NOPR Collection:

Thermodynamic and kinetic study of CO2 adsorption/desorptionon amine-functionalized sorbents

2019-11-01T00:00:00Z

Title: Thermodynamic and kinetic study of CO2 adsorption/desorptionon amine-functionalized sorbents Authors: Liu, Yamin; Wu, Junjie; Zhang, Chengbiao; Chen, Yilan; Xiong, Min; Shi, Ronghui; Lin, Xiaoying; Yu, Xiaojing Abstract: The thermodynamic and kinetic characteristics of CO₂ adsorption of SBA-16 loaded with pentaethylenehexamine (PEHA) have been investigated using adsorption column system. The Langmuir isotherm model fitts the CO₂ adsorption isotherms well, and the average isosteric heat of adsorption is 59.6 kJ/mol, indicating that the CO₂ adsorption on PEHA-loaded SBA-16 is chemisorption. The Avrami fractional dynamics model is very suitable for illustrating the adsorption behaviour of CO₂ adsorption, and the results of kinetic analysis show that increasing the partial pressure of CO₂ or the working temperature is beneficial to the adsorption of CO₂. Three desorption methods were evaluatedto achieve the optimal desorption method. The results show that VTSA and steam stripping method are effective methods for industrial CO₂ desorption. Steam stripping may be more suitable for plants that already have low-cost steam. The activation energy E_a of CO₂ adsorption/desorption is calculated using Arrhenius equation. The activation energy E_a of CO₂ adsorption/desorption was calculated using the Arrhenius equation. The results show that the absolute value of E_a (adsorption) decreases with the increase of CO₂ partial pressure. In addition, the E_avalue of vacuum rotary regeneration method and steam stripping method is smaller than the E_a value of temperature swing regeneration. Page(s): 473-482

Statistical optimization of the Zinc chloride activated biomass using Box-Behnken design

2019-11-01T00:00:00Z

Title: Statistical optimization of the Zinc chloride activated biomass using Box-Behnken design Authors: Das, Shilpi; Mishra, Susmita Abstract: The preparation of activated carbon from an economically sustainable precursor Limonia acidissima shell (an agricultural waste) by chemical activation method has been explored in the present study. This investigation emphasizes the application of a statistical tool, Response surface methodology (RSM) coupled with Box-Behnken design (BBD) to optimize the experimental conditions for the preparation of activated carbon from lignocellulosic wastes activated with ZnCl₂. The chemical activation is conducted at a different combination of impregnation ratios (IR), activation time and carbonization temperatures as suggested by the Design Expert software. The influences of these parameters on the responses i.e. iodine no. and yield of activated carbon has been investigated. Simultaneous optimization is performed using desirability approach. The desirability value reported for AC-ZnCl₂is 0.653. The carbon yield and iodine adsorption value approached 49.67% and 928.58 mg/g under the optimal conditions of impregnation ratio (1), activation time(57.09 min),and carbonization temperature (436.52°C). Important physicochemical properties of the optimized activated carbon is further confirmed by FTIR analysis, TEM analysis etc. Page(s): 483-493

Synthesis of green thermally resistant composite: A review

2019-11-01T00:00:00Z

Title: Synthesis of green thermally resistant composite: A review Authors: Dixit, Shobhit; Yadav, Vijay Laxmi Abstract: Rising demand for the sustainable environment has been enthused interest in the synthesis of a green composite. In the modern era, thermal insulating materials prepared from agro-waste have been concerned globally as they represent a biodegradability and inexpensive alternative to the conventionally derived materials. Nearly 350 million tons of agro-waste is generated through agricultural activity in India which are either land filled or incinerated. The reuse of renewable waste fibers as filler for reinforcement of a polymer composite is a worthwhile option to the environment. This extensive review explores the utilization of agro-waste for synthesis biodegradable thermal resistant composite and methods used for thermal conductivity measurement. Proper utilization of agro-waste is the need of the modern world. In this review, Authors found that agro-waste such as corn cob, corn stalk, rice waste, date palm fiber, durian peel fiber, coconut coir, and straw bales etc. can be blended into the polymer to enhancing its thermal resistant property by lowering their thermal conductivity. This review also investigated an effect of different parameters such as particle size, moisture content, density, and concentration of agro-waste in composite preparation. Page(s): 494-503

Synthesis and characterization of two novel antibacterial dendritic methacrylate-based dental monomers

2019-11-01T00:00:00Z

Title: Synthesis and characterization of two novel antibacterial dendritic methacrylate-based dental monomers Authors: Abbasian, Mojtaba; Jaymand, Mehdi; Lotfi, Mehrdad; Kimyai, Soodabeh Abstract: This study explores the synthesis and characterization of two novel antibacterial dendritic methacrylate-based dental monomers. For this purpose, two dendritic esters have been synthesized via condensation reaction and then reacted with methacryloyl chloride to afford methacrylate-end caped dendritic esters. These compounds are subsequently converted to quaternary ammonium ﬂuoride monomers (QAFMs) with decyl substituted side chain to produce two novel antibacterial dendreticdental monomers. The chemical structures of synthesized samples have been characterized using Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (¹H NMR) spectroscopies.The obtained monomers can be used to replace 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropyl)-phenyl]propane (Bis-GMA) as the base monomer of universal resin-based dental composites in the presence of a diluting monomer (e.g.,triethyleneglycoldimethacrylate; TEGDMA), mainly due to their superior characteristics such as multifunctionalities as well as antibacterial activities. Page(s): 504-513