly efficient electrode materials for a supercapacitor.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
POWDER TECHNOLOGY
·
2022
·
IF 5.64
Jie Yin,Jun Zhang,Li Lv,Hui Zhong
Heterogeneous condensation preconditioning technology has generated broad interest in removing fine particles from coal-fired flue gas due to its economic and environmental advantages. Here, a flow cloud chamber was used to study the effect of 0%–90% CO 2 concentrations on the growth performance of insoluble fine particles with different operational conditions. The results suggest that a higher CO 2 concentration in the particle growth environment is detrimental to the fine particles growth. The higher the CO 2 concentration, the worse the growth performance. The adverse effect of CO 2 on the growth performance decreases with the increase of growth time and the increase of supersaturation caused by temperature, and does not change significantly with the increasing particle concentration.
研究领域:
环境科学
·
大气科学
✓ 已验证
DOI
高影响因子
International Journal of Minerals Metallurgy and Materials
·
2021
·Vol. 29
·期 3
·521-528
·
IF 2.232
Wang Yu,Zhang Guohua,Chou Kuochih
ZrC and ZrB 2 are both typical ultra-high temperature ceramics, which can be used in the hyperthermal environment. In this study, a method for preparing ultrafine ZrC-ZrB 2 composite powder was provided, by using the raw materials of nano ZrO 2 , carbon black, B 4 C, and metallic Ca. It is worth pointing out that ZrC-ZrB 2 composite powder with any proportion of ZrC to ZrB 2 could be synthesized by this method. Firstly, a mixture of ZrC and C was prepared by carbothermal reduction of ZrO 2 . By adjusting the addition amount of B 4 C, ZrC was boronized by B 4 C to generate ZrC-ZrB 2 composite powder with different compositions. Using this method, five composite powders with different molar ratios of ZrC and ZrB 2 (100ZrC, 75ZrC-25ZrB 2 , 50ZrC-50ZrB 2 , 25ZrC-75ZrB 2 , and 100ZrB 2 ) were prepared. When the temperature of boronization and decarburization process was 1473 K, the particle size of product was only tens of nanometres. Finally, the oxidation characteristics of different composite powders were investigated through oxidation experiments. The oxidation resistance of ZrC-ZrB 2 composite powder continued to increase as the content of ZrB 2 increased.
研究领域:
材料科学
·
陶瓷
·
高温材料
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2017
·
IF 2.986
Yumao Sheng,Guanglu Li,Hao Meng,Yide Han,Yan Xu,Junbiao Wu,Junli Xu,Zhongqiao Sun,Yufeng Liu,Xia Zhang
Herein we develop an improved carbothermal process using cellulose as organic carbon resources to synthesize uniform B 4 C particles in fine-grained size. The improvement of the proposed carbothermal processes lies in two points: (i) we use immiscible hexane/water solvents to obtain high-dispersed boric acid (BA), which promotes the esterification of BA with organic carbon; (ii) the boron oxide/carbon resources are ground sufficiently before high-temperature carbonization. The purpose of these two procedures is to increase the homogeneity of precursors, and their effects on the final crystalline structure and morphology of B 4 C are studied systematically. The results show that uniform fine-grained B 4 C in about 4 µm is successfully fabricated, indicating the homogeneity of precursors can effectively meliorate the B 4 C powder in a smaller size. The photoelectrochemical and photoelectrocatalytic performances of the as-prepared fine-gained B 4 C powder are also investigated. Interestingly, the fine B 4 C microparticles exhibited a good photoelectrocatalytic hydrogen generation activity in water reduction.
研究领域:
材料科学
·
化学工程
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2017
·
IF 4.601
Yiquan Guo,Yongchun Zhao,Shaolong Wang,Cheng Jiang,Junying Zhang
Fly ash fine particles emitted from flue gas during coal combustion are the primary atmospheric pollutants in China. The purpose of this study was to investigate the characteristics of the zeta potential of fine particle suspensions. The relationship between the zeta potential and the fine particle removal efficiency was also discussed. Batch experiments were conducted to evaluate the zeta potential of fine particle aqueous solutions under various pH, ion concentration, surfactant, polymer, and chemical agglomeration solution conditions. A chemical agglomeration system was designed to simulate the removal process of the fine particles. The test results indicated that the zeta potential absolute value of the solution decreased initially and then increased as the pH increased. As the pH increased from 4 to 12, the zeta potential decreased from Zp = 9.4 mV to Zp = −45.4 mV. The isoelectric point (IEP) was 4.3. Also at the IEP, the highest fine particle removal efficiency of 25.9% was achieved. The zeta potential increased as the metal cation concentration of the solutions increased. The trivalent cation Al 3+ exhibited the best performance, which increased Zp from −32.1 mV to −11.2 mV and produced the highest fine particle removal efficiency of 9.2%. Polymers significantly impacted the zeta potential. As the concentration of kappa-carrageenan (CAR) increased from 0.01% to 5%, the zeta potential increased from −30.1 mV to 12.6 mV. The highest fine particle removal efficiency of 41.8% was acquired at a concentration of 0.5%, which had the lowest zeta potential absolute value of 3.5 mV. It can be inferred that the increase in the zeta potential induced the growth of the energy barrier, which prevented particle agglomeration. The suspension with a lower zeta potential exhibited a better fine particle removal efficiency.
研究领域:
环境科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2021
·
IF 8.128
Yanming Feng,Xinyue Lv,Xi Ran,Caifeng Jia,Lujie Qin,Maoshen Chen,Ruijuan Qi,Hui Peng,Hechun Lin
Cuprous oxide (Cu 2 O) and cupric oxide (CuO) are widely available and low cost raw materials. Their applications as precursors for wet chemical synthesis of metallic Cu materials are greatly limited due to their insoluble in water and most organic solvents . In this work, copper superfine particles (Cu SPs) are synthesized using Cu 2 O and CuO as precursors via a heating process in monoethanoamine (MEA). Due to the strong coordinating character, Cu 2 O and CuO can be partially dissolved in MEA. The dissolved copper source is reduced by MEA at elevated temperature with the drastically releasing of NH 3 . As the dissolved copper source is reduced, more oxide will be dissolved and finally leads to the full reduction of Cu 2 O and CuO to produce the Cu SPs. The advantage of this synthesis method is that MEA acts as both the solvent and the reducing agent. The antimicrobial properties are investigated to find that the obtained Cu SPs depress the growth of Escherichia coli (E. coli) and Staphylococcus aureus (St. aureus) efficiently. More interesting, the composites produced via curing Cu 2 O and CuO with a small amount of MEA also exhibit excellent antimicrobial activity, indicating the MEA curing method is high-efficiency. The synthesis is low cost, high-efficiency, high atom-economy and up-scale synthesizing easily, which will benefit the wide applications of Cu SPs.
研究领域:
材料科学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2018
·
IF 6.653
Qingcai Chen,Haoyao Sun,Mamin Wang,Zhen Mu,Yuqin Wang,Yanguang Li,Yansong Wang,Lixin Zhang,Zimeng Zhang
To understand the nature and possible sources of environmentally persistent free radicals (EPFRs) in atmospheric aerosols, the present study used a solvent extraction method to fractionate aerosol components with different polarities and solvent resistance in fine particulate matter (PM2.5) from Xi’an, China. The characteristics of EPFRs, that is., their concentration, type and lifetime, were obtained based on their electron paramagnetic resonance spectra. The results showed that the EPFRs in the PM2.5 samples were carbon-centered with a nearby heteroatom (g = 2.0031) and had a long half-life of more than 3 years. Nearly all of the extractable EPFRs were detected in the water-insoluble organic fraction and showed characteristics indicating that may contain oxygen-centered radical (g = 2.0038). Most of the total EPFRs in the PM2.5 were derived from solvent-resistant organic matter (88%), which likely consisted of graphene oxide analogues. The results suggest that previous studies may have missed the major proportion of EPFRs in atmospheric particulates if they only focused on solvent-extractable or metallic oxide-formed EPFRs. Our results showed that the EPFR concentration was significantly and positively correlated with the elemental carbon and NO2 concentrations, suggesting that traffic emissions may be an important source of EPFRs in PM2.5 over Xi’an.
研究领域:
环境科学
·
大气化学
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2024
·
IF 12.2
Yanhao Zhang,Zifang Peng,Peiru Luo,Lin Zhu,Qingyun He,Congcong Pei,Dan Yin,Wenfen Zhang,Shusheng Zhang,Zongwei Cai
The broad application of various pesticides guarantees the development of agriculture all over the word but has ultimately led to their ubiquitous release into the environment as hazardous chemical residues. Diamide insecticides (DAIs) are regarded as new choice for prevention and protection of agricultural crops and city landscaping plants from the pests in more and more countries. However, their presence in fine particulate matter (PM 2.5 ) and associated health risks have not been studied. We reported for the first time the extensive distributions of PM 2.5 -bound DAIs in rural and urban areas of China, one of the world’s largest agricultural countries. Eight DAIs were analyzed, and five were consistently detected in PM 2.5 samples at concentrations primarily of pg m −3 level. Evident spatial/temporal variations were observed, with generally more serious DAIs’ contamination and long-term health risks in rural areas during spring, summer and autumn. The first exploration of DAIs’ toxicities on human bronchial epithelial cells discovered their capability of inhibiting cell viabilities, further demonstrating the potential detrimental effects of these emerging pollutants in PM 2.5 . This study confirms the widespread appearance of DAIs in PM 2.5 , emphasizing the need and urgency for concern about their pollution in both rural and urban air.
研究领域:
环境科学
·
毒理学
·
公共卫生
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）