Synthesis and comparison studies of activated carbons based folium cycas for ciprofloxacin adsorption

Abstract

The comparison of activated carbons with bicarbonate as the activating agents for antibiotics adsorption have rarely been studied. In this study, the four samples were synthesized from low-cost and green raw material (folium cycas) by potassium bicarbonate or sodium bicarbonate activation with or without urea as the assist activating agent in one step. The product carbons were characterized by N2 adsorption/desorption isotherm, scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), Boehm’s titration methods. The results show that potassium bicarbonate and urea are favorable for the development of pores and the formation of functional groups, carbon activated by potassium bicarbonate and urea (FPU-C) has the highest BET surface area and amounts of functional groups. Adsorption data of the four carbons for ciprofloxacin hydrochloride (CIP) were analyzed by four isotherm models (Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich), indicating Langmuir and Temkin models were more suitable in expressing adsorption process. Compared with other carbons, FPU-C reflects more than 100% higher adsorption capacity for CIP. The maximum adsorption capacity attained 204.08 mg CIP per gram of FPU-C. The results suggest that potassium bicarbonate and urea as the weak base could play the role of activation mutually to acquire excellent activated carbon for CIP removal.