Removal of reactive violet 5 azodye (V5R) using bamboo, and calabash biochar

Abstract

We assess the adsorption capacity of bamboo and calabash biochar (BB and CB). Using 10–50 mg/L Reactive Violet 5 Azo dye (V5R) adsorbate, the kinetics, and adsorption isotherms are investigated. We pyrolyzed the bamboo, and calabash biomass at 500 °C, washed, and oven dried at 120 °C for 48 h. The Brunauer–Emmett–Teller (BET) method indicates that the BB and CB average pore diameters are 21.1 nm and 26.5 nm, with specific surface areas of 174.67 m2/g and 44.78 m2/g, respectively. The SEM reveals a larger granular shape of the CB having pinholes on the surface, but the BB exhibited interconnected structures like a mesh. The FTIR shows C=C, C=O, O–H, and C–O–C as the predominant functional groups on both BB and CB. The adsorption of V5R on BB and CB follows pseudo-second-order kinetics and favors Langmuir isotherm with maximum adsorption capacities of 5.106 mg/g, and 0.010 mg/g, respectively. The BB adsorbs 70.9–96% V5R, whilst CB adsorbs 0.1–0.2 % only. The results suggest that bamboo biochar has the potential to eliminate 70.9–96% of 10–50 mg/L V5R from an aqueous solution, hence suitable for removing V5R. In this study, we have also presented a prototype expected to eliminate 91.6%–99.8% of the V5R from an aqueous solution.

Keywords

• Adsorption isotherm
• Kinetics
• Adsorptive capacity