Investigation of TiO2/PPy nanocomposite for photocatalytic applications; synthesis, characterization, and combination with various substrates: a review.

The use of photocatalysis technology, specifically visible light photocatalysis that relies on sustainable solar energy, is the most promising for the degradation of contaminants. The interaction of conducting polymer and titanium dioxide (TiO2) leads to the exchange that enhances the alteration of the semiconductor's surface and subsequently decreases the bandgap energy. Polypyrrole (PPy) and TiO2 nanocomposites have promising potential for photocatalytic degradation. Chemically and electrochemical polymerization are two predominant methods for adding inorganic nanoparticles to a conducting polymer host matrix. The most commonly utilized method for producing PPy/TiO2 nanocomposites is the in-situ chemical oxidative polymerization technique. Immobilizing PPy/TiO2 on substrates causes more charge carriers (electron/hole pairs) to be produced on the surface of TiO2 and enhances the rate of photocatalytic degradation compared to pure TiO2. The increased surface charge affects how electron/hole pairs are formed when visible light is used. This study provides a comprehensive investigation into the synthesis, characterization, application, efficiency, and mechanism of PPy/TiO2 nanocomposites in the photocatalytic degradation process of various pollutants. Furthermore, the effect of stabilizing the TiO2/PPy nanocomposite on various substrates will be investigated. In conclusion, the review outlines the ongoing challenges in utilizing these photocatalysts and highlights the essential concerns that require attention in future research. Its objective is to help researchers better understand photocatalysts and encourage their use in wastewater treatment.

Design of 2D/2D ß-Ni(OH)2/ZnO heterostructures via photocatalytic deposition of nickel for sonophotocatalytic degradation of tetracycline and modeling with three supervised machine learning algorithms.

Due to the expansive use of tetracycline antibiotics (TCs) to treat various infectious diseases in humans and animals, their presence in the environment has created many challenges for human societies. Therefore, providing green and cost-effective solutions for their effective removal has become an urgent need. Here, we will introduce 2D/2D p-n heterostructures that exhibit excellent sonophotocatalytic/photocatalytic properties for water-soluble pollutant removal. In this contribution, for the first time, ß- Ni(OH)2 nanosheets were synthesized through visible-light-induced photodeposition of different amounts of nickel on ZnO nanosheets (ß-Ni(x)/ZNs) to fabricate 2D/2D p-n heterostructures. The PXRD patterns confirmed the formation of wurtzite phase for ZNs and the hexagonal crystal structure of ß-Ni(OH)2. The FESEM and TEM micrographs showed that the ß-Ni(OH)2 sheets were dispersed on the surface of ZNs and formed 2D/2D p-n heterojunction in ß-Ni(x)/ZNs samples. With the photodeposition of ß-Ni(OH)2 nanosheets on ZNs, the surface area, pore volume, and pore diameter of ß-Ni(x)/ZNs heterostructures have increased compared to ZNs, which can have a positive effect on the sonophotocatalytic/photocatalytic performance of ZNs. The degradation experiments showed that ß-Ni(0.1)/ZNs and ß-Ni(0.4)/ZNs have the highest degradation percentage in photocatalytic (51 %) and sonophotocatalytic (71 %) degradation of TC, respectively. Finally, the sonophotocatalytic/photocatalytic degradation process of TC was systematically validated through modeling with three powerful and supervised machine learning algorithms, including Support Vector Regression (SVR), Artificial Neural Networks (ANNs), and Stochastic Gradient Boosting (SGB). Five statistical criteria including R2, SAE, MSE, SSE, and RMSE were calculated for model validation. It was observed that the developed SGB algorithm was the most reliable model for predicting the degradation percent of TC. The results revealed that using fabricated 2D/2D p-n heterojunctions (ß-Ni(x)/ZNs) is more sustainable than the conventional ZnO photocatalytic systems in practical applications.

Simultaneous separation and degradation of methylene blue by a thin film nanocomposite membrane containing TiO2/MWCNTs nanophotocatalyst.

ABSTRACTAn innovative photocatalytic thin film nanocomposite (TFN) membrane was prepared and used for the simultaneous separation/degradation of methylene blue (MB) under UV irradiation. For this purpose, we used the sol-gel method to prepare the TiO2/MWCNTs nanophotocatalyst and added to the 1,3-phenylenediamine (MPD) solution during interfacial polymerization (IP) of 1,3,5-benzenetricarbonyl chloride (TMC) and 1,3-phenylenediamine monomers on the polysulfone (PSF) support. Using scanning electron microscopy (SEM) analysis and studying the cross-sectional images of membrane samples, it was revealed that the polyamide (PA) thin layer was well fabricated over the support membrane. The attendance of the TiO2/MWCNTs nanophotocatalyst in the PA thin layer of TFN samples was also proved using EDX (energy-dispersive X-ray) analysis. According to the results of the contact angle (CA), it is clear that the hydrophilicity of membrane samples first increased and then decreased by enhancing the TiO2/MWCNTs nanophotocatalyst content in the PA thin layer. In comparison with the pristine thin film composite (TFC) membrane, TFN samples showed higher water flux and MB removal when they were exposed to UV light. Finally, it turned out that the TFN membrane comprising 0.2 wt. % TiO2/MWCNTs nanophotocatalyst (TFN 0.2) had the foremost efficiency among TFNs with the water flux of 13 L/m2·hr and dye separation/degradation of almost 100% under UV irradiation.