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Title: PH-NEUTRAL CONCRETE FOR ATTACHED MICROALGAE AND ENHANCED CARBON DIOXIDE FIXATION - PHASE I

Abstract

The novelty/innovation of the proposed work is as follows. Supercritical carbon dioxide (SC-CO {sub 2})-based extrusion and molding technology can be used to produce significantly improved (in terms of strength/unit weight, durability, hardness and chemical resistance) cement-based products. SC-CO{sub 2} can rapidly convert the calcium hydroxide in cured cement to calcium carbonate, which increases the density and unconfined compressive strength in the treated region. In cured concrete, this treated region is typically a several-mm thick layer (generally <{approx}5mm, unless treatment time is excessive). However, we have found that by treating the entire cement matrix with SC-CO{sub 2} as part of the curing process, we can carbonate it rapidly, regardless of the thickness. By ''rapidly'' we mean simultaneous carbonation/curing in < 5 ks even for large cement forms, compared to typical carbonation times of several days or even years at low pressures. Carbonation changes the pH in the treated region from {approx}13 to {approx}8, almost exactly compatible with seawater. Therefore the leaching rates from these cements is reduced. These cement improvements are directed to the development of strong but thin artificial reefs, to which can be attached microalgae used for the enhanced fixation of CO{sub 2}. It is shown below thatmore » attached microalgae, as algal beds or reefs, are more efficient for CO{sub 2} fixation by a factor of 20, compared to the open ocean on an area basis. We have performed preliminary tests of the pH-neutral cements of our invention for attachment of microalgae populations. We have found pH-neutral materials which attach microalgae readily. These include silica-enriched (pozzolanic) cements, blast-furnace slags and fly ash, which are also silica-rich. We have already developed technology to simultaneously foam, carbonate and cure the cements; this foaming process further increases cement surface areas for microalgae attachment, in some cases to >10 m{sup 2}/g internal surface area. This project involves a team of researchers with backgrounds in cement technology, supercritical fluid technology, materials science, oceanography, and wetland biogeochemistry.« less

Authors:
; ;
Publication Date:
Research Org.:
Federal Energy Technology Center, Morgantown, WV (US); Federal Energy Technology Center, Pittsburgh, PA (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
778919
Report Number(s):
AC26-98FT40411-01
TRN: US200301%%326
DOE Contract Number:
AC26-98FT40411
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 31 May 1999
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; 54 ENVIRONMENTAL SCIENCES; CALCIUM CARBONATES; CALCIUM HYDROXIDES; CARBON DIOXIDE FIXATION; CONCRETES; FLY ASH; REEFS; SYNTHETIC MATERIALS; WETLANDS; ALGAE; IMMOBILIZED CELLS; SUPERCRITICAL GAS EXTRACTION; CARBON DIOXIDE; SLAGS; WASTE PRODUCT UTILIZATION

Citation Formats

Kerry M. Dooley, F. Carl Knopf, and Robert P. Gambrell. PH-NEUTRAL CONCRETE FOR ATTACHED MICROALGAE AND ENHANCED CARBON DIOXIDE FIXATION - PHASE I. United States: N. p., 1999. Web. doi:10.2172/778919.
Kerry M. Dooley, F. Carl Knopf, & Robert P. Gambrell. PH-NEUTRAL CONCRETE FOR ATTACHED MICROALGAE AND ENHANCED CARBON DIOXIDE FIXATION - PHASE I. United States. doi:10.2172/778919.
Kerry M. Dooley, F. Carl Knopf, and Robert P. Gambrell. Mon . "PH-NEUTRAL CONCRETE FOR ATTACHED MICROALGAE AND ENHANCED CARBON DIOXIDE FIXATION - PHASE I". United States. doi:10.2172/778919. https://www.osti.gov/servlets/purl/778919.
@article{osti_778919,
title = {PH-NEUTRAL CONCRETE FOR ATTACHED MICROALGAE AND ENHANCED CARBON DIOXIDE FIXATION - PHASE I},
author = {Kerry M. Dooley and F. Carl Knopf and Robert P. Gambrell},
abstractNote = {The novelty/innovation of the proposed work is as follows. Supercritical carbon dioxide (SC-CO {sub 2})-based extrusion and molding technology can be used to produce significantly improved (in terms of strength/unit weight, durability, hardness and chemical resistance) cement-based products. SC-CO{sub 2} can rapidly convert the calcium hydroxide in cured cement to calcium carbonate, which increases the density and unconfined compressive strength in the treated region. In cured concrete, this treated region is typically a several-mm thick layer (generally <{approx}5mm, unless treatment time is excessive). However, we have found that by treating the entire cement matrix with SC-CO{sub 2} as part of the curing process, we can carbonate it rapidly, regardless of the thickness. By ''rapidly'' we mean simultaneous carbonation/curing in < 5 ks even for large cement forms, compared to typical carbonation times of several days or even years at low pressures. Carbonation changes the pH in the treated region from {approx}13 to {approx}8, almost exactly compatible with seawater. Therefore the leaching rates from these cements is reduced. These cement improvements are directed to the development of strong but thin artificial reefs, to which can be attached microalgae used for the enhanced fixation of CO{sub 2}. It is shown below that attached microalgae, as algal beds or reefs, are more efficient for CO{sub 2} fixation by a factor of 20, compared to the open ocean on an area basis. We have performed preliminary tests of the pH-neutral cements of our invention for attachment of microalgae populations. We have found pH-neutral materials which attach microalgae readily. These include silica-enriched (pozzolanic) cements, blast-furnace slags and fly ash, which are also silica-rich. We have already developed technology to simultaneously foam, carbonate and cure the cements; this foaming process further increases cement surface areas for microalgae attachment, in some cases to >10 m{sup 2}/g internal surface area. This project involves a team of researchers with backgrounds in cement technology, supercritical fluid technology, materials science, oceanography, and wetland biogeochemistry.},
doi = {10.2172/778919},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon May 31 00:00:00 EDT 1999},
month = {Mon May 31 00:00:00 EDT 1999}
}

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