Penambahan Silikon Dioksida (SiO2) Dari Bottom Ash Boiler Pabrik Kelapa Sawit dalam Pembuatan Komposit PVA/SiO2 Untuk Pemisahan Zat Warna Methylene Blue

Abstract

Methylene blue used by industry which when discharged into the environment disrupts the activity of aquatic organisms. Removal of methylene blue is carried out to maintain environmental sustainability. Adsorption is the most widely used method because it is cheap and practical. The selection of adsorbents is based on adsorption capacity, production costs and regeneration performance. Polymer-based adsorbents have attractive properties such as uniform pore distribution and are easy to recycle. PVA (Polyvinyl Alcohol) is used because of its biocompatible, non-toxic and easily biodegradable properties. SiO2 (Silicon Dioxide) has a high surface area composited with PVA to increase the thermal, mechanical and surface area stability of the composite. Bottom ash of palm oil mill (PKS) boilers is a source of SiO2 with a content of 63.90%. Therefore, it is necessary to conduct research on the manufacture of PVA and SiO2-based composites from PKS boiler bottom ash with the aim of analyzing the effect of SiO2 variations on the characteristics of PVA/SiO2 composites. This study consists of three stages, namely: (1) extraction of SiO2 using HCl and NaOH from the bottom ash of the PKS boiler and characterization (SEM, XRF, XRD, FTIR), (2) making composites with variations in silica composition of 5, 10, 15, 20% by weight of PVA and characterization (SEM, FTIR, Swelling, BET, and UTM), and (3) composites as methylene blue adsorbents with variations in time (60, 120, 180, 240, and 300 minutes) and adsorption lighting (dark and light). The optimum condition of the composite with a silica composition of 20% at an adsorption time of 240 minutes under bright conditions showed a methylene blue removal rate of 90.25%. The adsorption kinetics study showed that the experimental data for dark and bright conditions were in accordance with the Pseudo-Second Order model, with R2 values ranging from 0.9321 and 0.9861.