The degradation of methylparaben (MP) through 20 kHz ultrasound coupled with a bimetallic Co-Fe carbon xerogel (CX/CoFe) was investigated in this work. Experiments were performed at actual power densities of 25 and 52 W/L, catalyst loadings of 12.5 and 25 mg/L, MP concentrations between 1 and 4.2 mg/L and initial pH values between 3 and 10 in ultrapure water (UPW). Matrix effects were studied in bottled water (BW) and secondary treated wastewater (WW), as well as in UPW spiked with bicarbonate, chloride or humic acid. The pseudo-first order kinetics of MP degradation increase with power and catalyst loading and decrease with MP concentration and matrix complexity; moreover, the reaction is also favored at near-neutral conditions and in the presence of dissolved oxygen. The contribution of the catalyst is synergistic to the sonochemical degradation of MP and the extent of synergy is quantified to be >45%. This effect was ascribed to the ability of CX/CoFe to catalyze the dissociation of hydrogen peroxide, formed through water sonolysis, to hydroxyl radicals. Experiments in UPW spiked with an excess of tert-butanol (radical scavenger), sodium dodecyl sulfate or sodium acetate (surfactants) led to substantially decreased rates (i.e. by about 8 times), thus implying that the liquid bulk and the gas-liquid interface are major reaction sites. The stability of CX/CoFe was shown by performing reusability cycles employing magnetic separation of the catalyst after the treatment stage. It was found that the CX/CoFe catalyst can be reused in up to four successive cycles without noteworthy variation of the overall performance of the sonocatalytic process.

中文翻译：

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使用钴铁磁性碳干凝胶通过声催化降解对羟基苯甲酸甲酯。

在这项工作中，研究了通过20 kHz超声和双金属Co-Fe碳干凝胶（CX / CoFe）降解对羟基苯甲酸甲酯（MP）的方法。在超纯水（UPW）中，实际功率密度为25和52 W / L，催化剂负载为12.5和25 mg / L，MP浓度为1和4.2 mg / L，初始pH值为3和10，进行了实验。研究了瓶装水（BW）和二次处理废水（WW）以及加有碳酸氢盐，氯化物或腐殖酸的UPW中基质的影响。MP降解的拟一级反应动力学随功率和催化剂负载的增加而增加，随MP浓度和基质的复杂性而降低。此外，在接近中性的条件下和存在溶解氧的情况下，该反应也是有利的。催化剂的贡献与MP的声化学降解具有协同作用，并且协同作用的程度被量化为> 45％。这种作用归因于CX / CoFe催化通过水声分解形成的过氧化氢分解为羟基自由基的能力。在UPW中加入过量的叔丁醇（自由基清除剂），十二烷基硫酸钠或乙酸钠（表面活性剂）的实验导致速率大大降低（即降低了约8倍），因此暗示液体体积和气液界面是主要的反应场所 通过在处理阶段之后使用催化剂的磁性分离进行可重复使用的循环来显示CX / CoFe的稳定性。