alireza ziapour; zahra Kazemi Karchegini; negin Kazemi Karchegini
Abstract
The color of wastewater is considered as a major environmental problem. Chemical and biological treatment of dye containing wastewater is difficult due to the low adsorption level and chemical stability of dyes. Activated carbon is usually used for adsorption of these materials, but because of high prices ...
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The color of wastewater is considered as a major environmental problem. Chemical and biological treatment of dye containing wastewater is difficult due to the low adsorption level and chemical stability of dyes. Activated carbon is usually used for adsorption of these materials, but because of high prices and restore problems, researchers are trying to find available low-cost materials with high adsorption. In this research, soybean lignocellulosic waste has been investigated for absorption of Rimosol Black B (RBB) dye. First, the effect of dye RBB concentration, pH, temperature and contact time on the absorption value was investigated, and then the adherence of the adsorption isotherm to the Langmuir and Freundlich models was investigated. The results showed that the absorption efficiency depended strongly on pH and slightly on the temperature. The absorption rate of RBB dye with soybean residue is high and the absorption is complete in a short period of time. The results of the adsorption isotherm analysis showed that both models are suitable for describing the adsorption of RBB dye with soybean. The maximum absorption capacity of RBB dye by soybean waste was calculated 90.9 mg/g, which is more than some cheap absorbents studied and less than others such as rapeseed lignocellulosic waste.
Narges Ramezani; Amir Khosravani; Hamidreza Rudi
Abstract
Chitosan is one of the biopolymers which possesses unique properties and has been recently considered in various applications such as paper-making. This polymer is soluble in acidic conditions and has the potential to act as a polyelectrolyte under the colloidal condition in the pulp. However, according ...
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Chitosan is one of the biopolymers which possesses unique properties and has been recently considered in various applications such as paper-making. This polymer is soluble in acidic conditions and has the potential to act as a polyelectrolyte under the colloidal condition in the pulp. However, according to the studies, the capability of this polyelectrolyte was better in alkaline condition, in improving the drainage, retention and even strength properties of paper. Therefore, in this study, the performance of chitosan was studied in different conditions and the results were investigated based on the interpretation of the adsorption process and chitosan configuration using silicon wafer model and ellipsometry technique. For this purpose, bleached kraft softwood fibers were refined to a Canadian standard freeness of 300 ml and after addition of chitosan and nano-silica at different pH levels, freeness and fines retention parameters were evaluated. The results of this study confirmed that chitosan polyelectrolyte showed a good performance in increasing drainage and retention at alkaline pH, compared to the other pH levels, lonely and with the addition of nano silica. However in freenes test at acidic pH, the addition of chitosan along with nanosilica reduced the drainage, and no significant effect was observed at neutral and acidic pHs in the case of fine retentions. In order to interpret these observations and to ratiocinate the behavior of chitosan polyelectrolyte, the data obtained from the ellipsometry technique was investigated to determine the configuration and the thickness of the adsorbed chitosan layer which showed a higher thickness of the polymeric adsorbed layer at alkaline pH, and thus, the possibility of the longer tail and loops configurations in the environment and more effective interractions beyond the electrical double layer.
Chemistry of wood
Seyed Hassan Sharifi; Saltanat Archin; Leila Aghanaghifar
Abstract
DOR:98.1000/1735-0913.1398.34.16.66.1.1575.1603 One of the most important sources of environmental pollution is dye from industrial wastewater which is harmful for human health and environment. Therefore, the aim of this study was to evaluate removal of Methylene Blue (MB) dye from aqueous solutions ...
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DOR:98.1000/1735-0913.1398.34.16.66.1.1575.1603 One of the most important sources of environmental pollution is dye from industrial wastewater which is harmful for human health and environment. Therefore, the aim of this study was to evaluate removal of Methylene Blue (MB) dye from aqueous solutions by straw using ultrasonic wave with response surface methodology. The batch experiment was conducted to evaluate the effect of dye concentration, contact time, adsorbent dosage and pH on dye removal from aqueous solution. Response surface methodology was applied to appraise the effect of these different variables. The dye concentration in the solutions was measured by spectrophotometer at the wavelength of 664 nm. The results showed that the optimum parameter values for maximum color removal efficiency were: dye concentration 20 mg/L, reaction time 8 min, dose of adsorbent 4 g/L and pH=9. The Maximum and minimum dye removal were obtained 92.29 and 47.5 percent, respectively. Analysis of variances test showed that the quadratic model was the best model to explain the interaction of variables. Based on analysis of variance (ANOVA), the coefficient of determination value (R2 =0.9116) was high, showing that the experimental values fitted well with the predicted values. In addition, the statistical analysis of the results indicated that in the range studied, dose of adsorbent and pH had a significant effect on color removal efficiency. The Gibbs free energy and enthalpy data verified its spontaneous and endothermic nature. In addition, survey of pseudo first and second order kinetics models presented that the adsorption process was compatible to pseudo-second order kinetics equation.
Chemistry of wood
alireza ziapour; Abbas Zare
Abstract
Chemical and biological treatment of dye- containing wastewaters is difficult due to the low adsorption level and chemical stability of dyes. Activated carbon is usually used for adsorption of these materials, but because of high prices and restore problems, researchers trying to find available low-cost ...
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Chemical and biological treatment of dye- containing wastewaters is difficult due to the low adsorption level and chemical stability of dyes. Activated carbon is usually used for adsorption of these materials, but because of high prices and restore problems, researchers trying to find available low-cost materials with high adsorption. In this study, bagasse was used for adsorption of Remzol Black B dye and its capability was examined. Variables were concentration, temperature, pH and contact time, and the degree of adsorption was examined in different situations. Then, adsorption isotherm according to Langmuir and Freundlich models was investigated. The results showed that the adsorption efficiency depends more on pH of solution and less on temperature of the solution. Maximum adsorption of Remzol Black B dye by bagasse occurred in the first 15 minutes of contact. The study of adsorption isotherm showed that both models are suitable for description of adsorption of Remzol Black B dye by bagasse. Maximum adsorption of Remzol Black B dye by bagasse was calculated as 7.51 mg/g. Results of this study showed that bagasse could be used as a low-cost bio adsorbent for the adsorption of Remzol Black B from aqueous solution.
Chemical conversion
alireza ziapour; Abbas Zare; Mohammad Bakhshi
Abstract
Chemical and biological treatment of dye- containing wastewaters is difficult due to the low adsorption level and chemical stability of dyes. Activated carbon is usually used for adsorption of these materials, but because of high prices and restore problems, researchers trying to find available low-cost ...
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Chemical and biological treatment of dye- containing wastewaters is difficult due to the low adsorption level and chemical stability of dyes. Activated carbon is usually used for adsorption of these materials, but because of high prices and restore problems, researchers trying to find available low-cost materials with high adsorption. In this study, bagasse was used for adsorption of Acid Grange7 dye and its capability was examined. Variables were concentration, temperature, pH and contact time, and the degree of adsorption was examined in different situations. Then, adsorption isotherm according to Langmuir and Freundlich models was investigated. The results showed that the adsorption efficiency depends more on pH of solution and less on temperature of the solution. Maximum adsorption of Acid Orange7 dye by bagasse occurred in the first 15 minutes of contact. The study of adsorption isotherm showed that both models are suitable for description of adsorption of Acid Orange7 dye by bagasse. Maximum adsorption of Acid Orange7 dye by bagasse was calculated as 18.56 mg/g. Results of this study showed that bagasse could be used as a low-cost bio adsorbent for the adsorption of Acid Orange7 from aqueous solution.
Chemical conversion
Mahmoud Rouhbakhsh Bidaei; Mohammad Azadfallah; Rasoul Yarahmadi
Abstract
Dyes release into waste water due to its toxicity for some organisms results in major environmental pollution problems. The activated carbon (AC) is an efficient adsorbent to remove this kind of pollutants from aqueous phase. Hence, in this research activated carbon was prepared from sound and rotted ...
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Dyes release into waste water due to its toxicity for some organisms results in major environmental pollution problems. The activated carbon (AC) is an efficient adsorbent to remove this kind of pollutants from aqueous phase. Hence, in this research activated carbon was prepared from sound and rotted beech wood by chemical activation method and its adsorption capacity for removal of Rhodamine B was assessed. The carbonization and activation steps were performed at single stage with impregnating the substrate by zinc chloride as activating agent and with the ratio of 75, 100 and 125 percent to raw material mass at 400 and 500 ºC. The results showed that with increasing the impregnating agent content, the iodine number of ACs from both woods enhanced. The yield of AC from sound wood decreased with increasing impregnating agent while it was not predictable for AC resulted from rotted wood. Scanning electron microscopic (SEM) studies revealed much morphological changes in the surface of rotted wood-AC in comparison with sound wood -AC after treatment with activating agent. Also, raising the activating temperature from 400 to 500 ºC caused to enhance the iodine number. All prepared ACs performed much efficient in removal of Rhodamine B from aqueous solution. The maximum adsorption of the dye was obtained for ACs prepared under impregnating ratio of 125 and activating temperature of 500 ºC.
