Climate change caused by the greenhouse gases CO2 remains a topic of global concern. To mitigate the excessive levels of anthrophonic CO2 in the atmosphere, CO2 capture methods have been developed and among these, adsorption is an especially promising method. This paper presents a series of amine functionalized biochar obtained from desiccated coconut waste (amine-biochar@DCW) for use as CO2 adsorbent. They are ethylenediamine-functionalized biochar@DCW (EDA-biochar@DCW), diethylenetriamine-functionalized biochar@DCW (DETA-biochar@DCW), triethylenetetramine-functionalized biochar@DCW (TETA-biochar@DCW), tetraethylenepentamine-functionalized biochar@DCW (TEPA-biochar@DCW), and pentaethylenehexamine-functionalized biochar@DCW (PEHA-biochar@DCW). The adsorbents were obtained through amine functionalization of biochar and they are characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, Brunauer-Emmett-Teller (BET), and thermogravimetric analysis (TGA). The CO2 adsorption study was conducted isothermally and using a thermogravimetric analyzer. From the results of the characterization analyses, a series of amine-biochar@DCW adsorbents had larger specific surface area in the range of 16.2 m2/g-37.1 m2/g as compare to surface area of pristine DCW (1.34 m2/g). Furthermore, the results showed an increase in C and N contents as well as the appearance of NH stretching, NH bending, CN stretching, and CN bending, suggesting the presence of amine on the surface of biochar@DCW. The CO2 adsorption experiment shows that among the amine modified biochar adsorbents, TETA-biochar@DCW has the highest CO2 adsorption capacity (61.78 mg/g) when using a mass ratio (m:m) of biochar@DCW:TETA (1:2). The adsorption kinetics on the TETA-biochar@DCW was best fitted by the pseudo-second model (R2 = 0.9998), suggesting the adsorption process occurs through chemisorption. Additionally, TETA-biochar@DCW was found to have high selectivity toward CO2 gas and good reusability even after five CO2 adsorption-desorption cycles. The results demonstrate the potential of novel CO2 adsorbents based on amine functionalized on desiccated coconut waste biochar.
Orally disintegrating tablets are a solid dosage form that will disintegrate rapidly within 3 minutes upon contact with saliva. Fillers or diluents are excipients that are used to make up the volume of orally disintegrating tablets, and some might act as a disintegrant or binder that will affect the physical properties of orally disintegrating tablets. The objective of this study was to formulate and evaluate physical properties of orally disintegrating tablets containing Annona muricata leaves extract by a freeze-drying method using different fillers at different concentrations. In this study, fifteen formulations of orally disintegrating tablets were prepared by a freeze-drying method with different fillers such as starch, lactose, microcrystalline cellulose, StarLac, and CombiLac at 5%, 10%, and 15%. The orally disintegrating tablets were evaluated for hardness, thickness, weight variation, friability, and disintegration time test. The optimum formulation was chosen and incorporated with Annona muricata leaves extract. The results obtained in this work indicated that Formulation 3, with 15% starch, was the most optimum formulation due to the shortest disintegration time (21.08 seconds ± 4.24 seconds), and all the physical tests were within the acceptable range. The orally disintegrating tablets containing Annona muricata leaves extract possessed antioxidant activity and stable at least for 3 months under 60°C and 75% relative humidity.