Straioto Henrique, Viotti Paula Valéria, Moura Alexandre Amado de, Diório Alexandre, Scaliante Mara Heloisa Neves Olsen, Moreira Wardleison Martins, Vieira Marcelo Fernandes, Bergamasco Rosângela
Department of Chemical Engineering, State University of Maringá, Maringá, Brazil.
Environ Technol. 2023 Nov;44(26):3949-3964. doi: 10.1080/09593330.2022.2077134. Epub 2022 May 29.
The clinoptilolite natural zeolites (NZs) posses low herbicide adsorption capacity demanding acid-, alkali-, or salt chemical modifications that enhance its adsorption. However, this may affect the material structure and charge distribution. Alternatively, zeolites may be synthesized at a high cost and time-consuming process. Consequently, new methods, such as the hydrothermal method, for NZ modification needs to be studied. In this sense, a novel surface-modified zeolite (SMZ), using hexadecyltrimethylammonium bromide (CTAB), in acid media was produced by the hydrothermal method and applied for the adsorption of Atrazine (ATZ), Diuron (DIU) and 2,4-D. Commercial NZ and SMZ were characterized by SEM, XRD, TGA, FT-IR, AA spectroscopy, pH, Zeta potential and N-physisorption. The SMZ chosen for the adsorption experiments was the one with the highest modification yield and adsorption capacity obtained from a complete design of experiments (CTAB=0.74 ; D=12 Mesh; HCl=0.1 M; t=6 h and T=205 ºC). The adsorption experiments revealed that the SMZ adsorption capacity for the herbicide 2,4-D (q=9.02 mg/g) was greater than that obtained for ATZ (q=2.11 mg/g) and DIU (q=1.85 mg/g), which was explained by the presence of the hydroxyl group and by geometric characteristics of the 2,4-D. Adsorption models' fitting showed that the adsorption of 2,4-D onto SMZ were best described by pseudo-second order kinetic (k=0.005-0.006 g/mg.min; q=7.122-8.614 mg/g) and Langmuir isothermal model (K=0.283-0.499 L/mg; q=7.167-7.995 mg/g). These results indicate that the hydrothermal method is a viable alternative to enable the use of NZs for the adsorption of emerging contaminants from wastewater.
斜发沸石天然沸石（NZs）对除草剂的吸附能力较低，需要进行酸、碱或盐化学改性以增强其吸附性能。然而，这可能会影响材料结构和电荷分布。另外，合成沸石的成本高且过程耗时。因此，需要研究用于NZ改性的新方法，如水热法。从这个意义上说，通过水热法在酸性介质中使用十六烷基三甲基溴化铵（CTAB）制备了一种新型表面改性沸石（SMZ），并将其用于吸附阿特拉津（ATZ）、敌草隆（DIU）和2,4-二氯苯氧乙酸（2,4-D）。通过扫描电子显微镜（SEM）、X射线衍射（XRD）、热重分析（TGA）、傅里叶变换红外光谱（FT-IR）原子吸收光谱（AA）、pH值、zeta电位和N-物理吸附对商用NZ和SMZ进行了表征。用于吸附实验的SMZ是通过完整的实验设计获得的改性产率和吸附容量最高的一种（CTAB = 0.74；D = 12目；HCl = 0.1 M；t = 6小时；T = 205℃）。吸附实验表明，SMZ对除草剂2,4-D的吸附容量（q = 9.02 mg/g）大于对ATZ（q = 2.11 mg/g）和DIU（q = 1.85 mg/g）的吸附容量，这可以通过羟基的存在以及2,4-D的几何特征来解释。吸附模型拟合表明，2,4-D在SMZ上的吸附最好用伪二级动力学（k = 0.005 - 0.006 g/mg·min；q = 7.122 - 8.6名4 mg/g）和朗缪尔等温模型（K = 0.283 - 0.499 L/mg；q = 7.167 - 7.995 mg/g）来描述。这些结果表明，水热法是使NZs用于吸附废水中新兴污染物的一种可行替代方法。
