Carbon dioxide removal

The human cardiovascular system (CVS) and respiratory system (RS) work together in order to supply oxygen (O2) and other substrates needed for metabolism and to remove carbon dioxide (CO2). Global and local control mechanisms act on the CVS in order to adjust blood flow to the different parts of the body. This, in turn, affects the RS since the amount of O2 and CO2 transported, respectively to and away from the tissues depends on the cardiac output and blood flow in both the systemic and pulmonary circuits of the CVS...

In this study a new mathematical model to quantify greenhouse gas emissions (namely, carbon dioxide and nitrous oxide) from membrane bioreactors (MBRs) is presented. The model has been adopted to predict the key processes of a pilot plant with pre-denitrification MBR scheme, filled with domestic and saline wastewater. The model was calibrated by adopting an advanced protocol based on an extensive dataset. In terms of nitrous oxide, the results show that an important role is played by the half saturation coefficients related to nitrogen removal processes and the model factors affecting the oxygen transfer rate in the aerobic and MBR tanks...

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Noninvasive ventilation is an important respiratory management technique for the treatment of mild or moderate respiratory failure in the neonatal intensive care unit. Its reasonable application can effectively avoid the use of invasive ventilation and related complications. Recent studies have found that noninvasive high-frequency oscillatory ventilation has the advantages of both nasal continuous positive airway pressure and high-frequency ventilation and can rapidly improve oxygenation, effectively remove carbon dioxide, and improve respiratory failure...

Air-starved combustion of biomass and fossil fuels releases aerosols, including airborne carbonaceous particles, causing negative climatic and health effects. Radiocarbon analysis of the elemental carbon (EC) fraction can help apportion sources of its emission, which is greatly constrained by the challenges in isolation of EC from organic compounds in atmospheric aerosols. The isolation of EC using thermo-optical analysis is however biased by the presence of interfering compounds that undergo pyrolysis during the analysis...

Large-scale biomass plantations (BPs) are a common factor in climate mitigation scenarios as they promise double benefits: extracting carbon from the atmosphere and providing a renewable energy source. However, their terrestrial carbon dioxide removal (tCDR) potentials depend on important factors such as land availability, efficiency of capturing biomass-derived carbon and the timing of operation. Land availability is restricted by the demands of future food production depending on yield increases and population growth, by requirements for nature conservation and, with respect to climate mitigation, avoiding unfavourable albedo changes...

The objective of this new paper was to evaluate the enzymatic esterification reaction conducted in supercritical or near-critical CO2, catalyzed by immobilized lipase B from Candida antarctica (CALB). The biocatalyst was prepared through the immobilization of CALB by covalent attachment using chitosan sequentially activated with Glycidol, ethylenediamine (EDA) and glutaraldehyde as support. In order to determine the best operational conditions of the esterification reaction (1: 1 (alcohol-acid); biocatalyst content, 10% (by substrate mass); 45 °C), an experimental design (2(3)) was conducted to evaluate the effects of the following parameters: alcohol to oil molar ratios, reaction time and temperature...

PURPOSE: Our previous work demonstrated that intentional peritoneal injury reduces the incidence of recurrence of a patent processus vaginalis even after removal of the suture. Therefore, the necessity of permanent suture has been brought into question because of the risk of suture granuloma formation. The purpose of this study was to evaluate the efficacy of absorbable, braided versus permanent, braided suture in a rabbit survival model of laparoscopic percutaneous ligation of the processus vaginalis with intentional peritoneal injury...

The use of tethers allows to overcome reactivity and selectivity issues often encountered with intermolecular reactions. Although tethers have been successfully applied for decades, their installation and removal usually requires additional steps. This minireview highlights the recent development of tethers that can be installed in situ on (homo)-allyl amines or alcohols for Tsuji-Trost allylation or double bond functionalization. In particular, the use of (hemi-)acetal tethers for highly regioselective and enantioselective Tsuji-Trost allylation was recently reported...

Nitrous oxide (N2O) is an important pollutant which is emitted during the biological nutrient removal (BNR) processes of wastewater treatment. Since it has a greenhouse effect which is 265 times higher than carbon dioxide, even relatively small amounts can result in a significant carbon footprint. Biological nitrogen (N) removal conventionally occurs with nitrification/denitrification, yet also through advanced processes such as nitritation/denitritation and completely autotrophic N-removal. The microbial pathways leading to the N2O emission include hydroxylamine oxidation and nitrifier denitrification, both activated by ammonia oxidizing bacteria, and heterotrophic denitrification...

The direct synthesis of carbamates from amines and carbon dioxide in the presence of Ti(OR)4 (R = nBu (1), Me (2), Et (3), nPr (4)) was investigated. Aniline was reacted with the titanium n-butoxide (1) in the presence of carbon dioxide (5 MPa) to give the corresponding n-butyl N-phenylcarbamate (BPC) in nearly quantitative yield (99%) within 20 min. Furthermore, 1 could be regenerated upon reaction with n-butanol during water removal. The recovered 1 could then be reused in a subsequent reaction.

Facile and mild ionic cross-linking and freezing/thawing technologies were applied to prepare double strengthened core-shell particles by using water-soluble chitosan (WSC), sodium alginate (SA) and poly(vinyl alcohol) (PVA) as starting materials. The aqueous solution contained WSC and PVA was dropped in ethanol to form beads. The beads were converted into WSC/PVA hydrogel particles by being subjected to three freeze/thaw cycles. Subsequently, ionic cross-linked hydrogel layer was formed around each WSC/PVA particle to generate core-shell particulates...

BACKGROUND: Critically ill patients with acute respiratory distress syndrome and acute exacerbations of chronic obstructive pulmonary disease often develop hypercapnia and require mechanical ventilation. Extracorporeal carbon dioxide removal can manage hypercarbia by removing carbon dioxide directly from the bloodstream. Respiratory hemodialysis uses traditional hemodialysis to remove CO2 from the blood, mainly as bicarbonate. In this study, Stewart's approach to acid-base chemistry was used to create a dialysate that would maintain blood pH while removing CO2 as well as determine the blood and dialysate flow rates necessary to remove clinically relevant CO2 volumes...

Negative emission technologies (NETs) target the removal of carbon dioxide (CO2) from the atmosphere, and are being actively investigated as a strategy to limit global warming to within the 1.5-2°C targets of the 2015 UN climate agreement. Enhanced silicate weathering (ESW) proposes to exploit the natural process of mineral weathering for the removal of CO2 from the atmosphere. Here, we discuss the potential of applying ESW in coastal environments as a climate change mitigation option. By deliberately introducing fast-weathering silicate minerals onto coastal sediments, alkalinity is released into the overlying waters, thus creating a coastal CO2 sink...

In patients with severe respiratory failure, either hypoxemic or hypercapnic, life support with mechanical ventilation alone can be insufficient to meet their needs, especially if one tries to avoid ventilator settings that can cause injury to the lungs. In those patients, extracorporeal membrane oxygenation (ECMO), which is also very effective in removing carbon dioxide from the blood, can provide life support, allowing the application of protective lung ventilation. In this review article, we aim to explore some of the most relevant aspects of using ECMO for respiratory support...

The goal of this article was to provide an overview of the literature available on carbon dioxide intoxication. Articles were included based on their focus on medical or physiological effects of carbon dioxide. Studies related to decompression sickness were excluded. Mechanisms of carbon dioxide poising (both as an asphyxiant and as a toxicant) were described. Our review suggested that precautions are needed when handling dry ice or while working in confined spaces. Pre-hospital responders also need to pay attention for the possible diagnosis of CO2 intoxication for their own safety...

Algae were able to grow healthy on bacteria-containing centrate wastewater in a pilot-scale bioreactor. The batch experiment indicated that the co-cultivation of algae and wastewater-borne bacteria improved the removal efficiencies of chemical oxygen demand and total phosphorus in centrate wastewater to 93.01% and 98.78%, respectively. A strain of beneficial aerobic bacteria, Acinetobacter sp., was isolated and its biochemical characteristics were explored. Synergistic cooperation was observed in the growth of algae and Acinetobacter sp...

Cyanuric acid hydrolases are of industrial importance because of their use in aquatic recreational facilities to remove cyanuric acid, a stabilizer for the chlorine. Degradation of excess cyanuric acid is necessary to maintain chlorine disinfection in the waters. Cyanuric acid hydrolase opens the cyanuric acid ring hydrolytically and subsequent decarboxylation produces carbon dioxide and biuret. In the present study, we report the X-ray structure of TrzD, a cyanuric acid hydrolase from Acidovorax citrulli. The crystal structure at 2...

The aim of this work was to study the ability of using Hydrocabonoclastic native microbial and Spongiochloris sp microalgae in airlift bioreactors couples in order to restore hydrocarbons wastewater and develop the capacity of natural systems to reduce greenhouse effect through maximal control of CO2 gas emission in atmosphere. The kinetic parameters of CO2 gas fixation level and conversion it into biological material by microalgae as the biodegradation process effect in hydrocarbon have been evaluated. The result present that maximum specific growth rate μmax of Spongiochloris sp was (0...

Bicarbonate species in the aqueous phase is the primary source for CO2 for the growth of microalgae. The potential of carbon dioxide (CO2) fixation by Chlorella pyrenoidosa in enriched bicarbonate medium was evaluated. In the present study, effects of parameters such as pH, sodium bicarbonate concentration and inoculum size were assessed for the removal of CO2 by C. pyrenoidosa under mixotrophic condition. Central composite design tool from response surface methodology was used to validate statistical methods in order to study the influence of these parameters...