Activated Charcoal Granules Research Articles

Shelf life enhancement technique of Musa acuminata in a controlled environment and optimization of process parameters affecting shelf life using genetic algorithm.

An economical and effective storage solution has been designed in this work for the storage of postharvest fruits and vegetables. Musa acuminata or banana has a shelf life of 5-6 days in open uncontrolled environment. This article reports a storage solution of M. acuminata in a controlled enclosure containing titanium oxide (TiO2 )-coated inner walls and irradiated with ultraviolet ray of band "C," an air filtration unit, 5% by volume potassium permanganate (KMnO4 ) solution in a clay pot, grow lights, and activated charcoal granules. The same fruit was kept in an uncontrolled environment too. The percentages of dark spots on banana (M. acuminata) upon storage in controlled and uncontrolled environments have been estimated using an image-processing algorithm. The prediction of dark spots was conducted using multi-linear and multivariate polynomial regression. Experimentation with optimum process parameters obtained with genetic algorithm resulted in a shelf life extension of 6 days as compared to its storage in an uncontrolled environment. The setup can be used in vegetable and fruit markets for the extension of shelf life of postharvest perishable items in a compact and cost-effective manner. The setup does not use any refrigeration process thereby decreasing energy requirement.

Improved degradation of tetracycline, norfloxacin and methyl orange wastewater treatment with dual catalytic electrode assisted self-sustained Fe2+ electro-Fenton system: Regulatory factors, mechanisms and pathways

The environmental hazards associated with the presence of antibiotics and dyes in water sources require the development of efficient and appropriate wastewater treatment technologies. In the research, a dual catalytic electrode assisted self-sustained Fe2+ electro-Fenton system was constructed to degrade tetracycline, norfloxacin and methyl orange in wastewater efficiently and economically. The novel titanium mesh based PbO2/SnO2 anode electrode was prepared by electrodeposition with the best oxidation performance at the ratio of Sn to Pb 0.5:1, and silver doped Zinc-based organic framework ([email protected]) mixed crystal cathode catalyst was synthesized by precipitation at room temperature. Meanwhile, a sacrificial iron anode was introduced into the system in an acidic solution without a power supply, realizing the endogenous supply of Fe2+. The results indicated that the process was capable of self-supporting H2O2 and Fe2+ under the optimized conditions of pH range of 3.5–4.0, iron area of 10 cm2 and current intensity of 9 mA. The current efficiency was calculated to be as high as 369.5%. The type of conductive substrate supported cathode catalyst is an important factor determining the performance of the novel coupled electric-Fenton system. Electro-Fenton system using [email protected] catalytic electrode loaded with conductive substrates (stainless steel mesh (SS), carbon felt (CF), and activated charcoal granules (ACG)) was constructed to degrade tetracycline (TC), with the degradation efficiencies of 100% (k = 0.03048), 99.7% (k = 0.01831), 99.7% (k = 0.01421). Moreover, the experiment group of [email protected] electrode had achieved good degradation effects for TC, norfloxacin (NOR), methyl orange (MO), and the degradation efficiency was 99.1%, 92.8% and 100%, respectively. The possible degradation pathways of TC, NOR and MO were proposed by analyzing the intermediates. This work demonstrates the scaling-up potential of the system in the treatment of antibiotics and dye wastewater.

Experimental Investigation of Thermal Properties of Materials Used to Develop Cryopump

A cryopump works on the principle of cooling down a metal surface or a surface coated with a porous material, namely, cryopanels, to cryogenic temperature. The gases stick to cryopanels thus lowering pressure and thereby creating a vacuum in an enclosed space. Materials used in the development of cryopumps include metals like copper and steel as structural materials, composite material like G10 for supports, thermal insulation, adhesive to fix sorbent to the metal surface, Vespel as an insulator, and various kinds of coatings on metal surfaces. Thermal properties govern heat load management and thereby the temperature of the cryopanels and hence pumping phenomena. This paper focuses on the experimental investigation of properties like specific heat, thermal diffusivity, thermal conductivity of materials, and their variation with lowering of temperature to cryogenic levels. A study was carried out to quantify the thermal properties of adhesive to fix the sorbent, the metal sheet of the cryopanel coated with activated charcoal granules using the adhesive, materials like G10 and Vespel, and high-emissivity black coating. The thermal conductivity (studied up to −150°C) for different kinds of adhesives was found to be in the range of 0.48 to 0.9 W/m‧K; for Vespel SP21 and G10, it is 0.58 and 0.8 W/m‧K, respectively. The emissivity at room temperature of the sorbent-coated cryopanels was 0.94, and for the high-emissivity black coating, it was in the range of 0.93 to 0.94.

Development of a prototype anti-pollution filter for volatile anesthetics.

The use of volatile agents during cardiopulmonary bypass allows a "single drug anesthesia" and is associated with reduced peak postoperative troponin levels. Connecting the exhaust systems to the oxygenator's gas outlet port is mandatory and allows to prevent operating room (but not atmospheric) pollution by volatile agents. The aim of this study was to create a prototype filter for volatile agents and to test its adsorption efficacy during an ex-vivo simulated conventional cardiopulmonary bypass test. We carried out bench tests to conceive a prototype filter that could prevent room and environment pollution without damaging membrane oxygenators. We performed the tests at the Engineering Center for Circulatory Assistance Laboratory, Dante Pazzanese Institute of Cardiology, São Paulo, Brazil. Bench tests included simulation of integral adsorption tests, filter dimensions and design, flow versus pressure curve, sizing, and tightness. Calgon AT 410 was the best kind of activated charcoal granules for adsorption of sevoflurane, isoflurane, and desflurane. Filter dimension tests showed that a chamber of 30-cm width over 10-cm diameter filled with 200 g of the Calgon AT410 granules was the minimum required to fully adsorb sevoflurane for 90 min. Adsorption tests showed that the prototype filter fully adsorbed isoflurane in 100 ± 2.3 min, sevoflurane in 95 ± 3.4 min, and desflurane in 95 ± 4.3 min. The new version of our prototype filter adsorbed most of the volatile anesthetics agents during an ex-vivo simulated conventional cardiopulmonary bypass test.

Dynamic adsorption behaviour of cabin air filters

In recent years cabin air combination filters for cars have become increasingly popular. They are designed to eliminate both particles and gaseous pollutants from the cabin air. The removal of noxious gases takes place through adsorption by a layer of activated charcoal granules. According to German and international standards these cabin air filters are tested at a temperature of 23 °C and 50% relative humidity. But in practice they are exposed to a wider range of temperatures, humidity and input concentrations. These parameters have a strong effect on adsorption, so they also influence the adsorption capacity of cabin air filters. Experiments on a filter test stand at the Department of Chemical Engineering, University of Duisburg, with varying temperature, relative humidity and input concentrations show that adsorption capacity is significantly reduced at higher temperatures or higher relative humidity. When the temperature or the relative humidity rises or when the input concentration falls desorption of previously adsorbed pollutants occurs.

Effect of Cell Adsorption on Photosterilization of Escherichia coli over Titanium Dioxide-Activated Charcoal Granules.

TiO2 particles were immobilized on activated charcoal granules by means of a sol-gel method to use as a photosterilization catalyst capable of adsorbing microbial cells. The amounts of Escherichia coli cells adsorbed to the TiO2-immobilized activated charcoal (T/AC) granules were determined at temperatures of 288 to 303 K, and the maximum and minimum amounts of adsorbed cells were obtained at 288 and 293 K, respectively. At a temperature of 298 K, the relation between the amounts of adsorbed and suspended cells can be expressed by the Freundlich adsorption isotherm in the range of T/AC concentrations of 0.1 to 1.0 kg/m3. Under light irradiation with a black light fluorescent lamp, sterilization of E. coli cells was carried out in the slurry of T/AC granules at temperatures of 288 to 303 K and T/AC concentrations of 0 to 0.4 kg/m3. The sterilization rates changes depending on the temperatures, and the highest and lowest rates are obtained at 288 and 293 K, respectively. The apparent sterilization rate constants are determined on the basis of a series-event model under various sterilization conditions. The rate constants can be correlated with the concentration of T/AC granules by taking into account the adsorption of cells to the T/AC granules.

Effect of ageing and moisture on the retention of hydrogen cyanide by impregnated activated charcoals

The effect of ageing and humidity on the uptake of hydrogen cyanide (HCN) and cyanogen ((CN) 2) by activated charcoal granules (ACG) and cloth (ACC) impregnated with copper and chromate was studied. Accelerated ageing was achieved by means of storage at 80% RH and 60°C for several days. The presence of sodium hydroxide, (above 2.8% w/w) as a third impregnant, improved the primary performance of impregnated activated charcoal granules, but had little effect on ageing. Granules age with respect to HCN and (CN) 2 breakthrough times, while ACC ages mainly with respect to the (CN) 2 breakthrough time. Thus, ageing appears to manifest itself with respect to pore size distribution. Chromium (VI) which can be adsorbed in all pores is gradually reduced to chromium (III) ions with time. Copper (II) impregnant only ages in ACG that has large enough pores (macro- and mesopores) to take it up. The effect of moisture (80% RH) and its absence (<1% RH) in air streams containing HCN or (CN) 2 challenge gas on the uptake of these gases by activated charcoal cloth (ACC) impregnated with copper and chromium of various valencies and sodium hydroxide was investigated. It was found that moisture was generally detrimental to HCN uptake. Only in the presence of Cu (II), capable of catalysing a chain mechanism removing HCN, was the presence of moisture in the gas stream advantageous and then only if Cr (VI) was available to remove the cyanogen (CN) 2 that had been formed in the process. ACC impregnated with Cu (II) was more effective than Cu (I) or Cu (0) in removing HCN, while chromate, moisture and NaOH catalysed the formation of HCN from (CN) 2. The results can be explained in terms of a circuit of interlinked reaction mechanisms. An empirical formula is proposed grading the impregnated ACC filter material: [HCN held − (CN) 2formed] × t shortest breakthrough time.

Surface modification of charcoal by glow-discharge: The effect on blood cells

Glow discharge polymerization of hexamethyldisiloxane was carried out on activated charcoal granules through the application of capacitively coupled RF plasma. The coats were examined with Auger and IR spectroscopies, and with SEM. The surface topography and the tenacity of samples coated with plasma were compared with that of the solution-coated ones. Mercury porosimetry was used to study the effect of the coat on pore size distribution. The effect of contact with blood on the number of blood cells were studied.

Determination of Dimethyl Selenide in Breath Air of Mice by Gas Chromatography

Determination of dimethyl selenide(DMSe) in the breath air of mice was studied by GC. Collection of DMSe was carried out using a charcoal column(0.9×10cm) packed with 2g of activated charcoal granules. The charcoal was transferred into a 25ml glass-stoppered tube, and the tube was placed in chilled water. After 10ml of CS2 was added to the tube, the tube was immediately stoppered and the mixture was shaken for 30min. The extracts were filtered through glass wool and adjusted to 10ml. The extraction was repeated twice. A 5μl-aliquot of the extract was injected into the GC apparatus using a VZ-7 column and the peak height of the associated component was measured (Rt=2.5min). The recovery was 70-76%, and the observed relative standard deviation was 4.2-9.6%. The amounts of DMSe in the breath air of 10 mice after the oral administration of selenite (50 μmol-Se/kg/d) for 5 consecutive days were in a range of 32-78μg.

Polymer coating for hemoperfusion over activated charcoal.

Plasma polymerization (glow discharge) was used to make a polymeric coat with hexamethyldisiloxane on the surface of activated charcoal granules. These samples were examined with ESCA and SEM for surface chemical analysis, coat thickness, and uniformity, and for changes in surface topography. The effects of the coat on absorptive capacity and release of fine particles were examined.

Permeability of heparinized hydrophilic polymer (H-RSD): application to semipermeable membrane for microencapsulation of activated charcoal.

A series of heparinized hydrophilic polymers (H-RSD) composed of a hydrophobic element, a nonionic hydrophilic element, a cationic element and ionically bound heparin was synthesized. The permeability of the H-RSD polymers with various chemical compositions and water contents was investigated. From the studies on the permeability, it has been found that in order to maintain good permeability after heparinization, the nonionic hydrophilic element is necessary. In addition, the microencapsulation of activated charcoal granules using a H-RSD polymer with a similar permeability to that of Cuprophan was examined. In vitro adsorption studies and in vivo direct hemoperfusion studies on the activated charcoal microencapsulated with the H-RSD polymer, show that the H-RSD coating prevents clot formation without loss of the absorption power of the activated charcoal.

The use of polyamide coatings for selective adsorption control on activated charcoal

Polymer-coated, activated charcoal granules have found considerable use for the direct detoxification of blood in cases of uraemia and drug overdose. Although polymer coating materials are presently selected for their biocompatibility, more selective polymers could be used to increase the adsorption capacity for specific drugs and toxins. To gain an understanding of the fundamental factors influencing these adsorbent systems, we have investigated a possible selective coating material, nylon 6 and studied its influence on adsorption rates of simple model compounds when applied as a thin coat to activated charcoal granules. Thermodynamic studies have shown that phenolic compounds interact with the polymer by a hydrogen bonding mechanism, whereas nonphenolic compounds probably bind less strongly due to Van der Waals type interactions. Kinetic studies have shown that the selectivity of charcoal granules for phenolic compounds was increased by coating the granules with a thin layer of nylon 6. The increase in selectivity is probably a result of the different binding mechanism between solute and the polymer. These studies have shown that possible selective coatings may be evaluated more effectively on the basis of simple preliminary drug-plastics interaction studies.

A New Combined Enzyme-Charcoal System formed by Enzyme Adsorption on Charcoal followed by Polymer Coating

A method is described for a new combined enzyme-charcoal system. A model enzyme, urease, was adsorbed on activated charcoal granules which was then coated with ultrathin cellulose nitrate. The assayed activity of this immobilized enzyme was 28.1% /+- 3.12% (mean /+- S.D.) of the activity of urease in solution. The enzyme did not leak out after immobilization and worked efficiently. The assayed urease activity increased with greater amounts of urease/gm immobilized enzyme, but reached a plateau after 40 sumner units/gm. Immobilized urease has good storage and operational stabilities at refrigerator, room and body temperatures. In-vivo studies show that about 90% conversion urea in one single pass is possible.

Platelet-surface interaction: effect of albumin coating or heparin complexing on thrombogenic surfaces.

Platelet–surface interaction was studied using activated charcoal granules (AC), cellulose nitrate coated, activated charcoal granules (CAC), albumin – cellulose nitrate coated, activated charcoal granules (ACAC), and benzokonium – heparin – cellulose nitrate coated, activated charcoal granules (BHCAC). In studies where blood from dogs was recirculated through shunts, each containing 300 g of one of the above systems, it was found that both AC and CAC lowered the systemic blood platelet levels after 2 h of hemoperfusion. In hemoperfusion across these two systems, there was also an increase in the adhesiveness of platelets. In the case of ACAC and BHCAC, hemoperfusion for 2 h did not result in any significant decrease in the systemic blood platelet levels, nor was there an increase in the adhesiveness of platelets perfused across these two systems. Scanning electron microscopic studies were carried out with the CAC and ACAC systems before and after contact with blood. There was marked platelet and fibrin deposition and entrapment of formed elements of blood in the case of the CAC. In the case of the ACAC there was no platelet adhesion, fibrin deposition, or entrapment of formed elements of blood. This study has led to the use of the ACAC microcapsule artificial kidney in the treatment of patients with chronic renal failure and acute intoxication.

541. 放射性浮遊ヨウ素に対する活性炭含浸濾紙の捕集特性

Two types of charcoal-impregnated filter paper CP-20A and CP-20B manufactured by Toyo Filter Paper Co., Ltd., Tokyo were tested for their collection performance on airborne iodine generated during 131l production at the lsotope Test Production Plant, which is successively filtered through traps in the cell and through two installed air cleaning systems. In order to observe the effect brought upon the collecting efficiency by differences in charcoal granule size, the CP-20A and -20B were impregnated with activated charcoal granules of about 2μ and about 70μ in the average diameter. This paper describes the experimental results and discussions on the dependence of collecting efficiency on (1) the nature of the airborne iodine, (2) the relative humidity of the sampling air, (3) the sampling period, and (4) the face velocity. In general, better performance for collecting airborne iodine was shown by the CP-20B as compared with the CP-20A.

CIGARETTE SMOKE: CHARCOAL FILTERS REDUCE COMPONENTS THAT INHIBIT GROWTH OF CULTURED HUMAN CELLS.

Water-soluble components of total cigarette smoke inhibit cell growth and protein synthesis by the KB line of human cells. The cytotoxic components were in both the gas phase and the particulate phase of smoke. Conventional filters of cellulose acetate reduced cytotoxicity of the particulate phase in proportion to the weight of particles trapped, that is, they did not alter the specific activity of the particulate phase. Appropriately designed filters containing activated charcoal granules selectively reduced cytotoxic components in cigarette smoke which would have appeared in both phases, although the reduction, as anticipated, occurred to a greater extent in the gas phase.