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Transport, retention, and long-term release behavior of ZnO nanoparticle aggregates in saturated quartz sand: Role of solution pH and biofilm coating.
Water Res. 2016 Mar 01; 90:247-257.WR

Abstract

The transport, retention, and long-term release of zinc oxide nanoparticle aggregates (denoted below as ZnO-NPs) were investigated in saturated, bare and biofilm (Pseudomonas putida) coated sand packed columns. Almost complete retention of ZnO-NPs occurred in bare and biofilm coated sand when the influent solution pH was 9 and the ionic strength (IS) was 0.1 or 10 mM NaCl, and the retention profiles were always hyper-exponential. Increasing the solution IS and biofilm coating produced enhanced retention of ZnO-NPs near the column inlet. The enhanced NPs retention at high IS was attributed to more favorable NP-silica and NP-NP interactions; this was consistent with the interaction energy calculations. Meanwhile, the greater NPs retention in the presence of biofilm was attributed to larger roughness heights which alter the mass transfer rate, the interaction energy profile, and lever arms associated with the torque balance; e.g., scanning electron and atomic force microscopy was used to determine roughness heights of 33.4 nm and 97.8 nm for bare sand and biofilm-coated sand, respectively. Interactions between NPs and extracellular polymeric substances may have also contributed to enhanced NP retention in biofilm-coated sand at low IS. The long-term release of retained ZnO-NPs was subsequently investigated by continuously injecting NP-free solution at pH 6, 9, or 10 and keeping the IS constant at 10 mM. The amount and rate of retained ZnO-NP removal was strongly dependent on the solution pH. Specifically, almost complete removal of retained ZnO-NPs was observed after 627 pore volumes when the solution pH was 6, whereas much less Zn was recovered when the eluting solution pH was buffered to pH = 9 and especially 10. This long-term removal was attributed to pH-dependent dissolution of retained ZnO-NPs because: (i) the solubility of ZnO-NPs increases with decreasing pH; and (ii) ZnO-NPs were not detected in the effluent. The presence of biofilm also decreased the initial rate and amount of dissolution and the subsequent transport of Zn(2+) due to the strong Zn(2+) re-adsorption to the biofilm. Our study indicates that dissolution will eventually lead to the complete removal of retained ZnO-NPs and the transport of toxic Zn(2+) ions in groundwater environments with pH ranges of 5-9.

Authors+Show Affiliations

Department of Mineral Resources and Energy Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756, Republic of Korea.Department of Mineral Resources and Energy Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756, Republic of Korea.Department of Mineral Resources and Energy Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756, Republic of Korea.USDA, ARS, US Salinity Laboratory, Riverside, CA 92507, USA.Risk Assessment Division, National Institute of Environmental Research, Hwangyeong-ro 42, Seo-gu, Incheon 404-708, Republic of Korea.Risk Assessment Division, National Institute of Environmental Research, Hwangyeong-ro 42, Seo-gu, Incheon 404-708, Republic of Korea.Risk Assessment Division, National Institute of Environmental Research, Hwangyeong-ro 42, Seo-gu, Incheon 404-708, Republic of Korea.Department of Chemical and Biomolecular Engineering, KAIST, Daejeon 305-701, Republic of Korea.Department of Mineral Resources and Energy Engineering, Chonbuk National University, Jeonju, Jeonbuk 561-756, Republic of Korea. Electronic address: kshjkim@jbnu.ac.kr.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

26741396

Citation

Han, Yosep, et al. "Transport, Retention, and Long-term Release Behavior of ZnO Nanoparticle Aggregates in Saturated Quartz Sand: Role of Solution pH and Biofilm Coating." Water Research, vol. 90, 2016, pp. 247-257.
Han Y, Hwang G, Kim D, et al. Transport, retention, and long-term release behavior of ZnO nanoparticle aggregates in saturated quartz sand: Role of solution pH and biofilm coating. Water Res. 2016;90:247-257.
Han, Y., Hwang, G., Kim, D., Bradford, S. A., Lee, B., Eom, I., Kim, P. J., Choi, S. Q., & Kim, H. (2016). Transport, retention, and long-term release behavior of ZnO nanoparticle aggregates in saturated quartz sand: Role of solution pH and biofilm coating. Water Research, 90, 247-257. https://doi.org/10.1016/j.watres.2015.12.009
Han Y, et al. Transport, Retention, and Long-term Release Behavior of ZnO Nanoparticle Aggregates in Saturated Quartz Sand: Role of Solution pH and Biofilm Coating. Water Res. 2016 Mar 1;90:247-257. PubMed PMID: 26741396.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Transport, retention, and long-term release behavior of ZnO nanoparticle aggregates in saturated quartz sand: Role of solution pH and biofilm coating. AU - Han,Yosep, AU - Hwang,Gukhwa, AU - Kim,Donghyun, AU - Bradford,Scott A, AU - Lee,Byoungcheun, AU - Eom,Igchun, AU - Kim,Pil Je, AU - Choi,Siyoung Q, AU - Kim,Hyunjung, Y1 - 2015/12/17/ PY - 2015/08/24/received PY - 2015/11/21/revised PY - 2015/12/06/accepted PY - 2016/1/8/entrez PY - 2016/1/8/pubmed PY - 2016/10/26/medline KW - Biofilm KW - Long-term release KW - Saturated quartz sand KW - Solution pH KW - Transport and retention KW - ZnO nanoparticle aggregates SP - 247 EP - 257 JF - Water research JO - Water Res. VL - 90 N2 - The transport, retention, and long-term release of zinc oxide nanoparticle aggregates (denoted below as ZnO-NPs) were investigated in saturated, bare and biofilm (Pseudomonas putida) coated sand packed columns. Almost complete retention of ZnO-NPs occurred in bare and biofilm coated sand when the influent solution pH was 9 and the ionic strength (IS) was 0.1 or 10 mM NaCl, and the retention profiles were always hyper-exponential. Increasing the solution IS and biofilm coating produced enhanced retention of ZnO-NPs near the column inlet. The enhanced NPs retention at high IS was attributed to more favorable NP-silica and NP-NP interactions; this was consistent with the interaction energy calculations. Meanwhile, the greater NPs retention in the presence of biofilm was attributed to larger roughness heights which alter the mass transfer rate, the interaction energy profile, and lever arms associated with the torque balance; e.g., scanning electron and atomic force microscopy was used to determine roughness heights of 33.4 nm and 97.8 nm for bare sand and biofilm-coated sand, respectively. Interactions between NPs and extracellular polymeric substances may have also contributed to enhanced NP retention in biofilm-coated sand at low IS. The long-term release of retained ZnO-NPs was subsequently investigated by continuously injecting NP-free solution at pH 6, 9, or 10 and keeping the IS constant at 10 mM. The amount and rate of retained ZnO-NP removal was strongly dependent on the solution pH. Specifically, almost complete removal of retained ZnO-NPs was observed after 627 pore volumes when the solution pH was 6, whereas much less Zn was recovered when the eluting solution pH was buffered to pH = 9 and especially 10. This long-term removal was attributed to pH-dependent dissolution of retained ZnO-NPs because: (i) the solubility of ZnO-NPs increases with decreasing pH; and (ii) ZnO-NPs were not detected in the effluent. The presence of biofilm also decreased the initial rate and amount of dissolution and the subsequent transport of Zn(2+) due to the strong Zn(2+) re-adsorption to the biofilm. Our study indicates that dissolution will eventually lead to the complete removal of retained ZnO-NPs and the transport of toxic Zn(2+) ions in groundwater environments with pH ranges of 5-9. SN - 1879-2448 UR - https://www.unboundmedicine.com/medline/citation/26741396/Transport_retention_and_long_term_release_behavior_of_ZnO_nanoparticle_aggregates_in_saturated_quartz_sand:_Role_of_solution_pH_and_biofilm_coating_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0043-1354(15)30405-X DB - PRIME DP - Unbound Medicine ER -