Institute of Environmental Sciences, Bogazici University, 34342 Istanbul, Turkey.
Institute of Environmental Sciences, Bogazici University, 34342 Istanbul, Turkey.
Ultrason Sonochem. 2019 Nov;58:104623. doi: 10.1016/j.ultsonch.2019.104623. Epub 2019 May 31.
Sonocatalytic degradation of methylparaben (MPB) in the presence of a low-cost clay mineral (sepiolite) was optimized using a multivariable center composite design protocol based on response surface methodology (RSM). Using the data generated with varying MPB concentrations, pH, frequency and catalyst dose, two semi-empirical expressions were developed to describe the relation between the apparent reaction rate constant of the parent compound and the most significant control variables. It was found that ultrasonic power, pH, sepiolite dose and its interactions with time and pH were the most significant parameters influencing the rate of MPB decay under high frequency ultrasound. The models also showed that the rate constant was a convex function of time, as it decreased during the first 35-min of sonolysis and increased thereafter, indicating the formation and depletion of competing oxidation byproducts. Finally, the models predicted that the rate of MPB decay was a maximum either at alkaline pH and a high sepiolite dose (k = 1.68 × 10 min), or at acidic pH and a considerably lower dose of the mineral (k = 1.48 × 10 min).
采用基于响应面法（RSM）的多变量中心复合设计方案，优化了在廉价粘土矿物（海泡石）存在下的对羟基苯甲酸甲酯（MPB）的超声降解。利用不同 MPB 浓度、pH 值、频率和催化剂剂量生成的数据，开发了两个半经验表达式，以描述母体化合物的表观反应速率常数与最重要的控制变量之间的关系。结果表明，超声功率、pH 值、海泡石剂量及其与时间和 pH 值的相互作用是高频超声下影响 MPB 降解速率的最重要参数。模型还表明，速率常数是时间的凸函数，因为它在超声降解的前 35 分钟内降低，然后增加，表明形成和耗尽了竞争的氧化副产物。最后，模型预测 MPB 降解的速率在碱性 pH 值和高海泡石剂量（k=1.68×10-1min-1）或酸性 pH 值和较低的矿物剂量（k=1.48×10-1min-1）下达到最大值。
