Processing and activation of tire-derived char: A review

An indispensable component of many land-based transportation systems are tires. Tires are constructed from constituents resistant to both physical and chemical degradation, thus resulting in significant environmental challenges at the end of their life. One way of reducing the negative impact of waste tires is by recycling. Pyrolysis is often used to recycle used tires, yielding an attractive by-product: carbon. This carbon can be modified to produce activated carbon (AC), a material of significant industrial relevance. This review article analyzes the work done on activation of carbon char obtained from the pyrolysis of waste tires. Factors affecting the conversion of waste tires (type of reactor, temperature, time, heating rate, particle size, atmosphere, and demineralization) to carbon char (via pyrolysis) are examined. Major routes for the activation of carbon-based materials, i.e., physical and chemical activation, are discussed in detail. The effect of the surface area of the char on the production of activated carbon with different activating agents is also presented. This paper aims to explore the current challenges involved with the activation of carbon originating from waste tires and the review concludes with an outlook on future research opportunities for the commercial use of tire-derived activated carbon.