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Farideh Azimfar,Alireza Badiei,Seyed Mehdi Ghafelebashi,Majid Daftari-Besheli,Abbas Rezaee Shirin-Abadi 한국화학공학회 2018 Korean Journal of Chemical Engineering Vol.35 No.4
Three types of nanoporous silica support were modified by methylaluminoxane MAO and characterized by using BET, SEM, XRD and TGA. Dimethylsilyl (N-tert-butylamido)(tetramethylcyclopentadienyl) titanium dichlride was synthesized and immobilized on modified support. The prepared complex was then used as a reactive catalyst for ethylene polymerization. The effect of immobilization conditions on catalyst performance was studied. The results revealed elevated temperature grafting, decrease in precatalyst loading. Also, increasing of immobilization reaction time showed an increase in activity to 130 Kg poly/mol Ti.h.bar. The effects of polymerization temperature and [Al]/[Ti] ratio on the catalyst behavior, namely activity and bulk density, were investigated. According to the results, the activity of single-site catalyst depends on condition of immobilization and structure of nanoporous silica support.
A Study of the Diastereoselectivity of Diels-Alder Reactions on the Ce-SiO2 as Support
Ghodsi Mohammadi Ziarani*,Alireza Badiei,Azam Miralami 대한화학회 2008 Bulletin of the Korean Chemical Society Vol.29 No.1
The diastereoselectivity of Diels-Alder reactions were studied on the silica surface supported with different concentrations of cerium ion as efficient Lewis acid catalysts under solvent-free conditions. The results showed that the diastereoselectivity of reaction was highly improved in these conditions. The cerium ion was grafted on silica surface by using ion exchange method.
Rashin Bahrami,Maryam Pourhajibagher,Alireza Badiei,Reza Masaeli,Behrad Tanbakuchi 대한치과교정학회 2023 대한치과교정학회지 Vol.53 No.1
Objective: We aimed to evaluate the cell viability and antimicrobial effects of orthodontic bands coated with silver or zinc oxide nanoparticles (nano-Ag and nano-ZnO, respectively). Methods: In this experimental study, 30 orthodontic bands were divided into three groups (n = 10 each): control (uncoated band), Ag (silver-coated band), and ZnO (zinc oxide-coated band). The electrostatic spray-assisted vapor deposition method was used to coat orthodontic bands with nano-Ag or nano-ZnO. The biofilm inhibition test was used to assess the antimicrobial effectiveness of nano-Ag and nano-ZnO against Streptococcus mutans, Lactobacillus acidophilus, and Candida albicans. Biocompatibility tests were conducted using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. The groups were compared using one-way analysis of variance with a post-hoc test. Results: The Ag group showed a significantly higher reduction in the number of L. acidophilus, C. albicans, and S. mutans colonies than the ZnO group (p = 0.015, 0.003, and 0.005, respectively). Compared with the control group, the Ag group showed a 2-log10 reduction in all the microorganisms' replication ability, but only S. mutants showed a 2-log10 reduction in replication ability in the ZnO group. The lowest mean cell viability was observed in the Ag group, but the difference between the groups was insignificant (p > 0.05). Conclusions: Coating orthodontic bands with nano-ZnO or nano-Ag induced antimicrobial effects against oral pathogens. Among the nanoparticles, nano-Ag showed the best antimicrobial activity and nano-ZnO showed the highest biocompatibility.
Afsaneh Shahbazi,Habibollah Younesi,Alireza Badiei 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.9
Organofunctionalized nanostructured silica SBA-15 with tri(2-aminoethyl)amine tetradentate-amine ligandwas synthesized and applied as adsorbent for the removal of Cu2+, Pb2+, and Cd2+from both synthetic wastewater andreal paper mill and electroplating industrial effluents. The prepared materials were characterized by XRD, N2 adsorp-tion-desorption, TGA, and FT-IR analysis. The Tren-SBA-15 was found to be a fast adsorbent for heavy metal ionsfrom single solution with affinity for Cu2+, Pb2+, than for Cd2+due to the complicated impacts of metal ion electronega-tivity. The kinetic rate constant decreased with increasing metal ion concentration due to increasing of ion repulsionforce. The equilibrium batch experimental data is well described by the Langmuir isotherm. The maximum adsorptioncapacity was 1.85 mmol g−1for Cu2+, 1.34 mmol g−1for Pb2+, and 1.08 mmol g−1for Cd2+at the optimized adsorptionconditions (pH=4, T=323 K, t=2 h, C0=3mmol L−1, and adsorbent dose=1 g L−1). All Gibbs energy was negative asexpected for spontaneous interactions, and the positive entropic values from 103.7 to 138.7 J mol−1K−1also reinforcedthis favorable adsorption process in heterogeneous system. Experiment with real wastewaters showed that approxi-mately a half fraction of the total amount of studied metal ions was removed within the first cycle of adsorption. Hence,desorption experiments were performed by 0.3M HCl eluent, and Tren-SBA-15 successfully reused for four adsorp-tion/desorption cycles to complete removal of metal ions from real effluents. The regenerated Tren-SBA-15 displayedalmost similar adsorption capacity of Cu2+, Pb2+, and Cd2+even after four recycles. The results suggest that Tren-SBA-15is a good candidate as an adsorbent in the removal of Cu2+, Pb2+, and Cd2+from aqueous solutions.
A Study of the Diastereoselectivity of Diels-Alder Reactions on the Ce-SiO<sub>2</sub> as Support
Ziarani, Ghodsi Mohammadi,Badiei, Alireza,Miralami, Azam Korean Chemical Society 2008 Bulletin of the Korean Chemical Society Vol.29 No.1
The diastereoselectivity of Diels-Alder reactions were studied on the silica surface supported with different concentrations of cerium ion as efficient Lewis acid catalysts under solvent-free conditions. The results showed that the diastereoselectivity of reaction was highly improved in these conditions. The cerium ion was grafted on silica surface by using ion exchange method.
Norouzy, Amir,Habibi-Rezaei, Mehran,Qujeq, Durdi,Vatani, Maryam,Badiei, Alireza Korean Chemical Society 2010 Bulletin of the Korean Chemical Society Vol.31 No.1
A sensory element against carbaryl, as a widely used pesticide was prepared based on adsorbed acetylcholine esterase (AChE) from Torpedo california. Octadecyl was substituted on macro-porous silica, confirmed by infra-red (IR) spectroscopy and quantitatively estimated through thermo-gravimetric analysis (TGA). Immobilization of the enzyme was achieved by adsorption on this support. Activity of the immobilization product was measured as a function of the loaded enzyme concentration, and maximum binding capacity of the support was estimated to be 43.18 nmol.mg-1. The immobilized preparations were stable for more than two months at storage conditions and showed consistency in continuous operations. Possible application of the immobilized AChE for quantitative analysis of carbaryl is proposed in this study.
Amir Norouzy,Mehran Habibi-Rezaei,Durdi Qujeq,Maryam Vatani,Alireza Badiei 대한화학회 2010 Bulletin of the Korean Chemical Society Vol.31 No.1
A sensory element against carbaryl, as a widely used pesticide was prepared based on adsorbed acetylcholine esterase (AChE) from Torpedo california. Octadecyl was substituted on macro-porous silica, confirmed by infra-red (IR) spectroscopy and quantitatively estimated through thermo-gravimetric analysis (TGA). Immobilization of the enzyme was achieved by adsorption on this support. Activity of the immobilization product was measured as a function of the loaded enzyme concentration, and maximum binding capacity of the support was estimated to be 43.18 nmol․mg-1. The immobilized preparations were stable for more than two months at storage conditions and showed consistency in continuous operations. Possible application of the immobilized AChE for quantitative analysis of carbaryl is proposed in this study.