Tracking ultrasonically structural changes of natural aquatic organic carbon: chemical fractionation and spectroscopic approaches

Al-Juboori, Raed A. and Yusaf, Talal and Aravinthan, Vasantha and Bowtell, Leslie (2016) Tracking ultrasonically structural changes of natural aquatic organic carbon: chemical fractionation and spectroscopic approaches. Chemosphere, 145. pp. 231-248. ISSN 0045-6535

Abstract

In this study, the structural alteration to DOC for a range of ultrasound treatments was investigated with chemical fractionation and UVevis spectroscopic measurement. Ultrasound treatments were applied in continuous and pulsed modes at power levels of 48 and 84 W for effective treatment times of 5 and 15 min. Overall results show that the ultrasound treatments tended to degrade the hydrophobic aromatic fraction, while increasing the hydrophilic fraction to a lesser extent. The highest recorded reduction of hydrophobic DOC (17.8%) was achieved with pulse treatment of 84 W for15 min, while the highest increase in the hydrophilic DOC (10.5%) was obtained with continuous treatment at 84 W and 5 min. The optimal ultrasound treatment conditions were found to be pulse mode at high power and short treatment time, causing a minimal increase in the hydrophilic fraction of 1.3% with moderate removal of the hydrophobic fraction of 15.52%. The same treatment conditions, with longer treatment time, resulted in the highest removal of SUVA254 and SUVA280 of 17.09% and 16.93, respectively. These results indicate the potential for ultrasound treatments in DOC structural alteration. The hydrophobic fraction showed strong and significant correlations with UV absorbance at 254 and 280 nm. A254/A204 also exhibited strong and significant correlations with the hydrophobic/hydrophilic ratio. The other UV ratios (A250/A365 (E2/E3) and A254/A436) had weak and insignificant correlations with the hydrophobic/hydrophilic ratio. This confirms the applicability of UV indices as a suitable surrogate method for estimating the hydrophobic/hydrophilic structure.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Files associated with this item cannot be displayed due to copyright restrictions.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering
Date Deposited: 04 Jul 2016 00:29
Last Modified: 28 Sep 2017 04:14
Uncontrolled Keywords: pulsed ultrasound; continuous ultrasound; chemical fractionation; spectroscopic properties; hydrophobicity; hydrophilicity; DOC; water treatment
Fields of Research : 03 Chemical Sciences > 0301 Analytical Chemistry > 030108 Separation Science
09 Engineering > 0904 Chemical Engineering > 090410 Water Treatment Processes
09 Engineering > 0907 Environmental Engineering > 090703 Environmental Technologies
03 Chemical Sciences > 0305 Organic Chemistry > 030501 Free Radical Chemistry
09 Engineering > 0913 Mechanical Engineering > 091301 Acoustics and Noise Control (excl. Architectural Acoustics)
03 Chemical Sciences > 0301 Analytical Chemistry > 030101 Analytical Spectrometry
09 Engineering > 0906 Electrical and Electronic Engineering > 090699 Electrical and Electronic Engineering not elsewhere classified
Identification Number or DOI: 10.1016/j.chemosphere.2015.11.079
URI: http://eprints.usq.edu.au/id/eprint/28271

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