{"id":3242,"date":"2022-09-15T13:03:00","date_gmt":"2022-09-15T18:03:00","guid":{"rendered":"https:\/\/www.oxidationtech.com\/blog\/?p=3242"},"modified":"2022-09-02T13:19:16","modified_gmt":"2022-09-02T18:19:16","slug":"sudden-decrease-of-the-dissolved-ozone-concentrationin-sprays-a-mass-transfer-phenomenon","status":"publish","type":"post","link":"https:\/\/www.oxidationtech.com\/blog\/sudden-decrease-of-the-dissolved-ozone-concentrationin-sprays-a-mass-transfer-phenomenon\/","title":{"rendered":"Sudden Decrease of the Dissolved Ozone Concentrationin Sprays: A Mass Transfer Phenomenon?"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">We recently posted an article about the decrease of dissolved ozone concentration in spraying water.  Find that post here:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/www.oxidationtech.com\/blog\/?p=3233\">https:\/\/www.oxidationtech.com\/blog\/?p=3233<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">We have always known and operated with the fact that ozone levels in water decrease through the process of spraying water.  However, there has been limited research on this phenomenon.  We are excited with this research and want to share as much as we can.  Below are samples from that paper for easy review.  Or, review full research here:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\"><a href=\"https:\/\/www.oxidationtech.com\/Downloads\/ozone-water\/Dissolved-ozone-spray-research.pdf\">https:\/\/www.oxidationtech.com\/Downloads\/ozone-water\/Dissolved-ozone-spray-research.pdf<\/a><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Authors:<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Axel Canado, Marine Tournois, Marielle Pages, Michel Roustan, Wilfried Remus-Borel, Nicolas Dietrich, Fr\u00e9d\u00e9ric Violleau, Gilles H\u00e9brard<\/p>\n\n\n\n<h2 class=\"wp-block-heading\"><strong>Abstract<\/strong><\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Ozone is known to be a powerful oxidant with low persistence and has been shown to possess<br>biocidal activity against a wide number of fungi and bacteria. These properties make ozone a good<br>candidate as a substitute for chemical phytosanitary products in agriculture. However, when water<br>containing dissolved ozone is sprayed, the concentration of ozone decreases dramatically with the<br>spraying distance. This study aims to better understand this ozone loss during spraying and, in<br>particular to identify whether mass transfer occurs. Identification was performed by dioxygen<br>absorption and comparison of its concentration profiles with those for ozone desorption. Droplets<br>were collected at different heights in the spray to measure the dissolved concentrations. Image<br>analysis was used to determine the diameters and velocities of the droplets. Ozone self-<br>decomposition kinetics were not able to explain the experimental concentration variation obtained<br>in the droplets. The decrease of dissolved ozone in the liquid is then only caused by mass transfer.<br>Most of the mass transfer seems to take place in the liquid sheet that leaves the nozzle. Volumetric2<br>mass transfer coefficients have been assessed for different regions of the spray. From mass<br>transfer correlations, a model has been made to predict the concentration profile in droplets of the<br>spray.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Introduction<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The main goal of the present study was to provide a better understanding of the loss of dissolved13<br>ozone in droplets during spraying. Solute quantifications along the spray allowed a distinction to be14<br>made between an ozone mass transfer phenomenon and its self-decomposition. Thus, overall15<br>characterizations were performed at different distances from the atomizer to track the16<br>concentration of solute dissolved in the spray. From the measurements, the volumetric mass17<br>transfer coefficient was assessed for different regions of the spray (Film region and droplets18<br>region) to highlight the part of the spray where transfer was the most noteworthy. From image19<br>analysis, the interfacial area of each region has been assessed, then the corresponding has20<br>also been estimated. A model able to describe the concentration profile of dissolved ozone along21<br>the spraying distance has been built. This paper may also provide a way to encourage sellers of22<br>OW sprayers to exercise caution when claiming to reproduce the in vitro effect of OW with spraying23<br>techniques<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Results<\/h2>\n\n\n\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/www.oxidationtech.com\/blog\/wp-content\/uploads\/2022\/09\/Ozone-in-spraying-water-decreases-with-distance.png\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"560\" src=\"https:\/\/www.oxidationtech.com\/blog\/wp-content\/uploads\/2022\/09\/Ozone-in-spraying-water-decreases-with-distance-1024x560.png\" alt=\"\" class=\"wp-image-3244\" srcset=\"https:\/\/www.oxidationtech.com\/blog\/wp-content\/uploads\/2022\/09\/Ozone-in-spraying-water-decreases-with-distance-1024x560.png 1024w, https:\/\/www.oxidationtech.com\/blog\/wp-content\/uploads\/2022\/09\/Ozone-in-spraying-water-decreases-with-distance-300x164.png 300w, https:\/\/www.oxidationtech.com\/blog\/wp-content\/uploads\/2022\/09\/Ozone-in-spraying-water-decreases-with-distance-768x420.png 768w, https:\/\/www.oxidationtech.com\/blog\/wp-content\/uploads\/2022\/09\/Ozone-in-spraying-water-decreases-with-distance.png 1246w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><figcaption>Ozone levels in water decrease as the distance from the spray nozzle to the surface increases.<\/figcaption><\/figure>\n\n\n\n<h2 class=\"wp-block-heading\">Conclusions<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">An experimental study has been conducted to identify the phenomenon that causes the loss of2<br>dissolved ozone in droplets when ozonated water is sprayed. Mass transfer between liquid droplets3<br>and the ambient air is responsible for these ozone losses. It occurs because the ozone dissolved in4<br>the droplets is much more concentrated than the saturation concentration in air, which it is naturally5<br>low. The phenomenon has been identified on the one hand, through performing desorption of6<br>ozonated water by spraying an ozone-rich liquid in ambient air and, on the other hand, by7<br>assessing the absorption of dioxygen from air in dioxygen-free water. Concentration profiles have8<br>been compared and show a significantly similar trend: about 60% to 70% of the transfer is9<br>achieved within the first few centimetres after the outlet of the nozzle. We have shown that ozone10<br>self-decomposition kinetics were not able to explain the experimental concentration variation11<br>obtained into the droplets. The decrease of dissolved ozone in the liquid is then only caused by12<br>mass transfer phenomenon.13<br>From mass balances and mass transfer theories, a model has been constructed to predict the14<br>dissolved concentration along the spraying distance. The calculation requires the droplet diameters15<br>and velocities in the system to be known. These hydrodynamic parameters were determined by16<br>particle image analysis, and averaged values have proved suitable to provide an accurate fit with17<br>the experimental data. The model exhibits discrepancies in the centimetres of the spray near the18<br>nozzle, which can be explained by the presence of a liquid film that is not yet atomized into19<br>droplets in this region. Thus, the model considering spherical droplets cannot be applied. Then, the20<br>model has been applied to the droplets part of the spray and provide a reasonable prediction of the21<br>solute variation. Further study of the liquid film would allow the mass transfer in this region to be22<br>predicted. Interface sizing and local measurements of the solute in the liquid film would confirm if23<br>the high mass transfer reached there is due to surface enhancement and\/or improvement in the24<br>hydrodynamics conditions.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>We recently posted an article about the decrease of dissolved ozone concentration in spraying water. Find that post here: https:\/\/www.oxidationtech.com\/blog\/?p=3233 We have always known and [&hellip;]<\/p>\n","protected":false},"author":10,"featured_media":3244,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[3],"tags":[1100],"class_list":["post-3242","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-tech-tips","tag-ozone-water-spraying"],"_links":{"self":[{"href":"https:\/\/www.oxidationtech.com\/blog\/wp-json\/wp\/v2\/posts\/3242","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.oxidationtech.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.oxidationtech.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.oxidationtech.com\/blog\/wp-json\/wp\/v2\/users\/10"}],"replies":[{"embeddable":true,"href":"https:\/\/www.oxidationtech.com\/blog\/wp-json\/wp\/v2\/comments?post=3242"}],"version-history":[{"count":1,"href":"https:\/\/www.oxidationtech.com\/blog\/wp-json\/wp\/v2\/posts\/3242\/revisions"}],"predecessor-version":[{"id":3245,"href":"https:\/\/www.oxidationtech.com\/blog\/wp-json\/wp\/v2\/posts\/3242\/revisions\/3245"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.oxidationtech.com\/blog\/wp-json\/wp\/v2\/media\/3244"}],"wp:attachment":[{"href":"https:\/\/www.oxidationtech.com\/blog\/wp-json\/wp\/v2\/media?parent=3242"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.oxidationtech.com\/blog\/wp-json\/wp\/v2\/categories?post=3242"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.oxidationtech.com\/blog\/wp-json\/wp\/v2\/tags?post=3242"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}