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Water Chemistry
Published in Frank R. Spellman, The Science of Water, 2020
Ionization: The formation of ions by splitting of molecules or electrolytes in a solution. Water molecules are in continuous motion, even at lower temperatures. When two water molecules collide, a hydrogen ion is transferred from one molecule to the other. The water molecule that loses the hydrogen ion becomes a negatively charged hydroxide ion. The water molecule that gains the hydrogen ion becomes a positively charged hydronium ion. This process is commonly referred to as the self-ionization of water.
Lightweight mobile stick-type water-based triboelectric nanogenerator with amplified current for portable safety devices
Published in Science and Technology of Advanced Materials, 2022
Kyunghwan Cha, Jihoon Chung, Deokjae Heo, Myunghwan Song, Seh-Hoon Chung, Patrick T.J. Hwang, Dongseob Kim, Bonwook Koo, Jinkee Hong, Sangmin Lee
Considering these aspects, we developed a lightweight mobile stick-type water-based triboelectric nanogenerator (MSW-TENG) that can produce electrical output through mechanical motion applied to the device. As the water inside the MSW-TENG directly contacts the electrode, a high electrical output can be generated through the charge separation and accumulation induced by the self-ionization of water. For an input of 1.5 Hz, a single MSW-TENG could generate an open-circuit voltage (VOC) and closed-circuit current (ICC) of up to 710 V and 2.9 mA, respectively. As the size of the generator and amount of liquid considerably influence the portability and output production of the device, quantitative analyses were performed considering the size ratio of the electrode, physical space between the electrodes, and amount of water to determine the optimized device design. The proposed TENG could be utilized as a traffic safety light baton that can power 100 LEDs each time an operator manually shakes the baton. Notably, the proposed device can be used as a self-powered safety device, which widens the potential for implementing TENGs in everyday applications.
Remediation approach for organic compounds and arsenic co-contaminated soil using the pressurized hot water extraction process
Published in Environmental Technology, 2019
Mohammad Nazrul Islam, Young-Tae Jo, Yeon-Jae Jeong, Jeong-Hun Park
Generally, remediation techniques are being applied separately for the remediation of inorganic [13–16] and organic pollutants [17,18] in contaminated soil. In this study, the development of mixed pollutants contaminated soil remediation technology was of great interest. The hypothesis of this study was to extract/degrade organic compounds and As in soil. Pressurized hot water (PHW) extraction treatment could be an effective remediation technique for this purpose. The primary mechanisms of organics removal by PHW are, in sequence, desorption, diffusion, and dissolution in water, and then elimination by mass transfer [19], offering a unique opportunity for separation. In addition, concentrations of H+ and OH− are increased greatly by the self-ionization of water molecules under subcritical conditions (100 ≤ T ≤ 374°C and < 22.1 MPa) [20,21]. Accordingly, it is hypothesized that PHW can also effectively oxidize many organic contaminants in soil, resulting in their degradation during the extraction process. Furthermore, the increased H+ and OH− ions in PHW water may be a factor in the removal of As by oxidation and dissolution of As-bearing minerals [22,23].
Water Dissolution of Nitrogen Oxides Produced by Ozone Oxidation of Nitric Oxide
Published in Ozone: Science & Engineering, 2021
Hadi Noori, Jüri Raud, Rasmus Talviste, Indrek Jõgi
The reaction R14 becomes important at pH above 6–7 and the decomposition chains of ozone are started with hydroxide ion (OH–) which is due to the self-ionization of water. In present study, the pH remained below 5 and this suggests that the reaction R12 is mainly responsible for the ozone decomposition. The OH produced in reaction R12 will start a chain reaction for ozone decomposition by reactions O3aq + OH → HO2 + O2 and O3aq + HO2 → OH + 2O2 (Sotelo et al. 1987).