Optimization of Rhodamine Natural Dye Extraction from Sawdust Waste of Switenia Mahagoni and Shorea Sp. and Determination of Extractor Design Parameters
Currently, there is an increase in the usage of natural dyes as an alternative to synthetic dyes which can cause severe health problems such as cancer and heart diseases. Thus, there is an urgent need to improve the technology in natural dyes recovery and to explore its natural sources. One of the most valuable natural dyes is Rhodamine which can be extracted from the waste of wood based industries. In this study, Switenia Mahagoni and Shorea Sp. trees were chosen. The objective of this study is to optimize the operating condition of extraction and to determine the extractor design parameters. Furthermore, it is hope that the industries produce zero emission, eco-friendly and give beneficial to the communities financially. Spectrophotometric method was used to determine the quality and quantity of Rhodamine extracted at wavelength of 530 nm. The highest yield was resulted (about 10 %) by varying solvent, time of extraction, temperature and ratio of sawdust per solvent volume. Design parameters were presented as mass transfer coefficient (Kc) and effective diffusivity (De), and calculated using implicit finite difference approximation in combination with Hooke-Jeeves algorithm. The correlation among Kc (g/(cm2/min)) and its variables can be defined in equation consisted of Sherwood (Sh), Reynolds (Re) and Smith (Sc). The correlation was Sh = 2 + 8.5 x 10(-3).Re(0.617). Sc(0.33) for Switenia Mahagoni, while Shorea Sp. gave Sh = 2 + 5.7 x 10(-1).Re(0.197). Sc(0.33). De of both sawdust was in the range of 2.23 x 10-3 – 7.94 x 10-3 cm2/min.