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Individual and Co Transport Study of Titanium Dioxide NPs and Zinc Oxide NPs in Porous Media.

Kumari J, Mathur A, Rajeshwari A, Venkatesan A, S S, Pulimi M, Chandrasekaran N, Nagarajan R, Mukherjee A - PLoS ONE (2015)

Bottom Line: The transport of TiO2 NPs at pH 5 was not significantly affected by ZnO NPs in solution.At pH 7, a decrease in TiO2 NP transport was noted with co-existence of ZnO NPs, while at pH 9 an increase in the transport was observed.At pH 5 and 7, the transport of ZnO NPs was decreased when TiO2 NPs was present in the solution, and at pH 9, an increase was noted.

View Article: PubMed Central - PubMed

Affiliation: Centre for Nanobiotechnology, VIT University, Vellore, Tamil Nadu, India.

ABSTRACT
The impact of pH and ionic strength on the mobility (individual and co-transport) and deposition kinetics of TiO2 and ZnO NPs in porous media was systematically investigated in this study. Packed column experiments were performed over a series of environmentally relevant ionic strengths with both NaCl (0.1-10 mM) and CaCl2 (0.01-0.1mM) solutions and at pH 5, 7, and 9. The transport of TiO2 NPs at pH 5 was not significantly affected by ZnO NPs in solution. At pH 7, a decrease in TiO2 NP transport was noted with co-existence of ZnO NPs, while at pH 9 an increase in the transport was observed. At pH 5 and 7, the transport of ZnO NPs was decreased when TiO2 NPs was present in the solution, and at pH 9, an increase was noted. The breakthrough curves (BTC) were noted to be sensitive to the solution chemistries; the decrease in the breakthrough plateau with increasing ionic strength was observed under all examined pH (5, 7, and 9). The retention profiles were the inverse of the plateaus of BTCs, as expected from mass balance considerations. Overall, the results from this study suggest that solution chemistries (ionic strength and pH) are likely the key factors that govern the individual and co-transport behavior of TiO2 and ZnO NPs in sand.

No MeSH data available.


Related in: MedlinePlus

Retention profile of TiO2 NPs at pH 5 (with and without ZnO NPs).Retention graph of TiO2 NPs in presence and absence of ZnO NPs sand. In suspensions at 0.1, 1, and 10 mM ionic strengths in NaCl solutions and 0.01, 0.05, and 0.1 mM CaCl2 solutions at pH 5. Replicate experiments were performed under all conditions (n ≥ 2). Similar retention profile was observed in both individual (TiO2 NPs) and co transport experiment (TiO2 NPs and ZnO NPs).
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pone.0134796.g007: Retention profile of TiO2 NPs at pH 5 (with and without ZnO NPs).Retention graph of TiO2 NPs in presence and absence of ZnO NPs sand. In suspensions at 0.1, 1, and 10 mM ionic strengths in NaCl solutions and 0.01, 0.05, and 0.1 mM CaCl2 solutions at pH 5. Replicate experiments were performed under all conditions (n ≥ 2). Similar retention profile was observed in both individual (TiO2 NPs) and co transport experiment (TiO2 NPs and ZnO NPs).

Mentions: At pH 5, under all examined ionic strength conditions in the absence of ZnO NPs in suspensions, the retained concentration of TiO2 NPs in quartz sand decreased log−linearly with increase in distance. Retained concentrations of TiO2 NPs in quartz sand decreased non-exponentially with distance. However, the retention profile of TiO2 NPs in presence of ZnO NPs was similar to the profile acquired in the absence of ZnO NPs (Figs 7, 8 and 9). This study demonstrated that the copresence of ZnO NPs in suspensions did not affect the retention of TiO2 NPs in sand at pH 5.


Individual and Co Transport Study of Titanium Dioxide NPs and Zinc Oxide NPs in Porous Media.

Kumari J, Mathur A, Rajeshwari A, Venkatesan A, S S, Pulimi M, Chandrasekaran N, Nagarajan R, Mukherjee A - PLoS ONE (2015)

Retention profile of TiO2 NPs at pH 5 (with and without ZnO NPs).Retention graph of TiO2 NPs in presence and absence of ZnO NPs sand. In suspensions at 0.1, 1, and 10 mM ionic strengths in NaCl solutions and 0.01, 0.05, and 0.1 mM CaCl2 solutions at pH 5. Replicate experiments were performed under all conditions (n ≥ 2). Similar retention profile was observed in both individual (TiO2 NPs) and co transport experiment (TiO2 NPs and ZnO NPs).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4529095&req=5

pone.0134796.g007: Retention profile of TiO2 NPs at pH 5 (with and without ZnO NPs).Retention graph of TiO2 NPs in presence and absence of ZnO NPs sand. In suspensions at 0.1, 1, and 10 mM ionic strengths in NaCl solutions and 0.01, 0.05, and 0.1 mM CaCl2 solutions at pH 5. Replicate experiments were performed under all conditions (n ≥ 2). Similar retention profile was observed in both individual (TiO2 NPs) and co transport experiment (TiO2 NPs and ZnO NPs).
Mentions: At pH 5, under all examined ionic strength conditions in the absence of ZnO NPs in suspensions, the retained concentration of TiO2 NPs in quartz sand decreased log−linearly with increase in distance. Retained concentrations of TiO2 NPs in quartz sand decreased non-exponentially with distance. However, the retention profile of TiO2 NPs in presence of ZnO NPs was similar to the profile acquired in the absence of ZnO NPs (Figs 7, 8 and 9). This study demonstrated that the copresence of ZnO NPs in suspensions did not affect the retention of TiO2 NPs in sand at pH 5.

Bottom Line: The transport of TiO2 NPs at pH 5 was not significantly affected by ZnO NPs in solution.At pH 7, a decrease in TiO2 NP transport was noted with co-existence of ZnO NPs, while at pH 9 an increase in the transport was observed.At pH 5 and 7, the transport of ZnO NPs was decreased when TiO2 NPs was present in the solution, and at pH 9, an increase was noted.

View Article: PubMed Central - PubMed

Affiliation: Centre for Nanobiotechnology, VIT University, Vellore, Tamil Nadu, India.

ABSTRACT
The impact of pH and ionic strength on the mobility (individual and co-transport) and deposition kinetics of TiO2 and ZnO NPs in porous media was systematically investigated in this study. Packed column experiments were performed over a series of environmentally relevant ionic strengths with both NaCl (0.1-10 mM) and CaCl2 (0.01-0.1mM) solutions and at pH 5, 7, and 9. The transport of TiO2 NPs at pH 5 was not significantly affected by ZnO NPs in solution. At pH 7, a decrease in TiO2 NP transport was noted with co-existence of ZnO NPs, while at pH 9 an increase in the transport was observed. At pH 5 and 7, the transport of ZnO NPs was decreased when TiO2 NPs was present in the solution, and at pH 9, an increase was noted. The breakthrough curves (BTC) were noted to be sensitive to the solution chemistries; the decrease in the breakthrough plateau with increasing ionic strength was observed under all examined pH (5, 7, and 9). The retention profiles were the inverse of the plateaus of BTCs, as expected from mass balance considerations. Overall, the results from this study suggest that solution chemistries (ionic strength and pH) are likely the key factors that govern the individual and co-transport behavior of TiO2 and ZnO NPs in sand.

No MeSH data available.


Related in: MedlinePlus