Trihalomethane, dihaloacetonitrile, and total N-nitrosamine precursor adsorption by carbon nanotubes: the importance of surface oxides and pore volume

Needham, Erin M.; Sidney, Shelby M.; Chimka, Justin R.; Fairey, Julian L.

doi:10.1039/c6ew00193a

Cited by 6 publications

(7 citation statements)

References 52 publications

(73 reference statements)

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“…UV 254 indicates the aromatic fraction of NOM (Hua & Reckhow, 2007;Hua, Reckhow, & Abusallout, 2015;Weishaar et al, 2003). Despite being widely used, DOC and UV 254 are not the only means of tracking NOM responsible for DBP formation (Bridgeman, Bieroza, & Baker, 2011;Her, Amy, McKnight, Sohn, & Yoon, 2003;McKnight et al, 2001;Needham, Sidney, Chimka, & Fairey, 2016). NOM reactivity with chlorine can also be predicted by characterizing the NOM MW or size distribution.…”

Section: Promulgation Of the Stage 2 Disinfectants And Disinfectionmentioning

confidence: 99%

Chlorine addition prior to granular activated carbon contactors improves trihalomethane control

Fischer

Ghosh²,

Talabi³

et al. 2019

AWWA Water Science

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Optimizing granular activated carbon (GAC) operation can reduce costs for removing disinfection byproducts or their precursors. This article investigates prechlorination to enhance the removal of total trihalomethane (TTHM) precursors and reduce TTHM concentrations in finished water. Rapid small‐scale column tests (RSSCTs) and pilot tests using virgin and reactivated GAC were conducted on water with and without prechlorination. Prechlorination (1 or 2 mg Cl2/L) increased (by 15 and 30%, respectively) the number of bed volumes treated by GAC. On the basis of size exclusion chromatography, prechlorination followed by GAC preferentially removed low‐molecular‐weight dissolved organic carbon by GAC. Simulated distribution system (SDS) chlorination tests on GAC effluent showed lower TTHM concentrations with prechlorination. Prechlorination lowered the bromine incorporation factor values in GAC effluents after SDS tests, which suggests a reduction in toxicity potential from trihalomethanes. RSSCT results were validated by pilot testing, showing that RSSCTs can be used to optimize the prechlorination process.

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Section: Promulgation Of the Stage 2 Disinfectants And Disinfectionmentioning

confidence: 99%

Chlorine addition prior to granular activated carbon contactors improves trihalomethane control

Fischer

Ghosh²,

Talabi³

et al. 2019

AWWA Water Science

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“…Raw water characteristics were measured upon collection and are summarized in Tables , S1, and S2. Fluorescence excitation–emission matrices (EEMs) and water quality parameters were measured following the procedure described by Needham et al, with the exception of TDN, which is detailed in the Supporting Information. Dissolved organic nitrogen (DON) was calculated as the difference between TDN and inorganic nitrogen (Table ).…”

Section: Methodsmentioning

confidence: 99%

“…The DBP formation potential (DBPFP) was measured using the protocol developed by Do et al, which was modified from Standard Methods 5710-B and -D, with a monochloramine dose of 250 mg L –1 as Cl 2 at pH 7. TTHMFP and DHANFP were measured by gas chromatography with an electron capture detector to test the assumption that the AF4-FLD metrics were most applicable to TONOFP.…”

Section: Methodsmentioning

confidence: 99%

“…Similar to precursor surrogates for trihalomethanes (TTHMs) and dihaloacetonitriles (DHANs), a useful surrogate would consist of spectroscopic measurement(s) on waters prior to chloramination that strongly correlate with the TONO formation potential (TONOFP). Preliminary work showed only moderate fluorescence-based correlations with TONOFP ( R 2 < 0.50), but a recent study points to a possible improvement. Wang et al showed that the presence of humics led to underestimation of proteins (35–52%) because of fluorescence quenching.…”

Section: Introductionmentioning

confidence: 92%

“…Wang et al showed that the presence of humics led to underestimation of proteins (35–52%) because of fluorescence quenching. This is notable because protein-like fluorophores are a likely source of TONO precursors. ,, …”

Section: Introductionmentioning

confidence: 99%

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Revealing a Size-Resolved Fluorescence-Based Metric for Tracking Oxidative Treatment of Total N-Nitrosamine Precursors in Waters from Wastewater Treatment Plants

Needham

Luis

Chimka

et al. 2017

Environ. Sci. Technol. Lett.

Self Cite

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N-Nitrosamines make up a nonhalogenated group of disinfection byproducts that form during chloramination, particularly in drinking waters impacted by wastewater treatment plant (WWTP) effluents. Here, we reveal a size-resolved fluorescence-based precursor surrogate for tracking total N-nitrosamine formation potential (TONOFP) through oxidative treatment. Samples were collected at seven WWTPs, at the finished effluent and prior to final disinfection (i.e., secondary effluent). Asymmetric flow field-flow fractionation (AF4) with inline fluorescence detection at excitation and emission wavelengths of 280 and 340 nm, respectively (i.e., I 280/340), showed protein-rich natural organic matter peaks between 10–445 and 445–1500 kDa. TONOFP was measured by chemiluminescence on samples dosed with 250 mg L–1 Cl2 monochloramine at pH 7 for 7 days. Metrics from AF4 I 280/340 (i.e., area under the curve and peak height) and I 257/277 from whole water excitation–emission matrices were leveraged in multivariate models to develop correlations with TONOFP. The TONOFP of the finished effluent divided by that of the secondary effluent (i.e., the TONOFP Ratio) was strongly correlated (R 2 = 0.996; p = 0.000) to a model of AUC for the 10–445 kDa peak, maximal peak height, and I 257/277. This TONOFP precursor surrogate requires 2 mL of sample and is transformational with respect to assessing the impact of oxidative treatments on N-nitrosamine precursor concentrations.

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Monodisperse CNT Microspheres for High Permeability and Efficiency Flow‐Through Filtration Applications

2018

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Carbon nanotube (CNT)-based filters have the potential to revolutionize water treatment because of their high capacity and fast kinetics in sorption of organic, inorganic, and biological pollutants. To date, CNT filters either rely on CNTs dispersed in liquids, which are difficult to recover and cause safety concerns, or on CNT buckypaper, which offers high efficiency, but suffers from an intrinsic trade-off between filter permeability and capacity. Here, a new approach is presented that bypasses this trade-off and achieves buckypaper-like efficiency combined with filter-column-like permeability and capacity. For this, CNTs are first assembled into porous microspheres and then are packed into microfluidic column filters. These microcolumns exhibit large flow-through filtration efficiencies, while maintaining membrane permeabilities an order of magnitude larger then CNT buckypaper and specific permeabilities double that of activated carbon for similar flowrates (232 000 L m h bar , 1.23 × 10 m ). Moreover, in a test to remove sodium dodecyl sulfate (SDS) from water, these microstructured CNT columns outperform activated carbon columns. This improved filtration efficiency and permeability is an important step toward a broader implementation of CNT-based filtration devices.

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Trihalomethane, dihaloacetonitrile, and total N-nitrosamine precursor adsorption by carbon nanotubes: the importance of surface oxides and pore volume

Abstract: Carboxyl groups on CNTs enhanced pore volume and in turn disinfection byproduct precursor adsorption.

Cited by 6 publications

References 52 publications

Chlorine addition prior to granular activated carbon contactors improves trihalomethane control

Chlorine addition prior to granular activated carbon contactors improves trihalomethane control

Revealing a Size-Resolved Fluorescence-Based Metric for Tracking Oxidative Treatment of Total N-Nitrosamine Precursors in Waters from Wastewater Treatment Plants

Monodisperse CNT Microspheres for High Permeability and Efficiency Flow‐Through Filtration Applications

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