Preparation of petroleum asphalt-based porous materials for iodine vapor adsorption via ball-milling method

ZHANG Chengxin; WANG Yulian; SONG Jinze; GU Junze; WANG Binyan; XIAO Kunfu; ZHANG Yan; WANG Yihan; HU Fang; MA Ruiting

doi:10.13732/j.issn.1008-5548.2026.01.015

Abstract：Objective Among various clean energy sources,nuclear energy is one of the most widely used and technologically advanced options,offering significant advantages such as high energy density,large output power,environmental cleanliness,and eco-nomic efficiency.However,nuclear power generation releases energy from atomic nuclei through nuclear fission,inevitably pro-ducing radioactive pollutants.Radioactive iodine isotopes(such as 129I and 131I)are typical gaseous radionuclides that readily dif-fuse in the air,causing serious pollution to the atmosphere,water systems,and ecosystems.Therefore,the safe and effective capture of radioactive iodine is a significant concern.Recently,porous materials have been utilized to adsorb iodine vapor due to their excellent adsorption properties,achieving promising results.Compared to traditional inorganic porous materials(e.g.,activated carbon,zeolites),porous organic polymers(POP)offer advantages such as low density,high physical and chemical stability,large specific surface area,excellent adsorption performance,and good recyclability,making them suitable for radio-active iodine capture. Methods In this study,three novel POP,i.e.,PA-POP-A,PA-POP-B,and PA-POP-C,were prepared using petroleum asphalt(PA)as the raw material and three different crosslinking agents,1,4-bis(chloromethyl)benzene,4,4'-bis(chloro-methyl)biphenyl,and 9,10-bis(chloromethyl)anthracene.The materials were prepared using a fast and efficient ball-milling method.The reagents and catalyst were loaded into a 250 mL zirconia grinding jar with 50 zirconia spheres(10 mm diameter)under an argon atmosphere.The planetary high-energy ball mill was operated at 400 r/min for 2 hours at room temperature.After milling,100 mL of anhydrous methanol was added to quench the reaction.Subsequently,the mixture was filtered using a Buchner funnel,washed repeatedly with methanol and chloroform,and then dried under vacuum at 60 ℃ for 24 hours,yielding three dark brown powder products.For iodine adsorption experiments,0.20 g of each porous material was accurately weighed and placed into a pre-weighed cylindrical sample bottle.Then,2.0 g of solid iodine was added to an identical sample bottle.Both sample bottles were placed in a sealed 250 mL glass container and then heated in a 75 ℃ drying oven to simulate a satu-rated iodine vapor environment.At fixed time intervals(1,2,3,4,5,6,8,12,16,20,and 24 hours),samples were removed,cooled down,and weighed to calculate iodine uptake.Each iodine adsorption experiment was conducted in triplicate to evaluate reproducibility and experimental error. Results and Discussion Under mechanical ball-milling conditions,the raw materials underwent Friedel-Crafts alkylation reac-tion to form porous polymers with stable chemical structures and well-developed pore channels,as confirmed by Fourier trans-form infrared spectroscopy(FTIR),solid-state nuclear magnetic resonance(NMR),and N2 adsorption characterization.The specific surface areas of PA-POP-A,PA-POP-B,and PA-POP-C were 1 048,1 700,and 843 m2/g,respectively.N2 adsorption-desorption isotherms indicated that all three porous materials contained abundant micropores(＜2 nm),mesopores(2-50 nm),and a small amount of macropores.Iodine adsorption reached equilibrium after 8 hours,with maximum mass uptakes of 623％,652％,and 582％for PA-POP-A,PA-POP-B,and PA-POP-C,respectively.After 5 adsorption-desorption experiments,only slight decreases in iodine uptake were observed.After 10 days of storage at room temperature and atmospheric pressure,the residual iodine contents were 568％,612％,and 510％,respectively,indicating excellent retention performance and minimal iodine loss. Conclusion In this study,three novel organic porous materials(PA-POP-A,PA-POP-B,and PA-POP-C)were prepared using low-cost PA as the raw material through a simple and feasible mechanical ball-milling method.The resulting materials exhibit high specific surface areas and abundant microporous structures,with excellent iodine vapor adsorption and retention per-formance.After multiple reuse cycles and prolonged exposure under ambient conditions,the materials maintained high adsorp-tion capacity with minimal iodine loss.This preparation method offers notable advantages such as high efficiency,operational simplicity,and feasibility,as well as low energy and organic solvent consumption.These features provide significant benefits in energy conservation and environmental sustainability,demonstrating potential for large-scale industrial applications.