Preparation, characterization and atrazine adsorption potential of mesoporous carbonate-induced activated biochar (CAB) from Calligonum Comosum biomass: Parametric experiments and kinetics, equilibrium and thermodynamic modeling

The present work reports the preparation and characterization of a biocahr activated with K2CO3 from waste Calligonum Comosum biomass making carbonate-induced activated biochar (CAB). The carbon activated with a 5% K2CO3 solution had the highest potential for pesticide atrazine adsorption. The CAB was characterized and the results showed that it is a mesoporous material with the BET specific surface area of 1473 m2/g and a high amount of oxygenated surface functional groups. The maximum atrazine adsorption onto CAB was observed at the neutral water pH. The atrazine adsorption onto the CAB was best fitted with the pseudo-second-order model and the adsorption rate improved with the increase in solution temperature. The intraparticle diffusion controlled the rate of atrazine adsorption onto CAB under the selected conditions. The adsorption equilibrium results have best fitness with the Langmuir isotherm model. The maximum adsorption capacity onto CAB increase from 370.4 mg/g at solution temperature of 10 °C to 714.3 mg/g when the solution temperature was increased to 40 °C. The maximum adsorption capacity of CAB was over times of that of standard activated carbon under the maximum tested solution temperature. The thermodynamic analysis indicated that the atrazine adsorption onto CAB is a spontaneous chemisorption and endothermic process. The findings highlight the promise of CAB for high rate and efficient treatment of pesticide-contaminated water.