Adsorption behavior and kinetic of creatinine on coconut shell activated carbon with different pore structures

The adsorption behaviors of creatinine(CR) on coconut-shell activated carbons with different pore structures was investigated, and the relationship between BET surface area/pore size distribution and the adsorption capacity for creatinine was studied. Several kinetic models, such as pseudo-first-order, pseudo-second-order, and intra-particle diffusion kinetic models, were studied on the basis of adsorption data. Results showed that the micropores with pore size of 1-2.5 nm were beneficial for adsorption of CR. The adsorption capacity reached 104 mg/g on the coconut-shell activated carbon with average pore size 2.2 nm. The adsorption capacity of activated carbon for creatinine depended on the combination of the surface area, total pore volume and microporosity. The intraparticle diffusion was not the only rate-determining step. It was found that the adsorption kinetics followed pseudo-second-order kinetic model, which correlation indexes were higher than 0.99. This suggested that the adsorption of CR on activated carbon was a chemisorption process. ©, 2015, Editorial Board of Chemistry and Industry of Forest Products. All right reserved.