Sintesis dan Karakterisasi Komposit Kitosan–Silika dengan Metode Sol – Gel dari Ampas Tebu sebagai Adsorben Logam Berat Besi (III)

Abstract

Bagasse is a by-product obtained from the sugar industry and can be utilised as bagasse ash. Bagasse ash contains a high amount of silica, which has the potential to be synthesised into silica. Silica has stability, physical strength, and structural parameters that are easily controlled, but needs to be modified with organic compounds such as chitosan. In this study, chitosan silica composite was synthesised to be applied as iron (III) heavy metal adsorbent. This research aims to: (1) Isolate silica from bagasse waste (2) Know the mechanism of making chitosan silica composite (3) Analyse the characteristics of chitosan silica adsorbent by sol gel process (4) Analyse and apply chitosan silica adsorbent to the adsorption process of heavy metal iron (III). This research consists of several stages, including preparation of raw materials, isolation of silica from bagasse ash, preparation of sodium silicate solution, preparation of silica precipitates, preparation of silica chitosan composites, and adsorption of iron (III) heavy metal ions with pH variations (2,3,4,5,6). The results of analysis using XRF showed that the silica content in bagasse ash was 56.7%. Chitosan silica composite was synthesised using sol gel method. Analysis using FTIR showed the presence of Si-O group of siloxane group (Si-O-Si) and silanol group (Si-OH) in chitosan silica composite. Characterisation using SEM-EDX showed that the chitosan silica composite was unevenly distributed and contained 44.59% Si. The chitosan silica composite has potential as an adsorbent for iron(III) heavy metals in water with the results of (1) The best adsorbed iron(III) heavy metal occurs at pH 5 with an adsorbed iron(III) percentage of 63.97%. (2) Maximum absorption occurred at a concentration of 40 ppm iron solution with a percentage removal of 99.33% (3) The right model to describe the adsorption process of iron (III) on the surface of silica chitosan composites is the Langmuir isotherm model. A series of characterisations that have been carried out validate the potential of chitosan silica composites as adsorbents of iron (Fe) metal ions in water.