ADSORPTIVE REMOVAL OF METHYL ORANGE DYE USING BIOCHAR PREPARED FROM HIBISCUS FLOWER JUICE RESIDUE

Abstract

Dyes are natural or synthetic soluble organic colourants containing chromophoric compounds within their chemical structure. They are employed in different industrial sectors such as textile, food, pharmaceutical, leather, plastics etc, About, 10-15 % of these get streamlined into water bodies as effluents leading to several environmental and health problems. Biochar is a porous, carbonaceous, black solid residue similar to charcoal obtained by the pyrolysis of biomass at a temperature range of 350-900℃ in an
oxygen-deficient environment. In this study, biochar was produced by slow pyrolysis method in a muffle furnace at three different temperatures (300, 400 and 500℃) using Hibiscus sabdariffa flower residue for the adsorptive removal of methyl orange dye. It was characterized and applied for adsorptive removal of 50mg/L methyl orange with different adsorbent dosages (0.2-1g) and time (10-60minutes) The proximate parameters of the biochar were also analysed and HRB 500℃ had the highest yield (93.26%) and highest carbon content (75.10%) with the least moisture content (4.87%). The SEM image and FTIR spectra of the biochar produced at 500℃ were analysed for functional groups and surface properties respectively. SEM image showed a rough flaky texture with cracks and crevices suggesting a well-developed surface area of carbonaceous material. The OH and COOH groups aided adsorption through hydrogen bonding. The biochar produced at 500℃ was applied for the adsorption of methyl orange while varying the adsorbent dosage (0-1g) and time (0-60mins) at a fixed initial concentration and volume. The Langmuir and Freundlich adsorption isotherms constants were determined and adsorption occurred through both monolayer and multilayer interactions.