Heavy metal pollution due to industrial activities and technological development due to their toxicity, biodegradability and bioaccumulation is a serious threat to the environment and public health. Due to the relatively high cost of various heavy metal removal methods, inexpensive adsorbents are used to reduce heavy metals in saline environments. In the meantime, the use of crop residues and agricultural wastes has been considered due to its cheapness and easy access. Bio-carbon is a carbon material with a special surface and high porosity, which is used as one of the most widely used industrial attractions for the removal of heavy metals due to its high adsorption capacity. In this research, bio-charcoal produced from sesame meal was used as a waste of one of the production industries of Ardakan city. Experiments using adsorbent treatment in four types (sesame meal, bio-charcoal at temperatures of 400, 500 and 600 ° C) and at four salinity levels (5, 10, 20 and 35 dS / m) in three replications The factorial experiment was performed in a completely randomized design in two discontinuous and continuous environments and the ions of water salinity in this adsorbent were tested in the presence of copper metal and without its presence for adsorption. Adsorption isotherm tests at different concentrations of heavy metal containing copper (10, 25, 50, 80, 150 mg / l) for the best adsorption state (bio-charcoal adsorbent 600) and to eva‎luate the adsorption rate and equilibrium time, Kinetic experiments of copper metal adsorption at a concentration of 100 mg / l were also performed. For continuous testing, among the treatments, the treatment that had the greatest effect on the removal of heavy metals was selected and tested under long and short columns with constant volume. The results showed that the specific surface area of biochar at different temperatures of 400, 500 and 600 ° C using BET method is 198.43, 238.17 and 317.21 m2 / g, respectively, which shows With increasing carbonation temperature, the specific surface area of bio-coal has increased. De-desalination capacity without copper in the best adsorbent (bio-charcoal 600) in 5, 10, 20 and 35 dS / m electrical conductivity respectively 43.7, 80.9, 188.9 and 411.6 mm It was obtained that these values of adsorption reduced the total ions of water salinity by 22.7%, 24.6%, 27.8% and 30.1%, with a significant difference of 5%. have. If the desalination capacity in the presence of copper in the best absorber (bio-charcoal 600) in the conductivity of 5, 10, 20 and 35 dS / m, respectively, 39.9, 73.8, 174.4 and 2 / It is 382 mg / g, which indicates that the adsorption capacity has decreased by about 8% due to the competition between ions. Also, the adsorption capacity of copper in the best absorber (bio-coal 600) in electrical conductivity of 5, 10, 20 and 35 dS / m, respectively 2.46, 2.39, 2.30 and 2.21 mg / m It got hot. With increasing copper concentration, the adsorption capacity of biochar was also increased. Accordingly, in general, at different salinity levels, the highest copper uptake capacity was provided by bio-coal prepared at 600 ° C and the lowest copper uptake capacity was shown by sesame meal. The Freundlich model better described the adsorption isotherm of copper by the bio-charcoal adsorbent 600, and also the quasi-quadratic kinetics had a very good ability to predict the adsorption of copper by the bio-charcoal 600 in the saline drainage water. In order to complete the studies on the studied adsorbent, columnar experiments with different heights were performed. The highest copper uptake was obtained by biochar 600 in continuous conditions at a height of 20 cm, equal to 49.2 mg / l. The removal rate of copper heavy metal in continuous conditions has decreased by 40.4% in the best case compared to discontinuous conditions.

7/26/2021 12:00:00 AM

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WSE1

محمدمهدي حسن آبادي