Synthetic organic dyes are coloring agents used in various industries. Despite the fact that they offer exciting colors and long-lasting effects, certain organic dyes can have harmful impacts on human health and aquatic ecosystems. This study investigates the photocatalytic degradation of malachite green dye using Ni–TiO₂ nanoparticles (NPs) and Ni–TiO₂/PANI nanocomposites (NCs) in various reaction conditions. The surface and compositional change of synthesized photocatalysts were characterized by XRD, FTIR, AAS, and UV–vis spectrophotometer. Accordingly, the XRD results signify the crystal structure of photocatalysts found to be tetragonal anatase phase while the FT-IR spectra indicate the titanium has predominantly form a coordination compound upon reaction with nitrogen atom through weakening the bond strength between C═N, C═C, and C─N in the PANI. The UV–vis measurement shows that the energy bandgaps were decreased from 3.20 to 2.77 eV and 2.59 eV for Ni–TiO₂ NPs and Ni–TiO₂/PANI NCs, respectively. From AAS data, the authors confirmed that Ni metal has significantly existed in the aforementioned photocatalysts after the calcination process. The photocatalytic degradation of Ni–TiO₂ NPs and Ni–TiO₂/PANI NCs on the model dye has studied and their efficiency was 94.22% and 99.09%, respectively. The photocatalytic degradation follows pseudo-first order with 2.23 × 10⁻² min⁻¹ reaction rate at optimum conditions of pH 8.5, initial dye concentration of 0.2 g/L, catalyst load of 0.2 g/L, and irradiation time of 90 min. With this, the outstanding result recorded using Ni–TiO₂/PANI NCs is ascribed to the smaller particle size as compared to Ni–TiO₂ NPs, and it is found to be the promising photocatalyst for the removal of wastewater containing organic dyes.

中文翻译：

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聚苯胺修饰Ni-TiO2表面孔雀石绿染料光催化降解动力学及机理研究

合成有机染料是用于各个行业的着色剂。尽管某些有机染料提供令人兴奋的颜色和持久的效果，但它们可能对人类健康和水生生态系统产生有害影响。本研究研究了在不同反应条件下使用 Ni-TiO ₂纳米粒子 (NPs) 和 Ni-TiO ₂ /PANI 纳米复合材料 (NCs)光催化降解孔雀石绿染料。通过 XRD、FTIR、AAS 和紫外可见分光光度计对合成光催化剂的表面和成分变化进行了表征。因此，XRD结果表明光催化剂的晶体结构为四方锐钛矿相，而FT-IR光谱表明钛在与氮原子反应时主要通过削弱C=N、C=C之间的键强度形成配位化合物。 ，以及 PANI 中的 C─N。 UV-vis测量表明Ni-TiO ₂ NPs和Ni-TiO ₂ /PANI NCs的能带隙分别从3.20降低到2.77 eV和2.59 eV。根据AAS数据，作者证实，在煅烧过程后，上述光催化剂中明显存在Ni金属。研究了Ni-TiO ₂ NPs和Ni-TiO ₂ /PANI NCs对模型染料的光催化降解效果，其效率分别为94.22%和99.09%。在pH 8.5、初始染料浓度0.2 g/L、催化剂负载量0.2 g/L、照射时间90 min的最佳条件下，光催化降解遵循准一级反应速率2.23 × 10 -2 ^min  -1 ^。因此，使用 Ni-TiO ₂ /PANI NCs 记录的出色结果归因于与 Ni-TiO ₂ NPs 相比较小的粒径，并且它被发现是用于去除含有有机染料的废水的有前途的光催化剂。