Drying Kinetics and Mathematical Modeling of Casuarina Equisetifolia Wood Chips at Various Temperatures

Casuarina equisetifolia wood is extensively used as fire wood and is also being used extensively in gassifiers. Drying is an important procedure which has to be carried out before the wood is burnt. Experiments on Casuarina wood chips of dimension 5.08 cm × 5.08 cm with 2.54 cm thickness were carried out between 80oC to 100oC in a tray drier using air flow velocity of 0.5m/s. Initial moisture content was found to be 48% on dry basis. The experimental drying curves showed only the falling rate period. Eleven thin-layer drying kinetic models were fitted with the experimental drying kinetics values and individual model constants were found. These models were compared using statistical measures like correlation coefficient, root mean square error, mean bias error and reduced chi-square to estimate the best model that would fit for the experiment. The drying rate and effective diffusion coefficient (Deff) were found to increase with temperature

Drying Kinetics and Mathematical Modeling of Casuarina Equisetifolia Wood Chips at Various Temperatures

Casuarina equisetifolia wood is extensively used as fire wood and is also being used extensively in gassifiers. Drying is an important procedure which has to be carried out before the wood is burnt. Experiments on Casuarina wood chips of dimension 5.08 cm × 5.08 cm with 2.54 cm thickness were carried out between 80oC to 100oC in a tray drier using air flow velocity of 0.5m/s. Initial moisture content was found to be 48% on dry basis. The experimental drying curves showed only the falling rate period. Eleven thin-layer drying kinetic models were fitted with the experimental drying kinetics values and individual model constants were found. These models were compared using statistical measures like correlation coefficient, root mean square error, mean bias error and reduced chi-square to estimate the best model that would fit for the experiment. The drying rate and effective diffusion coefficient (Deff) were found to increase with temperature

High temperature CO2 sorption using Ca(OH)2 in pilot scale packed column

Carbon dioxide is the major content of greenhouse gases, which is released by many industries such as paper, cement and steel industries etc. Removal or separation of CO2 from the atmosphere is a challenging task for the researchers as it related to the human health and affects environment. Many methods and techniques have been tried for the removal of CO2, among them sorption method was found to be more simple and economical. Majority of research work related to CO2 sequestration was carried out using Thermo Gravimetric Analysis (TGA). In the present study an attempt was made to study high temperature CO2 sorption using self-fabricated packed bed column in pilot scale. In this work the absorption column was designed to utilize the flue gas temperature for effective sorption of carbon dioxide using Calcium hydroxide [Ca(OH)2] as a sorbent. The Ca(OH)2 was made into cylindrical extrudates. The gas mixture containing nitrogen and carbon dioxide was heated and subjected to CO2 sorption using Ca(OH)2. The sorption process for various temperatures was studied at a constant flow rate and fixed bed height. Concentration of CO2 was measured using a flue gas analyzer (NDIR sensors). The temperature was found to be major factor affecting sorption process. The optimum temperature was found to be 300 °C. Increase in the temperature above 300 °C, resulted in sintering and weight loss of the sorbent. The conversion of Ca(OH)2 to CaCO3 is confirmed by FT-IR, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis(EDAX) and XRD

Combustion Assisted Synthesis of CuO Nanoparticles and Structure-Property Evaluation in nano-CuO Polymer Composites

Metal oxide-based nanoparticle as a filler in epoxy polymer composites has diverse applications in various industries, including adhesives, automobiles, aerospace, wind energy, and civil engineering. However, these composites must fulfill essential properties encompassing chemical, curing, optical, and thermal attributes. This study focuses on enhancing epoxy polymer by integrating copper oxide (CuO) nanoparticles synthesized through solution combustion. Varied CuO loadings (0.5–2.5 wt.%) were impregnated into the epoxy, critically impacting the structural attributes of the resulting nano-CuO polymer composites. Various material characterization techniques were employed to study the synthesized materials' morphology, elemental composition, phase formation, identification of the presence of functional groups, thermal stability, and optical properties. SEM images show the presence of spherical particles with porous structures. EDX confirmed the presence of Cu and O elements, while the XRD pattern showed the formation of CuO with an average crystallite size of 46 nm. FTIR confirms the presence of O-H, C-H, and C=C functional groups. TGA showed thermal stability and revealed minimal mass loss below 250 °C for nano-CuO polymer composites and minimal mass loss occurred for CuO nanoparticles at 900 °C. Photoluminescence exhibited redshifted luminescence spectra. The study suggests improved qualities due to CuO nanoparticle integration into epoxy. CuO loading crucially influences nano-CuO polymer composite properties, rendering them ideal for high-temperature applications, supported by remarkable thermal stability evidenced by substantial residual mass in TGA

Carica papaya-Derived Carbon Nanodots for the Detection of Fe (III) Ions

Carbon dots (CDs) possess distinctive optical and electronic properties as well as dimensions smaller than 10 nm, making them a unique category of carbon-based nanomaterials. They have been widely utilized across various domains including sensors, photocatalysis, biomedicine, and optoelectronics. This study investigates the use of a one-step hydrothermal synthetic approach to produce nanocarbon dots derived from Carica papaya seeds. Through the application of sophisticated characterization methods, the structural properties of the carbon nanoparticles were verified. These techniques included UV-visible absorption spectroscopy, fluorescence spectroscopy, Fourier transform infrared spectroscopy, and high-resolution transmission electron microscopy (HR-TEM). The photoluminescence emission of carbon dots (CDs) has been found to depend on excitation, as determined by photoluminescence (PL) spectroscopy. This study has explored the interaction between various metal ions and the photoluminescent properties of CDs, revealing a particularly noteworthy interaction with Fe (III) ions. The Stern-Volmer equation is utilized to examine the extinction mechanism linked with the sensing capability of carbon dots, resulting in the establishment of a recognition threshold of 0.36 μM. The existence of surface functional groups, which enable the formation of complexes with Fe (III) ions is a primary factor contributing to the sensing capabilities observed. This paper explores the fabrication and advancement of environmentally friendly sensor systems for detecting metal ions in biomedical and environmental contexts

Photocatalytic degradation of methylene blue using a zinc oxide-cerium oxide catalyst

The photocatalytic degradation of methylene blue in aqueous solution was studied using a UV source in the presence of zinc oxide-cerium oxide (ZnO-Ce2O3) as photocatalyst, which was synthesized by a gel combustion technique and characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy. The particle size of the catalyst was found to be in between 45 to 60 nm. The effects of catalyst loading (1.0-8.0 g/L), pH (4.0-9.2) and dye concentration (5.0-20.0 mg/L) on the degradation were studied in a batch reactor. The degradation rate was found to be strongly dependent on these experimental parameters. Appreciable degradation of methylene blue was achieved when the catalyst was calcined before use. Best results were observed with a catalyst loading of 5 g/L at pH = 9.2

Silicon Carbide-Coated Ceramic Membrane Bioreactor for Sustainable Water Purification

In the present study, a submerged ceramic membrane bioreactor was used to effectively treat industrial wastewater. The outcome of membrane coatings on the efficacy of the membrane was investigated using a silicon carbide (SiC) coating. The flux data obtained from the study were fitted into two mathematical models, namely, the standard pore blocking model (SPBM) and the complete pore plugging model (CPPM) in order to determine the fouling mechanism. It was observed that the SPBM fit with a minimum coefficient of regression of 0.95, suggesting that particles retained on the pore walls were smaller than the average size of membrane pores. An increase in dissolved oxygen (DO) of up to 225% was noted. The significant improvement of the water quality in terms of DO, chemical oxygen demand (COD) and turbidity of coated membrane emphasizes the fact that the membrane coating increases the efficacy of water treatment in membrane bioreactors