Pyrolysis self-activation: An environmentally friendly method to transform biowaste into activated carbon for arsenic removal

[Display omitted] •Activated carbon are prepared without any added activators and auxiliary gases.•The activated carbon exhibits excellent arsenic adsorption property.•The mechanism of self-activation is explored and direct evidence is provided.•The gaseous product of self-activation has a high higher heating value. A green method for production of activated carbon and combustible gas was introduced. Without any external reagents and gases, the H2O and CO2 produced by the pyrolysis of bamboo shoot shells were used as activators. The prepared activated carbon had good arsenic adsorption properties with the maximum adsorption capacities of 10.9 mg/g for As(III) and 16.0 mg/g for As(V). The gaseous products were mostly CO and H2, with higher heating value of 11.7 MJ/Nm3. Thermogravimetric experiments were performed in N2, H2O and CO2 atmospheres to simulate the self-activation process and investigate the self-activation mechanism. This work will help to improve the competitiveness of self-activation technology and reduce the production cost of activated carbon.