Contaminants of emerging concerns (CECs) spread across a wide range of organic product compounds. As biorecalcitrants, their removal from conventional wastewater treatment systems remains a herculean task. To address this issue, heterogenous solar driven advanced oxidation process based-TiO₂ and other semiconductor materials has been extensively studied for their abatement from wastewater sources. In this study, we have synthesized by hydrothermal assisted co-precipitation Ag doped ZnSnO₃. Structural and morphological characterizations were performed via X-ray diffraction (XRD), Fourier transform infra-red (FTIR), N₂ adsorption-desorption at 77 K by Brunauer-Emmet-Teller (BET) and Barrett, Joyner, and Halenda (BJH) methods, Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy coupled with Energy dispersive spectroscopy (SEM-EDS), and UV-visible absorption in Diffuse reflectance spectroscopy (UV-vis/DRS) mode. Crystallite size estimate for Ag-ZnSnO₃ and undoped form was 19.4 and 29.3 nm, respectively, while respective TEM particle size estimate was 79.0 nm and 98.2 nm. BET surface area and total pore volume by BJH for Ag-ZnSnO₃ were estimated with respective values of 17.2 m²/g and 0.05 cm³/g in comparison to 18.8 m²/g and 0.06 cm³/g for ZnSnO₃. Derived energy band gap (Eg) values were 3.8 eV for Ag-ZnSnO₃ and 4.2 eV for ZnSnO₃. Photocatalytic performance of Ag-ZnSnO₃ was tested towards caffeine achieving about 68% removal under (natural) unmodified pH = 6.50 and almost 100% removal at initial pH around 7.5 after 4 h irradiation. The effect of initial pH, catalyst dosage, pollutant concentration, charge scavengers, H₂O₂, contaminant inorganic ions (anions) as well as humic acid (HA) on the photocatalyst activity over caffeine degradation were assessed. In accordance with the probation test of the reactive species responsible for photocatalytic degradation process, a reaction mechanism was deduced.

中文翻译：

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银掺杂锡酸锌（Ag-ZnSnO3）在咖啡因下光催化降解咖啡因

新兴关注点（CEC）的污染物散布在各种有机产品化合物中。作为生物顽固剂，将其从常规废水处理系统中去除仍然是一项艰巨的任务。为了解决这个问题，已经广泛研究了基于异质太阳能驱动的先进氧化工艺-TiO ₂和其他半导体材料对废水的消除作用。在这项研究中，我们通过水热辅助共沉淀法合成了Ag掺杂的ZnSnO ₃。通过X射线衍射（XRD），傅立叶变换红外（FTIR），N ₂进行结构和形态表征Brunauer-Emmet-Teller（BET）和Barrett，Joyner和Halenda（BJH）方法，透射电子显微镜（TEM），X射线光电子能谱（XPS），扫描电子显微镜和能量色散方法在77 K下进行吸附-解吸光谱（SEM-EDS）和漫反射光谱（UV-vis / DRS）模式下的紫外可见吸收。Ag-ZnSnO ₃和未掺杂形式的微晶尺寸估计分别为19.4和29.3 nm，而相应的TEM粒度估计为79.0 nm和98.2 nm。通过BJH测得的Ag-ZnSnO _3的BET表面积和总孔体积分别为17.2 m ² / g和0.05 cm ³ / g，而18.8 m ² / g和0.06 cm ³/ g表示ZnSnO ₃。衍生的能带隙（Eg）值分别为3.8eV为银ZnSnO ₃和4.2电子伏特为ZnSnO ₃。测试了Ag-ZnSnO ₃对咖啡因的光催化性能，在（天然）未修饰的pH = 6.50下实现了约68％的去除，在辐照4 h后在约7.5的初始pH下实现了近100％的去除。评估了初始pH，催化剂用量，污染物浓度，电荷清除剂，H ₂ O ₂，污染物无机离子（阴离子）以及腐殖酸（HA）对咖啡因降解过程中光催化剂活性的影响。根据负责光催化降解过程的反应物种的试用测试，推导了反应机理。