Influence of Carbon Sorbent Quantity on Breakthrough Time in Absorbent Filters for Antismog Half Mask Application

In this article, we present polymer non-woven fabrics with the addition of carbon sorbents being tested to estimate the breakthrough time and efficient protection against vapors present in smog. For this purpose, three substances were selected, which constitute an inhalation hazard and are smog components: cyclohexane, toluene, and sulfur dioxide. It was demonstrated that an increased quantity of carbon sorbent in polymeric filters significantly prolongs the breakthrough time. However, high sorbent quantities may increase the filter surface mass and air flow resistance. To optimize the protective parameters with functionality, a compromise between the two has to be found. By comparing the breakthrough times for different carbon sorbent quantities, the optimal filter composition was elaborated. The analyzed non-woven fabrics were manufactured by the melt-blown process and filled with ball-milled carbon sorbents supplied directly into the fabric blowing nozzle. Both protective performance and textural properties were analyzed for two commercially available carbon sorbents. Furthermore, it was proven that high values of sorbent-specific surface area translates directly into greater filter performance.

Regression models of adsorbing nickel (II) ions by carbon sorbents

The use of inexpensive materials such as sorbents increases the competitive advantages of removing heavy metal ions, including nickel (II) ions, from aqueous solutions and wastewater. Such materials include active carbons – carbon sorbents. The oxidized carbon sorbent AD-05-2 and its original analogue have been used as the object of this research. The oxidation of carbon sorbent AD-05-2 was conducted using a solution of nitric acid and urea following a conventional method. Oxidation resulted in improvement of the textural characteristics of the carbon sorbent. The total pore volume increased, including the volume of micropores, which had a positive effect on the sorption properties of the obtained sample. This article studies the adsorption of nickel (II) ions by the oxidized carbon sorbent AD-05-2 and its original analogue. For both models, the total time of establishing adsorptive equilibrium in the system adsorbate–adsorbent was 4 hours, pH = 9,6, and the range of temperatures – 298–338 K. The obtained experimental data on the nickel (II) ion adsorption are processed in the software package Statgraphics Plus. Adsorption isotherms are described using parabolic regression models, which cover 98.86–99.99% of the experimental data. The adsorption of nickel (II) ions increases with temperature, as indicated by a higher value of the first derivative dA/dCp, apparently, due to accelerated external diffusion. A significant steep rise of the isotherms corresponds to the temperature of 338 K, which indicates the diffusion effect on the adsorption process. The estimates of the accuracy of regression models are provided by the mean square σ and absolute Δ errors. Autocorrelation of experimental data is estimated using Durbin – Watson (DW) test. The obtained regression models can be applied for calculating the optimum parameters of nickel (II) ions’ adsorption from aqueous solutions and process stream using the oxidized carbonic sorbent AD-05-2 and its original analog.

CHARACTERISTICS OF NEW PROMISING BENTONITE COAL SORBENTS MODIFIED BY DIFFERENT COMPOUNDS

Introduction. Bentonite clays are traditional inexpensive and effective adsorbents that have a high potential for removing heavy metals from wastewater due to their abundance, chemical and mechanical stability, high exchange ability, and unique structural properties.Problem Statement. To obtain activated carbon, high-temperature muffle furnaces are used with the consumption of a large amount of electricity, which is economically unprofitable. In addition, the resulting sorbents must be in the form of granules or tablets, have high strength and the ability to be repeatedly used in technological processes.Purpose. Development of a method for the production of low-cost granular sorbents based on bentonite as amineral component, activated carbon, as well as natural production waste (sunflower husk, straw, sawdust, etc. as modifiers), which can be removed from the activation process to increase porosity of these materials.Materials and Methods. Angren brown coal; bentonite of the Navbakhor deposit was used as a sorbent and a basic substance for the granules formation; modifiers were sodium chloride, potassium, chopped straw, sawdust. Methods of thermal decarbonization and activation of the obtained granules under the optimal conditions (950 °С, 45 min) were applied; the bulk density, the specific surface area, pore types and their total volume was determined by optical microscopy and nitrogen adsorption methods.Results. Inexpensive hybrid bentonite-carbon sorbents in the form of high-strength granules were synthesized.The optimal ratio of the main components is Bentonite:Coal = 1 : 2, size (2.5 mm) and strength of granules (83—99%), total pore volume 0.863—1.01 cm3/g, confirmed the presence of macro-, meso- and micropores. The most promising sample has a specific surface area (Langmuir) 184 m2/g.Conclusions. The method for obtaining new effective granular carbon sorbents of low cost, having high sorption capacity relative to organic and inorganic pollutants for purification of industrial process waters has been proposed.