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RISS 인기검색어
- 검색키워드
- 저자 : Sabriye Piskin (검색결과 2 건)
- 무료
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Synthesis, crystal structure and dehydration kinetics of NaB(OH)4·2H2O
Sabriye Piskin,Aysel Kanturk,Muge Sari 한국화학공학회 2008 Korean Journal of Chemical Engineering Vol.25 No.6
Sodium metaborate tetrahydrate (NaB(OH)4·2H2O) was synthesized by reaction of anhydrous borax (Na2O· 2B2O3) with sodium hydroxide (NaOH) under conditions at 90 oC for 150 min. The structure was characterized by Xray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM) and Thermogravimetric (TG) analyses. Moreover, dehydration kinetics of NaB(OH)4·2H2O was carried out under non-isothermal conditions and the Coats-Redfern method was applied to analyze the TG data for calculation of activation energies (Ea) and pre-exponential factors (ko) for different heating rates. It was determined that dehydration of sodium metaborate tetrahydrate occurred in five steps. According to the Coats-Redfern non-isothermal model, Ea and ko were calculated as 50.89 kJ/mol and 26×104 min−1 for region I, 18.51 kJ/mol and 0.87×103 min−1 for region II, 15.72 kJ/mol and 0.52× 103 min−1 for region III, 4.37 kJ/mol and 0.04×103 min−1 for region IV and 37.42 kJ/mol and 8.56×103 min−1 for region V, respectively.
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Thermal degradation characteristic of Tetra Pak panel boards under inert atmosphere
Sabriye Piskin,Aysel Kantürk Figen,Evren Terzi,Nural Yilgör,Saip Nami Kartal 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.4
Thermal degradation characteristics of Tetra Pak panel boards (TPPB) can be useful to improve usage of such panels as an alternative to wood-based products such as plywood, fiberboard, and particleboard. In the study, samples from the TPBBs manufactured from waste Tetra Pak packages (WTPP) were heated in a nitrogen atmosphere at different heating rates (10, 15 and 20 oC/min) using a thermal analysis system. The Coats-Redfern kinetic model was applied to calculate kinetic parameters. The degradation rate equations were then established. In addition, the kinetic compensation effect (KCE) was used to correlate the pre-exponential factor (ko) with activation energy (Ea) and the existence of the KCE was accepted. TG-FT/IR analyses were applied to the TPPB degradation and then the FT-IR stack plot was used to analyze gas products (CO2, CH4, HCOOH, and CH3OH). Infrared vibrational frequencies and the micro,crystal structure of the TPPBs were investigated by Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscope (SEM) and X-Ray diffraction analysis (XRD), respectively.
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