School of Environmental Studies, China University of Geosciences, Wuhan 430078, China.
State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430078, China.
Int J Environ Res Public Health. 2022 May 24;19(11):6396. doi: 10.3390/ijerph19116396.
Phenol is the most common organic pollutant in many industrial wastewaters that may pose a health risk to humans due to its widespread application as industrial ingredients and additives. In this study, waste green tea leaves (WGTLs) were modified through chemical activation/carbonization and used as an adsorbent in the presence of ultrasound (cavitation) to eliminate phenol in the aqueous solution. Different treatments, such as cavitation, adsorption, and sono-adsorption were investigated to remove the phenol. The scanning electron microscope (SEM) morphology of the adsorbent revealed that the structure of WGTLs was porous before phenol was adsorbed. A Fourier Transform Infrared (FTIR) analysis showed an open chain of carboxylic acids after the sono-adsorption process. The results revealed that the sono-adsorption process is more efficient with enhanced removal percentages than individual processes. A maximum phenol removal of 92% was obtained using the sono-adsorption process under an optimal set of operating parameters, such as pH 3.5, 25 mg L phenol concentration, 800 mg L adsorbent dosage, 60 min time interval, 30 ± 2 °C temperature, and 80 W cavitation power. Removal of chemical oxygen demand (COD) and total organic carbon (TOC) reached 85% and 53%. The Freundlich isotherm model with a larger correlation coefficient (R, 0.972) was better fitted for nonlinear regression than the Langmuir model, and the sono-adsorption process confirmed the pseudo-second-order reaction kinetics. The findings indicated that WGTLs in the presence of a cavitation effect prove to be a promising candidate for reducing phenol from the aqueous environment.
苯酚是许多工业废水中最常见的有机污染物，由于其作为工业原料和添加剂的广泛应用，可能对人类健康构成威胁。在本研究中，通过化学活化/碳化对废绿茶（WGTL）进行了改性，并在超声（空化）存在的情况下将其用作吸附剂，以消除水溶液中的苯酚。研究了不同的处理方法，如空化、吸附和超声吸附，以去除苯酚。吸附剂的扫描电子显微镜（SEM）形貌表明，在吸附苯酚之前，WGTL 的结构是多孔的。傅里叶变换红外（FTIR）分析表明，在超声吸附过程后存在羧酸的开链。结果表明，超声吸附过程比单独的过程更有效，去除率更高。在最佳操作参数下，使用超声吸附过程可获得 92%的最大苯酚去除率，例如 pH 3.5、25 mg L 苯酚浓度、800 mg L 吸附剂剂量、60 min 时间间隔、30 ± 2°C 温度和 80 W 空化功率。化学需氧量（COD）和总有机碳（TOC）的去除率分别达到 85%和 53%。与 Langmuir 模型相比，具有较大相关系数（R，0.972）的 Freundlich 等温模型更适合非线性回归，超声吸附过程证实了准二级反应动力学。研究结果表明，在空化效应存在的情况下，WGTL 被证明是从水环境中减少苯酚的有前途的候选物。
