Sintesis dan Karakterisasi Hidrogel Berbasis Selulosa dari Tandan Kosong Kelapa Sawit sebagai Media Tanam pada Sistem Hidroponik

Abstract

Oil palm empty fruit bunches are a source of natural fiber from the abundant waste material found in the North Sumatra region. The fiber of empty palm fruit bunches has a high cellulose content and has the potential to be used as a hydrogel filler. This study aims to determine the optimum conditions for making cellulose fiber-based hydrogel from empty palm oil bunches and to determine the characteristics of a hydrogel based on carboxymethyl cellulose cross-linked with citric acid as a hydrogel growing medium in hydroponic systems (HNFC). This research began with the preparation of empty palm fruit bunches fiber, followed by the process of isolating α-cellulose from empty palm oil bunches using the steam explosion and acid hydrolysis methods. The α-cellulose obtained was then ultrasonicated and homogenized, resulting in cellulose nanofiber powder (NSS) with an average diameter distribution of 24,28 nm. NSS characterization was carried out by FT-IR, SEM, TEM, and XRD. The resulting NSS is used as a filler in hydrogels made from sodium carboxymethyl cellulose (NaCMC) with citric acid crosslinkers. Hydrogel characterization was carried out by FT-IR, SEM, TEM and TGA/DTG, water absorption test, water retention test, degree of cross-linking test, gel fraction and antimicrobial test using bacteria and fungi. Based on the thermal properties, morphological properties, from the results of the characterization and tests on the hydrogel it was found that the most potential to be developed as a cellulose-based hydrogel planting medium was at a concentration of 1.25%. This can be seen from the high degree of cross-linking (90.48%), water absorption capacity (118%) and water retention ability (339.0), and has good inhibition of bacteria and fungi compared to other NSS concentration variations. Statistical analysis on the growth of pakcoy plants (Brassica rapa) with 1.25% HNFC hydrogel growing media. obtained the highest yield for plant height and number of leaves, compared to the control, namely rockwool in the hydroponic system, where the best treatment was N7 = Rockwool : HNFC1.25 = 30 : 70. This indicated that the hydrogel was HNFC1.25. with a concentration of 1.25% has a potential of 70% to be used as a planting medium in an axis hydroponic system, as an alternative planting medium for rockwool.