High surface area mesoporous activated carbon from tomato processing solid waste by zinc chloride activation: process optimization, characterization and dyes adsorption

The aim of this study is to produce the activated carbon at optimum production conditions from the tomato processing waste by ZnCl2 activation. The influences of the production variables, such as impregnation ratio, carbonization temperature, and carbonization time on the some pore characteristics of produced carbons have been investigated, and the best production conditions were determined. The optimal activated carbon which had the highest surface area and pore volume was obtained by these conditions as follows: 6:1 impregnation ratio, 600 °C carbonization temperature and 1 h carbonization time. The optimum conditions resulted in an activated carbon with a carbon content of 53.92% and a yield of 38.20%, while the surface area of 1093 m2/g, with the total pore volume of 1.569 cm3/g, mesoporosity of 91.78% and average pore diameter of 5.92 nm. It was characterized by some physical and chemical techniques. Its adsorptive performance was tested using methylene blue and metanil yellow dyes. The adsorption behavior was well described by the Langmuir isotherm model, showing a maximum adsorption capacity for methylene blue and metanil yellow of 400 mg/g and 385 mg/g, respectively. The results revealed the potential use of optimal activated carbon for removal of cationic and anionic dyes.