Fluorescent Characteristics and Metal Binding Properties of Different Molecular Weight Fractions in Stratified Extracellular Polymeric Substances of Activated Sludge
Abstract
:1. Introduction
2. Materials and Methods
2.1. Sludge Samples
2.2. Reagents and Instruments
2.3. Experimental Method
2.3.1. The Extraction of EPSs
2.3.2. Molecular Weight Classification of EPSs
2.3.3. Spectral Conditions
2.3.4. Fluorescence Quenching Experiment of Pb2+, Cu2+, Cd2+, and Zn2+
2.3.5. Parallel Factor Analysis (PARAFAC)
3. Results and Discussion
3.1. Fluorescence Characteristics of EPSs of Activated Sludge
3.2. Fluorescence Quenching Mechanism
3.2.1. Stern–Volmer Equation
3.2.2. Binding Constant and Number of Binding Sites
3.3. Interaction between Heavy Metals and EPSs of Activated Sludge with Different Molecular Weights
3.4. The Quenching Effect of Heavy Metals on Activated Sludge EPSs
4. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Acknowledgments
Conflicts of Interest
References
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Quencher | Different Molecular Weight EPSs | Fluorescence Peak | Ksv 1 × 103 L/moL | Kq 1 × 1011 L/(moL·s) | R2 | |
---|---|---|---|---|---|---|
Pb2+ | S-EPSs | S-EPS1 | Peak A | 9.160 | 9.000 | 0.965 |
S-EPS2 | 5.942 | 5.940 | 0.953 | |||
S-EPS3 | 6.071 | 6.070 | 0.984 | |||
S-EPS4 | 2.791 | 2.790 | 0.843 | |||
S-EPS5 | 8.632 | 8.630 | 0.937 | |||
Cu2+ | S-EPSs | S-EPS1 | 7.851 | 7.850 | 0.988 | |
S-EPS2 | 3.061 | 3.060 | 0.911 | |||
S-EPS3 | 3.429 | 3.430 | 0.967 | |||
S-EPS4 | 3.051 | 3.050 | 0.986 | |||
S-EPS5 | 6.155 | 6.160 | 0.900 |
Quencher | Different Molecular Weight EPSs | Fluorescence Peak | Ksv 1 × 103 L/moL | Kq 1 × 1011 L/(moL s) | R2 | |
---|---|---|---|---|---|---|
Pb2+ | S-EPSs | S-EPS1 | Peak A | 9.160 | 9.160 | 0.965 |
S-EPS2 | 5.942 | 5.942 | 0.953 | |||
S-EPS3 | 6.071 | 6.071 | 0.984 | |||
S-EPS4 | 2.791 | 2.791 | 0.843 | |||
S-EPS5 | 8.633 | 8.633 | 0.937 | |||
LB-EPSs | LB-EPS1 | 8.684 | 8.684 | 0.980 | ||
LB-EPS2 | 8.512 | 8.512 | 0.988 | |||
LB-EPS3 | 6.393 | 6.393 | 0.865 | |||
LB-EPS4 | 8.096 | 8.096 | 0.934 | |||
LB-EPS5 | 1.217 | 12.17 | 0.935 | |||
TB-EPSs | TB-EPS1 | 21.39 | 21.39 | 0.996 | ||
TB-EPS2 | 10.77 | 10.77 | 0.982 | |||
TB-EPS3 | 11.99 | 11.99 | 0.986 | |||
TB-EPS4 | 10.70 | 10.70 | 0.954 | |||
TB-EPS5 | 20.70 | 20.70 | 0.981 |
EPSs | Fraction | Peak | n | logKb | R2 |
---|---|---|---|---|---|
S-EPSs | S-EPS1 | Peak A | 0.8117 | 2.926 | 0.980 |
Peak B | 0.6477 | 2.246 | 0.982 | ||
S-EPS2 | Peak A | 0.6041 | 1.844 | 0.927 | |
Peak B | 0.7065 | 2.095 | 0.968 | ||
S-EPS3 | Peak A | 0.6353 | 1.948 | 0.964 | |
Peak B | 0.5400 | 1.382 | 0.945 | ||
S-EPS4 | Peak A | 0.6418 | 1.947 | 0.977 | |
Peak B | 0.3564 | 0.7760 | 0.955 | ||
S-EPS5 | Peak A | 1.009 | 3.670 | 0.846 | |
Peak B | 0.5678 | 1.662 | 0.940 | ||
LB-EPSs | LB-EPS1 | Peak A | 0.4933 | 1.812 | 0.992 |
Peak B | 0.4865 | 1.694 | 0.992 | ||
LB-EPS2 | Peak A | 0.8362 | 3.117 | 0.942 | |
Peak B | 0.3871 | 1.262 | 0.993 | ||
LB-EPS3 | Peak A | 0.4731 | 1.693 | 0.975 | |
Peak B | 0.4189 | 1.434 | 0.995 | ||
LB-EPS4 | Peak A | 0.4587 | 1.413 | 0.895 | |
Peak B | 0.3241 | 0.7769 | 0.884 | ||
LB-EPS5 | Peak A | 0.3418 | 1.133 | 0.969 | |
Peak B | 0.2820 | 0.8228 | 0.995 | ||
TB-EPSs | TB-EPS1 | Peak A | 0.7795 | 2.993 | 0.949 |
Peak B | 0.5460 | 1.942 | 0.967 | ||
TB-EPS2 | Peak A | 0.3248 | 1.172 | 0.993 | |
Peak B | 0.3881 | 1.285 | 0.988 | ||
TB-EPS3 | Peak A | 0.3599 | 1.278 | 0.998 | |
Peak B | 0.3490 | 1.091 | 0.993 | ||
TB-EPS4 | Peak A | 0.5879 | 2.092 | 0.910 | |
Peak B | 0.3651 | 0.8295 | 0.943 | ||
TB-EPS5 | Peak A | 0.6084 | 2.122 | 0.953 | |
Peak B | / | / | / |
Heavy Metal Salt | EPSs Molecular Weight Fraction | S-EPSs | LB-EPSs | TB-EPSs | |||
---|---|---|---|---|---|---|---|
Peak A | Peak B | Peak A | Peak B | Peak A | Peak B | ||
Cd(NO3)2 | 1 | 534.9 | 345.30 | 323.5 | 80.30 | 2220 | 435.0 |
2 | 91.20 | −14.70 1 | 140.1 | 29.00 | 521.6 | 113.2 | |
3 | 179.4 | 64.90 | 181.0 | 61.10 | 320.0 | 17.60 | |
4 | 299.9 | 150.9 | 147.5 | 24.00 | 224.0 | −52.40 1 | |
5 | 82.30 | 24.40 | 101.3 | 45.10 | −236.3 1 | −201.5 | |
Pb(NO3)2 | 1 | 663.1 | 292.8 | 460.7 | 85.60 | 3396 | 1010 |
2 | 317.2 | −8.300 1 | 144.1 | 49.36 | 642.6 | 149.3 | |
3 | 453.2 | 139.5 | 83.60 | 24.66 | 749.2 | 171.6 | |
4 | 192.2 | 50.40 | 184.9 | 51.30 | 273.2 | 74.40 | |
5 | 90.00 | 27.10 | 79.99 | 21.61 | 276.9 | 139.4 | |
Cu(NO3)2 | 1 | 577.7 | 405.6 | 699.8 | 319.3 | 3746 | 1929 |
2 | 187.5 | 79.70 | 142.3 | 83.79 | 1355 | 501.9 | |
3 | 227.7 | 124.5 | 218.7 | 114.0 | 1123 | 488.4 | |
4 | 131.2 | 98.90 | 92.10 | 39.59 | 305.3 | 75.00 | |
5 | 54.84 | 23.37 | 90.28 | 41.30 | 104.7 | 11.10 | |
Zn(NO3)2 | 1 | 311.2 | 123.2 | 598.3 | 202.1 | 2343 | 442.0 |
2 | 176.8 | 42.70 | 116.1 | 17.40 | 1022 | 244.2 | |
3 | 165.4 | 39.00 | 61.00 | −31.80 1 | 798.8 | 192.2 | |
4 | 183.7 | 51.70 | 40.10 | −11.50 1 | 231.8 | 19.00 | |
5 | 96.30 | 19.50 | 47.30 | −36.22 1 | 144.4 | −30.80 1 |
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Lian, J.; Yang, Y.; Qiu, W.; Huang, L.; Wang, C.; Chen, Q.; Ke, Q.; Wang, Q. Fluorescent Characteristics and Metal Binding Properties of Different Molecular Weight Fractions in Stratified Extracellular Polymeric Substances of Activated Sludge. Separations 2021, 8, 120. https://0-doi-org.brum.beds.ac.uk/10.3390/separations8080120
Lian J, Yang Y, Qiu W, Huang L, Wang C, Chen Q, Ke Q, Wang Q. Fluorescent Characteristics and Metal Binding Properties of Different Molecular Weight Fractions in Stratified Extracellular Polymeric Substances of Activated Sludge. Separations. 2021; 8(8):120. https://0-doi-org.brum.beds.ac.uk/10.3390/separations8080120
Chicago/Turabian StyleLian, Jingwen, Yang Yang, Weiyi Qiu, Lijie Huang, Chuanhua Wang, Qiongzhen Chen, Qiang Ke, and Qi Wang. 2021. "Fluorescent Characteristics and Metal Binding Properties of Different Molecular Weight Fractions in Stratified Extracellular Polymeric Substances of Activated Sludge" Separations 8, no. 8: 120. https://0-doi-org.brum.beds.ac.uk/10.3390/separations8080120