Role of Divalent Cations on Deposition ofCryptosporidium parvumOocysts on Natural Organic Matter Surfaces

Manufactured nanoparticles (MNPs) are increasingly released into the environment and thus research on their fate and behaviour in complex environmental samples is urgently needed. The fate of MNPs in the aquatic environment will mainly depend on the physico-chemical characteristics of the medium. The presence and concentration of natural organic matter (NOM) will play a significant role on the stability of MNPs by either decreasing or exacerbating the aggregation phenomenon. In this study, we firstly investigated the effect of NOM concentration on the aggregation behaviour of manufactured Fe-oxide nanoparticles. Then, the stability of the coated nanoparticles was assessed under relevant environmental conditions. Flow field-flow fractionation, an emerging method which is gaining popularity in the field of nanotechnology, has been employed and results have been compared to another size-measurement technique to provide increased confidence in the outcomes. Results showed enhanced stability when the nanoparticles are coated with NOM, which was due to electrosteric stabilisation. However, the presence of divalent cations, even at low concentration (i.e. less than 1 mM) was found to induce aggregation of NOM-coated nanoparticles via bridging mechanisms between NOM and Ca2+.

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The Role of Natural Organic Matter in the Biodecontamination of Freshwaters from the Endocrine Disruptor Bisphenol A

Functions of Natural Organic Matter in Changing Environment ◽

10.1007/978-94-007-5634-2_167 ◽

2012 ◽

pp. 915-919

Author(s):

G. Castellana ◽

E. Loffredo ◽

A. Traversa ◽

N. Senesi

Keyword(s):

Organic Matter ◽

Bisphenol A ◽

Natural Organic Matter ◽

Endocrine Disruptor

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Application of composite flocculants for removing organic matter and mitigating ultrafiltration membrane fouling in surface water treatment: the role of composite ratio

Environmental Science Water Research & Technology ◽

10.1039/c9ew00528e ◽

2019 ◽

Vol 5 (12) ◽

pp. 2242-2250

Author(s):

Xue Shen ◽

Baoyu Gao ◽

Kangying Guo ◽

Qinyan Yue

Keyword(s):

Organic Matter ◽

Water Treatment ◽

Surface Water ◽

Membrane Permeability ◽

Natural Organic Matter ◽

Membrane Fouling ◽

Ultrafiltration Membrane ◽

Surface Water Treatment ◽

Ultrafiltration Membrane Fouling

Coagulation prior to the ultrafiltration (UF) process was implemented to improve natural organic matter (NOM) removal and membrane permeability.

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Investigation of membrane fouling by synthetic and natural particles

Water Science & Technology ◽

10.2166/wst.2004.0724 ◽

2004 ◽

Vol 50 (12) ◽

pp. 279-285 ◽

Cited By ~ 1

Author(s):

J.H. Kweon ◽

D.F. Lawler

Keyword(s):

Organic Matter ◽

Natural Organic Matter ◽

Membrane Fouling ◽

Membrane Surface ◽

Research Articles ◽

Clay Material ◽

Dramatic Effect ◽

Flux Decline ◽

Scanning Electron

The biggest impediment for applying membrane processes is fouling that comes from mass flux (such as particle and organic matter) to the membrane surface and its pores. Numerous research articles have indicated that either particles or natural organic matter (NOM) has been the most detrimental foulant. Therefore, the role of particles in membrane fouling was investigated with two synthetic waters (having either particles alone or particles with simple organic matter) and a natural water. Membrane fouling was evaluated with flux decline behavior and direct images from scanning electron microscopy. The results showed that the combined fouling by kaolin and dextran (a simple organic compound selected as a surrogate for NOM) showed no difference from the fouling with only the organic matter. The similarity might stem from the fact that dextran (i.e., polysaccharide) has no ability to be adsorbed on the clay material, so that the polysaccharide behaves the same with respect to the membrane with or without clay material being present. In contrast to kaolin, the natural particles showed a dramatic effect on membrane fouling.

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Removal of Humic Substances by Coagulation

Water Science & Technology ◽

10.2166/wst.1999.0440 ◽

1999 ◽

Vol 40 (9) ◽

pp. 47-54 ◽

Cited By ~ 32

Author(s):

C.R. O’Melia ◽

W.C. Becker ◽

K.-K. Au

Keyword(s):

Water Quality ◽

Organic Matter ◽

Complex Formation ◽

Natural Organic Matter ◽

Divalent Cations ◽

Water Source ◽

Quality Characteristic ◽

Oxide Surfaces ◽

Water Quality Characteristic ◽

Coagulant Dosage

Measurements and modeling of the adsorption of natural organic matter (NOM) on oxide surfaces are presented and compared. Agreement is good and supports the view that the adsorption of NOM on oxides depends significantly on complex formation reactions between specific sites on oxide surfaces and functional groups on the NOM. Coagulant requirements can and often are set by the total organic carbon (TOC) concentration in a water source. Frequently there is a stoichiometric relationship between the required coagulant dosage and the TOC of the water to be treated. Other important factors include pH and the concentration of divalent cations. Ozone may benefit or retard coagulation, depending on coagulant type and the water quality characteristic that is dominant in setting the optimum coagulant dose.

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