Author
Yuming Gao
Other affiliations: Academia Sinica
Bio: Yuming Gao is an academic researcher from Brown University. The author has contributed to research in topics: Fly ash & Liquid crystal. The author has an hindex of 22, co-authored 32 publications receiving 1147 citations. Previous affiliations of Yuming Gao include Academia Sinica.
Topics: Fly ash, Liquid crystal, Graphene, Carbon, Oxide
Papers
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TL;DR: This work characterizes the time-resolved release of mercury vapor from broken CFLs and from underlying substrates after removal of glass fragments to simulate cleanup, and successfully suppressed Hg vapor escape following CFL fracture.
Abstract: The projected increase in the use of compact fluorescent lamps (CFLs) motivates the development of methods to manage consumer exposure to mercury and its environmental release at the end of lamp life. This work characterizes the time-resolved release of mercury vapor from broken CFLs and from underlying substrates after removal of glass fragments to simulate cleanup. In new lamps, mercury vapor is released gradually in amounts that reach 1.3 mg or 30% of the total lamp inventory after four days. Similar time profiles but smaller amounts are released from spent lamps or from underlying substrates. Nanoscale formulations of S, Se, Cu, Ni, Zn, Ag, and WS2 are evaluated for capture of Hg vapor under these conditions and compared to conventional microscale formulations. Adsorption capacities range over 7 orders of magnitude, from 0.005 (Zn micropowder) to 188 000 microg/g (unstabilized nano-Se), depending on sorbent chemistry and particle size. Nanosynthesis offers clear advantages for most sorbent chemistries. Unstabilized nano-selenium in two forms (dry powder and impregnated cloth) was successfully used in a proof-of-principle test for the in situ, real-time suppression of Hg vapor escape following CFL fracture.
146 citations
TL;DR: In this paper, the fundamental interaction mechanisms between fly ash and air-entraining admixtures are identified and the results indicate that the interaction is time-dependent and occurs to a degree that correlates only crudely with the amount of carbon present.
123 citations
TL;DR: In this paper, the authors examined the general mechanism of surfactant adsorption on carbon and its suppression by surface oxidation and found that the main mechanism of oxidative suppression is the destruction of this non-polar surface, though micropore blockage and increased negative surface charge may also contribute.
117 citations
TL;DR: In this paper, the authors focused on the specific sorptive behavior of carbon black, which is used as a pigment in some concrete formulations and also serves as a convenient model substance for soot, which may be present in fly ash from coal combustion.
Abstract: The most important commercial outlet for coal ash is in the concrete industry as a partial replacement for Portland cement. In many concrete mixtures careful control of air entrainment is required, but the presence of solid carbon disrupts the air entrainment process. An earlier study focused on the fundamental role of carbons, which were found to adsorb air-entraining admixtures, the specialty surfactants used in concrete mixtures, rendering them less active for their primary function as stabilizing agents for air bubbles. The present paper focuses on the specific sorptive behavior of carbon black, which is used as a pigment in some concrete formulations and also serves as a convenient model substance for soot, which may be present in fly ash from coal combustion. The paper also describes microscopic examination of several commercial fly ash samples for the possible presence of soot. The results show that eight commercial carbon blacks interact strongly with the air-entraining admixtures, the degree of i...
75 citations
TL;DR: The addition of gold to all of these samples increased their photocatalytic activity as mentioned in this paper, and their catalytic activities were compared to samples of commercial TiO2 (P25).
58 citations
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TL;DR: In this paper, photo-induced superhydrophilicity was used on the surface of a wide-band gap semiconductor like titanium dioxide (TiO 2 ) for photocatalytic activity towards environmentally hazardous compounds.
4,241 citations
TL;DR: In this article, the utilization of fly ash in construction, as a low-cost adsorbent for the removal of organic compounds, flue gas and metals, light weight aggregate, mine back fill, road sub-base, and zeolite synthesis is discussed.
2,117 citations
TL;DR: In this paper, the presence of transition metal ions in photocatalytic reactions is reviewed according to two main approaches: (a) the influence of metal ions on the rate of photocatalysis and (b) the transformation of the ions to less toxic species or their deposition on the semiconductor catalyst surface for recovery of expensive and useful metals.
Abstract: The presence of transition metal ions in photocatalytic reactions is reviewed according to two main approaches: (a) the influence of transition metal ions on the rate of photocatalytic reactions (mainly oxidation) and (b) the transformation of the ions to less toxic species or their deposition on the semiconductor catalyst surface for recovery of expensive and useful metals. Most of the proposed mechanisms are discussed, together with experimental physicochemical evidences that support the involved pathways. Practical applications related to environmental protection and industrial processes are described.
1,294 citations
TL;DR: In this paper, the authors present a review of coal fly ash at the global level, focusing on its current and potential applications, including use in the soil amelioration, construction industry, ceramic industry, catalysis, depth separation, zeolite synthesis, etc.
1,167 citations
TL;DR: Particle surface area, number of ultrafine particles, bioavailable transition metals, polycyclic aromatic hydrocarbons (PAH), and other particle-bound organic compounds are suspected to be more important than particle mass in determining the effects of air pollution.
Abstract: Particulate matter (PM) emissions from stationary combustion sources burning coal, fuel oil, biomass, and waste, and PM from internal combustion (IC) engines burning gasoline and diesel, are a significant source of primary particles smaller than 2.5 μm (PM2.5) in urban areas. Combustion-generated particles are generally smaller than geologically produced dust and have unique chemical composition and morphology. The fundamental processes affecting formation of combustion PM and the emission characteristics of important applications are reviewed. Particles containing transition metals, ultrafine particles, and soot are emphasized because these types of particles have been studied extensively, and their emissions are controlled by the fuel composition and the oxidant-tem-perature-mixing history from the flame to the stack. There is a need for better integration of the combustion, air pollution control, atmospheric chemistry, and inhalation health research communities. Epidemiology has demonstrated t...
1,018 citations