Adsorption studies of methylene blue and phenol onto black stone cherries prepared by chemical activation

The production of granular activated carbon (GAC) basically depends on the correct selection of carbonization temperature, activation ratio and agent (physical or chemical) as well as the raw material. Black cherry, available in Mexico with relative abundance, is of the same genus as the European cherry, whose stones have yielded good GAC production results. Black cherry stones were tried as raw material for GAC production with phosphoric acid as the activating agent. Optimum carbonization temperatures were found to be between 500 and 550 °C with an activation ratio of 1.0 g of phosphoric acid/g raw material. Under these conditions the maximum yield was 48.16 g of GAC/100 g black cherry stones. The experimental adsorption parameters fitted into Langmuir's model with a maximum adsorption of 321.75 mg of methylene blue/g GAC and 133.33 mg of phenol/g GAC. Black cherry shells are an abundant agricultural by-product with no uses, and therefore are an alternative for producing GAC.