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Development of practical decontamination process for the removal of uranium from gravel
Kim, Ilgook,Kim, Gye-Nam,Kim, Seung-Soo,Choi, Jong-Won Informa UK (TaylorFrancis) 2018 Environmental Technology Vol.39 No.1
<P>In this study, a practical decontamination process was developed to remove uranium from gravel using a soil washing method. The effects of critical parameters including particle size, H2SO4 concentration, temperature, and reaction time on uranium removal were evaluated. The optimal condition for two-stage washing of gravel was found to be particle size of 1-2 mm, 1.0 M H2SO4, temperature of 60 degrees C, and reaction time of 3 h, which satisfied the required uranium concentration for self-disposal. Furthermore, most of the extracted uranium was removed from the waste solution by precipitation, implying that the treated solution can be reused as washing solution. These results clearly demonstrated that our proposed process can be indeed a practical technique to decontaminate uranium-polluted gravel.</P>
Co-production of biodiesel and alginate from <i>Laminaria japonica</i>
Kim, Ga-Yeong,Seo, Yeong Hwan,Kim, Ilgook,Han, Jong-In Elsevier 2019 Science of the Total Environment Vol.673 No.-
<P><B>Abstract</B></P> <P>A process to produce both biodiesel and alginate in an integrated manner from a brown seaweed, <I>Laminaria japonica</I>, was established. Mannitol, a major carbon constituent in <I>L. japonica</I>, served to produce neutral lipids via the heterotrophic cultivation of an oleaginous yeast, <I>Cryptococcus</I> sp<I>.</I>; and simultaneously alginate, a high value product, was extracted to enhance the economic feasibility of the entire process. Only autoclave pretreatment, without need of any chemical agents, was enough to recover all the essential nutrients for the yeast cultivation. Specifically, it could recover 6.4 g L<SUP>−1</SUP> of mannitol to a degree comparable to 6.6 g L<SUP>−1</SUP> obtained by acid-aided pretreatment using 1.5% (v/v) of H<SUB>2</SUB>SO<SUB>4</SUB>. Maximum fatty acids methyl esters (FAME) content was 30.37% with FAME productivity of 0.56 g L<SUP>−1</SUP> d<SUP>−1</SUP>, and the produced FAME could meet the biodiesel quality standards. Na<SUB>2</SUB>CO<SUB>3</SUB>-based method showed the best efficiency of alginate recovery, yielding 21.06% (w/w)<I>.</I> This study supports that <I>L. japonica</I> can indeed be a promising low-cost feedstock for biodiesel production, and it is more so when a high-value product alginate is co-produced.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An integrated system co-producing biodiesel and alginate was developed. </LI> <LI> <I>Laminaria japonica-</I>based biorefinery concept was suggested. </LI> <LI> <I>Laminaria japonica</I> was used as low-cost feedstock for biodiesel production. </LI> <LI> Mild autoclave pretreatment was enough to culture the oleaginous yeast. </LI> <LI> Value-added alginate, was extracted to enhance the competitiveness of entire process. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>