Improving CO2 concentration and retention via nanobubble generation in aqueous solutions

In this study, nano bubbles (NBs) of around 100 nm size were generated by using GoodSam-NB generator (made by S company) which utilizes cavitation technique. The generated NBs were directly applied to the strawberry cultivation process to monitor the productivity of strawberry. When the aqueous nutrient solution with NBs was supplied to the strawberry culture medium, it had a slightly higher initial concentration of dissolved oxygen (DO) compared to the nutrient solution prepared with ordinary groundwater at a concentration of about 9 mg/L and did not decrease over time. In other words, NBs helped to supply DO to support the development of roots in the early stage of strawberry's growth, thereby promoting the overall growth of strawberries. After feeding the NBs nutrient solution, the nitrate concentration of the discharged solution was analyzed. The concentration of the nitrate in the effluent was reduced, hence the growth of strawberry was promoted. It can be concluded that the DO contained in aqueous nutrient solution with NBs helped the nitrate to be smoothly taken from the soil.

The environmental nanotechnology is a technical discipline which research features of natural and man-made nanomaterials, applications, techniques for their characterization, integration processes and transformation into ecosystems. Microbubbles have the capability to change the normal characteristic of water. The microbubbles (MBs) have diameter more than 100 μm, the micro-nanobubbles (MNBs) have diameter between 1 to 100 μm and the nanobubbles (NBs) have diameter less than 1 μm within the fluid field. Microbubbles (MBs) possess special properties such as the capacity for generating free. Such properties have typically attracted much attention in the fields of food science and agriculture. MNBs have now attracted attention for applications in engineering areas such as the sewage treatment of wastewater by air flotation. Keywords: environment, micronanobubbles, microbubbles, nanobubbles, treatment REFERENCES [1] J. Choung, G.H. Luttell, R.H. Yoon. 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Optimization of cavitation venturi tube design for pico and nano bubbles generation

Generation of nanobubbles by ceramic membrane filters: The dependence of bubble size and zeta potential on surface coating, pore size and injected gas pressure

Nanobubbles (NBs), with their unique physicochemical properties and promising applications, have become an important research topic. Generation of monodispersed bulk NBs with specified gas content remains a challenge. We developed a simple method for generating bulk NBs, using porous alumina films with ordered straight nano-scaled holes. Nanoparticle tracking analysis (NTA) is used to confirm NB formation. The NTA data demonstrates that NB size is distributed discretely with a uniform increment factor of √2. To explain the observed characteristic size distribution of NBs, we propose a simple model in which two NBs of the same size are assumed to preferentially coalesce.

Global atmospheric carbon dioxide concentration, presently at about 350 μl 1-1, is expected to continue to increase in the future (Lindzen, 1993) and may double by the end of the next century (Gates, 1983; Keeling et al., 1989; Houghton and Woodwell, 1989). Higher levels of carbon dioxide may increase the growth rate of trees and the productivity of forests (Teskey, 1995). At the present-day, ambient carbon dioxide concentration and under optimal conditions, the photosynthesis of plants is limited by the supply of carbon dioxide (Arp, 1991). Numerous studies have shown increased plant growth in elevated levels of carbon dioxide (Higginbotham et al., 1983, 1985; Stewart and Hoddinott, 1993; Gunderson et al., 1993), but these studies have used potted seedlings, optimum levels of resources (including water and nutrients), and short-term exposure to higher carbon dioxide concentrations. Because seedlings differ from older trees both physiologically and morphologically (Cregg et al., 1989), it is unknown how much carbon gain in trees will be affected by long-term exposures to elevated carbon dioxide levels under field conditions in which water and nutrient availability may limit growth.

In their annual indoor air quality assessment for ADNOC Schools, the Abu Dhabi Education Council has reported hazardous levels (∼3000 ppm) of carbon dioxide in fifteen classrooms. Exposure of 5,090 students attending the school for ∼eight hours (typical school day) to such high levels of carbon dioxide would induce adverse health conditions like headaches, drowsiness, and lack of concentration on the short term and serious diseases like asthma and sick building syndrome on the long term. The Health, Safety, and Environment committee of the school has identified clogged air intake vents and dirty AC filters as the main cause of the high carbon dioxide concentrations reported. The outdoor (ambient) carbon dioxide level is measured and has an eight-hour average value of 419 ppm. After cleaning thoroughly, the indoor levels of carbon dioxide, temperature, and relative humidity were monitored simultaneously in each classroom and have average values of ∼1117 ppm, ∼24°C, and ∼37%, respectively. In addition, the average indoor-to-outdoor ratio of carbon dioxide has been improved from 3000 / 419 ≈ 7.2 before cleaning the AC filters to an average ratio of ( 1,117 / 419 ≈ 2.7 ) after cleaning. Thus, ventilation rates in the classrooms monitored in this project are adequate and the corrective actions taken were effective.

Effect of electrolytes and surfactants on generation and longevity of carbon dioxide nanobubbles

Objectives The purpose of this study is to examine changes in carbon dioxide concentration and noise levels in classrooms, and to analyze the effects of these changes on elementary school students' attention and problem behaviors. Methods First, To measure the change of carbon dioxide and noise levels in classrooms, theses levels were measured in general classroom, specific subject classroom, and specific subject classroom with ventilation system operating. Second, to analyze the effect of carbon dioxide and noise levels on students’ attention and problem behavior, situations where both carbon dioxide and noise levels are low (cLnL), only carbon dioxide levels are high (cHnL), and only noise levels are high (cLnH), and both carbon dioxide and noise levels are high (cHnH). Results The carbon dioxide concentration in each classroom ranged from 400 to 1951.8 ppm, and the noise level ranged from 12.6 to 96.6 db(A). As a result of analyzing the effects of carbon dioxide and noise levels on attention and problem behavior, it was resulted that the higher the noise level, the negatively correlated with Work instruction comprehension, Selective attention, and Sustained attention. In addition, problem behaviors occurred the least (3 times) in the cLnL group and the most (31 times) in the cHnH group. Conclusions Carbon dioxide concentration and noise levels in the school exceeded the standard. The learning environment can affect not only students' attention and problem behavior, but also their health. To improve this, physical environment improvement is required.

In the red‐eared slider turtle, Trachemys scripta, sex is determined by the incubation temperature of the egg: warm temperatures produce females, cool ones produce males, and a narrow range of intermediate temperatures produce both sexes. We asked whether the influence of temperature is modified by the effects of carbon dioxide. Under one current hypothesis, sex is more closely linked to total incubation time and than to temperature. Higher levels of carbon dioxide should lengthen total incubation time and thus mimic the longer incubation times produced by low incubation temperatures. By this hypothesis longer incubation times should increase the tendency to produce males. Trachemys scripta eggs were incubated in atmospheres containing various concentrations of carbon dioxide. While total incubation times were significantly lengthened with elevated carbon dioxide (as if mimicking cool temperatures), sex ratios were altered in favor of females (as if mimicking warm temperatures). This result is compatible with a hypothesis that pH changes affect sex in turtles with TSD. Turtles incubated at elevated levels of carbon dioxide absorbed less yolk, and had more residual yolk, and were somewhat smaller than turtles incubated at lower of carbon dioxide. In some cases, clutches were heterogeneous in their responses to the various levels of carbon dioxide. © 1992 Wiley‐Liss, Inc.

Nanobubbles (NBs) are very small gas-filled cavities in solvents, and when their sizes reach diameters around 200 nm, they remain in solution for extended periods of time, featuring special chemical and physical properties. Here, we investigate the application of NBs in electrospray ionization. We show that the addition of CO2 or N2 NBs into spray solvents significantly improves signal responses of small molecules in both positive and negative modes during ESI-MS. The magnitude of the increase depends on analyte identity, solvent system, NB gas composition, and the method for preparing the NBs. When NBs are used to analyze proteins, both signal intensities and charge states increase. This is tentatively attributed to NB's increasing the total area of the hydrophobic gas-liquid interface, on which proteins can unfold, and improved transport of analytes to the droplet surface. This increase in the interface is likely also a contributing factor in the further enhancement of the rate at which reagents are converted into products when NBs are present compared to those measured from accelerated reactions from microdroplets during reactive-ESI experiments. Moreover, NBs can overcome solubility barriers when one of the reagents is gaseous and, thus, can be incorporated into an NB. This was demonstrated in the reaction between N,N-dibutyl-1,3-propane diamine and carbon dioxide, where the reaction conversion rate could be significantly improved when N2 NBs were present in solution, but even more so when the bubbles were composed of CO2.

The finding that the shells of certain algae can contain a signature of low levels of atmospheric carbon dioxide has prompted the discovery of the emergence of this signature in the fossil record. Here, experts discuss the implications of this for climate science and ocean ecology. See Letter p.558 Coccolithophores, widely distributed in the marine plankton, are unique among algae in that they use carbon for both calcification and photosynthesis. In this study Clara Bolton and Heather Stoll use a model of cellular carbon fluxes to show that when carbon dioxide concentrations are low, these organisms will allocate carbon preferentially to photosynthesis rather than to calcification, particularly in larger cells. This is reflected in a difference between the isotopic signature of small and large coccoliths that diminishes at high levels of carbon dioxide. This pattern can be seen in the fossil record; the authors identify an isotopic divergence between small and large coccoliths at around 6 million years ago, and interpret this as a threshold response of the cells' carbon acquisition to a global decrease in carbon dioxide concentrations at the time.

Carbon assimilation at low carbon dioxide levels was measured on three Oryza specics (O. sativa L. cv. Toyonishiki, O. officinalis Wall, and O. meyriana Baill.), Brassica napus L. cv. Michinokunatane and Triticum aestivum L. cv. Konosu No.25. Measurements were made at two different oxygen concentrations; 140% and 21% (atmospheric pressure). An improvement in measurement device was made for ensuring an accuracy of the meter readings. That is, a recorder with a modulator was used to enlarge the differences in the carbon dioxide concentration; two- and five-fold for carbon dioxide levels above and below carbon dioxidc compensation point (gamma), respectively. It seems that HEATH and ORCHARD (1968) and HOLMGREN and JARVIS (1967) Changed the carbon dioxide concentration at large intervals, resulting in 3 to 5 measurements below gamma. Such a few measurements would obscure the statistics of the carbon dioxide exchangc rate at low carbon dioxide levels. The changes of carbon dioxide concentration in this experiment, however, were made at intervals of about 2 or 4 ppm from 0 ppm to gamma, resulting in 7 to 14 mean values below it. As the characteristics of carbon dioxide absorption at low carbon dioxide levels, GABRIELSEN (1948) proposed the 'threshold hyPothesis' in which gamma was regarded as a threshold value below which no assimilaton occurred, while HEATH and 0RCHARD (1968) postulated the existence of a 'third process', in addition to ordinary (dark) respiration and assimilation, which could be expected to have a different balance between respiration and assimilation. They denied the adoptation of the threshold hypothesis. From the prescnt experiment in which the carbon dioxide exchange rates were traced by Changing the Carbon dioxide concentrations at very small intervals, hwever, it appeared that the rate of carbon dioxide uptake at low carbon dioxide levels and atmospheric oxygen pressure tended to decrease toward 1/2 gamma carbon dioxide level, and the carbon dioxide uptake seems to cease and only the carbon dioxide release secms to occur below it. In case of measurements at 14% oxygen concentration the situation was similar to those at 2l% oxygen concentration, but a considerable decrease of the value of gamma. Thus, the process of carbon dioxide uptake at low carbon dioxide levels seems to imply the threshold hypothesis and 1/2 gamma seems to be an approximation of the threshold value. The assimilation rate is estimated as the ratio of carbon dioxide concentration differences between ambient air and assimilation center to the sum of diffusion resistances.As an estimate of carbon dioxide levels in the assimilation center in this formula, GAASTRA (1959) proposed zero, while BIERHUIZEN and SLAYTER (1964) adopted the Practise of using gamma to estimate it. From the results mentioned above, we could propose to use 1/2 gamma as its primary approximation because the photosynthetic center would be exposed to this carbon dioxide level but not absorb it.

Graphene oxide in generation of nanobubbles using controllable microvortices of jet flows

Assessing the growth-stimulating effect of tea waste compost in urban agriculture while identifying the benefits of household waste carbon dioxide