Biodegradable natural carbohydrate polymeric sustainable adsorbents for efficient toxic dye removal from wastewater

The toxic anionic dye of methyl orange encapsulation was studied using biodegradable natural carbohydrate polymeric adsorbents of rice flour (RF) and graham flour (GF). The adsorbents were characterized by several instrumentations to understand the functionality and potential use. The dye adsorption parameter was measured based on the solution acidity, contact time, initial concentration effect, competing anions affinity, bonding mechanism, maximum adsorption capacity and reuses with biodegradability. The solution acidity was exhibited the key factor, and the suitable pH 7.0 and 5.50 were selected for RF and GF adsorbent, respectively based on the efficiency. The competing ions were not adversely affected in the dye adsorption as defined by the stable bonding mechanism. The adsorption data were highly fitted with the Langmuir adsorption model with monolayer coverage. The determined maximum adsorption was 173.24 and 151.27 mg/g for RF and GF, respectively, which was comparable with the other forms of materials. The desorption data was promising as the RF and GF adsorbents were used several cycles and therefore, the biodegradable adsorbents are promising to use in the real sample treatment to clean up the contaminated water. (C) 2020 Elsevier B.V. All rights reserved.