Karakteristik Lignin Daun Tebu yang Diisolasi dengan Asam Konsentrasi Rendah

Abstract

Lignin daun tebu merupakan salah satu komponen biomassa yang berpotensi sebagai sumber bahan kimia alami. Sifat kimia dan metode isolasi mempengaruhi sifat bioproduk. Penelitian ini bertujuan mengkaji pengaruh metode sekeunsial pra-perlakuan daun tebu dan metode isolasi lignin terhadap rendeman isolasi lignin, sifat fisikokimia dan termal. Padatan kemudian dikarakterisasi fisikokimia dan termal (TGA dan DSC). Hasil penelitian menunjukkan kadar αselulosa pra-perlakuan asam microwave-basa autoclave lebih tinggi dibandingkan dengan pra-perlakuan asam microwave-basa microwave dengan kelarutan hingga mencapai 94%. Hasil isolasi pra-perlakuan asam microwave-basa microwave lebih tinggi dibandingkan dengan pra-perlakuan asam microwave-basa autoclave yang mencapai diatas 68%. Lignin hasil isolasi kedua proses pra-perlakuan memiliki nisbah S/G yang sama. Isolat lignin menunjukkan keberhasilan proses isolasi yang ditandai dengan adanya gugus fungsi penciri lignin dalam spektra FTIR seperti - CH, C=O dan C-O. Analisis TGA lignin masing-masing pra-pelakuan memiliki karakteristik degradasi termal yang sama. Analisis DSC menunjukkan adanya satu titik transisi glass (Tg) dengan masing-masing suhu Tg hasil pra-perlakuan asam microwave -basa microwave dan asam microwave-basa autoclave yaitu 128,44 oC dan 131,02 oC

Sugarcane leaf lignin is one of the chemical components of biomass that have prospects for natural chemicals. The chemical characteristics and the isolation method of lignin influence the bioproduct properties. The research examined the effect of the sequential pre-treatment method of sugarcane leaf and lignin isolation method on isolated lignin's yield, physicochemical and thermal characteristics. The pulp was then characterized by the chemical component and the yield, while the isolated lignin was analyzed the physicochemical and the thermal (TGA, DSC) characteristics. The results showed that the cellulose content of pretreated with acid microwave-alkaline autoclave was higher than the pre-treatment of the acid microwave-alkaline microwave with the lignin removal reached up to 94 %. The yield of isolated lignin derived from acid microwave-alkaline microwave was higher than the pre-treatment of acid microwave-alkaline autoclave, which was reached 68 %. The isolated lignin from both pre-treatment methods has the same S/G ratio. FTIR spectra indicate the functional groups of typical lignin such as -CH, C=O, and CO, indicating the isolation method's success. TGA analysis of lignin indicated that both lignins have similar thermal degradation characteristics. In contrast, DSC analysis showed a glass transition (Tg) with each Tg temperature to sugarcane trash lignin from the acid microwave-alkaline microwave and acid microwave-alkaline autoclave were 128.44 °C and 131.02 °C, respectively.