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Environmental Remediation (environmental + remediation)

Distribution by Scientific Domains
Polymers and Materials Science57%

Selected Abstracts

Heterointegration of Pt/Si/Ag Nanowire Photodiodes and Their Photocatalytic Properties

ADVANCED FUNCTIONAL MATERIALS, Issue 18 2010
Yongquan Qu
Abstract Photocatalyst mediated photoelectrochemical processes can make use of the photogenerated electrons and holes onsite for photocatalytic redox reactions, and enable the harness and conversion of solar energy into chemical energy, in analogy to natural photosynthesis. However, the photocatalysts available to date are limited by either poor efficiency in the visible light range or insufficient photoelectrochemical stability. Here, it is shown that a Pt/Si/Ag nanowire heterostructure can be rationally synthesized to integrate a nanoscale metal-semiconductor Schottky diode encased in a protective insulating shell with two exposed metal catalysts. The synthesis of Pt/Si/Ag nanowire diodes involves a scalable process including the formation of silicon nanowire array through wet chemical etching, electrodeposition of platinum and photoreduction of silver. The Pt/Si/Ag diodes exhibit highly efficient photocatalytic activity for a wide range of applications including environmental remediation and solar fuel production in the visible range. In this article, photodegradation of indigo carmine and 4-nitrophenol are used to evaluate the photoactivity of Pt/Si/Ag diodes. The Pt/Si/Ag diodes also show high activity for photoconversion of formic acid into carbon dioxide and hydrogen. [source]

Heterointegration of Pt/Si/Ag Nanowire Photodiodes and Their Photocatalytic Properties

ADVANCED FUNCTIONAL MATERIALS, Issue 18 2010
Yongquan Qu
Abstract Photocatalyst mediated photoelectrochemical processes can make use of the photogenerated electrons and holes onsite for photocatalytic redox reactions, and enable the harness and conversion of solar energy into chemical energy, in analogy to natural photosynthesis. However, the photocatalysts available to date are limited by either poor efficiency in the visible light range or insufficient photoelectrochemical stability. Here, it is shown that a Pt/Si/Ag nanowire heterostructure can be rationally synthesized to integrate a nanoscale metal-semiconductor Schottky diode encased in a protective insulating shell with two exposed metal catalysts. The synthesis of Pt/Si/Ag nanowire diodes involves a scalable process including the formation of silicon nanowire array through wet chemical etching, electrodeposition of platinum and photoreduction of silver. The Pt/Si/Ag diodes exhibit highly efficient photocatalytic activity for a wide range of applications including environmental remediation and solar fuel production in the visible range. In this article, photodegradation of indigo carmine and 4-nitrophenol are used to evaluate the photoactivity of Pt/Si/Ag diodes. The Pt/Si/Ag diodes also show high activity for photoconversion of formic acid into carbon dioxide and hydrogen. [source]

Application of Six Sigma Methods for Improving the Analytical Data Management Process in the Environmental Industry

GROUND WATER MONITORING & REMEDIATION, Issue 2 2006
Christopher M. French
Honeywell applied the rigorous and well-documented Six Sigma quality-improvement approach to the complex, highly heterogeneous, and mission-critical process of remedial site environmental data management to achieve a sea change in terms of data quality, environmental risk reduction, and overall process cost reduction. The primary focus was to apply both qualitative and quantitative Six Sigma methods to improve electronic management of analytical laboratory data generated for environmental remediation and long-term monitoring programs. The process includes electronic data delivery, data QA/QC checking, data verification, data validation, database administration, regulatory agency reporting and linkage to spatial information, and real-time geographical information systems. Results of the analysis identified that automated, centralized web-based software tools delivered through Software as a Service (SaaS) model are optimal to improve the process resulting in cost reductions, while simultaneously improving data quality and long-term data usability and perseverance. A pilot project was completed that quantified cycle time and cost improvements of 50% and 65%, respectively. [source]

Photocatalytic and Magnetic Properties of the Fe-TiO2/SnO2 Nanofiber Via Electrospinning

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 3 2010
Rui Zhang
Fe-doped TiO2/0.03SnO2 hybrid nanofiber has been prepared via electrospinning method. The magnetic property versus Fe-doping content was characterized, and the corresponding photocatalytic activity under visible light radiation was evaluated by using Rhodamine B (RhB) degradation as a probe reaction. The hybrid nanofiber has proved to be an excellent visible light-excitable photocatalyst with much higher photocatalytic activity than undoped TiO2/SnO2 hybrid nanofibers. The magnetic properties have also been characterized for the Fe-TiO2/SnO2 nanofibers before and after annealing under vacuum atmosphere, and nanofibers shows obvious ferromagnetic property at room temperature as they were annealed. It is believed that this nanofiber may become a potential photocatalyst in environmental remediation. [source]

Preparation of Necklace-Structured TiO2/SnO2 Hybrid Nanofibers and Their Photocatalytic Activity

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2009
Rui Zhang
TiO2/SnO2 nanonecklace-structured hybrid nanofibers have been prepared via an electrospinning method. These hybrid nanofibers are characterized with SnO2 -rich beads and pure TiO2 chains. It is found that TiO2 in the beads shows a rutile structure, and the one in the chains is entirely composed of anatase phase. This novel microstructure enhanced the photocatalytic activity, as well as its ideal recyclable character. We believe that this fire-new type of nanofiber may potentially serve as a new generation photocatalyst in environmental remediation. [source]

Off-gas treatment carbon footprint calculator: Form and function

REMEDIATION, Issue 1 2008
Lowell Kessel
The quantification of greenhouse gas (GHG) emissions can be a powerful sustainability measurement indicator for assessing environmental impacts of various operations, which can include remediation of chemically impacted media or construction projects. A carbon footprint calculator was developed and is presented in this article as one tool for applying sustainable practices to environmental remediation,specifically to assess the GHG footprint for remediation projects. The calculator is constructed from a compilation of published metrics and "standards." © 2008 Wiley Periodicals, Inc. [source]

Review: Biological methylation of less-studied elements

APPLIED ORGANOMETALLIC CHEMISTRY, Issue 12 2002
John S. Thayer
Abstract Biological methylation is an enzymatic process in which a methyl group is transferred from one atom to another. For elements having atomic number greater than 11, biological methylation has been most extensively studied for three elements: arsenic, mercury and sulfur. However, many other elements also undergo biological methylation but have received less attention. Recent work on these less-studied elements and new applications of biological methylation to environmental remediation, along with a description of these reactions in terms of bonding models, is the focus of this review. Copyright © 2002 John Wiley & Sons, Ltd. [source]