Abstract

Azo dyes are extensively used in textile industry but their discharge with industrial effluents pollutes water resources which harms flora and fauna in the environment. Nanomaterials and composites have competent photo-catalytic efficiencies to reduce organic pollutants and inactivate micro-organisms. However, these photocatalysts suffer from structural leaching and instability, which makes their applications limited. The aim of present study is to overcome these limitations and to degrade methyl orange (MO) azo dye by providing organic-inorganic hetero-junction active sites under UV-visible light irradiation. Tween-80 templates were used to prepare porous methyacryl organo silicates (PMOS) by co-condensation of sodium silicate and 3-methacryloxypropyl trimethoxysilane. The fabrication of porous methyacryl organo silicate materials (Ag@PMOS) was carried out by reducing the silver moieties on and in the surfaces of PMOS. The resulting Ag@PMOS scaffolds were studied by Fourier transform infrared spectroscopy, which showed conformational vibrations of organic and silver moieties in fingerprint region. UV/visible spectroscopy was used to monitor photocatalytic efficiencies while thermogravimetric analysis displayed heat resistance competency of synthesized materials. Transmission electron microscopy demonstrated spherical particle shape of PMOS and well-ordered hexagonal patterns in Ag@PMOS, which were also enlightened by X-ray powder diffraction method. While, photoluminescence (PL) study examined the excessive formation of hydroxyl free radicals by Ag@PMOS during photocatalysis of MO. The synthesized material exhibited well-ordered crystalline networks of Ag@PMOS with good surface area, which made it effective for degradation of MO. The results showed 26% and 56% absorption reduction under visible and UV-conditions, respectively. Moreover, the reduction efficiency was increased remarkably after using hydrogen peroxide and found to be 53% and 85% under visible and UV-irradiation, respectively. The promising recycled results showed 24%, 21%, 17% (without using H₂O₂) and 54%, 51%, 48% (using H₂O₂) absorption decline under visible light irradiation. Moreover, 53%, 50%, 49% (without using H₂O₂) and 83%, 80%, 78% (using H₂O₂) absorption reductions were examined under UV-light irradiation without and with H₂O₂. Which pointed toward high reduction capabilities and better stability of Ag@PMOS. The synthesis of highly porous PMOS, efficient photo-degradation of MO under UV-light by fabricated Ag@PMOS and reproducibility of the degradation results made the present work more innovative for degradation of MO for water decontamination.

摘要

偶氮染料广泛用于纺织工业，但其随工业废水排放污染水资源，危害环境中的动植物。纳米材料和复合材料具有良好的光催化效率，可以减少有机污染物和灭活微生物。然而，这些光催化剂存在结构浸出和不稳定性的问题，这使得它们的应用受到限制。本研究的目的是克服这些限制并通过在紫外可见光照射下提供有机-无机异质结活性位点来降解甲基橙 (MO) 偶氮染料。Tween-80 模板用于通过硅酸钠和 3-甲基丙烯酰氧基丙基三甲氧基硅烷的共缩合制备多孔甲基丙烯酰有机硅酸盐 (PMOS)。多孔甲基丙烯酸有机硅酸盐材料 (Ag@PMOS) 的制备是通过还原 PMOS 表面上和表面中的银部分来进行的。通过傅里叶变换红外光谱研究了所得的 Ag@PMOS 支架，结果显示指纹区域中有机和银部分的构象振动。紫外/可见光谱用于监测光催化效率，而热重分析显示合成材料的耐热能力。透射电子显微镜显示了 PMOS 的球形颗粒形状和 Ag@PMOS 中有序的六边形图案，这也得到了 X 射线粉末衍射方法的启发。同时，光致发光 (PL) 研究检测了在 MO 光催化过程中 Ag@PMOS 过度形成羟基自由基。合成的材料表现出有序的Ag@PMOS晶体网络，具有良好的表面积，这使其有效降解MO。结果显示，在可见光和紫外光条件下，吸收分别减少了 26% 和 56%。此外，使用过氧化氢后还原效率显着提高，在可见光和紫外线照射下的还原效率分别为 53% 和 85%。有希望的回收结果显示 24%、21%、17%（不使用 H 分别。有希望的回收结果显示 24%、21%、17%（不使用 H 分别。有希望的回收结果显示 24%、21%、17%（不使用 H₂ O ₂ )和54%、51%、48%(使用H ₂ O ₂ )的吸收在可见光照射下下降。_{此外，在没有和有 H 2} O ₂的紫外光照射下，检测了53%、50%、49%（不使用 H ₂ O ₂）和 83%、80%、78%（使用 H ₂ O ₂ ）的吸收减少. 这表明 Ag@PMOS 具有较高的还原能力和更好的稳定性。高度多孔 PMOS 的合成、通过制造的 Ag@PMOS 在紫外光下对 MO 的有效光降解以及降解结果的可重复性使目前的工作在水净化中降解 MO 方面更具创新性。