High-efficiency removal of antibiotic pollutants by magnetic carbon aerogel: Inherent roles of adsorption synergistic catalysis

For the persulfate-based advanced oxidation processes (AOPs), the difficulty of separating powdered carbon catalyst, the leaching of pure metal catalyst and high consumption of catalyst limit the large-scale application of this technique. To overcome the above-mentioned drawbacks, the magnetic carbon aerogels (SA-Fe, SA-Co and SA-Ni) with high specific surface area were synthesized by using sodium alginate as carbon precursor, KOH as pore-forming agent, and various metal salts as magnetic dopants. The specific surface area of SA-Fe, SA-Co and SA-Ni reached up to 2760, 2988, and 2420 m2/g, which showed excellent removal performance for high concentration tetracycline hydrochloride (TC) wastewater. Among them, SA-Fe with Fe0 nanoparticles and graphitized structure displayed the optimal removal capacity of 2000 mg/g for TC, which was attributed to the synergistic effect of adsorption, radical pathway and non-radical pathway. The removal efficiencies of TC and total organic carbon (TOC) at high concentration of 200 ppm were 100% and 71.66% by only using 0.1 g/L of SA-Fe. SA-Fe also displayed excellent reusability, and the TC removal efficiency after 5 cycles only lost 4%. More interestingly, the adsorption and singlet oxygen (1O2) played more important roles than other mechanisms. The combing of carbon materials and metal dopants not only provided a magnetic property but also changed the degradation pathway. This study provided a high-performance, eco-friendly and cost-effective catalyst for the removal of antibiotic pollutants by persulfate-based AOPs.