Showing papers by "Lawrence B. Alemany published in 2011"

Engineered Graphite Oxide Materials for Application in Water Purification

Abstract: Retaining the inherent hydrophilic character of GO (graphite-oxide) nanosheets, sp2 domains on GO are covalently modified with thiol groups by diazonium chemistry. The surface modified GO adsorbs 6-fold higher concentration of aqueous mercuric ions than the unmodified GO. “Core–shell” adsorbent granules, readily useable in filtration columns, are synthesized by assembling aqueous GO over sand granules. The nanostructured GO-coated sand retains at least 5-fold higher concentration of heavy metal and organic dye than pure sand. The research results could open avenues for developing low-cost water purification materials for the developing economies.

In situ synthesis of polymer-modified mesoporous carbon CMK-3 composites for CO2 sequestration.

Abstract: Here we report carbon-based composites polyethylenimine-mesocarbon (PEI-CMK-3) and polyvinylamine-mesocarbon (PVA-CMK-3) that can be used to capture and rapidly release CO2. CO2 uptake by the synthesized composites was determined using a gravimetric method at 30 °C and 1 atm; the 39% PEI-CMK-3 composite had ∼12 wt % CO2 uptake capacity and the 37% PVA-CMK-3 composite had ∼13 wt % CO2 uptake capacity. A desorption temperature of 75 °C was sufficient for regeneration. The CO2 uptake was the same when using 10% CO2 in a 90% CH4, C2H6, and C3H8 mixture, underscoring this composite’s efficacy for CO2 sequestration from natural gas.

Structural Dislocations in Anthracite

Abstract: Anthracite is composed primarily of polycyclic aromatic hydrocarbons that exist as curved layers of graphenic sheets of various sizes. The bright field high-resolution transmission electron microsc...

Functionalization by Reductive Alkylation and Mapping of a Subbituminous Coal by Energy Dispersive X-ray Spectroscopy

Abstract: Reduction of a subbituminous coal by lithium in liquid ammonia yields a coal salt that can be reacted with 1-iodododecane to yield dodecylated coal that is partially soluble in organic solvents. The coal salt also acts as an initiator for the in situ oligomerization of alkenes onto the surface of the coal nanoplatelets. Atomic force microscopy and high-resolution transmission electron microscopy images of this material have been recorded. Energy-dispersive X-ray spectroscopy has been used to identify minerals that occur in the coal.

Reductive Alkylation of Anthracite: Edge Functionalization

Abstract: Reduction of anthracite by electron transfer from either lithium or sodium in liquid ammonia yields a salt that can be alkylated by 1-iodododecane to yield nanocoal that is partially soluble in common organic solvents. NMR indicates that the dodecyl groups are attached to the edges of the aromatic ring systems, with many of the dodecyl groups extending into void spaces. Thermal gravimetric analysis shows that sodium gives a slightly higher level of functionalization. Atomic force microscopy (AFM) images of soluble dodecylated anthracite reveal nanoparticles that vary from 3 to 12 nm high. Scanning electron microscopy (SEM) and bright field high-resolution transmission electron microscopy (HRTEM) of the raw anthracite reveal a layered structure with dislocations. Inorganic materials that occur in the raw anthracite were identified by energy dispersive X-ray spectroscopy (EDS). Simple alkenes were found to react with the coal salt to give oligomers of the alkene that are grafted onto the surface of the coal.