@misc{BuschMeissnerPotthoffetal.2011, author = {Busch, Jan Philip and Meißner, Tobias and Potthoff, Annegret and Oswald, Sascha}, title = {Plating of nano zero-valent iron (nZVI) on activated carbon : a fast delivery method of iron for source remediation?}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-53792}, year = {2011}, abstract = {The use of nano zerovalent iron (nZVI) for environmental remediation is a promising new technique for in situ remediation. Due to its high surface area and high reactivity, nZVI is able to dechlorinate organic contaminants and render them harmless. Limited mobility, due to fast aggregation and sedimentation of nZVI, limits the capability for source and plume remediation. Carbo-Iron is a newly developed material consisting of activated carbon particles (d50 = 0,8 µm) that are plated with nZVI particles. These particles combine the mobility of activated carbon and the reactivity of nZVI. This paper presents the first results of the transport experiments.}, language = {en} } @article{BuschMeissnerPotthoffetal.2014, author = {Busch, Jan Philip and Meissner, Tobias and Potthoff, Annegret and Oswald, Sascha}, title = {Transport of carbon colloid supported nanoscale zero-valent iron in saturated porous media}, series = {Journal of contaminant hydrology}, volume = {164}, journal = {Journal of contaminant hydrology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0169-7722}, doi = {10.1016/j.jconhyd.2014.05.006}, pages = {25 -- 34}, year = {2014}, abstract = {Injection of nanoscale zero-valent iron (nZVI) has recently gained great interest as emerging technology for in-situ remediation of chlorinated organic compounds from groundwater systems. Zero-valent iron (ZVI) is able to reduce organic compounds and to render it to less harmful substances. The use of nanoscale particles instead of granular or microscale particles can increase dechlorination rates by-orders of magnitude due to its high surface area. However, classical nZVI appears to be hampered in its environmental application by its limited mobility. One approach is colloid supported transport of nZVI, where the nZVI gets transported by a Mobile colloid. In this study transport properties of activated carbon colloid supported nZVI (c-nZVI; d(50) = 2.4 mu m) are investigated in column tests using columns of 40 cm length, which were filled with porous media. A suspension was pumped through the column under different physicochemical conditions (addition of a polyanionic stabilizer and changes in pH and ionic strength). Highest observed breakthrough was 62\% of the injected concentration in glass beads with addition of stabilizer. Addition of mono- and bivalent salt, e.g. more than 0.5 mM/L CaCl2, can decrease mobility and changes in pH to values below six can inhibit mobility at all. Measurements of colloid sizes and zeta potentials show changes in the mean particle size by a factor of ten and an increase of zeta potential from -62 mV to -80 mV during the transport experiment. However, results suggest potential applicability of c-nZVI under field conditions. (C) 2014 Elsevier B.V. All rights reserved.}, language = {en} } @article{BuschMeissnerPotthoffetal.2014, author = {Busch, Jan Philip and Meissner, Tobias and Potthoff, Annegret and Oswald, Sascha}, title = {Investigations on mobility of carbon colloid supported nanoscale zero-valent iron (nZVI) in a column experiment and a laboratory 2D-aquifer test system}, series = {Environmental science and pollution research : official organ of the EuCheMS Division for Chemistry and the Environment, EuCheMS DCE}, volume = {21}, journal = {Environmental science and pollution research : official organ of the EuCheMS Division for Chemistry and the Environment, EuCheMS DCE}, number = {18}, publisher = {Springer}, address = {Heidelberg}, issn = {0944-1344}, doi = {10.1007/s11356-014-3049-7}, pages = {10908 -- 10916}, year = {2014}, abstract = {Nanoscale zero-valent iron (nZVI) has recently gained great interest in the scientific community as in situ reagent for installation of permeable reactive barriers in aquifer systems, since nZVI is highly reactive with chlorinated compounds and may render them to harmless substances. However, nZVI has a high tendency to agglomerate and sediment; therefore it shows very limited transport ranges. One new approach to overcome the limited transport of nZVI in porous media is using a suited carrier colloid. In this study we tested mobility of a carbon colloid supported nZVI particle "Carbo-Iron Colloids" (CIC) with a mean size of 0.63 mu m in a column experiment of 40 cm length and an experiment in a two-dimensional (2D) aquifer test system with dimensions of 110x40x5 cm. Results show a breakthrough maximum of 82 \% of the input concentration in the column experiment and 58 \% in the 2D-aquifer test system. Detected residuals in porous media suggest a strong particle deposition in the first centimeters and few depositions in the porous media in the further travel path. Overall, this suggests a high mobility in porous media which might be a significant enhancement compared to bare or polyanionic stabilized nZVI.}, language = {en} } @phdthesis{Busch2015, author = {Busch, Jan Philip}, title = {Investigations on mobility of carbon colloid supported nanoscale zero-valent iron (nZVI) for groundwater remediation}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-76873}, school = {Universit{\"a}t Potsdam}, pages = {X, 127, XLIII}, year = {2015}, abstract = {Injection of nanoscale zero-valent iron (nZVI) is an innovative technology for in situ installation of a permeable reactive barrier in the subsurface. Zerovalent iron (ZVI) is highly reactive with chlorinated hydrocarbons (CHCs) and renders them into less harmful substances. Application of nZVI instead of granular ZVI can increase rates of dechlorination of CHCs by orders of magnitude, due to its higher surface area. This approach is still difficult to apply due to fast agglomeration and sedimentation of colloidal suspensions of nZVI, which leads to very short transport distances. To overcome this issue of limited mobility, polyanionic stabilisers are added to increase surface charge and stability of suspensions. In field experiments maximum transport distances of a few metres were achieved. A new approach, which is investigated in this thesis, is enhanced mobility of nZVI by a more mobile carrier colloid. The investigated composite material consists of activated carbon, which is loaded with nZVI. In this cumulative thesis, transport characteristics of carbon-colloid supported nZVI (c-nZVI) are investigated. Investigations started with column experiments in 40 cm columns filled with various porous media to investigate on physicochemical influences on transport characteristics. The experimental setup was enlarged to a transport experiment in a 1.2-m-sized two-dimensional aquifer tank experiment, which was filled with granular porous media. Further, a field experiment was performed in a natural aquifer system with a targeted transport distance of 5.3 m. Parallel to these investigations, alternative methods for transport observations were investigated by using noninvasive tomographic methods. Experiments using synchrotron radiation and magnetic resonance (MRI) were performed to investigate in situ transport characteristics in a non-destructive way. Results from column experiments show potentially high mobility under environmental relevant conditions. Addition of mono-and bivalent salts, e.g. more than 0.5 mM/L CaCl2, might decrease mobility. Changes in pH to values below 6 can inhibit mobility at all. Measurements of colloid size show changes in the mean particle size by a factor of ten. Measurements of zeta potential revealed an increase of -62 mV to -82 mV. Results from the 2D-aquifer test system suggest strong particle deposition in the first centimetres and only weak straining in the further travel path and no gravitational influence on particle transport. Straining at the beginning of the travel path in the porous medium was observed with tomographic investigations of transport. MRI experiments revealed similar results to the previous experiments, and observations using synchrotron radiation suggest straining of colloids at pore throats. The potential for high transport distances, which was suggested from laboratory experiments, was confirmed in the field experiment, where the transport distance of 5.3 m was reached by at least 10\% of injected nZVI. Altogether, transport distances of the investigated carbon-colloid supported nZVI are higher than published results of traditional nZVI.}, language = {en} } @article{BuschMeissnerPotthoffetal.2015, author = {Busch, Jan Philip and Meißner, Tobias and Potthoff, Annegret and Bleyl, Steffen and Georgi, Anett and Mackenzie, Katrin and Trabitzsch, Ralf and Werban, Ulrike and Oswald, Sascha}, title = {A field investigation on transport of carbon-supported nanoscale zero-valent iron (nZVI) in groundwater}, series = {Journal of contaminant hydrology}, volume = {181}, journal = {Journal of contaminant hydrology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0169-7722}, doi = {10.1016/j.jconhyd.2015.03.009}, pages = {59 -- 68}, year = {2015}, abstract = {The application of nanoscale zero-valent iron (nZVI) for subsurface remediation of groundwater contaminants is a promising new technology, which can be understood as alternative to the permeable reactive barrier technique using granular iron. Dechlorination of organic contaminants by zero-valent iron seems promising. Currently, one limitation to widespread deployment is the fast agglomeration and sedimentation of nZVI in colloidal suspensions, even more so when in soils and sediments, which limits the applicability for the treatment of sources and plumes of contamination. Colloid-supported nZVI shows promising characteristics to overcome these limitations. Mobility of Carbo-Iron Colloids (CIC) - a newly developed composite material based on finely ground activated carbon as a carrier for nZVI - was tested in a field application: In this study, a horizontal dipole flow field was established between two wells separated by 53 m in a confined, natural aquifer. The injection/extraction rate was 500 L/h. Approximately 12 kg of CIC was suspended with the polyanionic stabilizer carboxymethyl cellulose. The suspension was introduced into the aquifer at the injection well. Breakthrough of CIC was observed visually and based on total particle and iron concentrations detected in samples from the extraction well. Filtration of water samples revealed a particle breakthrough of about 12\% of the amount introduced. This demonstrates high mobility of CIC particles and we suggest that nZVI carried on CIC can be used for contaminant plume remediation by in-situ formation of reactive barriers. (C) 2015 Elsevier B.V. All rights reserved.}, language = {en} }