Assessment of Key Environmental Factors Influencing the Sedimentation and Aggregation Behavior of Zinc Oxide Nanoparticles in Aquatic Environment
Abstract
:1. Introduction
2. Materials and Methods
2.1. Chemicals and Materials
2.2. Preparation of Stock Solutions
2.2.1. Preparation of ZnO NPs Stock Solution
2.2.2. Preparation of Inorganic Salt and NOM Solutions
2.3. Characterization and Measurement
2.4. Sedimentation Experimental Procedure
2.4.1. Aggregation Kinetics
2.4.2. Influence and Interaction of Multi-Environmental Factors
2.5. Preparation of Environmental Water Samples
2.6. Data Analysis
3. Results and Discussions
3.1. Characterization of ZnO NPs Solution
3.2. Single Factor Effect on Sedimentation
3.2.1. Effect of Solution pH on Sedimentation of ZnO NPs
3.2.2. Effect of Monovalent and Divalent Cations on Sedimentation of ZnO NPs
3.2.3. Impact of NOM on the Sedimentation of ZnO NPs
3.2.4. FT-IR Analysis Pristine NOM and ZnO-NOM Complexes
3.2.5. ZnO NPs Aggregation Kinetics Exposed to Various Environmental Factors
3.2.6. Influence of Multi-Environmental Parameters on ZnO NPs Sedimentation
3.2.7. Sedimentation Behavior of ZnO NPs in Aquatic Environments
3.3. Environmental Implications
4. Conclusions
Supplementary Materials
Author Contributions
Acknowledgments
Conflicts of Interest
References
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Experiment Type | Solution Chemistry |
---|---|
A (pH) | 3.0 to 12.0 |
B (Electrolyte type and concentration) | KCl (0.01 to 100 mM) Na2SO4 (0.01 to 100 mM) MgCl2 (0.01 to 25 mM) |
C (NOM type and concentration) | Humic acid (0.5 to 100 mg/L) Salicylic acid (0.5 to 100 mg/L) Citric acid (0.5 to 100 mg/L) |
Factor | pH | Electrolyte Conc; (mM) | NOM Conc: (mg/L) | Electrolyte Type | NOM Type | Temperature (°C) |
---|---|---|---|---|---|---|
Level 1 | 7.0 | 25 | 5 | KCl | Humic acid | 15 |
Level 2 | 8.0 | 50 | 10 | Na2SO4 | Salicylic acid | 25 |
Level 3 | 9.5 | 100 | 25 | MgCl2 | Citric acid | 35 |
Trial No | A | B | C | D | E | F | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
pH | Elec. Conc; (mM) | (A × B)1 | (A × B)2 | NOM Conc; (mg/L) | # | # | (B × C)1 | Electrolyte Type | NOM Type | (B × C)2 | Temperature (°C) | # | SE% | |
1 | 7.0 | 25 | 10 | KCl | Humic acid | 15 | 22.12 | |||||||
2 | 7.0 | 25 | 25 | Na2SO4 | Salicylic acid | 25 | 20.15 | |||||||
3 | 7.0 | 25 | 50 | MgCl2 | citric acid | 35 | 47.06 | |||||||
4 | 7.0 | 50 | 10 | Na2SO4 | Salicylic acid | 35 | 30.4 | |||||||
5 | 7.0 | 50 | 25 | MgCl2 | citric acid | 15 | 55.56 | |||||||
6 | 7.0 | 50 | 50 | KCl | Humic acid | 25 | 6.56 | |||||||
7 | 7.0 | 100 | 10 | MgCl2 | citric acid | 25 | 75.02 | |||||||
8 | 7.0 | 100 | 25 | KCl | Humic acid | 35 | 36.8 | |||||||
9 | 7.0 | 100 | 50 | Na2SO4 | Salicylic acid | 15 | 29.78 | |||||||
10 | 8.0 | 25 | 10 | Na2SO4 | citric acid | 25 | 28.94 | |||||||
11 | 8.0 | 25 | 25 | MgCl2 | Humic acid | 35 | 57.78 | |||||||
12 | 8.0 | 25 | 50 | KCl | Salicylic acid | 15 | 7.78 | |||||||
13 | 8.0 | 50 | 10 | MgCl2 | Humic acid | 15 | 65.56 | |||||||
14 | 8.0 | 50 | 25 | KCl | Salicylic acid | 25 | 26.67 | |||||||
15 | 8.0 | 50 | 50 | Na2SO4 | citric acid | 35 | 16.50 | |||||||
16 | 8.0 | 100 | 10 | KCl | Salicylic acid | 35 | 49.89 | |||||||
17 | 8.0 | 100 | 25 | Na2SO4 | citric acid | 15 | 41.40 | |||||||
18 | 8.0 | 100 | 50 | MgCl2 | Humic acid | 25 | 53.22 | |||||||
19 | 9.5 | 25 | 10 | MgCl2 | Salicylic acid | 35 | 47.41 | |||||||
20 | 9.5 | 25 | 25 | KCl | citric acid | 15 | 9.25 | |||||||
21 | 9.5 | 25 | 50 | Na2SO4 | Humic acid | 25 | 4.35 | |||||||
22 | 9.5 | 50 | 10 | KCl | citric acid | 25 | 39.12 | |||||||
23 | 9.5 | 50 | 25 | Na2SO4 | Humic acid | 35 | 28.6 | |||||||
24 | 9.5 | 50 | 50 | MgCl2 | Salicylic acid | 15 | 43.44 | |||||||
25 | 9.5 | 100 | 10 | Na2SO4 | Humic acid | 15 | 63.13 | |||||||
26 | 9.5 | 100 | 25 | MgCl2 | Salicylic acid | 25 | 78.0 | |||||||
27 | 9.5 | 100 | 50 | KCl | citric acid | 35 | 52.46 | |||||||
L1 | 35.90 | 27.21 | 43.49 | 38.28 | 46.70 | 35.69 | 39.30 | 35.64 | 27.90 | 37.58 | 38.26 | 36.60 | 39.20 | |
L2 | 38.59 | 34.63 | 33.12 | 42.30 | 39.31 | 39.50 | 37.65 | 39.72 | 29.28 | 37.05 | 38.05 | 38.01 | 36.27 | |
L3 | 40.61 | 53.30 | 38.60 | 34.60 | 29.05 | 39.85 | 38.20 | 38.25 | 58.10 | 40.60 | 38.90 | 40.80 | 37.69 | |
R | 4.71 | 26.09 | 10.37 | 7.7 | 17.65 | 4.16 | 1.65 | 4.08 | 30.20 | 3.55 | 0.85 | 4.20 | 2.93 |
Environmental Parameters | k (h−1) | R2 | Environmental Parameters | k (h−1) | R2 | ||
---|---|---|---|---|---|---|---|
pH | 3 | 0.1507 | 0.9975 | NOM type | Conc. (mg/L) | ||
7 | 0.0620 | 0.9986 | Humic Acid | 1 | 0.0808 | 0.9865 | |
9 | 0.3473 | 0.9876 | 25 | 0.0267 | 0.9275 | ||
12 | 0.1738 | 0.9981 | 100 | 0.0118 | 0.8509 | ||
Electrolyte Conc. (mM) | Salicylic Acid | 1 | 0.0722 | 0.9781 | |||
KCl | 1 | 0.0620 | 0.9987 | 25 | 0.0295 | 0.9322 | |
50 | 0.2431 | 0.9879 | 100 | 0.0202 | 0.7876 | ||
Na2SO4 | 10 | 0.1714 | 0.9932 | Citric Acid | 1 | 0.0457 | 0.9237 |
100 | 0.3172 | 0.9943 | 25 | 0.0199 | 0.8401 | ||
MgCl2 | 25 | 0.3786 | 0.9914 | 100 | 0.0713 | 0.8048 |
Variance Parameters | Degree of Freedom | Sum of Squares (SS) | Mean Squared (MS) | F Ratio | % Contribution |
---|---|---|---|---|---|
pH (A) | 2 | 100.18 | 50.09 | 0.80 a | 0.90% |
Electrolyte conc. (B) | 2 | 3248.55 | 1624.28 | 25.95 b | 29.08% |
NOM conc. (C) | 2 | 1442.27 | 721.13 | 11.52 b | 12.91% |
Electrolyte Type (D) | 2 | 5253.95 | 2626.97 | 41.98 c | 47.03% |
NOM Type (E) | 2 | 65.59 | 32.80 | 0.52 a | 0.59% |
Temperature (F) | 2 | 77.25 | 38.63 | 1.85 a | 0.69% |
(A × B) | 4 | 753.9 | 188.47 | 3.01* | 6.75% |
(B × C) | 4 | 104.27 | 26.06 | 0.41* | 0.93% |
Error | 6 | 125.14 | 62.57 | 1.12% | |
Total | 26 | 11171.1 | 5329.285 | 100.00% |
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Khan, R.; Inam, M.A.; Zam, S.Z.; Park, D.R.; Yeom, I.T. Assessment of Key Environmental Factors Influencing the Sedimentation and Aggregation Behavior of Zinc Oxide Nanoparticles in Aquatic Environment. Water 2018, 10, 660. https://doi.org/10.3390/w10050660
Khan R, Inam MA, Zam SZ, Park DR, Yeom IT. Assessment of Key Environmental Factors Influencing the Sedimentation and Aggregation Behavior of Zinc Oxide Nanoparticles in Aquatic Environment. Water. 2018; 10(5):660. https://doi.org/10.3390/w10050660
Chicago/Turabian StyleKhan, Rizwan, Muhammad Ali Inam, Saba Zam Zam, Du Ri Park, and Ick Tae Yeom. 2018. "Assessment of Key Environmental Factors Influencing the Sedimentation and Aggregation Behavior of Zinc Oxide Nanoparticles in Aquatic Environment" Water 10, no. 5: 660. https://doi.org/10.3390/w10050660
APA StyleKhan, R., Inam, M. A., Zam, S. Z., Park, D. R., & Yeom, I. T. (2018). Assessment of Key Environmental Factors Influencing the Sedimentation and Aggregation Behavior of Zinc Oxide Nanoparticles in Aquatic Environment. Water, 10(5), 660. https://doi.org/10.3390/w10050660