Integrating bench- and full-scale nanofiltration testing for two surface waters

Lamsal, Rupa; Chaulk, Mike; Zevenhuizen, Emily; Walsh, Margaret E.; Gagnon, Graham A.

doi:10.2166/aqua.2012.089

Cited by 3 publications

(2 citation statements)

References 37 publications

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“…The limitations in the accuracy of EDS elemental analyses of complex samples discussed in Section 4.3 are compounded by the common practice of coating membrane samples with a layer of gold-palladium alloy prior to SEM imaging to prevent surface charging and provide better quality imaging [12,[62][63][64]. Predicting X-ray adsorption in multi-element coatings presents substantial challenges [24], particularly when considering that the coating density and elemental deposition ratios may vary significantly from those of the native alloy.…”

Section: Edsmentioning

confidence: 99%

Elemental composition of membrane foulant layers using EDS, XPS, and RBS

Gorzalski

Donley

Coronell

2017

Journal of Membrane Science

101

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Existing studies investigating the elemental composition of membrane foulant layers typically use one of the following analytical techniques: energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), or Rutherford backscattering spectrometry (RBS). However, given that EDS, XPS, and RBS have different capabilities, limitations, and depths of analysis, these techniques may provide differing results from each other. Thus, to understand the suitability of each technique for the analysis of membrane foulant layers, a thorough study is needed that compares EDS, XPS, and RBS results for a diverse set of fouled membranes. As such, the objectives of this study were to identify the strengths, weaknesses, and limitations of EDS, XPS and RBS in the characterization of the elemental composition of foulant layers, and evaluate whether the three techniques yield consistent and/or complementary results for sample composition and structure. We studied four diverse fouled membranes, each before and after cleaning, as well as the original unfouled membranes, and assessed the suitability of each technique for various applications, such as the detection of major elements in thick and thin layers, characterization of sample depth heterogeneity, evaluation of overall membrane cleaning efficacy, among others. Results show that in the analysis of membranes and foulant layers: (i) applying a single technique may lead to incomplete or incorrect conclusions about composition or structure; (ii) RBS is the most advantageous technique for elemental analysis; (iii) EDS has important limitations, but is appropriate for evaluating overall elemental composition of foulant

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Section: Edsmentioning

confidence: 99%

Elemental composition of membrane foulant layers using EDS, XPS, and RBS

Gorzalski

Donley

Coronell

2017

Journal of Membrane Science

101

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“…As a result, the majority of TOC and DOC removal at this facility is through nanofiltration causing significant NOM loading to the nanofilter and increasing fouling rates. The difficulties with the membrane process at this treatment facility have been documented elsewhere (Lamsal et al, 2012). As shown in Figure 4, similar to TOC and DOC removal, reduction in peCOD with UF was also limited, with the majority of peCOD removed with nanofiltration demonstrating the ability of peCOD to provide similar treatment performance information to TOC and DOC.…”

Section: Resultsmentioning

confidence: 94%

Application of photoelectrochemical chemical oxygen demand to drinking water

Stoddart

Gagnon

2014

Journal AWWA

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MATERIALS AND METHODSModel compound preparation. Three amino acids (tyrosine, tryptophan, phenylalanine), three carboxylic acids (sodium acetate, sodium oxalate, and sodium formate), and two reference standards (potassium hydrogen phthalate [KHP] and caffeine) were used as model organic compounds. These model organic compounds are summarized in Table 1.Carboxylic acids and amino acids are found in natural waters and can make up 8% and 2-3% of COD in natural waters, respectively (Langlais et al, 1991). Relative proportions of amino acids to organic matter surrogates such as DOC can vary considerably from source to source. In a survey of 16 utilities across the United States, Dotson and Westerhoff (2009) found that raw water total amino acid concentration accounted for between 0.19 and 11.6%, or 3.5%, on average, of raw water DOC. As summarized by Dotson and Westerhoff (2009), amino acids are precursors to regulated and unregulated DBPs, and amino acids with aromatic side chains, such as tryptophan and tyrosine, can have the highest DBP yields on a carbon basis. KHP was chosen because it is commonly used as a reference standard for TOC determination. Finally, caffeine was chosen as it is commonly used as a marker for human contamination.Model compound stock solutions (100 mg C/L) were prepared by diluting chemical in deionized (DI) water (Millipore). Stock solutions were then further diluted with DI water to 0.25, 0.5, 1, 3, and 5 mg C/L as TOC in the range of 1.5-5 mg/L represents common raw and treated water TOC content in surface water in Nova Scotia. Model compounds were prepared for TOC and COD.Surface water collection. Samples were collected from four surface water treatment plants in Nova Scotia. Treatment trains included one biofiltration plant (Pockwock Lake), one ultrafiltration/nanofiltration membrane plant (Fletcher Lake), and two conventional filtration plants (Lake Major and Bennery Lake). Details of the treatment process for each plant are described in Table 2.Samples included raw water, prefiltered water, filtered water, and finished water from each location, with the exception of prefiltered water and finished water from Fletcher Lake. Raw water samples were taken from the plant's raw water intake at all locations. Prefiltered water was taken from the final flocculation tank for the Pockwock and Bennery Lake samples, and from the top of the clarifier, prior to prechlorine addition, for the Lake Major sample. A prefiltered sample was not taken at Fletcher Lake because no

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A review of advances in EDCs and PhACs removal by nanofiltration: Mechanisms, impact factors and the influence of organic matter

Wang

et al. 2021

Chemical Engineering Journal

124

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Integrating bench- and full-scale nanofiltration testing for two surface waters

Cited by 3 publications

References 37 publications

Elemental composition of membrane foulant layers using EDS, XPS, and RBS

Elemental composition of membrane foulant layers using EDS, XPS, and RBS

Application of photoelectrochemical chemical oxygen demand to drinking water

A review of advances in EDCs and PhACs removal by nanofiltration: Mechanisms, impact factors and the influence of organic matter

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