The pyrolysis process of coconut residue and the activated carbon was investigated using thermogravimetric analysis in the range of 25 to 900 °C, with three altered heating rates: 3, 5, and 10 °C/min. The results of the thermal decomposition showed that it occurred in three distinct phases: dehydration, active pyrolysis, and passive pyrolysis. The derivative thermogravimetric analysis indicated that increasing the heating rate led to a shift in the maximum weight loss rate towards higher temperatures. To better understand the kinetics constraints, the Coats–Redfern method was applied to determine the activation energy (Ea) and the frequency factor (A). The activation energies for the pyrolysis process varied between 159.57 and 177.45 kJ/mol for RCR and from 132.62 to 147.1 kJ/mol for ACCR at different heating rates. Additionally, the physical properties of the samples were investigated using techniques like scanning electron microscopy and the Brunauer–Emmett–Teller surface analysis. The findings of the study demonstrated that the activation energies of the activated carbon were lower than those of the original biomass. Furthermore, the activation energy values achieved from the D1–D4 models were considered reliable, indicating that the D model was more suitable compared to other models for describing the pyrolysis process and predicting its kinetics.

The gasification kinetics of pellets obtained from organic solid wastes (OWS) and raw materials were studied using the Coats–Redfern and DAEM methods. The different methods were comparatively analyzed for mutual verification, and the similar activation energies obtained by each method affirmed the accuracy of the kinetics calculation. Overall, the activation energies of the char gasification stage ranged from 200 to 265 kJ mol⁻¹, higher than those of the devolatilization stage, which ranged from 130 to 200 kJ mol⁻¹ for all pellets and raw materials. During the devolatilization stage, the activation energies of the pellets were invariably higher than those of their corresponding raw materials, which was the opposite for the char gasification stage. A detailed comparison between the calculation results from the Coats–Redfern and DAEM methods confirmed that the devolatilization stage is controlled by one-dimensional diffusion, and the gasification stage is controlled by two-dimensional or three-dimensional diffusion for pellets and raw materials.

Investigation relevant to the influence of activated carbon (AC) supports biomass of Eucalyptus Lanceolata as an adsorbent was not reported previously. The recent work synthesized a series of studies to know various experimental parameters equilibration time and temperature of the adsorbent for the elimination of dye. Physical structure characterization measured that the surface area of activated carbon increased from 399 to 475 m2.g-1 revealed that the raw biomass had more compact surface than those of activated carbon. FTIR bands were found in the region between 3406.29 cm-1 and 3414.0 cm-1 indicates (-OH) stretching group which leads to hydrogen bonding. Adsorption of Methylene blue was studied on raw and activated carbon. The average activation energy of the activated carbon was 33.67 kJ.mol-1, slightly lower than those of raw carbon, which was 49.14 kJ.mol-1. Intraparticle diffusion, Elovich and Bhangam models were applied to evaluate kinetics studies at 20, 30 and 40 ºC. Thermodynamic parameters, ΔH≠, ΔS≠ and ΔE≠ were calculated from the adsorption of kinetics. Results indicate that adsorption is a spontaneous process. The negative value of entropy determined that the acid molecules take an oriented position on the surface of the adsorbent. The results show that all the models were best fitted for adsorption. Resumen. Una investigación relevante y no reportada previamente respecto a la influencia del carbón activado (CA) apoya que la biomasa de Eucalyptus Lanceolata es un adsorbente. El reciente trabajo sintetizó una serie de estudios para conocer diversos parámetros experimentales de tiempo de equilibrio y temperatura del adsorbente para la eliminación del colorante. La caracterización de la estructura física determinó que el aumento del área superficial del carbón activado de 399 a 475 m2.g-1 revela que la biomasa cruda tenía una superficie más compacta que las del carbón activado. Se encontraron bandas FTIR en la región entre 3406.29 cm-1 y 3414.0 cm-1 indicando el estiramiento del grupo (-OH) que conduce al enlace de hidrógeno. Se estudió la adsorción de azul de metileno en carbón crudo y activado. La energía de activación media del carbón activado fue de 33,67 kJ.mol-1, ligeramente inferior a la del carbón bruto, que fue de 49,14 kJ.mol-1. Se aplicaron modelos de difusión intrapartícula, Elovich y Bhangam para evaluar estudios cinéticos a 20, 30 y 40 ºC. Los parámetros termodinámicos, ΔH≠, ΔS≠ y ΔE≠ se calcularon a partir de la cinética de adsorción. Los resultados indican que la adsorción es un proceso espontáneo. El valor negativo de la entropía determinó que las moléculas de ácido toman una posición orientada en la superficie del adsorbente. Los resultados muestran que todos los modelos se ajustaron mejor para la adsorción.

This study reports the aggregation behavior of polylactic acid (PLA) with ionic surfactants e.g. sodium dodecyl sulphate (SDS) and hexadecyltrimethylammonium bromide (CTAB) at different temperatures. Surface tension and conductivity techniques were used to investigate these physicochemical properties. Surface tension measurements were carried out to find out critical micelle concentration (CMC), free energy change of micellization (ΔG _m), free energy change of adsorption (ΔG _ads) and surface excess concentration (Γ). Conductivity measurements were used to determine CMC, degree of ionization (α) and degree of counter ion binding (β). The values of α and β obtained for SDS were (0.389 and 0.611 respectively), while for CTAB the values of α and β were (0.239 and 0.761 respectively). This type of electrostatic interactions is very important which can be applied in various industrial applications (e.g. pharmaceutical, industrial foaming, oil recovery etc.).