Research Abstract:
Over
the last decade, discussion has evolved from whether exponentially
increasing anthropogenic CO 2 emissions will adversely affect the global
environment, to the timing and magnitude of their impact. A variety of
sequestration technologies are being explored to mitigate CO 2
emissions. These technologies must be both environmentally benign and
economically viable. Mineral carbonation is an attractive candidate
technology as it disposes of CO 2 as geologically stable,
environmentally benign mineral carbonates, clearly satisfying the first
criteria. The primary challenge for mineral carbonation is
cost-competitive process development. Mg-rich lamellar hydroxides offer
exciting potential as widely available, low-cost feedstock materials
(e.g., serpentines). Furthermore, dehydroxylation offers the intriguing
potential to disrupt these materials down to the atomic level,
substantially enhancing their carbonation reactivity, a key component in
reducing process cost. Over the past year and a half, we have been
studying dehydroxylation/carbonation reaction processes for the
prototype Mg-rich lamellar-hydroxide: Mg(OH) 2. The primary goal is to
develop the fundamental mechanistic understanding needed to enhance
carbonation reactivity. Recently, we discovered Mg(OH) 2 dehydroxylation
is best described as a lamellar nucleation and growth process, which
can access a range of new, potentially high-surface-area, lamellar
oxyhydroxide intermediate materials, Mg x+y O x (OH) 2y. These materials
provide access to a broad range of new carbonation reaction pathways
via dehydroxylation/rehydroxylation, which can dramatically increase
carbonation reactivity. Similar mechanisms may be more broadly
applicable to Mg/Ca-rich lamellar-hydroxide-based mineral (e.g.,
serpentine) carbonation processes, offering substantial potential for
reducing CO 2 mineral sequestration process costs. This effort is a part
of the Mineral Carbonation Study Program managed by DOE, which also
includes participants from the ...
see the full file in attached file