Electrochemical methodology to study labile trace metal/natural organic matter complexation at low concentration levels in natural waters

2004 ◽  
Vol 521 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Rute F. Domingos ◽  
Marc F. Benedetti ◽  
Jean P. Croué ◽  
José P. Pinheiro
Author(s):  
Khan M. G. Mostofa ◽  
Cong-qiang Liu ◽  
Xinbin Feng ◽  
Takahito Yoshioka ◽  
Davide Vione ◽  
...  

Carbon ◽  
2004 ◽  
Vol 42 (3) ◽  
pp. 547-557 ◽  
Author(s):  
Seyed A Dastgheib ◽  
Tanju Karanfil ◽  
Wei Cheng

2009 ◽  
Vol 60 (6) ◽  
pp. 1385-1392 ◽  
Author(s):  
B. R. H. Peiris ◽  
H. Budman ◽  
C. Moresoli ◽  
R. L. Legge

A method that would allow for fast and reliable measurements of dissolved organic matter (DOM), both at low and high concentration levels would be a valuable tool for online monitoring of DOM. This could have applications in a variety of areas including membrane treatment systems for drinking water applications which is of interest to our group. In this study, the feasibility of using fluorescence spectroscopy for monitoring DOM at very low concentration levels was demonstrated with an emphasis on optimizing the instrument parameters necessary to obtain reproducible fluorescence signals. Signals were acquired using a cuvette or a fibre optic probe assembly, the latter which may have applications for on-line or in-line monitoring. The instrument parameters such as photomultiplier tube (PMT) voltage, scanning rate and slit width were studied in detail to find the optimum parameter settings required. The results showed that larger excitation and emission slit widths were preferred, over larger PMT voltage or lower scanning rates, to obtain reproducible and rapid measurements when measuring very low concentration levels of DOM. However, this approach should be implemented with caution to avoid any reduction of the signal resolution.


Author(s):  
G. V. Korshin ◽  
J. F. Ferguson ◽  
M. E. Rock

Natural organic matter (NOM) is a ubiquitous and important component of natural waters. Polymeric species related to humus found in soils constitute the major part of NOM. NOM is of major importance for the speciation of metals in waters but its effects on metal corrosion are little known. The influence of NOM on the morphology of corroding copper surfaces is discussed in this communication. The studies were performed for copper coupons exposed for 7 weeks to waters supporting an intense localized corrosion attack called pitting. Two types of waters were used: highly mineralized water at pH close to 7.3 (water A) and soft water at pH close to 9.3 (water B). The morphology of the surface was examined using conventional photography and SEM (JEOL 5200). The range of accelerating voltages was from 10 to 25 kV.Profound effects of NOM on the state of the corroding copper surface were found.


2006 ◽  
Vol 6 (2) ◽  
pp. 25-30 ◽  
Author(s):  
M. Koh ◽  
M.M. Clark ◽  
K.P. Ishida

Rejection by membrane adsorption has been observed and widely reported. However, little is known about whether membranes possess an adsorption capacity. Experimental data showed that when a hydrophobic polypropylene (PP) microfilter was used to filter a large volume of particle-free surface water containing dissolved natural organic matter (NOM), later batches of microfiltration (MF) permeate caused more flux decline to a fresh 20K-Dalton polyethersulfone (PES) ultrafilter. This suggests that membranes can have an adsorption capacity for foulants. In this research, the gradual increase in absorbance of ultraviolet (UV) light by subsequent batches of MF permeate was observed, and supports the findings from previous studies, that only a small fraction of NOM causes membrane fouling. Attenuated total reflectance Fourier transform infrared spectrometry and energy dispersive spectroscopy of fouled PP and PES membranes suggests foulants containing amide, aromatic, ether, hydroxyl and silicate functional groups. Silicates appear to participate in membrane fouling, and its removal with the small fraction of fouling NOM can reduce the fouling potential of water. These data improve our understanding of membrane fouling by natural waters, and have implications for the design of membrane plants that filter natural waters.


2011 ◽  
Vol 64 (9) ◽  
pp. 1876-1884 ◽  
Author(s):  
Anat Lakretz ◽  
Eliora Z. Ron ◽  
Tali Harif ◽  
Hadas Mamane

The main goal of this study was to examine the influence of natural organic matter (NOM) on the efficiency of H2O2/UV advanced oxidation process (AOP) as a preventive treatment for biofilm control. Pseudomonas aeruginosa PAO1 biofilm-forming bacteria were suspended in water and exposed to various AOP conditions with different NOM concentrations, and compared to natural waters. H2O2/UV prevented biofilm formation: (a) up to 24 h post treatment – when residual H2O2 was neutralized; (b) completely (days) – when residual H2O2 was maintained. At high NOM concentrations (i.e. 25 mg/L NOM or 12.5 mg/L DOC) an additive biofilm control effect was observed for the combined H2O2/UV system compared to UV irradiation alone, after short biofilm incubation times (<24 h). This effect was H2O2 concentration dependent and can be explained by the high organic content of these water samples, whereby an increase in NOM could enhance •OH production and promote the formation of additional reactive oxygen species. In addition, maintaining an appropriate ratio of bacterial surviving conc.: residual H2O2conc. post-treatment could prevent bacterial regrowth and biofilm formation.


2008 ◽  
Vol 606 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Yoann Louis ◽  
Petra Cmuk ◽  
Dario Omanović ◽  
Cédric Garnier ◽  
Véronique Lenoble ◽  
...  

2015 ◽  
Vol 12 (6) ◽  
pp. 673 ◽  
Author(s):  
Rhys M. Goodhead ◽  
Blair D. Johnston ◽  
Paula A. Cole ◽  
Mohammed Baalousha ◽  
David Hodgson ◽  
...  

Environmental context Nanoparticles are present in growing volumes of consumer products and are suspected to be released into the environment at detectable levels. We focus on cerium dioxide nanoparticles and investigate their availability to fish from the water column, where we found increasing concentrations of natural organic material increased the ceria measured in the fish gills. This complex interaction between nanoparticle behaviour and uptake from environmentally relevant test systems is significantly understudied. Abstract Natural organic colloids affect the fate and behaviour of nanoparticles in the aquatic environment but how these interactions affect the bioavailability of nanoparticles to organisms is a major knowledge gap in risk-assessment analysis. Here, we investigated interactions of citrate-coated cerium dioxide (CeO2) nanoparticles with fulvic acids, representing natural organic matter, and assessed their bioavailability to fish (common carp, Cyprinus carpio) exposed chronically (32days) via the water. We show a fulvic acid concentration-related enhancement in the uptake of cerium (Ce) into gill tissues, with some evidence for an enhanced Ce uptake also into kidney and brain tissues in the presence of fulvic acids, but with more variable responses. We present evidence for differences in the aggregation behaviour for CeO2 nanoparticles in the different exposure scenarios, with reduced CeO2 particle aggregate size with citrate coating and fulvic acids, as determined from dynamic light scattering. We highlight that multiple analytical approaches are essential for understanding the dynamic nature of the particles and also that interpretations on measured particle sizes and characteristics may differ depending on the technique(s) employed. We conclude that conditions in natural waters are likely to play a fundamental role in affecting bioavailability and thus potential biological effects of CeO2 particles.


2021 ◽  
Vol 11 (24) ◽  
pp. 11692
Author(s):  
Olena Stabnikova ◽  
Viktor Stabnikov ◽  
Andriy Marinin ◽  
Maris Klavins ◽  
Linards Klavins ◽  
...  

Major water-polluting microplastics (for example, polyethylene, polypropylene and others) have lower density than water. Therefore, they are concentrated in the neustonic layer near the water-air interface altogether with dissolved or colloidal natural organic matter, hydrophobic cells and spores of bacteria. This can cause environmental and public health problems because the floating micro- and nanoparticles of plastics could be coated with biofilm of hydrophobic and often putative pathogenic bacteria. Biofilm-coated microplastics are more attractive for consumption by aquatic animals than pure microplastics, and that increases the negative impacts of microplastics. So, impacts of even small quantities of microplastics in aquatic environments must be accounted for considering their accumulation in the micro-layer of water-air interphase and its interaction with bacterioneuston. Microorganisms attached to the surface of microplastic particles could interact with them, use them as substrates for growth, to change properties and biodegrade. The study of microbial life on the surface of microplastic particles is one of the key topics to understanding their role in the environment.


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