Iranian Research Organization for Science and Technology
Advances in Environmental Technology
2476-6674
2476-4779
3
4
2017
10
01
Removal of copper (II) from aqueous solutions by sodium alginate/hydroxy apatite hydrogel modified by Zeolite
185
192
EN
afsaneh
barekat
Department of Chemistry, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran
afsaneh.barekat@yahoo.com
Masoomeh
Mirzaei
Department of Chemical Engineering, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran
m.mirzaei@mhriau.ac.ir
10.22104/aet.2017.621
<span>The study presented in this article investigated the removal of copper ions from aqueous solutions by a synthetic hydrogel-forming adsorbent polymer based on sodium alginate (SA) and hydroxy apatite (HA) nanoparticles. The effect of adding Zeolite on the adsorption performance of this hydrogel was also investigated, and the optimum amount of Zeolite was determined by changing its quantity. The FTIR spectrum determined the structure of the synthesized adsorbent; non-continuous adsorption tests were performed to study the kinetics and thermodynamics of adsorption and also the recovery of the adsorbent. The degree of adsorption of the synthesized nanocomposite was compared with that of Zeolite, and the results showed that the maximum adsorption capacities of Zeolite and the nanocomposite for Cu ions were 29.7 and 75.8 mg/g, respectively. The kinetic studies indicated that the process of adsorption of Cu ions on both absorbents followed a pseudo second order kinetic equation. It took the Zeolite and the hydrogel 90 and 120 minutes, respectively, to reach equilibrium. The thermodynamic studies showed that Cu absorption by both adsorbents matched the Langmuir isotherm very well (R</span><span>2</span><span>=0.99). Since adsorbent recovery and its lifespan are of significant importance in absorption processes, recovery was carried out by hydrochloric acid (2% by weight). The repulsion coefficient of the recovered adsorbent and its efficiency in five recovery cycles were measured. The results of the tests indicated that the repulsion coefficient of Cu was 70-82.75 percent and the adsorption efficiency of Cu after 5 recovery cycles was 75 percent of the initial adsorbent. </span>
Copper,Hydrogel,Zeolite,Sodium alginate,Adsorption
https://aet.irost.ir/article_621.html
https://aet.irost.ir/article_621_7a116867cb1c20334826b40f84c0e8a3.pdf
Iranian Research Organization for Science and Technology
Advances in Environmental Technology
2476-6674
2476-4779
3
4
2017
10
01
Equilibrium, kinetic and thermodynamic studies on the adsorption of thiocyanate by Steel slag in an Aqueous System
193
203
EN
Yogesh
Dhoble
0000-0002-8766-9975
Research Scholar, Jamia Millia Islamia (Central University), New Delhi, India
yogeshdhoble@gmail.com
Sirajuddin
Ahmed
Professor, Jamia Millia Islamia (Central University), New Delhi, India
suahmed@jmi.ac.in
10.22104/aet.2018.2670.1133
The use of steel slag in an adsorption process for the removal of thiocyanate has been studied for the first time. Steel slag, a readily available by-product of the steel industry, can be a suitable candidate for the study of the adsorption of thiocyanate found in coke oven effluent. The parameters considered for adsorption studies were pH, initial concentration, temperature, and the amount of adsorbent. It was found that the percentage removal of thiocyanate decreased with an increase in the initial concentration of thiocyanate. The rate of adsorption of thiocyanate increased with an increase in temperature. The adsorption process was spontaneous and exothermic in nature. The Langmuir isotherm was found to be the best fit for the adsorption process. The kinetic data follows the pseudo-second-order model. Main effect and interaction studies were done using the fractional factorial method. The FTIR studies confirmed that functional groups participated in the adsorption process. This made the steel slag a suitable adsorbent for the removal of thiocyanate.
Adsorption,isotherms,Kinetics,steel slag,Thermodynamics,thiocyanate,Factorial
https://aet.irost.ir/article_658.html
https://aet.irost.ir/article_658_7f1205e8af63f7e22fe8e881d7c3cdd1.pdf
Iranian Research Organization for Science and Technology
Advances in Environmental Technology
2476-6674
2476-4779
3
4
2017
10
01
Preparation, characterization and photocatalytic degradation of methylene blue by Fe3+ doped TiO2 supported on natural zeolite using response surface methodology
205
216
EN
Hadieh
Taghvaei
Department of Chemical Engineering, Faculty of Engineering, University of Isfahan, Isfahan, Iran
hadieh.tv88@yahoo.com
Mehrdad
Farhadian
Department of Chemical Engineering, Faculty of Engineering, University of Isfahan, Isfahan, Iran
mehrdadfarhadian@yahoo.com
nila
davari
Department of Chemical Engineering, Faculty of Engineering, University of Isfahan, Isfahan, Iran
nila.davari@yahoo.com
samira
maazi
Department of Chemical Engineering, Faculty of Engineering, University of Isfahan, Isfahan, Iran
samira_maazi@yahoo.com
10.22104/aet.2018.2462.1124
The photocatalytic degradation of methylene blue was investigated with TiO<sub>2</sub> and Fe<sub>2</sub>O<sub>3</sub> nanoparticles supported on natural zeolite. The synthesized photocatalyst was characterized by XRD, XRF, FT-IR, EDX, FE-SEM, and BET analyses. The results of XRD, FT-IR, and EDX confirmed the successful loading of Fe<sup>3+</sup> doped TiO<sub>2</sub><strong> </strong>nanoparticles on natural zeolite. Further, the FE-SEM results confirmed the deposition of TiO<sub>2</sub>/Fe<sub>2</sub>O<sub>3</sub> on the zeolite, with the approximate particle size being 52.3 nm. According to the XRF results, the synthesized nanoparticles had Fe<sup>3+</sup>/TiO<sub>2</sub> molar ratios of 0.06 in the synthesized photocatalyst. Based on BET analysis, the surface area of TiO<sub>2</sub>/Fe<sup>3+</sup>/natural zeolite was about 112.69 m<sup>2</sup>/g. The effects of operational factors such as pH (6-10), dye concentration (25-75 mg/L) and H<sub>2</sub>O<sub>2</sub> concentration (10-40 mg/L) were considered and optimized via response surface methodology utilizing Box-Behnken design. The optimization results indicated that the maximum percentage of degradation was achieved at a dye concentration of 25 mg/L, initial pH of 10, and H<sub>2</sub>O<sub>2</sub> concentration of 40 mg/L with a 90 min irradiation time and a 1 g/l photocatalyst concentration. The dye degradation efficiency reached 92% under this optimum condition.
Methylene Blue,Photocatalyst,TiO2/Fe2O3,Natural Zeolite,Response surface methodology
https://aet.irost.ir/article_655.html
https://aet.irost.ir/article_655_6b2d0e6d027ae67e027ca4d7871ed89b.pdf
Iranian Research Organization for Science and Technology
Advances in Environmental Technology
2476-6674
2476-4779
3
4
2017
10
01
Environmental sustainability enhancement of a petroleum refinery through heat exchanger network retrofitting and renewable energy
217
227
EN
Behrouz
Raei
Department of Chemical Engineering, Mahshahr Branch, Islamic Azad University, Mahshahr, Iran
b.raei@mhriau.ac.ir
Ali
Ghannadzadeh
Department of Chemical Engineering, Hamedan University of Technology, Hamedan, Iran
ali.ghannadzadeh@gmail.com
10.22104/aet.2018.2340.1118
This paper presents a case study on the enhancement of environmental sustainability in a petroleum refining process based on an exergetic diagnostic approach. The Life Cycle Assessment (LCA) pinpointed crude oil production and electricity generating systems as the main sources of environmental unsustainability. The existing hot utility demand of the process is 78.4 MW with a temperature difference of 40°C, where the area efficiency of the existing design is 0.7254. The targeting stage sets the minimum approach temperature at 18.96 °C, thereby establishing the scope for potential energy savings. The suggested design option with a total energy demand of 109,048 kW, the same as the existing one but 72,699 kW higher than the target, needs a 17,873 m<sup>2 </sup>area in 38 exchangers. Notably, this requires 2,914 m<sup>2 </sup>less surface area, suggesting the practicality of the project with a limited number of modifications such as the repiping of the existing exchanger units. Moreover, to enhance further the sustainability of the petroleum refining process, the possible solutions such as the renewables were evaluated through various scenarios; thus, resulting in a reduction in the environmental impacts from 2.34E-06 to 2.27E-06 according to ReCiPe, and thus paving the way towards a sustainable petroleum refining process.
Environmental sustainability,Energy integration,LCA,Exergy,Petroleum refinery
https://aet.irost.ir/article_654.html
https://aet.irost.ir/article_654_f5a18bbe0299507faf8e8177aa6a7825.pdf
Iranian Research Organization for Science and Technology
Advances in Environmental Technology
2476-6674
2476-4779
3
4
2017
10
01
Environmental study of waste energy recovery by using exergy and economic analysis in a fluid catalytic cracking unit
229
242
EN
Esmaeil
GhasemiKafrudi
Research and Development of Energy and Environment Pardise, Research Institute of Petroleum Industry, Tehran, Iran
goodarzvandf@gmail.com
Sahebeh
Yousefi
Petroleum University of Technology, Ahwaz Faculty of Petroleum, Ahwaz, Iran
sahebeh.yousefi86@yahoo.com
Fatemeh
Goodarzvand-Chegini
Faculty members of Research Institute of Petroleum Industry (RIPI), Tehran, Iran
goodarzvandf@ripi.ir
10.22104/aet.2018.2450.1123
An increase in fossil fuel consumption has significantly increased the concentration of greenhouse gases (GHGs). Waste energy recovery can reduce GHGs by reducing fossil fuel consumption. In the FCC unit in refineries, the catalyst is continuously regenerated by burning off the deposited coke with air and a large flux of waste gas with high temperature is generated which is vented into the atmosphere. The purpose of this study was to investigate the effect of waste heat/pressure recovery of the waste gas on the reduction of GHGs and air pollutant emissions. Based on this objective, exergy and economic analysis were carried out for two scenarios (S-1 and S-2). The S-1 scenario involved the installation of a Heat Recovery Steam Generator (HRSG), while S-2 applied the simultaneous usage of HRSG and a turbo-expander to evaluate electricity production using waste gas pressure. The exergy of waste gas was formulated and an in-house code was developed for solving the equations via a trial and error method. The results showed that exergy loss of the waste gas was higher than 660 MW and it was possible to recover about 64 MW and 75 MW in the S-1 and S-2, respectively. The amount of steam and the electrical energy produced were found to be about 88 ton/h and 8323 MWh/month, respectively. The results also showed that S-1 can reduce 72227 tCO2e of GHGs and 327 ton of air pollutant and S-2 can reduce 143464 tCO2e of GHGs and 649 ton of air pollutant annually. The economic indexes were evaluated and the results indicated that the internal rates of return (IRR) were found to be 33.18% and 36.76% for S-1 and S-2, respectively. This showed that the two scenarios were economically feasible, but from an environmental, economic and energy recovery standpoint, S-2 was the best scenario and the economic analysis on S-2 certified that there was no economic risk.
GHGs,Exergy analysis,HRSG,Turbo-expander,Economic index
https://aet.irost.ir/article_656.html
https://aet.irost.ir/article_656_5997f2fcb2318fd54676547b9b693a9e.pdf
Iranian Research Organization for Science and Technology
Advances in Environmental Technology
2476-6674
2476-4779
3
4
2017
10
01
Sonocatalysis degradation of methyl orange using zinc sulfide carbon nanotubes nanocatalyst
243
248
EN
Mohammad Reza
Rezaei Kahkha
Department of Environmental Health Engineering, Zabol University of Medical Sciences, Zabol, Iran
m.r.rezaei.k@gmail.com
Batool
Rezaei Kahkha
Department of Occupational Health Engineering, Kerman University of Medical Sciences, Kerman, Iran
batool.rezaei.k@gmail.com
Ali
Faghihi Zarandi
Department of Occupational Health Engineering, Kerman University of Medical Sciences, Kerman, Iran
alihealth1162@gmail.com
10.22104/aet.2018.2766.1135
Dye sewage is dangerous problem in our environmental aquatics that cause generation of harmful effects for living organism. In this work, because of simplicity, easy operation, high efficiency and no creating secondary pollutants, ultra sound radiation applied for degradation of a synthetic dye, methyl orange using zinc sulfide nano particles decorated on carbon nanotubes as nanocatalyst. ZnS/CNTs prepared by co-precipitation of carbon nanotubes and zinc aceate. Methyl orange (MO) is a cationic dye that used widely in some medical uses, coloring paper, dyeing cottons, wools, coating for paper stocks and etc. For achieving highest degradation efficiency several parameters such as pH, amount of nanocatalyst, initial dye concentration and time were evaluated and optimized. Results showed that highest degradation efficiency (100%) obtained at 0.3 gr of nanocatalyst while initial dye concentration is 30 mg/L at pH, 2. Comparison of several methods for degradation of methyl orange showed feasibility of applied method. In addition, reusability of nanocatalyst was suitable for degradation of MO in real wastewater samples.
nanocatalyst,sonocatalysis,Degradation efficiency,Methyl orange,Zinc sulfide,carbon nanotubes
https://aet.irost.ir/article_653.html
https://aet.irost.ir/article_653_ca6e82b14d838cb851aab5b5ad3df82e.pdf