ABSTRACT In this research, we are reporting the treatment of tequila vinasse by a coagulation–flocculation process coupled with heterogeneous photocatalysis using two types of titanium dioxide nanoparticles, i.e. (1) commercial nanoparticles, and (2) nanoparticles synthesized by sol–gel. The efficiency in the elimination of phenol, which is one of the most harmful contaminants in tequila vinasse, was also included in the evaluation of the treatment process. The synthesized titanium dioxide nanoparticles were annealed in air at 400°C for 1 h and were characterized by X-ray diffraction, transmission electron microscopy, ultraviolet-visible and Raman spectroscopy. Anatase phase was observed in both samples, with a crystallite size of 22.5 and 9.8 nm for commercial and synthesized nanoparticles respectively. Tequila vinasse was characterized before and after the treatments by measuring physicochemical parameters such as pH, chemical oxygen demand (COD), colour, total suspended solids (TSS), as well as using ultraviolet-visible spectroscopy and Raman spectroscopy to identify the presence of organic compounds, and gas chromatography (GC) for phenol quantification. Raw vinasse was treated initially by coagulation–flocculation producing clarified vinasse, which in turn was treated by photocatalysis for 3 h using hydrogen peroxide as oxidizing agent. The use of synthesized titanium dioxide nanoparticles allowed the highest efficiencies, reaching reductions of 99.4%, 86.0%, and 70.0% for TSS, colour, and COD respectively. GC results showed the reduction of phenol concentrations in 89.7% with our synthesized nanoparticles in contrast to 82.7% reduction, with commercial titanium dioxide nanoparticles. GRAPHICAL ABSTRACT

中文翻译：

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二氧化钛纳米粒子混凝-絮凝结合多相光催化处理龙舌兰酒糟去除苯酚

摘要 在这项研究中，我们报告了使用两种类型的二氧化钛纳米颗粒，即（1）商业纳米颗粒和（2）溶胶-凝胶合成的纳米颗粒，通过混凝-絮凝工艺结合异相光催化处理龙舌兰酒糟。龙舌兰酒糟液中最有害的污染物之一苯酚的去除效率也包括在处理过程的评估中。合成的二氧化钛纳米粒子在空气中在 400°C 下退火 1 小时，并通过 X 射线衍射、透射电子显微镜、紫外-可见光和拉曼光谱进行表征。在两个样品中都观察到锐钛矿相，商业和合成纳米颗粒的微晶尺寸分别为 22.5 和 9.8 nm。龙舌兰酒糟在处理前后通过测量物理化学参数如 pH 值、化学需氧量 (COD)、颜色、总悬浮固体 (TSS) 以及使用紫外-可见光谱和拉曼光谱来鉴定有机物的存在来表征。化合物，以及用于苯酚定量的气相色谱 (GC)。原料酒糟最初通过混凝-絮凝处理产生澄清的酒糟，然后使用过氧化氢作为氧化剂通过光催化处理 3 小时。使用合成的二氧化钛纳米粒子可实现最高效率，TSS、颜色和 COD 分别降低 99.4%、86.0% 和 70.0%。GC 结果显示，与我们合成的纳米颗粒相比，苯酚浓度降低了 89.7%，而降低了 82.7%，与商业二氧化钛纳米粒子。图形概要