活性炭的丙酮吸附性能与热稳定性及自燃机制研究OA

With the acceleration of industrialization,the emissions of volatile organic compounds(VOCs)have become increasingly serious,making them an important pollution source affecting atmospheric environmental quality and human health.Activated carbon is widely used in VOCs abatement due to its high specific surface area and excellent adsorption performance.However,during the VOCs adsorption process,some activated carbons have the risk of self-heating and even spontaneous combustion,which seriously threatens operational safety.It is urgent to deeply reveal the underlying mechanism from the perspective of intrinsic material properties and adsorption behavior.In this study,domestic activated carbon(GC-ACs)and imported activated carbon(JK-ACs)used in actual VOCs treatment processes were selected as the research objects,with acetone,a typical representative of VOCs,as the adsorbate.By characterizing the differences in their pore structures and surface chemical properties,the differences in adsorption performance and thermal stability between the two activated carbons were systematically analyzed.The results show that there are significant differences in structure and performance between the two activated carbons.JK-ACs,with a high specific surface area(1 300 m²/g),abundant micropore volume(0.45 cm³/g),and a low content of oxygen-containing functional groups(1.064 mmol/g),have a dynamic saturated acetone adsorption capacity of up to 248.8 mg/g,which is significantly higher than that of GC-ACs(62.3 mg/g).Meanwhile,GC-ACs has a high ash content(11.82%)and contains Ca and Fe oxides,which can catalyze the oxidation of the carbon skeleton,reduce the ignition point of the carbon skeleton,and easily induce spontaneous combustion during the adsorption process.In addition,after hydrochloric acid washing modification of GC-ACs,it is found that the ash content of the modified activated carbon(M-GC-ACs)is reduced to 3.28%,its adsorption capacity is increased to 162.7 mg/g,and its thermal stability is significantly improved.Therefore,the spontaneous combustion mechanism of activated carbon can be attributed to the synergistic effect of metal catalysis by high ash content,adsorption heat accumulation,and carboxyl oxidation,which leads to thermal runaway during the adsorption of VOCs and induces spontaneous combustion.This study is expected to provide a theoretical basis for the design of high-performance VOCs adsorbents.