Savun-Hekimoğlu Başak, Ince Nilsun H
Institute of Environmental Sciences, 34342 Boğaziçi University, Istanbul, Turkey.
Institute of Environmental Sciences, 34342 Boğaziçi University, Istanbul, Turkey.
Ultrason Sonochem. 2019 Jun;54:233-240. doi: 10.1016/j.ultsonch.2019.01.034. Epub 2019 Feb 4.
The first part of the study is about the degradation of a common PPCP-methylparaben by high-frequency ultrasound to highlight the operation parameters, the reaction sites, the oxidation byproducts and the role of OH radicals. The second part covers the catalytic effect of a highly abundant and cost-effective clay mineral-sepiolite, and investigates the role of surface modification and SDS-composites of the clay in improving the efficiency of the degradation reactions. It was found that the compound (C = 10 mg L) was readily and totally decomposed by 30-min sonication at neutral pH, producing phenolic and aliphatic intermediates, but with insignificant mineralization. The major reaction site was the bubble-liquid interface, where the reactions were governed by OH radical attack. Modification of the sepiolite surface by pre-sonication in an ultrasonic bath improved the rate of reaction and the degree of TOC decay. Further modification by the synthesis of 20-min sonicated (200 kHz bath) SDS-intercalates of the clay was found to yield significant enhancement in the rate of target compound decomposition and the fraction of TOC decay, provided that the reaction was operated at acidic pH.
该研究的第一部分是关于高频超声对一种常见的持久性有机污染物——对羟基苯甲酸甲酯的降解，以突出操作参数、反应位点、氧化副产物以及羟基自由基的作用。第二部分涵盖了一种储量丰富且成本效益高的粘土矿物——海泡石的催化作用，并研究了粘土的表面改性和十二烷基硫酸钠复合材料在提高降解反应效率方面的作用。研究发现，该化合物（浓度为10 mg/L）在中性pH值下经30分钟超声处理后很容易完全分解，产生酚类和脂肪族中间体，但矿化程度不显著。主要反应位点是气泡-液体界面，反应受羟基自由基攻击控制。通过在超声浴中预超声处理对海泡石表面进行改性，提高了反应速率和总有机碳（TOC）衰减程度。研究还发现，通过合成经20分钟超声处理（200 kHz浴）的粘土十二烷基硫酸钠插层物进行进一步改性，在酸性pH值下操作时，目标化合物的分解速率和TOC衰减比例显著提高。
