Researchers discover new method to generate nanobubbles in water
Researchers at University College Dublin (UCD) have discovered a new energy-efficient method to generate and release substantial volumes of metastable, nano-scale gas bubbles in water, in excess of natural solubility levels. The discovery has the potential to disrupt a number of industries including; wastewater treatment, gas storage, food, bio-pharma and brewing.
The nanobubble-generation discovery has been announced in a scientific paper entitled Massive Generation of Metastable Bulk Nanobubbles in Water by External Electric Fields just published in Science Advances, a peer-reviewed multidisciplinary open-access scientific journal.
Micron-sized bubbles are tiny gas bubbles with a diameter of less than 50 micron (μm), a micron (μm) is a millionth of a meter, and they have a number of industrial applications, including in wastewater treatment. However micron-sized bubbles decrease in size and eventually disappear underwater due to the rapid dissolution of their interior gas, which limits their industrial potential.
Nanobubbles are also tiny gas bubbles but on the nanometer (nm) scale. A nanometer is one billionth of a meter, and for example a DNA molecule is ca. 2.5 nm wide and a human hair is ca. 60,000—100,000 nm wide. Nanobubbles are thermodynamically metastable for many months or even longer, in contrast to micron-sized bubbles, and have therefore enhanced gas-transfer properties and greater industrial potential.
The challenge for scientists to date has been the development of easily controlled methods to promote nanobubble formation and nanobubble release.
The discovery of a new, energy-efficient and easily controlled method to generate and release large volumes of nanobubbles has been made by Professor Niall English and Dr. Mohammad Reza Ghaani at UCD's School of Chemical and Bioprocess Engineering.
Outlining the discovery, Professor Niall English, UCD School of Chemical and Bioprocess Engineering said, "Our new fundamental discovery involves the application of electric fields, which cause transient negative-pressure regions at gas-liquid interfaces, thereby resulting in gas incorporation in liquids in nanoscale-bubble form. It is very energy-efficient, additive-free, and works for a wide range of gases and the greatly enhanced gas solubility in water is highly metastable, lasting at least for many months."
He added, "Following the completion of a research program in collaboration with Professor Peter Kusalik at the University of Calgary, we have established a good theoretical understanding of nanobubble mobility in electric fields which contributes to our microscopic knowledge of nanobubble stability."
This development in nanobubble science has the potential to dramatically increase gas-transfer rates and deliver a step-change in operational efficiencies of a number of industrial sectors, including; gas storage, wastewater treatment, bio-pharma, brewing, agriculture and food.
Dr. Mohammad Reza Ghaani, UCD School of Chemical and Bioprocess Engineering, said, "Our new method of nanobubble generation has multiple commercial applications and has the potential to boost the ability to store gas directly in aqueous solutions over months. In addition it has the potential to boost by several-fold dissolved-gas levels, resulting in greater capacities to treat wastewater and also enhance mass transfer in oxygen-limited biochemical and biopharma reactions, such as fermentation processes in the food and brewing industries."
He added, "Working with UCD's knowledge transfer team at NovaUCD we have filed patent applications and we are also looking to commercialize the technology through a UCD spin-out company."
Paper co-author, Professor Peter Kusalik, Department of Chemistry, University of Calgary, said, "Our work also reveals the molecular origins for the apparent stability of nanobubbles, which might otherwise be expected not to be stable due to their very small size. The origins of the behavior can be traced to the unique structure of the water molecules at boundary between the liquid water and the gas."
"The explanation also accounts for why these otherwise uncharged bubbles can be seen to move when an electric field is applied. Thus, this study is able to provide a clear and consistent explanation to a previously puzzling problem."
Professor English concluded, "We would like to thank Irish company Particular Sciences for access to dynamic-light scattering (DLS) equipment used during this research."
The (open-access) article is titled "Massive Generation of Metastable Bulk Nanobubbles in Water by External Electric Fields."
More information: Mohammad Reza Ghaani et al. Massive generation of metastable bulk nanobubbles in water by external electric fields, Science Advances (2020). DOI: 10.1126/sciadv.aaz0094
Journal information: Science Advances
Provided by University College Dublin
Watafiti wa Chuo Kikuu cha Dublin (UCD) wamegundua njia mpya ya nishati ya kutengeneza na kutolewa kwa kiasi kikubwa cha metastable, nano-scale gesi Bubbles katika maji, zaidi ya viwango vya asili vya mumunyifu. Ugunduzi huo una uwezo wa kuvuruga viwanda kadhaa ikiwa ni pamoja na; matibabu ya maji taka, kuhifadhi gesi, chakula, bio-pharma na bia. Ugunduzi wa kizazi cha nanobubble umetangazwa katika karatasi ya kisayansi yenye kichwa kizazi kikubwa cha nanobubbles ya metastable kwa maji na mashamba ya umeme ya nje, iliyochapishwa hivi karibuni katika Maendeleo ya Sayansi, jarida la kisayansi la ufikiaji wa wazi la taaluma nyingi. Bubbles ndogo za gesi zenye ukubwa wa micron ni ndogo sana, na kipenyo cha micron ni chini ya 50 microns (μm), na zina matumizi kadhaa ya viwanda, ikiwa ni pamoja na katika matibabu ya maji taka. Hata hivyo, Bubbles micron-ukubwa kupungua kwa ukubwa na hatimaye kutoweka chini ya maji kutokana na kuyeyuka kwa kasi ya gesi yao ya ndani, ambayo hupunguza uwezo wao wa viwanda. Nanobubbles pia ni Bubbles ndogo gesi lakini juu ya nanometer (nm) kiwango. Nanometer ni sehemu ya bilioni moja ya mita, na kwa mfano molekuli ya DNA ni ca. Ni 2.5 nm kwa upana na nywele za binadamu ni ca. Urefu wa 60 000 nm Nanobubbles ni thermodynamically metastable kwa miezi mingi au hata zaidi, kinyume na micron-ukubwa Bubbles, na kwa hiyo kuwa na kuimarishwa gesi-uhamisho mali na uwezo mkubwa wa viwanda. Kwa sasa, wanasayansi wamekuwa wakijaribu kugundua njia za kuwezesha nanobubbles kuundwa na kutolewa. Ugunduzi wa njia mpya, yenye ufanisi wa nishati na rahisi kudhibitiwa ya kuzalisha na kutolewa kwa kiasi kikubwa cha nanobubbles umefanywa na Profesa Niall English na Dk Mohammad Reza Ghani katika Shule ya UCSD ya Uhandisi wa Kemikali na Bioprocess. "Profesa Niall English, Shule ya UCSD ya Uhandisi wa Kemikali na Bioprocess, alisema: ""Ugunduzi wetu mpya wa msingi unahusisha matumizi ya mashamba ya umeme, ambayo husababisha maeneo ya shinikizo hasi la muda mfupi kwenye viunganishi vya gesi-mchanganyiko, na hivyo kusababisha kuingizwa kwa gesi katika kioevu katika fomu ya nanoscale." Ni nishati ya ufanisi sana, additive-free, na kazi kwa ajili ya aina mbalimbali ya gesi na sana kuimarishwa gesi mumunyifu katika maji ni metastable sana, kudumu angalau kwa miezi mingi. "Ameongeza, ""Kufuatia kukamilika kwa mpango wa utafiti kwa kushirikiana na Profesa Peter Kusalik katika Chuo Kikuu cha Calgary, tumeanzisha uelewa mzuri wa nadharia wa uhamaji wa nanobubbles katika uwanja wa umeme ambao unachangia maarifa yetu ya microscopic ya utulivu wa nanobubbles.""" Maendeleo haya katika sayansi ya nanobubble yana uwezo wa kuongeza kasi ya uhamisho wa gesi na kutoa mabadiliko ya hatua katika ufanisi wa uendeshaji wa sekta kadhaa za viwanda, ikiwa ni pamoja na; kuhifadhi gesi, matibabu ya maji taka, bio-pharma, bia, kilimo na chakula. "Mwanasayansi wa UCD, Mohammad Reza Ghani, alisema: ""Njia yetu mpya ya kuzalisha nanobubbles ina matumizi mengi ya kibiashara na ina uwezo wa kuongeza uwezo wa kuhifadhi gesi moja kwa moja katika suluhisho la maji kwa miezi kadhaa." "Aidha, ina uwezo wa kuongeza kwa mara kadhaa viwango vya gesi zilizomwagika, na kusababisha uwezo mkubwa wa kusafisha maji taka na pia kuongeza uhamisho wa wingi katika athari za biochemical na biochemical zilizo na oksijeni ndogo, kama vile michakato ya uundaji katika viwanda vya chakula na bia. """ "Ameongeza, ""Kwa kushirikiana na timu ya uhamisho wa maarifa ya UCD katika NovaUCD tumeweka maombi ya hati miliki na pia tunatafuta kuuza teknolojia kupitia kampuni ya UCD." "Profesa Peter Kusalik, Mkurugenzi wa Chuo Kikuu cha Calgary, alisema: ""Kazi yetu pia inaonyesha asili ya molekuli kwa utulivu wa nano-bubbles, ambayo ingekuwa inatarajiwa kuwa imara kwa sababu ya ukubwa wao mdogo sana." "Mazazi ya tabia hii yanaweza kufuatiliwa hadi muundo wa kipekee wa molekuli za maji kwenye mpaka kati ya maji ya kioevu na gesi. """ "Ufafanuzi huo pia hueleza kwa nini Bubbles hizi ambazo hazina umeme zinaweza kuonekana zikienda wakati uwanja wa umeme unapotumiwa. Hivyo, utafiti huu unaweza kutoa ufafanuzi ulio wazi na wenye upatano kwa tatizo ambalo hapo awali lilikuwa lenye kutatanisha". "Profesa English alisema: ""Tunapenda kumshukuru kampuni ya Ireland ya Particular Sciences kwa kuwezesha vifaa vya kuenea kwa mwanga (DLS) vilivyotumiwa katika utafiti huu." Makala hiyo (ya upatikanaji wazi) ina kichwa "Massive Generation of Metastable Bulk Nanobubbles in Water by External Electric Fields". Habari zaidi: Mohammad Reza Ghaani et al. Mzunguko wa nanobubbles ya metastable katika maji na mashamba ya umeme ya nje, Maendeleo ya Sayansi (2020). "Ujumbe wa ""Science"" (Scientific Journal) wa 10 Aprili, 2009 na ""Scientific Journal"" (Scientific Journal) wa 10 Aprili, 2009 na ""Scientific Journal"" (Scientific Journal) ya 10 Aprili, 2009 na ""Scientific Journal"" (Scientific Journal) ya 10 Aprili, 2009 na ""Scientific Journal"" (Scientific Journal) ya 12 Aprili, 2009 na ""Scientific Journal"" (Scientific Journal) ya 12 Aprili, 2009."