Tetracycline adsorption by H3PO4-activated carbon produced from apricot nut shells: A batch study

• A H3PO4-activated carbon was prepared from apricot stone.
• The ACAS showed BET surface area of 307.6 m2 g−1 and mesoporous feature (61.1%).
• The mechanisms of tetracycline adsorption onto ACAS was investigated.
• The prepared porous activated carbon could remove tetracycline efficiently (qm = 308.33 mg g−1).

Tetracycline (TC) batch adsorption was investigated in a synthesized aqueous solution using activated carbon (AC) prepared from apricot shell. The adsorbent was produced via a chemical activation method using phosphoric acid. The specific surface area, total pore volume, and average pore diameter were 307.6 m2 g−1, 0.191 cm3 g−1, and 1.957 nm, respectively. Our analysis revealed that the material produced primarily consisted of mesopores (61.1%). The effect of adsorbent dosage, contact time, initial TC concentration, temperature, and initial pH of the solution on TC adsorption was studied. A thermodynamics analysis revealed that the adsorption process is endothermic and spontaneous. Adsorption isotherms were investigated, and it was shown that the Freundlich model was the best fit for the adsorption equilibrium data. The maximum adsorption capacity of TC onto activated carbon was 308.33 mg g−1, and the adsorption kinetics perfectly matched those of the pseudo-second order model. It was concluded that adsorption of TC is controlled by both intra-particle diffusion and film diffusion mechanisms. The results showed the successful application of synthesized activated carbon for effective removal of TC.