Health and environment
ahmad jonodi; Ayoob Rastegar
Volume 25, Issue 5 , November and December 2018, , Pages 639-648
Abstract
Back ground: Phenol and its derivatives are widely used as raw material in many petrochemical, chemical and pharmaceutical industries. Wastewaters from the industries mentioned above contain Phenolic compounds which are highly hazardous to aquatic life. Therefore, phenolic wastewaters must be specially ...
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Back ground: Phenol and its derivatives are widely used as raw material in many petrochemical, chemical and pharmaceutical industries. Wastewaters from the industries mentioned above contain Phenolic compounds which are highly hazardous to aquatic life. Therefore, phenolic wastewaters must be specially treated before disposing off the effluentsMaterials and methods: Hybrid aerogel with structure of hydrophobicity was prepared through sol–gel synthesis followed by drying at ambient. The aerogel was used for phenol adsorption from water and the effects of phenol concentration, also contact time were studied. Batch kinetic and isotherm studies were carried out to evaluate the effects of contact time and phenol concentration The Aerogel surface was characterized by nitrogen adsorption at 77 K.Results: The result showed that the maximum adsorption was in the concentration 250 mg L− 1 493/13 mg g− 1. The specific surface area of the synthesized aerogel is 543.4 g m-2, the pore size is 3.24 nm with a porosity of 44 and a contact angle of 156 degrees, The Langmuir model and the pseudo-second-order fited the experimental data Conclusion: the results showed that the phenol adsorption process involved both boundary layer diffusion and inter particle diffusion that hydrophilic and hydrophobic surface of the aerogel is synthesizedmain reason for its higher adsorption efficiency phenol.
Zahra Rezaei Gozal Abad; Ahmad Alah Abadi; Ahmad Hosseini-Bandegharaei; Ayoob Rastegar; Farzad Mohammadi; Shahram Nazari
Volume 23, Issue 4 , September and October 2016, , Pages 608-617
Abstract
Objectives Phenol is known as a toxic and carcinogen compound in the environment. It also produces unpleasant taste and odor in water reservoirs. In this study, the efficiencies of modified and conventional rice husk ashes as low-cost adsorbents were compared regarding phenol removal from aqueous solutions. ...
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Objectives Phenol is known as a toxic and carcinogen compound in the environment. It also produces unpleasant taste and odor in water reservoirs. In this study, the efficiencies of modified and conventional rice husk ashes as low-cost adsorbents were compared regarding phenol removal from aqueous solutions. Methods This study is an interventional laboratory research in which, at first carbonized rice husk was prepared at a temperature of 450°C. Then, to improve rice husk ash adsorption capacity, NH4CL was used for its modification. Then, the effects of physiochemical factors (pH, contact time, phenol concentration and adsorbent dose) on phenol removal were studied. Results Findings showed that the phenol removal by modified and conventional rice husk ash was 94.85% and 52.8%, respectively. The adsorption process for both adsorbents followed Freundlich isotherm (R2≥ 0. 99) and the pseudo-second order model (R2>0.99). Maximum adsorption capacity based on Langmuir model for the modified and conventional husk rice ashes were 66.6 mg/g and 4.7 mg/g, respectively. Conclusion Results indicated that efficiency of modified husk rice ash was more than that of the conventional type in phenol removal, causing less adsorbent consuming in the industrial treatment plants. Therefore, because of its availability and easy modification, it can be used in water and wastewater technology for phenol removal.
Somayyeh Akberi; Abdolmotalleb Seyyed Mohammadi; Javad Fardmal; Qorban Asgari
Volume 22, Issue 5 , November and December 2015, , Pages 870-878
Abstract
Background: Phenol is one of the toxic saline wastewater pollutants that is considered as priority pollutants since it is necessary treatment and reached the phenol concentration to the level of effluent discharge standard before discharge into the environment. In this study the performance of electro-Fenton ...
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Background: Phenol is one of the toxic saline wastewater pollutants that is considered as priority pollutants since it is necessary treatment and reached the phenol concentration to the level of effluent discharge standard before discharge into the environment. In this study the performance of electro-Fenton process in phenolic saline waste water treatment and the removal degree of COD were investigated. Materials and Methods: In this experimental study a reactor (1 litre) which was equipped to four iron electrodes and a DC power supply used to remove phenol and COD. The effect of operating parameters such as phenol initial concentration, H2O2 dosage, electrolyte concentration, pH, current density, connection time and type of electrode connection were investigated. Results: The results showed that this process using iron electrodes with parallel monopole connections is able to leave out the phenol from saline waste water by 96% and the removal COD equals 59% in operating conditions: pH= 3, initial phenol concentration=500mg/l, H2O2 concentration = 150 mg/L, Hydrogen peroxide at a current density = 15 mA/cm2at 10 minutes. Conclusion: The results showed that electrochemical processes can be considered as a better suitable substitute rather than other methods due to saline content and high electrical conductivity in saline wastewater.
Ferdovs Kord MostafaPor; Edris Bazrafshan; Farnaz Heidar Nejad
Volume 20, Issue 2 , May and June 2013, , Pages 142-153
Abstract
Background: Phenol is one of the main components concerned in the industrial wastewater. Physicochemical or conventional biological methods are usually used for the treatment of wastewater with high concentrations of phenol. At present study, the adsorption potential of phenol from aqueous solutions ...
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Background: Phenol is one of the main components concerned in the industrial wastewater. Physicochemical or conventional biological methods are usually used for the treatment of wastewater with high concentrations of phenol. At present study, the adsorption potential of phenol from aqueous solutions by Pistachio hull ash was investigated.
Materials and methods: Present study is an experimental survey that was performed in a batch system. To study the efficiency of Pistachio hull ash in phenol removal from aqueous solutions, the effect of critical variables such as contact time (15, 30, 45, 60, 75, 90, 105 and 120 min), initial phenol concentration (5, 10, 20, 30, 40, 50 and 100 mg/L), adsorbent dosage (0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 g/L) and initial pH of solution (2,3,4,5,6,7,8,9,10,11,12,13) was investigated.
Results: Maximum adsorption capacity of the Pistachio hull ash was 327.6 mg/g at pH 5, initial concentration of 100 mg/L and reaction time 45 min, which 98.28% of the phenol was removed. The adsorption equilibriums were analyzed by Langmuir and Freundlich isotherm models. It was found that the data fitted to Freundlich (R2=0.9436) better than Langmuir (R2=0.8395) model.
Conclusion: According to achieved results, it was observed that Pistachio hull not only was an inexpensive absorbent, but also a quite effective factor in removal of phenol from water and wastewater.