A new biosource for synthesis of activated carbon and its potential use for removal of methylene blue and eriochrome black T from aqueous solutions

Abstract

Flora is a cheap, eco-friendly and recycling source of activated carbon. In this study, activated carbon (AC) was prepared from Datura metel seeds (D. M. seeds). The prepared AC was then used as a bioadsorbent for the removal of cationic and anionic dyes. Initially, the AC was prepared by pyrolysis method and then characterized by using different techniques such as FTIR, BET, SEM, EDX and XRD. From the EDX analysis, it was found that the carbon contents was drastically increased from 65 to 85.5 by atomic%, while XRD analysis concluded the formation of graphitic carbon due to the presence of peak at 25° 2theta position. Different parameters were tested to assess the effectiveness of biomass and the prepared AC toward adsorption of two dyes i.e. methylene blue (MB) and Eriochrome black T (EBT). The results demonstrated that adsorption of MB and EBT were remarkably boosted with rising concentration of the dyes and the agitation speed. In contrast, it significantly decreased with rising the temperature, and the highest adsorption was observed at 10 °C. From contact time, it was found that equilibrium position was achieved in 60 min for both MB and EBT. The study of alteration of pH indicated that the optimum pH for adsorption of MB and EBT was 6 and 2, respectively. The current data for both the dyes well follow Langmuir isotherm compared to the Freundlich isotherm. Additionally, the adsorption process dynamics was measured in terms of rate constant and it was found that data well follow pseudo-2nd kinetic model. Generally, the adsorption of EBT was higher than MB on the prepared AC. These findings proposed that AC prepared from D. M. seeds is a promising alternative adsorbent that could be utilized as an efficacious adsorbent for the removal of cationic and anionic dyes.