Biological treatment characteristics of benzene and toluene in a biofilter packed with cylindrical activated carbon

2002 ◽  
Vol 46 (11-12) ◽  
pp. 51-56 ◽  
Author(s):  
G.-W. Li ◽  
H.-Y. Hu ◽  
J.-M. Hao ◽  
H.-Q. Zhang
Keyword(s):  
Carbon Dioxide ◽  
Activated Carbon ◽  
Gas Flow ◽  
Removal Rate ◽  
Carbon Dioxide Concentration ◽  
Organic Load ◽  
Filler Materials ◽  
Removal Capacity ◽  
Bacillus Spore ◽  
Maximum Removal

The biodegradation of toluene and benzene in a biofilter using cylindrical activated carbon as the filler materials was studied. Three gas flow rates, i.e. 0.25, 0.50 and 0.75 m3/h, corresponding to empty bed gas residence of 75, 37.5 and 25 s, respectively, and total organic load lower than 400 g/m3.h were tested. The biofilter proved to be highly efficient in biodegradation of toluene and benzene, and toluene was more easily degraded than benzene. When each inlet load was lower than 150 g/m3.h, removal rate increased with inlet load and reached a maximum, which was 150 and 120 g/m−3.h for toluene and benzene, respectively. For inlet load higher than the maximum removal capacity conditions, the removal rate decreased with inlet load. Carbon dioxide concentration profile through the biofilter revealed that the mass ratios of carbon dioxide produced to the toluene and benzene removed were 2.15 g(CO2)/g(toluene) and 1.67 g(CO2)/g(benzene), which furthermore, confirmed the biodegradation performance in biofilter. The observation of biotic community demonstrated that the microbes consisted of bacillus, spore bacillus and fungi, of which the spore bacillus was dominant.

scholarly journals Comparison of Circular and Parallel-Plated Membrane Lungs for Extracorporeal Carbon Dioxide Elimination

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 398
Author(s):  
Leonie S. Schwärzel ◽  
Anna M. Jungmann ◽  
Nicole Schmoll ◽  
Stefan Caspari ◽  
Frederik Seiler ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Gas Flow ◽  
Removal Rate ◽  
Low Flow ◽  
Chronic Obstructive ◽  
Co2 Removal ◽  
Circular Membrane ◽  
Flow Rates ◽  
Polypropylene Membrane ◽  
Removal Capacity

Extracorporeal carbon dioxide removal (ECCO2R) is an important technique to treat critical lung diseases such as exacerbated chronic obstructive pulmonary disease (COPD) and mild or moderate acute respiratory distress syndrome (ARDS). This study applies our previously presented ECCO2R mock circuit to compare the CO2 removal capacity of circular versus parallel-plated membrane lungs at different sweep gas flow rates (0.5, 2, 4, 6 L/min) and blood flow rates (0.3 L/min, 0.9 L/min). For both designs, two low-flow polypropylene membrane lungs (Medos Hilte 1000, Quadrox-i Neonatal) and two mid-flow polymethylpentene membrane lungs (Novalung Minilung, Quadrox-iD Pediatric) were compared. While the parallel-plated Quadrox-iD Pediatric achieved the overall highest CO2 removal rates under medium and high sweep gas flow rates, the two circular membrane lungs performed relatively better at the lowest gas flow rate of 0.5 L/min. The low-flow Hilite 1000, although overall better than the Quadrox i-Neonatal, had the most significant advantage at a gas flow of 0.5 L/min. Moreover, the circular Minilung, despite being significantly less efficient than the Quadrox-iD Pediatric at medium and high sweep gas flow rates, did not show a significantly worse CO2 removal rate at a gas flow of 0.5 L/min but rather a slight advantage. We suggest that circular membrane lungs have an advantage at low sweep gas flow rates due to reduced shunting as a result of their fiber orientation. Efficiency for such low gas flow scenarios might be relevant for possible future portable ECCO2R devices.

A new real-time and precision capnography for human respiration carbon dioxide concentration

Perfusion ◽  
2010 ◽  
Vol 25 (6) ◽  
pp. 399-408 ◽  
Author(s):  
Jiachen Yang ◽  
Bin Wang ◽  
Ran Xu ◽  
Lei Wang
Keyword(s):  
Carbon Dioxide ◽  
Real Time ◽  
Gas Flow ◽  
Measurement Accuracy ◽  
Carbon Dioxide Concentration ◽  
Main Stream ◽  
Temperature Drift ◽  
New Device ◽  
Human Respiration ◽  
Gas Measurement

This paper is a description of the designing of a new mainstream device to measure human respiration carbon dioxide concentration, based on non-dispersive infrared (NDIR) absorption technology. The device can be used to accurately monitor the cardiopulmonary status during anaesthesia and mechanical ventilation in real time. This new device can not only make up the error of real-time gas measurement of the side-stream device, but also make up the accuracy of the main-stream device. In the paper, four issues which can affect the measurement accuracy were considered: respiration gas flow, turbulence of the light source with all ranges of wavelength, temperature drift and signal noise. The experimental results showed that the device could produce a stable output signal and deviation of measurement accuracy could be achieved to within 4%.

Pharmaceutical removal by the activated carbon process

2013 ◽  
Vol 48 (2) ◽  
pp. 121-132 ◽  
Author(s):  
S. Piel ◽  
S. Blondeau ◽  
J. Pérot ◽  
E. Baurès ◽  
O. Thomas
Keyword(s):  
Activated Carbon ◽  
Removal Efficiency ◽  
Surface Waters ◽  
Activated Carbons ◽  
Removal Rate ◽  
Pharmaceutical Products ◽  
Jar Test ◽  
Pharmaceutical Removal ◽  
Target Molecules ◽  
Maximum Removal

The adsorption of some major pharmaceutical products (sulfamethoxazole, caffeine, iopromide and carbamazepine) in water was evaluated using four types of activated carbon, three powdered activated carbon (PAC) and one fluidized, coagulated and flocculated activated carbon (FAC) extracted from a Carboplus®P pilot. These substances were the most frequently quantified (in 50% of samples at least) in surface waters of the Vilaine's basin (Brittany, France) during three sampling campaigns. Jar test experiments were carried out in order to assess the removal efficiency of the four activated carbons. Carbamazepine and caffeine were well removed with PAC with a maximum removal rate of 80% whereas it was more difficult for sulfamethoxazole and iopromide with a maximum of 39%. For each molecule, removal rates are clearly dependent on PAC nature. The overall results with FAC are clearly distinguishable from PAC tests with gains of performance on all target molecules (from 80 to >95%).

Kinetics and equilibrium adsorption study of p-nitrophenol onto activated carbon derived from walnut peel

2015 ◽  
Vol 72 (12) ◽  
pp. 2229-2235 ◽  
Author(s):  
Xiaohong Liu ◽  
Fang Wang ◽  
Song Bai
Keyword(s):  
Activated Carbon ◽  
Sodium Hydroxide ◽  
Zinc Chloride ◽  
Activated Carbons ◽  
Removal Rate ◽  
Ammonium Hydroxide ◽  
First Order ◽  
Pseudo Second Order ◽  
Pseudo First Order ◽  
Maximum Removal

An original activated carbon prepared from walnut peel, which was activated by zinc chloride, was modified with ammonium hydroxide or sodium hydroxide in order to contrast the adsorption property of the three different activated carbons. The experiment used a static adsorption test for p-nitrophenol. The effects of parameters such as initial concentration, contact time and pH value on amount adsorbed and removal are discussed in depth. The thermodynamic data of adsorption were analyzed by Freundlich and Langmuir models. The kinetic data of adsorption were measured by the pseudo-first-order kinetics and the pseudo-second-order kinetics models. The results indicated that the alkalized carbon samples derived from walnut peel had a better performance than the original activated carbon treated with zinc chloride. It was found that adsorption equilibrium time was 6 h. The maximum removal rate of activated carbon treated with zinc chloride for p-nitrophenol was 87.3% at pH 3,whereas the maximum removal rate of the two modified activated carbon materials was found to be 90.8% (alkalized with ammonium hydroxide) and 92.0% (alkalized with sodium hydroxide) at the same pH. The adsorption data of the zinc chloride activated carbon were fitted to the Langmuir isotherm model. The two alkalized activated carbon samples were fitted well to the Freundlich model. The pseudo-second-order dynamics equation provided better explanation of the adsorption dynamics data of the three activated carbons than the pseudo-first-order dynamics equation.

Application of Biomass Burning Stove in the Greenhouse Environment

2014 ◽  
Vol 986-987 ◽  
pp. 990-993
Author(s):  
Shuang Cui ◽  
Zhi Ping Xue ◽  
Qing Yu Liu ◽  
Ying Yu Zhu ◽  
Bao Quan Zhao
Keyword(s):  
Carbon Dioxide ◽  
Growth And Development ◽  
Gas Flow ◽  
Carbon Dioxide Concentration ◽  
Fuel Utilization ◽  
Special Design ◽  
Fuel Burning ◽  
Sulfur Dioxide Concentration ◽  
Secondary Air ◽  
Pollution Emissions

According to the demands of greenhouse environmental conditions, this paper examines a solid fuel burning stove applied to compression molding of biomass in order to solve the issues which temperature is too low in greenhouses in winter north of China and carbon dioxide concentration is too low caused by insufficient ventilation number. The burning stove designed with big furnace, no grate and recalculated secondary air. Fuel utilization was improved in the largest degree in this design. Feed amount, feed rate and time are controlled by the PLC system which is adopted to make fuel fully burning, low pollution emissions and more automation. The temperature field and gas flow field changes is simulated by the FLUENT. The temperature of various sections and the formation of nitrogen oxides is reduced by the special design when burning. Experiment shows that sulfur dioxide concentration is about 0.41mg/m3, nitrogen dioxide is about 0.498mg/m3 which have no effect in growth and development of crops. This paper provides theoretic guidance for improving greenhouse conditions.

scholarly journals Preparation of Activated Carbon Supported Bead String Structure Nano Zero Valent Iron in a Polyethylene Glycol-Aqueous Solution and Its Efficient Treatment of Cr(VI) Wastewater

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 47 ◽  
Author(s):  
Chunlei Jiao ◽  
Xiao Tan ◽  
Aijun Lin ◽  
Wenjie Yang
Keyword(s):  
Activated Carbon ◽  
Polyethylene Glycol ◽  
Removal Rate ◽  
Zero Valent Iron ◽  
Efficient Treatment ◽  
Removal Capacity ◽  
Oxidation Reduction ◽  
String Structure ◽  
Nano Zero Valent Iron ◽  
Reduction Effect

Nanometer zero-valent iron (nZVI) has been widely used in the treatment of heavy metals such as hexavalent chromium (Cr(VI)). A novel composite of bead string-structured nZVI on modified activated carbon (nZVI–MAC) is prepared here, using polyethylene glycol as the stable dispersant rather than traditional ethanol during the loading process. The microstructure characterization shows that nZVI particles are loaded on MAC with a bead string structure in large quantity and stably due to the addition of hydroxyl functional groups on the surface by polyethylene glycol. Experiments on the treatment of Cr(VI) in wastewater show that the reaction process requires only 20 min to achieve equilibrium. The removal rate of Cr(VI) with a low concentration (80–100 mg/L) is over 99% and the maximum saturation removal capacity is up to 66 mg/g. The system converts Cr(VI) to trivalent chromium (Cr(III)) through an oxidation-reduction effect and forms an insoluble material with iron ions by coprecipitation, which is then adsorbed on the surface of the nZVI–MAC. The process conforms to the quasi-second order adsorption kinetics equation (mainly chemical adsorption process).

Optimization of Immobilized Microorganisms Technology to Cr (VI) in Wastewater

2015 ◽  
Vol 1092-1093 ◽  
pp. 886-891
Author(s):  
Yan Xu ◽  
Xiao Ming Chen ◽  
Chao Wang ◽  
Chen Ruan ◽  
Xiao Ling Liu ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Activated Carbon ◽  
High Efficiency ◽  
Removal Rate ◽  
Low Cost ◽  
Nutrient Source ◽  
Removal Capacity ◽  
Significant Difference ◽  
Immobilized Microorganisms ◽  
Immobilized Microorganism

In order to establish a low cost and high efficiency immobilized microorganism system to treat Cr (VI) wastewater, the effects to removal capacity to Cr (VI) of microbe strain, additives and medium were investigated. These strains were immobilized with SA (sodium alginate) by immobilized microorganism technology combined with three additives CNTs (carbon nanotubes), activated carbon, straw and nutrient source, respectively. The results showed that three kinds of additives could improve the removal effect to Cr (VI), and the removal rate up to 30% when Cr (VI) concentration was 10mg/L. There was not a significant difference among these additives. The solution contains 40% medium could significantly improve the removal capacity to Cr (VI). The removal rate could reach more than 98% when Cr (VI) concentrations were 10mg/L-20mg/L. Therefore, efficient strains, additives and medium could improve the removal capacity to Cr (VI) of immobilized microorganism technology. It can be widely used in chromium contaminated wastewater.

scholarly journals Evaluation of a scavenging system for use with inhalation anaesthesia techniques in rats

1980 ◽  
Vol 14 (3) ◽  
pp. 207-211 ◽  
Author(s):  
J. B. Glen ◽  
G. S. Cliff ◽  
A. Jamieson
Keyword(s):  
Carbon Dioxide ◽  
Gas Flow ◽  
Carbon Dioxide Concentration ◽  
Breathing Zone ◽  
Inhalation Anaesthesia ◽  
Arterial Carbon Dioxide ◽  
Vapour Concentration

A minimum fresh gas flow of 1 litre per minute per mask and an inspired concentration of 2-3% halothane was required to induce anaesthesia in rats in 1-2 min. Anaesthesia was maintained with an inspired concentration of 1·5-2% halothane. Arterial carbon dioxide concentration increased during anaesthesia and was not reduced by increasing the flow of fresh gas. Using the apparatus described here, halothane vapour concentration in the operator's breathing zone was 5 ppm. Prior to its introduction, levels of 250 ppm had been recorded in a poorly-ventilated animal room.

scholarly journals Development of a CO2 Sensor for Extracorporeal Life Support Applications

Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3613
Author(s):  
Michele Bellancini ◽  
Laura Cercenelli ◽  
Stefano Severi ◽  
Guido Comai ◽  
Emanuela Marcelli
Keyword(s):  
Carbon Dioxide ◽  
Gas Flow ◽  
Life Support ◽  
Removal Rate ◽  
Extracorporeal Life Support ◽  
Co2 Concentration ◽  
Co2 Removal ◽  
Exhaust Gas ◽  
Membrane Oxygenator

Measurement of carbon dioxide (CO2) in medical applications is a well-established method for monitoring patient’s pulmonary function in a noninvasive way widely used in emergency, intensive care, and during anesthesia. Even in extracorporeal-life support applications, such as Extracorporeal Carbon Dioxide Removal (ECCO2R), Extracorporeal Membrane Oxygenation (ECMO), and cardiopulmonary by-pass (CPB), measurement of the CO2 concentration in the membrane oxygenator exhaust gas is proven to be useful to evaluate the treatment progress as well as the performance of the membrane oxygenator. In this paper, we present a new optical sensor specifically designed for the measurement of CO2 concentration in oxygenator exhaust gas. Further, the developed sensor allows measurement of the gas flow applied to the membrane oxygenator as well as the estimation of the CO2 removal rate. A heating module is implemented within the sensor to avoid water vapor condensation. Effects of temperature on the sensor optical elements of the sensors are disclosed, as well as a method to avoid signal–temperature dependency. The newly developed sensor has been tested and compared against a reference device routinely used in clinical practice in both laboratory and in vivo conditions. Results show that sensor accuracy fulfills the requirements of the ISO standard, and that is suitable for clinical applications.

Sign in / Sign up

Export Citation Format

Share Document