Innovative green preparation of activated carbon by combining microwave pyrolysis and self-activation: Pyrolysis behavior, carbon characteristics and arsenic adsorption properties

Self-activation technology offers an eco-friendly strategy to produce activated carbons. This research attempted to enhance the production efficiency of self-activation by introducing microwave heating. Activated carbons were prepared as arsenic adsorbents from bamboo shoot shells (BSS) by combining microwave pyrolysis and self-activation. Microwave pyrolysis showed a faster thermal decomposition rate and lower pyrolysis temperature range than conventional pyrolysis, and H2O and CO2 from pyrolysis acted as activator. Besides, the prediction models of specific surface area (SSA), micropore volume (MPV) and As(V) adsorption capacity (qe) with high accuracy were established using response surface methodology. Based on the qe values, the optimum preparation condition was 1018 °C for 39 min under a microwave power of 1625 W. The activated carbon exhibited satisfactory As(V) adsorption capacity of 4.79 mg/g, with a total pore volume of 0.702 cm3/g and a SSA of 1330 m2/g. This work significantly improved self-activation technology's production efficiency and reduced the arsenic adsorbent's production cost. Furthermore, it also provided a promising strategy for green preparation of activated carbons from biomass resources. [Display omitted] •Activated carbons are prepared without any external activators.•Investigate the conventional pyrolysis and microwave pyrolysis characteristics.•The introduction of microwave significantly reduces the production time.•The prepared activated carbon exhibits excellent arsenic adsorption property.•Detailed prediction models for SSA, MPV, and adsorption capacity are established.