Removal of I–from Aqueous Solutions Using a Biomass Carbonaceous Aerogel Modified with KH-560

Materials capable of separating and removing iodine ions (I–) from aqueous solutions are significant to our society, especially human health. Adsorption is one of the effective I– separation methods. In this work, a novel biomass carbonaceous aerogel (CA) modified with 3-glycidyl-oxypropyl-trimethoxy-silane (KH-560) was prepared and used for I– adsorption for the first time. This preparation process of CA@KH-560 is easily accessible. The results of characterization demonstrated that CA and CA@KH-560 have three-dimensional porous structure with the sheetlike skeletons connected to each other, and KH-560 effectively entered into the matrix of CA. Adsorption experiments were carried out systematically by changing the pH, adsorption time, ionic strength, temperature, and ion concentration. The maximal adsorption capacity for I– is 2.5 mmol/g at an initial pH of 1.5. The adsorption can reach equilibrium within 24 h, and the data of adsorption kinetics fitted the pseudo-second-order model very well. The adsorption isotherm model Langmuir, Freundlich, and Tempkin isotherms were studied, and the results showed that the Langmuir model is the best-fitting one for the experimental results. Moreover, CA@KH-560 shows excellent regenerating ability, and the regeneration process is relatively simple.