Journal Articles
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Item Studies on biosorption of methylene blue from aqueous solutions by powdered palm tree flower (Borassus flabellifer)(2014) M Kini, M.S.; Saidutta, M.B.; Ramachandra Murty, V.R.Biosorption experiments were carried out for the removal of methylene blue (MB) using palm tree male flower (PTMF) as the biosorbent at various pH, temperature, biosorbent, and adsorbate concentration. The optimum pH was found to be 6.0. The kinetic data were fitted in pseudofirst-order and second-order models. The equilibrium data were well-fitted in Langmuir isotherm and the maximum equilibrium capacities of the biosorbent were found to be 143.6, 153,9, 157.3 mg/g at 303, 313, and 323 K, respectively. Thermodynamic data for the adsorption system indicated spontaneous and endothermic process. The enthalpy and entropy values for adsorption were obtained as 15.06 KJ/mol and 0.129 KJ/mol K, respectively, in the temperature range of 303-323 K. A mathematical model for MB transported by molecular diffusion from the bulk of the solution to the surface of PTMF was derived and the values of liquid phase diffusivity and external mass transfer coefficient were estimated. © 2014 M. Srinivas Kini et al.Item Dilatometer studies on LAMOX based electrolyte materials for solid oxide fuel cells(Elsevier Ltd, 2021) Das, A.; Lakhanlal, u.; Shajahan, I.; Prasad Dasari, H.P.; Saidutta, M.B.; Harshini, H.The present study deals with the citrate complexion synthesis of LAMOX-based Solid Oxide Fuel Cell (SOFC) electrolyte materials (La1.8Dy0.2Mo2-xWxO9 (x = 0, 0.1, 0.2, 0.5, and 1), La1.8Dy0.2Mo2-xGaxO9 (x = 0.1 and 0.2), and La1.8Dy0.2Mo2-xVxO9 (x = 0.025, 0.05, 0.1, and 0.2)) and their characterization to understand the sintering behaviour and phase stability. From the dilatometer studies, the linear shrinkage and shrinkage rate of the LDMW (x = 0, and 0.1) showed better shrinkage than LM and LDM. Gallium addition (LDMG) and Vanadium addition (LDMV) showed a negative impact on shrinkage behaviour. In the temperature range of 500–580 °C, the abrupt change in shrinkage rate showed the transition of phase from ? to ? for the LM. The modification of LM to LDM, LDMW, and LDMV suppressed the formation of the ? phase. During thermal expansion behaviour study in the temperature range of 100–500 °C and 550–800 °C, the LM sintered pellet showed the coefficient of thermal expansion (CTE) values of 13.3 ? 10?6/°C and 21.6 ? 10?6/°C respectively. The LDM and LDMW sintered pellets showed the CTE values in the range of 14–15 ? 10?6/°C and 16–19 ? 10?6/°C, respectively. The relative density of the sintered pellets (1100 °C/5 h in air) (LM, LDM, LDMW, and LDMG (x = 0.1)) is found to be >90%. It provides the suitability of these materials for further investigation as electrolytes of SOFCs/SOECs. © 2020 Elsevier B.V.Item Electrical conductivity studies on LAMOX based electrolyte materials for solid oxide fuel cells(Elsevier Ltd, 2022) Srijith; Lakhanlal, u.; Das, A.; Prasad Dasari, H.P.; Saidutta, M.B.In this study, the electrical conductivity of the LAMOX based electrolytes (La1.8Dy0.2Mo2-xWxO9 (x = 0, 0.1, 0.2, 0.5, and 1), and La1.8Dy0.2Mo2-xGaxO9 (x = 0.1)) synthesized by the citrate complexion method has been studied using DC four-probe method. The electrical conductivity of the electrolytes is measured in the temperature range of 800–400 °C in the air (∼100 ml min−1). The effect of W and Ga substitution at the Mo site on the electrical conductivity is evaluated. The long-term electrical conductivity stability test (time on stream) (5 h) is conducted at 650, 580, and 520 °C to study the effect of possible phase transition on electrical conductivity. A high-temperature XRD study is also conducted in the temperature range of 500–650 °C (during heating and cooling) on selected electrolyte materials (La1.8Dy0.2Mo2-xWxO9 (x = 0 and 0.1) and La1.8Dy0.2Mo2-xGaxO9 (x = 0.1)) to study the α↔β phase transition. The electrical conductivity of these electrolytes in the air at 800 °C is in the range of 5.3 × 10−2 – 14 × 10−2 S cm−1. The activation energy (EA) of these electrolytes is in the range of 1.11–1.62 eV. The VTF parameters σo, B, and To are in the range of 67.46–395.88 S cm−1 K0.5, 0.122–0.254 eV, and 247–347 °C, respectively. The La1.8Dy0.2Mo2-xWxO9 (x = 0.1) shows highest electrical conductivity (14 × 10−2 S cm−1, EA = 1.54 eV) among all electrolytes in air at 800 °C and for this material the VTF parameters σo, B, and To are 170.32 S cm−1 K0.5, 0.153 eV, and 302 °C, respectively. © 2022 Elsevier Ltd and Techna Group S.r.l.