Preparation of nitrogen doped magnetic carbon aerogel by sol-gel method combined with in-situ carbonization for simultaneous removal of p-nitrophenol and Pb(II)

The simultaneous removal of p-nitrophenol (PNP) and lead (Pb(II)) from wastewater has attracted increasing concern due to the potential alternations in their chemical states and resultant biological toxicity when they coexist. In this study, nitrogen doped magnetic carbon aerogel (N-MCA) was fabricated by sol-gel method combined with in-situ carbonization and applied for co-adsorption of PNP and Pb(II) to understand the adsorption properties and molecular mechanisms. The effects of nitrogen introduction and iron contents on the morphology, structure, magnetic properties and adsorption capacity of N-MCA were systematically investigated. Besides, batch experiments were conducted to evaluate the effects of the initial concentration, pH, temperature and time on the adsorption behavior of PNP and Pb(II) on N-MCA(10:3). Both adsorption kinetics and isotherms were thoroughly discussed. The findings revealed that the maximum adsorption capacity of PNP on N-MCA(10:3) is 146 mg center dot g(-1) (25 degrees C) and that of Pb(II) is 65 mg center dot g(-1) (25 degrees C). The interactions and underlying adsorption mechanisms of PNP and Pb(II) on N-MCA(10:3) were systematically investigated using single and binary systems, which showed that the co-adsorption capacity decreased because of competitive adsorption. Moreover, cyclic test showed that N-MCA(10:3) could be effectively reused up to four times and removed PNP and Pb(II) concurrently from practical water samples, signifying the economic viability and practical application. These insights shed a new light on the interaction mechanism of binary pollutants and the design of efficient adsorbents for their simultaneous removal.