Dioxide Water Research Articles

Flocculation of Titanium Dioxide with Functionalized Citrus Pectin

Modified polysaccharides were prepared by the reaction of citrus pectin with a cationic monomer, (1,2-epoxypropyl)triethylammonium chloride, in alkaline medium and under the action of microwave radiation in the reactor system microwave–ultrasonic–UV-induced synthesis. Organic hybrids were prepared by mixing aqueous solutions of natural polysaccharides (pectin and modified pectin with chitosan) under ambient conditions in 1 : 1 ratio. The influence of the concentration of citrus pectin, its modified samples, chitosan, and their organic hybrids on the flocculating properties was studied for a model disperse system, a suspension of titanium dioxide in water and aqueous salt solutions, under the conditions of free (unrestricted) sedimentation. The influence of the ionic strength on the conformational state of polysaccharide macromolecules and on the aggregation of titanium dioxide particles was analyzed.

Comparative environmental impact analysis of techniques for cleaning wood wine barrels

We compare four techniques that are commonly used for cleaning and disinfection of oak wine barrels with 225 l of capacity used in the red wine aging process through a life cycle analysis (LCA). The analysed techniques were pressurised water (at 90 °C) plus sulphur dioxide (SO2) wick (7.5 g per barrel), water vapour (at 105 °C) plus sulphur dioxide (SO2), ozone (O3) (4 ppm), and carbon dioxide (CO2) (50 kg/h for 180 s). The results showed that the barrel cleaning technique with the lowest impact on all water scarcity indexes and is the carbon dioxide, due mainly to low water usage. However, in the global warming category, carbon dioxide technology is the technique that has the greatest environmental impact with a value of 4.080 kg CO2 per cleaned barrel, due mainly to CO2 and air consumption.

Effect of molecular structure on excess molar enthalpy of amine-based carbon dioxide absorbent and water

Amine-based carbon dioxide absorbent has the characteristics of high selective absorption rate and strong absorption capacity and occupies the leading position in the carbon dioxide absorption process. The absorption performance of amine carbon dioxide absorbents is directly related to their thermodynamic properties. Accordingly, for the selection of new absorbents, the important thermodynamic properties such as the excess molar enthalpy of the system must be determined first. In this paper, the excess molar enthalpies for amine-based carbon dioxide absorbents in water were measured with C-80 calorimeter at atmospheric pressure. With the experimental data in this work and the literature data, the relationship between the molecular structure and excess molar enthalpy of amine-based carbon dioxide absorbent was studied.

Palaeophysiology of pH regulation in tetrapods.

The involvement of mineralized tissues in acid-base homeostasis was likely important in the evolution of terrestrial vertebrates. Extant reptiles encounter hypercapnia when submerged in water, but early tetrapods may have experienced hypercapnia on land due to their inefficient mode of lung ventilation (likely buccal pumping, as in extant amphibians). Extant amphibians rely on cutaneous carbon dioxide elimination on land, but early tetrapods were considerably larger forms, with an unfavourable surface area to volume ratio for such activity, and evidence of a thick integument. Consequently, they would have been at risk of acidosis on land, while many of them retained internal gills and would not have had a problem eliminating carbon dioxide in water. In extant tetrapods, dermal bone can function to buffer the blood during acidosis by releasing calcium and magnesium carbonates. This review explores the possible mechanisms of acid-base regulation in tetrapod evolution, focusing on heavily armoured, basal tetrapods of the Permo-Carboniferous, especially the physiological challenges associated with the transition to air-breathing, body size and the adoption of active lifestyles. We also consider the possible functions of dermal armour in later tetrapods, such as Triassic archosaurs, inferring palaeophysiology from both fossil record evidence and phylogenetic patterns, and propose a new hypothesis relating the archosaurian origins of the four-chambered heart and high systemic blood pressures to the perfusion of the osteoderms. This article is part of the theme issue 'Vertebrate palaeophysiology'.

Features of Measuring the Electrical Conductivity of Distilled Water in Contact with Air

The paper describes the results of experiments on measuring the electrical conductivity (specific conductance) of distilled water during prolonged contact with air. To carry out the experiments, a hardware-software complex was developed and manufactured that made it possible to measure the electrical conductivity of water with a relative error of the order of ±0.1% with a change in its temperature within 2–50°C, and a temperature error of ±0.06°C. It is shown that the time of diffusion and dissolution of carbon dioxide in water significantly affects the time dependence of the specific conductance of water when its temperature changes. The peculiarity of measuring the electrical conductivity of distilled water for open and closed systems is shown in the results of experiments with partially and completely filled conductometric cells. Thus, in a filled cell in the absence of gas exchange between water and air, the temperature coefficient of electrical conductivity of water is close to the known table value. In this case, in an empty cell, the gas exchange process significantly reduces the value of this coefficient, and the degree of decrease is proportional to the exposure time between the temperature setting and the moment of conductivity measurement. The experimental results are supplemented by theoretical dependences of the specific conductance of water on temperature for various gas exchange conditions between water and air. It is also shown that when measuring the temperature coefficient of electrical conductivity of distilled water in contact with air, it is necessary to take into account not only the time of dissolution of carbon dioxide in it, but also the design features of the electrolytic cell.

Blood as fuel: the metabolic cost of pedestrian locomotion in Rhodnius prolixus.

Active searching for vertebrate blood is a necessary activity for haematophagous insects, and it can be assumed that this search should also be costly in terms of energetic expenditure. Whether by swimming, walking, running or flying, active movement requires energy, increasing metabolic rate relative to resting situations. We analysed the respiratory pattern and energetic cost of pedestrian locomotion in the blood-sucking bug Rhodnius prolixus using flow-through respirometry, by measuring carbon dioxide emission and water loss before, during and after walking. We observed an increase in the metabolic rate during walking as compared with resting of up to 1.7-fold in male R. prolixus and 1.5-fold in females, as well as a change in their respiratory pattern, which switched from cyclic during rest to continuous when the insects started to walk, remaining in this condition during locomotion and for several minutes after stopping. Walking induced a significant loss of mass in both males and females. This can be explained by an increase in both metabolic rate and water loss during walking. These data constitute the first metabolic measures of active haematophagous insects and provide the first insights into the energetic expenditure associated with the active search for blood in this group.

GREENHOUSE GASES DISPOSAL IN GEOLOGICAL TRAPS FOR OIL AND GAS STIMULATION

Background The emission of technogenic greenhouse gases is closely related to the negative climate change on Earth. In this regard, the international community has recognized the need for coordinated measures to reduce emissions of all greenhouse gases, including CO2, into the atmosphere, establishing laws at the state level to protect the environment. Only significant changes in traditional power engineering, the transition to regenerative energy sources, and sequestration of technogenic CO2 will slow down growth and then completely reduce greenhouse gas emissions. One of the promising areas for Russia is the disposal of oil reservoirs and hydrate formations in greenhouse gas. There are no reserves of natural carbon dioxide in Russia, however, the reserves of greenhouse gases (flue gases and CO2) have unlimited resources and can be used for the extraction of hydrocarbons. CO2 sequestration for the production of hard-to-recover reserves (TRIZ) of oil can be more effective than traditional waterflooding due to increased oil recovery of depleted fields of low and medium viscosity oil. The main disadvantage of sequestration is the high investment cost. It is almost impossible to start a sequestration project without creating a plant for capturing, concentrating and dehydrating CO2, transport infrastructure and a fully equipped trap. There are also problems of increasing the capacity of water layers and increasing the safety of storing greenhouse gases in them. Thus, solving the problems of technological improvement and reducing the cost of greenhouse gas disposal is an urgent task. Aims and Objectives Development of scientific foundations of the process of greenhouse gases sequestration in geological traps for oil and gas stimulation, as well as increasing the capacity of geological traps and the reliability of the sequestrate storage. Results The processes of CO2 sequestration in a deep-lying aquifer, the influence of the injection of carbon dioxide water and the direction of the displacement front on the change in the volume of the geological trap are considered. Research on sequestration of greenhouse gases in Devonian reservoirs using flue gas and technogenic CO2 for oil production has been carried out. The oil-displacing and filtration characteristics of water-gas mixtures (WGM) containing greenhouse gases have been investigated. The dynamics of filtration when displacing the residual oil of the WGM from the enriched flue gas is indicated, and the optimal content of CO2 in the WGM for injection into injection wells with reduced injectivity is revealed.

Resilience of Oxygen Consumption Rates in the Juvenile Blue Crab Callinectes sapidus to Future Predicted Increases in Environmental Temperature and pCo2 in the Mesohaline Chesapeake Bay

Quantifying the physiological impact of environmental stressors on living organisms is critical to predicting the response of any given species to future climate scenarios. Oxygen consumption rates (μmol/g/min) were measured to examine the physiological response of the juvenile blue crab Callinectes sapidus from the Chesapeake Bay (Patuxent River, Maryland) to elevated temperature and dissolved carbon dioxide in water (pCO2) reflective of projected future climate scenarios. Treatment levels were selected to represent current conditions in the Chesapeake Bay (26°C and 800 μatm) and conditions predicted to occur by the year 2100 (31°C and 8,000 μatm). Crabs were exposed in a factorial design to these conditions throughout two successive molts (approximately 30 days). At the end of the exposure, the oxygen consumption rates of individual crabs were determined over at least a 10-h period using a flow-through respiration chamber equipped with optical oxygen electrodes. No significant effect of temperature or pCO2 on oxygen consumption was observed, suggesting the absence of a respiratory impact of these two climate stressors on juvenile blue crabs. Oxygen consumption rates were also determined for crabs that experienced a rapid increase in temperature without prior acclimation. The oxygen consumption rate of crabs may have acclimated to increased temperature during the 30-day exposure period before respiratory measurement. This potential acclimation, combined with high individual variability, and a relatively small difference in temperature treatments are likely the cause for the lack of a statistically significant difference in mean oxygen consumption rates by temperature in the core experiment. The results of this study suggest that the blue crab may be quite resilient to future climate stressors and underscore the need for species-specific studies to quantify the effects of climate change on estuarine crustaceans.

Influence of physical and chemical barrel sanitization treatments on the volatile composition of toasted oak wood

Various chemical and physical barrel sanitization methods were evaluated in terms of their effect on oak volatiles in situ. A gas chromatography–mass spectrometry (GC–MS) method using a programmable temperature vaporizing (PTV) injector in solvent-split mode was developed and validated for the analysis of oak volatiles extracted in aqueous acetone. Results revealed that barrel sanitization methods affected oak volatile compounds and that the degree of modification depended on the type of sanitization method and the duration or concentration of the applied treatment. Sanitization predominantly lowered concentrations of oak volatiles when hot water treatment at 80 °C, steam, ethanol treatment, and a 200 ppm peracetic acid treatment were applied. Gaseous sulphur dioxide, aqueous ozone, and hot water treatment at 60 °C, however, had no significant effect. This work provides the first direct comparison of an array of barrel sanitization methods in relation to their impact on desirable oak volatile compounds.

Effect of nutrient alteration on pCO2(water) and chlorophyll-a dynamics in a tropical aquaculture pond situated within a Ramsar site: a microcosm approach.

Tropical sewage-fed aquaculture ponds of East Kolkata Wetlands (EKW), a Ramsar site, act as deposition center of organic matter and nutrient-rich sewage from the Kolkata metropolis, which in turn is utilized as fish feed in aquaculture ponds. Increasing nutrient load due to multifarious anthropogenic activities usually alters the chlorophyll-a (chl-a) and the partial pressure of carbon dioxide in water [pCO2(water)] dynamics in such aquatic systems. In this regard, the effect of nutrient level alteration [8 times and 24 times, dissolved inorganic nitrogen (DIN) and dissolved inorganic phosphorus (DIP) in addition, respectively] on chl-a and pCO2(water) was tested upon waters of EKW aquaculture ponds in three different seasons by means of microcosm for 8 consecutive days. In both DIN 8× and DIP 8× treatments, an overall increase in chl-a concentrations was observed by the end of experiment; however, in DIN 24× and DIP 24× treatments, chl-a in most of the seasons was found to diminish after a steep rise in its concentration during 4th or 5th day. In all the seasons, the surface waters were supersaturated with CO2 under in situ conditions. The extent of supersaturation enhanced with nutrient addition during monsoon; however, in post-monsoon and pre-monsoon, nutrient addition led to undersaturation of CO2. Though chl-a concentration exhibited substantial variability during the microcosm experiments, the variation in trophic state index was not that much remarkable. In DIN-treated microcosms, uptake rate of DIP was significantly high compared to the reverse scenario, which implied that DIP has a more limiting character than DIN. In P-enriched treatments, the lack of N supplies probably limit production of autotrophic biomass. Thus it can be concluded that the nature of sewage and its DIN/DIP content can significantly alter the primary productivity the CO2 dynamics of such aquaculture ponds in future.

A review of the current environmental challenges of the steel industry and its value chain

The steel industry is the largest consumer of energy in the world among industrial sectors. It is generally acknowledged that energy and environment are intimately related. Steel production is an energy intensive process that has a significant environmental impact. This paper reviews the progress made on energy consumption, carbon dioxide emissions and water consumption in the steel industry worldwide. The reduction in the availability of fresh water resources combined with the effects of global warming and climate change have increased pressure on industries, especially steel, to reduce its overall pollution, and specifically its water and carbon footprint. The implications of these effects on the value chain is discussed in this review. The contribution of new emerging technologies of iron and steelmaking is also reviewed. Finally, the important issues that contribute to define a sustainable industrial activity such as the recycling of steel and of by-products of steel production are studied. The history of steel industry is full of lessons, one of which is the need to keep the dreams alive. There are indeed expectations to solve problems created by technical progress.

Effects of Sequence Preparation of Titanium Dioxide–Water Nanofluid using Cetyltrimethylammonium Bromide Surfactant and Tio2 Nanoparticles for Enhancement of Thermal Conductivity

Effects of Sequence Preparation of Titanium Dioxide–Water Nanofluid using Cetyltrimethylammonium Bromide Surfactant and Tio2 Nanoparticles for Enhancement of Thermal Conductivity

Factorial design fingerprint discrimination of Coffea arabica beans under elevated carbon dioxide and limited water conditions

Coffee is one of the most important commodities, showing sensitivity to environmental variations. The main effects and their interaction for two levels of atmospheric CO2 concentrations and two water regimes of a factorial design were investigated for the metabolic profiles of Coffea arabica raw beans using UV fingerprint analysis from a mixture design. UV fingerprint results obtained from pure ethanol and binary ethanol-dichloromethane mixtures showed the largest metabolic discriminations between CO2 levels and their extracts were investigated in detail. The biosynthesis of major metabolites, chlorogenic acids, cafestol, kahweol and caffeine were altered owing to environmental conditions. Higher amounts of chlorogenic acids and kahweol were observed in beans from unirrigated plants grown with enriched CO2 and irrigated ones at the current CO2 level. Water availability and CO2 concentration interaction affects the metabolite amounts. Besides a significant CO2 atmospheric effect water availability was a limiting factor for metabolite content only at current CO2 level, suggesting the successful metabolic coping of CO2 enriched Arabic coffee beans suffering future droughts.

Entropy optimization analysis in MHD nanomaterials (TiO2-GO) flow with homogeneous and heterogeneous reactions

BackgroundNanomaterials have higher inspiration in the growth of pioneering heat transportation fluids and good efforts were made in this field during the recent year. Nowadays numerous scientists and researchers have focused their struggle on nanomaterials study. Nanoliquids have advanced properties which make them efficient in various applications including engine cooling, hybrid-power engine, pharmaceutical processes, refrigerator and vehicle thermal management etc. Therefore such implication in mind the entropy optimization in magnetohydrodynamic nanomaterials (TiO2 − GO) flow between two stretchable rotating disks is discussed here. Energy expression subject to Joule heating, thermal radiation and viscous dissipation is modeled. Entropy optimization rate is based upon thermodynamic second law. Here titanium dioxide (TiO2) and graphene oxide (GO) and water (H2O) are used as nanoliquids. Homogeneous and heterogeneous reactions have been accounted. MethodsTransformation process reduced nonlinear PDE's to ordinary differential systems. Formulated systems are solved due to implementation of Newton built in shooting method. ResultsSalient behavior of influential variables on velocity, entropy optimization, temperature, Bejan number and concentration graphically illustrated for (TiO2 and GO). Surface drag force and gradient of temperature ((Cf1, Cf2) and (Nux1, Nux2)) are numerically computed for various interesting parameters at lower and upper disks respectively. Axial and radial velocities components boost up for larger (Re) but opposite is hold for tangential velocity. Entropy optimization and temperature are increased for higher Brinkman number (Br). ConclusionsA significant augmentation occurs in radial and axial velocities (f′(ξ) and f(ξ)) versus stretching parameter, while opposite is hold for tangential velocity (g(ξ)). For larger values of Reynold and Brinkman numbers the temperature increases. Temperature and entropy optimization have opposite effect for radiation parameter. Concentration has similar results for Reynold and Schmidt numbers. Entropy optimization and Bejan number for radiation parameter have similar outcome. Bejan number decays for Brinkman number.

New sensor measures biological activity in soil at field scale in real time

New sensor measures biological activity in soil at field scale in real time

Sustainability assessment of continuous-flow hydrothermal synthesis of nanomaterials in the context of other production technologies

Abstract In this paper, we provide a comprehensive techno-economic and life cycle environmental evaluation of the continuous-flow hydrothermal synthesis (CFHS) of nanoparticles in the context of current production technologies. This method is compared with a set of competitor technologies: Plasma syntheses; Flame pyrolysis; Sol-gel synthesis; Batch Solvo/Hydrothermal syntheses; and Altair hydrochloride process. Technical criteria such as scale and variability of production and material properties are accounted for in the environmental and economic analyses. Case study nanomaterials are investigated with a range of potential applications: titanium dioxide (smart coatings, electronics, and water purification); zinc oxide (smart coatings, cosmetics); zirconium dioxide (nanocomposites, electronics); and lithium phosphate (lithium ion battery cathode material). Results show that CFHS can be ranked among the most productive methods capable of producing up to 100–250 kg/h of different types of high quality NPs dispersed in water. In terms of the environmental impacts, this newly developed technology does not use any toxic solvents, there are no emissions into the environment and the risk of leakage of NPs into environment is negligible. Comparison of values of selected environmental impact categories Cumulative Energy Demand (CED) and Global Warming Potential (GWP) shows that CFHS can compete with industrial technologies with low production variability and limited product quality (e.g. sulfate and chloride processes) and achieves much better results in comparison with technologies with similar variability (e.g. HT plasma or sol-gel) and product quality (sol gel). The same conclusion can be made in the case of an economic assessment. The combination of large scale and variability of production and quality of produced NPs can be considered as the major source of competitive potential of CFHS.

(Invited) Excited State Processes in Semiconductor Nanocrystals and Their Relationships with Light-Driven Multi-Electron Catalysis

This presentation will focus on the excited state behavior of semiconductor nanocrystals as light absorbers that, coupled with redox catalysts, drive light-driven multi-electron transfer reactions. Reactions of interest include hydrogen generation, carbon dioxide reduction, nitrogen fixation, and water oxidation. We have demonstrated that nanocrystal excited state behavior, charge transfer dynamics, and surface chemistry play a governing role in the overall photochemistry of nanocrystal-catalyst complexes. This presentation will describe our most recent findings about how the reactions of interest can be driven and controlled through manipulation of nanocrystal excited state dynamics. In particular, the presentation will focus on: (i) measurement (by transient absorption spectroscopy), kinetic modeling, and control of electron transfer kinetics for injection of photoexcited electrons into redox enzymes; and (ii) elucidation of the motion of photoexcited holes on nanocrystal surfaces, using a combination of transient absorption measurements, modeling, and theory, and the implications of this motion on oxidation photochemistry.

Characteristics of Carbon Dioxide and Product Water Exhausts in a Direct Methanol Fuel Cell with Serpentine Channels

Abstract This study utilized a transparent direct methanol fuel cell, with serpentine channels with a width of 2 mm and an initial depth of 2 mm, and investigated the relationship between the behaviours of carbon dioxide (CO2) slugs, product water accumulations, and voltage fluctuation. It examined the exhaust volumes of CO2 slugs and product water accumulations from the channels over time, comparing an anode channel with a depth of 1.2 mm to one with a depth of 2 mm (without changing the cathode depth of 2 mm, nor the width of 2 mm in both the anode and the cathode). Results indicated that cell voltage fluctuated, rising while CO2 slugs were ejected, and falling between ejections. In the case of an anode channel depth of 2 mm and a lower methanol-water solution flow rate, CO2 slugs were ejected less frequently, so cell voltage fluctuated widely. (Product water accumulations in the cathode had a minimum effect on this cell voltage fluctuation.) In the case of a higher methanol-water solution flow rate, CO2 slugs were ejected more frequently, with less exhaust volume per CO2 slug, reducing the fluctuation in cell voltage. Finally, with an anode channel depth of 1.2 mm, the exhaust volume per CO2 slug became even smaller, and these small CO2 slugs were rapidly ejected. With this shallow depth, the cell voltage increased with a lower methanol-water solution flow rate, but decreased with a higher methanol-water solution flow rate by crossover.

(Invited) Accelerated Discovery for Solar Fuels

Efficient and selective synthesis of chemical fuels from sunlight, water, and carbon dioxide is a grand challenge for 21st century energy technology. Achieving rapid progress in this area requires accelerated discovery of mechanisms, materials, integration strategies, and device architectures designed for selective catalysis, light capture and conversion, charge transport, and product separation. The current mission of the Joint Center for Artificial Photosynthesis (JCAP) is to accelerate progress in mechanisms, materials, and integrated prototype designs for selective and efficient conversion of carbon dioxide to chemical fuels. In this talk, recent progress accomplished by JCAP will be discussed including discoveries that build upon our previous experience with hydrogen generation via photoelectrochemical water splitting. JCAP's experience with both carbon dioxide reduction and water splitting form a testbed for accelerated discovery, beginning with at the science frontier and culminating in team-oriented development of testbed prototype devices. The structure and achievements of JCAP and related Hub-level research from a materials perspective will be introduced.

Investigation of the Kinetics of Rechargeable Aqueous Zinc Ion Batteries

Rechargeable aqueous zinc ion batteries are currently receiving much attention as large-scale energy storage systems due to their inherent safety, fast ion kinetics, low cost materials and environmental friendliness. Considering the recent literature, the state-of-the-art zinc ion battery combines a manganese oxide cathode, a planar zinc foil anode and an aqueous, mildly acidic electrolyte [1]. Even though the corresponding electrochemical models are subject to recent discussions [2] it is possible to derive basic kinetic parameters allowing a further development of the cell design and electrode composition. For this purpose in this study, zinc foil is used as the anode, a slightly acidic zinc sulphate solution as electrolyte and a stainless steel foil coated with manganese dioxide as the cathode. The coating process of the cathode may greatly influence the kinetics of the battery due to the fact that the cathode thickness, the porosity and the particle size are decisive for the overall performance of the battery. The cathode slurry is a mixture of manganese dioxide, carbon black, binder and distilled water. Previous studies showed that particularly the particle size of the manganese oxide in the cathode has great influence on the capacity of the battery [3]. In order to understand the kinetics of the coated cathode it was investigated if the electrochemical process is mass or charge transfer controlled and corresponding parameters of the Butler-Volmer equation are determined by electrochemical characterization of the samples. These kinetic parameters are identified in order to implement a simulation model allowing a further optimization of the battery cell architecture and the required electrode properties. References Liu, J.; Xu, C.; Chen, Z.; Ni, S.; Shen, Z.X. Progress in aqueous rechargeable batteries. Green Energy & Environment 2018, 3, 20–41, doi:10.1016/j.gee.2017.10.001.Song, M.; Tan, H.; Chao, D.; Fan, H.J. Recent Advances in Zn-Ion Batteries. Adv. Funct. Mater. 2018, 28, 1802564, doi:10.1002/adfm.201802564.Bischoff, C.; Fitz, O.; Schiller, C.; Gentischer, H.; Biro, D.; Henning, H.-M. Investigating the Impact of Particle Size on the Performance and Internal Resistance of Aqueous Zinc Ion Batteries with a Manganese Sesquioxide Cathode. Batteries 2018, 4, 44, doi:10.3390/batteries4030044.