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Huiyan Zhang, Shanshan Shao, Mengmeng Luo, Rui Xiao
Catalyst deactivation is the main reason for low petrochemical yield in catalytic fast pyrolysis (CFP) of biomass. ZSM-5 catalysts modified by chemical liquid deposition (CLD) and acid dealumination (AD) were prepared to improve petrochemical yields for CFP of pinewood. The results showed that CLD by SiO2 led to the coverage of strong acid sites, while AD favored the removal of superficial acid sites. CFP of pinewood showed that the relative area ratio of BTX was boosted by 37.2% and 30.4% over modified ZSM-5 catalysts by CLD and AD, respectively...
August 9, 2017: Bioresource Technology
Jose A Rodriguez, Zongyuan Liu, Pablo Lustemberg, Ramon Gutierrez, John Carey, Robert Palomino, Mykhailo Vorohta, David Grinter, Pedro Ramirez, Vladimir Matolin, Michael Nolan, M Veronica Ganduglia-Pirovano, Sanjaya Senanayake
Studies with a series of M-CeO2(111) {M= Co, Ni, Cu} surfaces indicate that metal-oxide interactions can play a very important role for the activation of methane and its reforming with CO2 at relatively low temperatures (600-700 K). Among the systems examined, Co-CeO2(111) exhibits the best performance and Cu-CeO2(111) has negligible activity. Experiments using ambient pressure XPS indicate that methane dissociates on Co-CeO2(111), at temperatures as low as 300 K, generating CHx and COx species on the catalyst surface...
August 16, 2017: Angewandte Chemie
Christine Lors, Jean-François Ponge, Denis Damidot
A bioassay battery-integrated index was applied to different soils sampled from a former coke factory, with the aim to evaluate the discriminating capacity of the Ecoscore system (ES) to assess the environmental hazard of PAH-polluted soils. Two soils from a former coke factory, polluted with polycyclic aromatic hydrocarbons (PAHs), were evaluated for their ecotoxicity to terrestrial and aquatic organisms and their genotoxicity. These soils have been already presented in a previous paper but data have been reanalyzed for the present article in an endeavor to standardize the ES...
August 12, 2017: Environmental Science and Pollution Research International
R Cossu, F Garbo, F Girotto, F Simion, A Pivato
Only a small percentage of the separately collected plastic is recycled. The mechanical selection process of source segregated plastic materials generates considerable amounts of residues that are commonly named as Plasmix. By means of a life cycle assessment (LCA) modelling, the environmental performances of the main Plasmix management options (thermal treatment, energy recovery, and landfilling) were compared. Six treatment scenarios, with different pre-treatment alternatives, were evaluated. Landfilling after waste washing and Plasmix substitution of coke in a blast furnace represent the most favorable options, since the performances of thermal treatment and energy recovery are worsened by specific emissions of a variety of toxic compounds and heavy metals within plastic materials as additives...
August 9, 2017: Waste Management
Lei Zhang, Xin Wen, Zhenhua Ma, Lei Zhang, Xiangling Sha, Huibin He, Tianyou Zeng, Yusu Wang, Jihao Chen
Selective catalytic oxidation (SCO) method is commonly used in wet denitration technology; NO after the catalytic oxidation can be removed with SO2 together by wet method. Among the SCO denitration catalysts, pyrolysis coke is favored by the advantages of low cost and high catalytic activity. In this paper, SCO method combined with pyrolysis coke catalyst was used to remove NO from flue gas. The effects of different SCO operating conditions and different pyrolysis coke catalyst made under different process conditions were studied...
2017: PloS One
Yeshui Zhang, Yongwen Tao, Jun Huang, Paul Williams
The influence of catalyst support alumina-silica in terms of different Al2O3 to SiO2 mole ratios containing 20 wt.% Ni on the production of hydrogen and catalyst coke formation from the pyrolysis-catalysis of waste tyres is reported. A two-stage reactor system was used with pyrolysis of the tyres followed by catalytic reaction. There was only a small difference in the total gas yield and hydrogen yield by changing the Al2O3 to SiO2 mole ratios in the Ni-Al2O3/SiO2 catalyst. The 1:1 ratio of Al2O3:SiO2 ratio produced the highest gas yield of 27...
August 1, 2017: Waste Management & Research
Changsong Hu, Rui Xiao, Huiyan Zhang
Ex-situ and in-situ catalytic fast pyrolysis (CFP) of biomass over HZSM-5 were compared in a two-stage fluidized-bed/fixed-bed combination reactor. Ex-situ CFP gave a similar carbon yield of aromatics+olefins (∼20%) with in-situ CFP but produced much more olefins (10.3% vs. 5.8%) and less char+coke (42.7% vs. 48.4%). The effects of weight hourly space velocity (WHSV), carrier gas flow rate, pyrolysis temperature and catalysis temperature on product distribution in ex-situ CFP were further studied. The maximum carbon yield of aromatics+olefins (21...
July 6, 2017: Bioresource Technology
Lihui Gao, Hong Wen, Quanzhi Tian, Yongtian Wang, Guosheng Li
Coking coal, the raw material of a coke plant, was applied to the adsorption of coking wastewater. In this study, coking coal was directly treated with sulfuric acid to improve its surface properties and adsorption ability. Acid treatment was carried out at various concentrations, by varying from 0.001 to 1 mol/L. The samples were characterized by ash content analysis, scanning electron microscope (SEM), N2 adsorption-desorption analysis, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), wettability analysis, and zeta potential analysis...
July 2017: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Zheng Xing, Yeap Hung Ng, Siok-Wei Tay, Rachel Pek Har Oon, Liang Hong
This work investigates the effect of atmosphere on pyrolysis of a polymer matrix (precursor) for directing its transformation towards more disordered graphene species and smaller graphitic nanograins. These two structural characteristics are crucial to the generation of nano-channels (NCs) pertinent to nanofiltration (NF). Two measures are explored hereby to conduct the study: varying the pyrolysis atmosphere and implementing highly dispersed nickel atomic clusters (Ni-clusters) in the coating matrix undergoing pyrolysis...
August 16, 2017: Physical Chemistry Chemical Physics: PCCP
Mai-Anh Ha, Eric T Baxter, Ashley C Cass, Scott L Anderson, Anastassia N Alexandrova
Size-selected supported clusters of transition metals can be remarkable and highly tunable catalysts. A particular example is Pt clusters deposited on alumina, which have been shown to dehydrogenate hydrocarbons in a size-specific manner. Pt7, of the three sizes studied, is the most active and, therefore, like many other catalysts, deactivates by coking during reactions in hydrocarbon-rich environments. Using a combination of experiment and theory, we show that nanoalloying Pt7 with boron modifies the alkene-binding affinity to reduce coking...
August 11, 2017: Journal of the American Chemical Society
Alberto Rodriguez-Gomez, Rosa Pereñiguez, Alfonso Caballero
A series of four Ni catalysts supported on SBA-15 and on a high surface area SiO2 have been prepared by modified impregnation (ImU) and deposition-precipitation (DP) methods. The catalysts have been extensively characterized, including in situ XAS and XPS techniques, and their catalytic activities evaluated in the dry reforming reaction of methane (DRM). The combined use of a surface sensitive technique (XPS) with a bulk sensitive one (XAS) has allowed to determine the location of nickel particles on each catalyst after reduction at high temperature (750 oC)...
July 19, 2017: Journal of Physical Chemistry. B
Martha Georgiopoulou, Gerasimos Lyberatos
The benefits of using alternative fuels (AFs) in the cement industry include reduction of the use of non-renewable fossil fuels and lower emissions of greenhouse gases, since fossil fuels are replaced with materials that would otherwise be degraded or incinerated with corresponding emissions and final residues. Furthermore, the use of alternative fuels maximizes the recovery of energy. Seven different scenaria were developed for the production of 1 ton of clinker in a rotary cement kiln. Each of these scenaria includes the use of alternative fuels such as RDF (Refuse derived fuel), TDF (Tire derived fuel) and BS (Biological sludge) or a mixture of them, in partial replacement of conventional fuels such as coal and pet coke...
July 14, 2017: Journal of Environmental Management
Elwira Zajusz-Zubek, Tomasz Radko, Anna Mainka
Samples of PM1 were collected in the surroundings of coking plants located in southern Poland. Chemical fractionation provided information on the contents of trace elements As, Cd, Co, Cr, Hg, Mn, Ni, Pb, Sb and Se in all mobile (F1-F3) and not mobile (F4) fractions of PM1 in the vicinity of large sources of emissions related to energochemical processing of coal during the summer. The determined enrichment factors indicate the influence of anthropogenic sources on the concentration of the examined elements contained in PM1 in the areas subjected to investigation...
August 2017: Environmental Monitoring and Assessment
Yongmei Wang, Alejandro López-Valdivieso, Teng Zhang, Teza Mwamulima, Xiaolin Zhang, Shaoxian Song, Changsheng Peng
New microscale zero-valent iron adsorbent on fly ash and bentonite matrix for removal of crystal violet (CV) and methylene blue (MB) was synthesized through direct reduction of iron oxide using coke and palm kernel shell. The adsorbent was prepared as cylindrical shaped pellets to remove the CV and MB from the aqueous solution. Nitrogen adsorption-desorption isotherm and scanning electron microscopy (SEM) studies showed that the adsorbent is highly porous, and the iron particles are finely dispersed on the supporting material surfaces...
July 11, 2017: Environmental Science and Pollution Research International
Wenwen Gong, Heidelore Fiedler, Xiaotu Liu, Bin Wang, Gang Yu
Hexachlorobenzene (HCB) and pentachlorobenzene (PeCBz) have been listed as unintentional POPs in the annex of the Stockholm Convention and thus, attracted attention by government and researchers. Since the intentional production and use has ceased in most countries, the unintentional releases to the environment have increased. This study gathered 206 and 78 emission factors (EFs) of unintentional HCB and PeCBz from scientific publications and governmental reports, respectively. Most of the EFs referred to the release vector "air" (EFAir) and to a less extent to "product" (EFProduct)...
July 8, 2017: Environmental Pollution
Marcos L S Oliveira, Orlando G Navarro, Tito J Crissien, Bernardo F Tutikian, Kátia da Boit, Elba C Teixeira, Juan J Cabello, Dayana M Agudelo-Castañeda, Luis F O Silva
There are multiple elements which enable coal geochemistry: (1) boiler and pollution control system design parameters, (2) temperature of flue gas at collection point, (3) feed coal and also other fuels like petroleum coke, tires and biomass geochemistry and (4) fuel feed particle size distribution homogeneity distribution, maintenance of pulverisers, etc. Even though there is a large number of hazardous element pollutants in the coal-processing industry, investigations on micrometer and nanometer-sized particles including their aqueous colloids formation reactions and their behaviour entering the environment are relatively few in numbers...
July 7, 2017: Environmental Research
Enchao Li, Rongchang Wang, Xuewen Jin, Shuguang Lu, Zhaofu Qiu, Xiang Zhang
Global water shortages have resulted in increasing interest in water reuse and recycling. Therefore, in the present study, a biological denitrifying process using a sequencing batch reactor (SBR) was employed to treat reverse osmosis (RO) concentrate with high conductivity produced from a coking wastewater plant. From the results, the average removal efficiencies for chemical oxygen demand, total nitrogen, and nitrate were 79.5%, 90.5%, and 93.1%, respectively. Different microbial communities were identified after sequencing the V1-V3 region of the 16S rRNA gene using the MiSeq platform, and the major bacterial phyla in the SBR system were Proteobacteria and Bacteroidetes...
July 6, 2017: Environmental Technology
GuanNan Xiong, YunHui Zhang, YongHong Duan, ChuanYang Cai, Xin Wang, JingYa Li, Shu Tao, WenXin Liu
Samples of ambient air (including gaseous and particulate phases), dust fall, surface soil, rhizosphere soil, core (edible part), outer leaf, and root of cabbage from eight vegetable plots near a large coking manufacturer were collected during the harvest period. Concentrations, compositions, and distributions of parent PAHs in different samples were determined. Our results indicated that most of the parent PAHs in air occurred in the gaseous phase, dominated by low molecular weight (LMW) species with two to three rings...
June 27, 2017: Environmental Science and Pollution Research International
Roger P Dotsey, Elizabeth A S Moser, George J Eckert, Richard L Gregory
OBJECTIVE: To examine the effects of cola-flavored beverages and caffeine on growth and metabolism of Streptococcus mutans biofilm. This study was designed to determine if carbonated beverages or caffeine can increase S. mutans growth and biofilm formation and metabolic activity in vitro, potentially leading to increased S. mutans-associated cariogenicity in children that consume them. STUDY DESIGN: Six different cola-flavored products, plus pure caffeine, and pure high fructose corn syrup (HFCS), at different concentrations similar to those in the beverages were tested...
2017: Journal of Clinical Pediatric Dentistry
Amit U Raysoni, Rodrigo X Armijos, M Margaret Weigel, Patricia Echanique, Marcia Racines, Nicholas E Pingitore, Wen-Whai Li
Elemental characterization of fine particulate matter was undertaken at schools and residences in three low income neighborhoods in Quito, Ecuador. The three zones were located in the northern (Cotocollao), south central (El Camal), and south east (Los Chillos) neighborhoods and were classified as zones 1-3, respectively. Forty elements were quantified via ICP-MS analysis. Amongst the geogenic elements, the concentration of Si was the most abundant followed by S, Al, and Ca. Elements with predominantly anthropogenic sources such as Zn, V, and Ni were higher in zone 3 school followed by zone 2 and zone 1 schools...
June 23, 2017: International Journal of Environmental Research and Public Health
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