The effect of particle size on sonochemical desorption, degradation and change in bioaccessibility of polycyclic aromatic hydrocarbons (PAHs) on contaminated sediments was investigated. Batch experiments were performed with the whole sediment (WS < 850 μm), a large size range fraction (150 μm < LSR < 850 μm), and a small size range fraction (SSR < 150 μm) of the whole sediment. PAH degradation followed pseudo first-order kinetics; PAHs on LSR sediments underwent more rapid degradation than on SSR and WS sediments (ν_PAH,LSR > ν_PAH,WS > ν_PAH,SSR). In addition, a higher sediment slurry concentration resulted in slower degradation of PAHs. Results are consistent with the more rapid particle size reduction of the LSR. More rapid particle size reduction and faster PAH degradation for the LSR fraction combined with analysis of particle velocities in both size ranges indicates that microjets as opposed to particle–particle collisions due to shockwaves are effective in rapid particle size reduction and PAH degradation. Moreover, the bioaccessible fraction ($F_{\mathrm{P}\mathrm{A}\mathrm{H},\mathrm{f}\mathrm{a}\mathrm{s}\mathrm{t},\mathrm{t}}$) of sorbed PAHs in both particle size fractions was found to increase with sonication time but was more rapid with the LSR. Likewise, the more tightly bound PAHs, those in the slow desorbing fraction ($F_{\mathrm{P}\mathrm{A}\mathrm{H},\mathrm{s}\mathrm{l}\mathrm{o}\mathrm{w},\mathrm{t}}$) of PAHs, decreased faster with sonication of LSR particles compared to SSR particles, consistent with the trend of particle size reduction. Results of this study suggest that ultrasonic treatment is more effective for larger size particle sediments, although sonication is also viable for small sediment sizes.

研究了粒径对声化学解吸，降解以及受污染沉积物上多环芳烃（PAHs）生物可及性变化的影响。对整个沉积物的整个沉积物（WS <850μm），大尺寸范围分数（150μm<LSR <850μm）和小尺寸范围分数（SSR <150μm）进行批处理实验。PAH降解遵循拟一级动力学；与SSR和WS沉积物相比，LSR沉积物上的PAHs降解更快（νPAH _，LSR  >νPAH _，WS  >νPAH _，SSR）。另外，较高的沉积物淤浆浓度导致PAHs降解较慢。结果与LSR更快的粒度减小是一致的。LSR馏分的更快粒度降低和更快PAH降解，结合两个粒度范围内的颗粒速度分析表明，与冲击波引起的颗粒间碰撞相反，微喷对降低粒度和PAH降解有效。此外，生物可利用部分（$F_{\mathrm{P}\mathrm{一种}\mathrm{H}，\mathrm{F}\mathrm{一种}\mathrm{s}\mathrm{Ť}，\mathrm{Ť}}$发现两个粒径级分中吸附的PAHs随超声处理时间增加而增加，而LSR则更快。同样，结合力更强的PAH，解吸级分较慢的PAH（$F_{\mathrm{P}\mathrm{一种}\mathrm{H}，\mathrm{s}\mathrm{升}\mathrm{Ø}\mathrm{w}，\mathrm{Ť}}$）的PAHs与SSR颗粒相比，通过LSR颗粒的超声处理更快地降低，这与粒度减小的趋势一致。这项研究的结果表明，超声处理对于较大尺寸的颗粒沉积物更有效，尽管超声处理对于较小尺寸的沉积物也是可行的。