<?xml version="1.0" encoding="utf-8" standalone="yes"?><feed xmlns="http://www.w3.org/2005/Atom"><generator uri="https://gohugo.io" version="0.141.0">Hugo v0.141.0</generator><id>https://millironx.millironx.page/@indiewebpub/people/james-g.-moberly/</id><link rel="self" type="application/atom+xml" href="https://millironx.millironx.page/@indiewebpub/people/james-g.-moberly/feed.xml"/><link rel="alternate" type="text/html" href="https://millironx.millironx.page/@indiewebpub/people/james-g.-moberly/"/><updated>2025-03-31T00:14:19+00:00</updated><title>James G. Moberly's activity on Milliron X</title><entry><id>https://millironx.millironx.page/@indiewebpub/academia/hydronium-pva/</id><link rel="alternate" href="https://doi.org/10.1021/acsestengg.2c00107"/><title>Investigation of Hydronium Diffusion in Poly(vinyl alcohol) Hydrogels: A Critical First Step to Describe Acid Transport for Encapsulated Bioremediation</title><published>2022-09-02T00:00:00+00:00</published><updated>2022-09-02T00:00:00+00:00</updated><author><name>Carson J. Silsby</name><uri>https://millironx.millironx.page/@indiewebpub/people/carson-j.-silsby/</uri></author><author><name>Jonathan R. Counts</name><uri>https://millironx.millironx.page/@indiewebpub/people/jonathan-r.-counts/</uri></author><author><name>Thomas A. Christensen II</name><uri>https://millironx.millironx.page/@indiewebpub/people/thomas-a.-christensen-ii/</uri></author><author><name>Mark F. Roll</name><uri>https://millironx.millironx.page/@indiewebpub/people/mark-f.-roll/</uri></author><author><name>Kristopher v. Waynant</name><uri>https://millironx.millironx.page/@indiewebpub/people/kristopher-v.-waynant/</uri></author><author><name>James G. Moberly</name><uri>https://millironx.millironx.page/@indiewebpub/people/james-g.-moberly/</uri></author><category term="paper"/><category term="diffusion"/><category term="hydrogels"/><category term="ionic strength"/><category term="polymers"/><category term="transport properties"/><summary type="text">
Bioremediation of chlorinated aliphatic hydrocarbon-contaminated aquifers can be hindered by high contaminant concentrations and acids generated during remediation. Encapsulating microbes in hydrogels may provide a protective, tunable environment from inhibiting compounds; however, current approaches to formulate successful encapsulated systems rely on trial and error rather than engineering approaches because fundamental information on mass-transfer coefficients is lacking. To address this knowledge gap, hydronium ion mass-transfer rates through two commonly used hydrogel materials, poly(vinyl alcohol) and alginic acid, under two solidification methods (chemical and cryogenic) were measured. Variations in hydrogel crosslinking conditions, polymer composition, and solvent ionic strength were investigated to understand how each influenced hydronium ion diffusivity. A three-way ANOVA indicated that the ionic strength, membrane type, and crosslinking method significantly (p &lt; 0.001) contributed to changes in hydronium ion mass transfer. Hydronium ion diffusion increased with ionic strength, counter to what is observed in aqueous-only (no polymer) solutions. Co-occurring mechanisms correlated to increased hydronium ion diffusion with ionic strength included an increased water fraction within hydrogel matrices and hydrogel contraction. Measured diffusion rates determined in this study provide first principal design information to further optimize encapsulating hydrogels for bioremediation.</summary><content type="html" xml:lang="en" xml:base="https://millironx.millironx.page/@indiewebpub/">
&lt;p>Bioremediation of chlorinated aliphatic hydrocarbon-contaminated aquifers can be
hindered by high contaminant concentrations and acids generated during
remediation. Encapsulating microbes in hydrogels may provide a protective,
tunable environment from inhibiting compounds; however, current approaches to
formulate successful encapsulated systems rely on trial and error rather than
engineering approaches because fundamental information on mass-transfer
coefficients is lacking. To address this knowledge gap, hydronium ion
mass-transfer rates through two commonly used hydrogel materials, poly(vinyl
alcohol) and alginic acid, under two solidification methods (chemical and
cryogenic) were measured. Variations in hydrogel crosslinking conditions,
polymer composition, and solvent ionic strength were investigated to understand
how each influenced hydronium ion diffusivity. A three-way ANOVA indicated that
the ionic strength, membrane type, and crosslinking method significantly (&lt;em>p&lt;/em> &amp;lt;
0.001) contributed to changes in hydronium ion mass transfer. Hydronium ion
diffusion increased with ionic strength, counter to what is observed in
aqueous-only (no polymer) solutions. Co-occurring mechanisms correlated to
increased hydronium ion diffusion with ionic strength included an increased
water fraction within hydrogel matrices and hydrogel contraction. Measured
diffusion rates determined in this study provide first principal design
information to further optimize encapsulating hydrogels for bioremediation.&lt;/p>
</content></entry><entry><id>https://millironx.millironx.page/@indiewebpub/academia/pva-aiche/</id><link rel="alternate" href="/academia/pva-aiche/measuring_diffusion_of_trichloroethylene.pdf"/><title>Measuring Diffusion of Trichlorethylene Breakdown Products in Polyvinylalginate</title><published>2018-10-29T00:00:00+00:00</published><updated>2018-10-29T00:00:00+00:00</updated><author><name>Thomas A. Christensen II</name><uri>https://millironx.millironx.page/@indiewebpub/people/thomas-a.-christensen-ii/</uri></author><author><name>Samuel R. Wolfe</name><uri>https://millironx.millironx.page/@indiewebpub/people/samuel-r.-wolfe/</uri></author><author><name>Jonathan Counts</name><uri>https://millironx.millironx.page/@indiewebpub/people/jonathan-counts/</uri></author><author><name>Mark F. Roll</name><uri>https://millironx.millironx.page/@indiewebpub/people/mark-f.-roll/</uri></author><author><name>Kristopher v. Waynant</name><uri>https://millironx.millironx.page/@indiewebpub/people/kristopher-v.-waynant/</uri></author><author><name>James G. Moberly</name><uri>https://millironx.millironx.page/@indiewebpub/people/james-g.-moberly/</uri></author><category term="poster"/><category term="bioremediation"/><category term="polyoxometalate"/><category term="hydrogel polymers"/><category term="proton transport"/><category term="chemical engineering"/><summary type="text">
Trichloroethylene (TCE), a toxic and carcinogenic contaminant, presents unique challenges for cleanup because of its water solubility, density, and volatility. Bioremediation of TCE is a promising cleanup method; however, metabolism of TCE results in acid generation that inhibits remediating microorganisms. Calcium alginate(CA)-polyvinylalcohol (PVA) hydrogels show promise for protecting remediating microbes, however diffusion of TCE or its byproducts through these polymers is unknown. To measure the effective diffusion coefficient of TCE and byproducts through hydrogel membranes, we used a modified diaphragm cell. Measured effective diffusion coefficient of each species was (cm 2 /s × 106 ): 14.0 ± 1.91 for H+ ions, 12.4 ± 1.64 for TCE, 7.83 ± 0.54 for cis-1,2-dichloroethylene (DCE), and 4.68 ± 4.14 for vinyl chloride. These results aid in engineering biobeads and suggest that CA-PVA hydrogel blends are effective in slowing diffusion of protons, buffering acids produced by trichloroethylene metabolism, and remains suitable for encapsulation of microorganisms involved in bioremediation.</summary><content type="html" xml:lang="en" xml:base="https://millironx.millironx.page/@indiewebpub/">
&lt;p>Trichloroethylene (TCE), a toxic and carcinogenic contaminant, presents unique
challenges for cleanup because of its water solubility, density, and volatility.
Bioremediation of TCE is a promising cleanup method; however, metabolism of TCE
results in acid generation that inhibits remediating microorganisms. Calcium
alginate(CA)-polyvinylalcohol (PVA) hydrogels show promise for protecting
remediating microbes, however diffusion of TCE or its byproducts through these
polymers is unknown. To measure the effective diffusion coefficient of TCE and
byproducts through hydrogel membranes, we used a modified diaphragm cell.
Measured effective diffusion coefficient of each species was (cm &lt;sup>2&lt;/sup>
/s
× 10&lt;sup>6&lt;/sup>
): 14.0 ± 1.91 for H&lt;sup>&amp;#43;&lt;/sup>
 ions, 12.4 ± 1.64 for TCE,
7.83 ± 0.54 for cis-1,2-dichloroethylene (DCE), and 4.68 ± 4.14 for vinyl
chloride. These results aid in engineering biobeads and suggest that CA-PVA
hydrogel blends are effective in slowing diffusion of protons, buffering acids
produced by trichloroethylene metabolism, and remains suitable for encapsulation
of microorganisms involved in bioremediation.&lt;/p>
</content></entry><entry><id>https://millironx.millironx.page/@indiewebpub/academia/pva-inbre/</id><link rel="alternate" href="https://millironx.millironx.page/@indiewebpub/academia/pva-inbre/"/><title>Measuring diffusion of protons in polyvinyalginate</title><published>2018-07-31T00:00:00+00:00</published><updated>2018-07-31T00:00:00+00:00</updated><author><name>Thomas A. Christensen II</name><uri>https://millironx.millironx.page/@indiewebpub/people/thomas-a.-christensen-ii/</uri></author><author><name>Jonathan Counts</name><uri>https://millironx.millironx.page/@indiewebpub/people/jonathan-counts/</uri></author><author><name>James G. Moberly</name><uri>https://millironx.millironx.page/@indiewebpub/people/james-g.-moberly/</uri></author><category term="poster"/><summary type="text">
Trichloroethylene (TCE) is a toxic and carcinogenic contaminant that presents unique challenges for cleanup because of its density and volatility. Use of microorganisms may be a promising remediation method, however metabolism of TCE results in acid buildup, which consequently impedes the ability of microorganisms to perform this remediation. Polyvinylalginate (PVA) shows promise as a useful shield for microorganisms carrying out bioremediation of TCE by surrounding them in a protective biofilm-like layer, however, key information is missing which relates diffusion of TCE or its metabolic products through PVA. To measure the effective diffusion coefficient of H+ ions through a PVA membrane cross-linked with boric acid and calcium ions, we used a modified diaphragm cell. We found the effective diffusion coefficient to be 1.40 × 10-5 ± 1.91 × 10-6 cm2 s, a nearly seven-fold decrease in diffusivity compared to protons in water, with an unexpected significant but as of yet unquantified adsorption capacity. These results suggest that polyvinylalginate is effective in slowing diffusion of protons and buffering these acids produced by trichloroethylene metabolism, and remains suitable for encapsulation of microorganisms involved in bioremediation.</summary><content type="html" xml:lang="en" xml:base="https://millironx.millironx.page/@indiewebpub/">
&lt;p>Trichloroethylene (TCE) is a toxic and carcinogenic contaminant that presents
unique challenges for cleanup because of its density and volatility. Use of
microorganisms may be a promising remediation method, however metabolism of TCE
results in acid buildup, which consequently impedes the ability of
microorganisms to perform this remediation. Polyvinylalginate (PVA) shows
promise as a useful shield for microorganisms carrying out bioremediation of TCE
by surrounding them in a protective biofilm-like layer, however, key information
is missing which relates diffusion of TCE or its metabolic products through PVA.
To measure the effective diffusion coefficient of H&lt;sup>&amp;#43;&lt;/sup>
 ions through
a PVA membrane cross-linked with boric acid and calcium ions, we used a modified
diaphragm cell. We found the effective diffusion coefficient to be 1.40 ×
10&lt;sup>-5&lt;/sup>
 ± 1.91 × 10&lt;sup>-6&lt;/sup>
 cm&lt;sup>2&lt;/sup>
s, a nearly
seven-fold decrease in diffusivity compared to protons in water, with an
unexpected significant but as of yet unquantified adsorption capacity. These
results suggest that polyvinylalginate is effective in slowing diffusion of
protons and buffering these acids produced by trichloroethylene metabolism, and
remains suitable for encapsulation of microorganisms involved in bioremediation.&lt;/p>
</content></entry></feed>