Abstract
In this study, biomass of grass waste (GW) was utilized as sustainable precursor to produce highly porous activated carbon (GWAC) with mesoporosity using a K2CO3-assisted pyrolysis approach and tested for its methylene blue (MB) dye adsorption properties. The prepared GWAC was characterized using the various techniques of specific surface area (SSA), Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX), X-ray diffractometer (XRD), thermogravimetric analysis (TGA), and Fourier Transform Infrared (FT-IR) spectrophotometer. The characterization results indicate the successful conversion of GW into mesoporous GWAC with high and desirable surface area of 1245.6 m2/g. The adsorptive performance of GWAC towards MB uptake was evaluated. To attain higher performance of the activated carbon for MB adsorption, the adsorption key parameters such as GWAC dosage (A: 0.04–0.06 g/L), pH (B: 4–10), temperature (C: 30–60 °C), and time (D: 5–15 min) were optimized using the Box–Behnken design (BBD) method. The adsorption equilibrium data were accurately described by the Langmuir model, where the adsorption capacity (qm; 364.2 mg/g) was recorded at the optimized process temperature of 45 °C. The present research also examined the mechanisms associated with the removal of MB using GWAC and observed the contribution of various MB-GWAC surface interactions (e.g., electrostatic, π-π, and H-bonding interactions). The present investigation shows the utility and effectiveness of GW biomass based activated carbon due to its favorable mesoporosity and cationic dye uptake in aqueous media.
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•Grass waste activated carbon (GWAC) was produced via K2CO3 assisted pyrolysis.•The GWAC was used for adsorption of methylene blue dye.•Box–Behnken design was applied to enhance the adsorption process.•The adsorption capacity for methylene blue dye was 364.2 mg/g.