Lehigh University

About: Lehigh University is a education organization based out in Bethlehem, Pennsylvania, United States. It is known for research contribution in the topics: Catalysis & Fracture mechanics. The organization has 12684 authors who have published 26550 publications receiving 770061 citations.

Polymer supported inorganic nanoparticles: characterization and environmental applications

Abstract: Nanoscale Inorganic Particles (NIPs) and their agglomerates offer excellent opportunities conducive to selective removal of a wide array of target compounds from contaminated water bodies. For example, (i) hydrated Fe(III) oxides or HFO particles can selectively sorb dissolved heavy metals like zinc, copper or metalloids like arsenic oxyacids or oxyanions; (ii) Mn(IV) oxides are fairly strong solid phase oxidizing agents; (iii) magnetite (Fe 3 O 4 ) crystals are capable of imparting magnetic activity; (iv) elemental Zn o or Fe o are excellent reducing agents for both inorganic and organic contaminants. Very high surface area to volume ratio of these nanoscale particles offers favorable sorption and/or reaction kinetics. However, applications of NIPs in fixed-bed columns, in-situ reactive barriers and in similar flow-through applications are not possible due to extremely high pressure drops. Also, these NIPs are not durable and lack mechanical strength. Harnessing these inorganic nanoparticles and their aggregates appropriately within polymeric beads offers new opportunities that are amenable to rapid implementation in the area of environmental separation and control. While the NIPs retain their intrinsic sorption/desorption, redox, acid–base or magnetic properties, the robust polymeric support offers excellent mechanical strength, durability and favorable hydraulic properties in the flow-through systems. This paper discusses at length the preparation, characterization and environmental applications of two classes of polymer supported nanoparticles: (i) Hydrated Fe(III) Oxide (HFO) dispersed polymeric exchanger and their As(III), As(V), and heavy metals removal properties; (ii) Magnetically Active Polymeric Particles (MAPPs). The polymer supported nanoparticles are reusable and can be easily reprocessed over many cycles of operation.

Thin-Film Materials for the Protection of Semiconducting Photoelectrodes in Solar-Fuel Generators

Abstract: The electrochemical instability of semiconductors in aqueous electrolytes has impeded the development of robust sunlight-driven water-splitting systems. We review the use of protective thin films to improve the electrochemical stability of otherwise unstable semiconductor photoelectrodes (e.g., Si and GaAs). We first discuss the origins of instability and various strategies for achieving stable and functional photoelectrosynthetic interfaces. We then focus specifically on the use of thin protective films on photoanodes and photocathodes for photosynthetic reactions that include oxygen evolution, halide oxidation, and hydrogen evolution. Finally, we provide an outlook for the future development of thin-layer protection strategies to enable semiconductor-based solar-driven fuel production.

Applications of iron nanoparticles for groundwater remediation

Abstract: Iron nanoparticles are increasingly being applied in site remediation and hazardous waste treatment. Nearly a decade after it was first proposed in 1996, the iron nanoparticle technology is at a critical stage of its developmental process. Significant research innovations have been made in terms of synthetic methods, surface property modification, and enhancement for field delivery and reactions. Extensive laboratory studies have demonstrated that nanoscale iron particles are effective for the treatment of a wide array of common groundwater contaminants such as chlorinated organic solvents, organochlorine pesticides, polychlorinated biphenyls (PCBs), organic dyes, and various inorganic compounds. Several field tests have also demonstrated the promising prospective for in situ remediation. Nonetheless, there are still considerable knowledge gaps on many fundamental scientific issues (e.g., fate, transport, and environmental impact) and economic hurdles, which could determine the acceptance of the technology within the academic community as well as by regulators and the private sector. An overview of the iron nanoparticle technology is provided in this article, beginning with a description of the process fundamentals. This is followed by a discussion of the synthetic schemes for the nanoparticle types developed at Lehigh University. Next, a summary of the major research findings is provided, highlighting the key characteristics and remediation-related advantages of the iron nanoparticle technology versus the granular/microscale iron technology. A discussion of challenges related to its future directions and environmental impact is presented. © 2006 Wiley Periodicals, Inc.