Kinetic Monte Carlo simulation of 2,4,6-thrichloro phenol ozonation in the presence of ZnO nanocatalyst

Application of Engineered Nanomaterials as Nanocatalysts in Catalytic Ozonation: A Review

Given the growing scarcity of water and the continuous increase in emerging pollutants detected in water bodies, there is an imperative need to develop new, more effective, and sustainable treatments for wastewater. Advanced oxidation processes (AOPs) are considered a competitive technology for water treatment. Specifically, ozonation has received notable attention as a promising approach for degrading organic pollutants in wastewater. However, different groups of pollutants are hardly degradable via single ozonation. With continuous development, it has been shown that using engineered nanomaterials as nanocatalysts in catalytic ozonation can increase efficiency by turning this process into a low-selective AOP for pollutant degradation. Nanocatalysts promote ozone decomposition and form active free radicals responsible for increasing the degradation and mineralization of pollutants. This work reviews the performances of different nanomaterials as homogeneous and heterogeneous nanocatalysts in catalytic ozonation. This review focuses on applying metal- and carbon-based engineered nanomaterials as nanocatalysts in catalytic ozonation and on identifying the main future directions for using this type of AOP toward wastewater treatment.

Development, dilemma and potential strategies for the application of nanocatalysts in wastewater catalytic ozonation: A review

With the continuous development of nanomaterials in recent years, the application of nanocatalysts in catalytic ozone oxidation has attracted more and more researchers' attention due to their excellent catalytic properties. In this review, we systematically summarized the current research status of nanocatalysts mainly involving material categories, mechanisms and catalytic efficiency. Based on summary and analysis, we found most of the reported nanocatalysts were in the stage of laboratory research, which was caused by the nanocatalysts defects such as easy aggregation, difficult separation, and easy leakage. These defects might result in severe resource waste, economic loss and potentially adverse effects imposed on the ecosystem and human health. Aiming at solving these defects, we further analyzed the reasons and the existing reports, and revealed that coupling nano-catalyst and membrane, supported nanocatalysts and magnetic nanocatalysts had promising potential in solving these problems and promoting the actual application of nanocatalysts in wastewater treatment. Furthermore, the advantages, shortages and our perspectives of these methods are summarized and discussed.

Synthesis and Characterization of New Imidazole Phthalocyanine for Photodegradation of Micro-Organic Pollutants from Sea Water

In this study, a series of new metal phthalocyanines with imidazole function MPc(Imz) (M: Cd, Hg, Zn and Pd) were synthesized to improve the photocatalyst performances. All physical properties such as total energy, HOMO, LUMO energies of MPc(Imz), as well as their vibrational frequencies have been determined by DFT method using B3LYP theory level at 6-311G (d, p) and sdd basis set. The gap of energy level between work function (WF) of ITO and LUMO of PdPc(Imdz) was 1.53 eV and represents the highest barrier beneficial to electron injection compared to WF of ZnPc(Imz), HgPc(Imz), and CdPc(Imz). Furthermore, the PdPc(Imdz) thin films on indium tin oxide (ITO) glass were prepared by spin coating and vacuum evaporation technique, and were characterized by X-ray diffraction (XRD), surface electron morphology (SEM), atomic force microscopy (AFM), and UV–Vis spectroscopy. The photocatalytic activity of the ITO/glass supported thin films and degradation rates of chlorinated phenols in synthetic seawater, under visible light irradiation were optimized to achieve conversions of 80–90%. Experiments on synthetic seawater samples showed that the chloride-specific increase in photodegradation could be attributed to photochemically generated chloride radicals rather than other photoproduced reactive intermediates [e.g., excited-state triplet PdPc(Imz) (3PdPc(Imz)*), reactive oxygen species]. The major 2,3,4,5-Tetrachlorophenol degradation intermediates identified by gas chromatography-mass spectrometry (GC/MS) were 2,3,5-Trichlorophenol, 3,5-dichlorophenol, dichlorodihydroxy-benzene and 3,4,5-trichlorocatechol.

Catalytic ozonation for water and wastewater treatment: Recent advances and perspective

Ozonation process has been widely applied in water and wastewater treatment, such as for disinfection, for degradation of toxic organic pollutants. However, the utilization efficiency of ozone is low and the mineralization of organic pollutants by ozone oxidation is ineffective, and some toxic disinfection byproducts (DBPs) may be formed during ozonation process. Catalytic ozonation process can overcome these problems to some extent, which has received increasing attention in recent years. During catalytic ozonation, catalysts can promote O₃ decomposition and generate active free radicals, which can enhance the degradation and mineralization of organic pollutants. In this paper, the history of ozonation application in water treatment was briefly reviewed. The properties of the ozone molecule, the ozonation types and several ozone-based water treatment processes were briefly introduced. Various catalysts for catalytic ozonation, including homogeneous and heterogeneous catalysts, such as metal ions, metal oxidizes, carbon-based materials and their possible catalytic mechanisms were analyzed and summarized in detail. Furthermore, some inconsistent results of previous research on catalytic ozonation were analyzed and discussed. The application of catalytic oxidation for the degradation of toxic organic pollutants, including phenols, pesticides, dyes, pharmaceuticals and others, was summarized. Finally, several key aspects of catalytic ozonation, such as pH effect, the catalyst performance, the catalytic mechanism were proposed, to which more attention should be paid in future study.

Activated petroleum waste sludge biochar for efficient catalytic ozonation of refinery wastewater

Large quantities of hazardous activated petroleum waste sludge and wastewaters are generated from petroleum refining. The present disposal of the sludge via incineration or landfill may cause secondary pollution as well as additional costs. Treatment of petroleum refinery wastewater (PRW) by catalytic ozonation process (COP) remains a great challenge of developing low-cost and high-efficiency catalysts. Use of waste sludge derived biochar as catalysts in COP of PRW not only solves the solid wastes and wastewaters problems but also improves profitability. The elements of carbon (C), silicon (Si) and metals originally found in activated petroleum waste sludge contribute to the formation of active sites during pyrolysis. The biochar contains functional C groups, SiO structures, and metallic oxides that promote oxidation through the formation of hydroxyl radicals (OHs) mineralizing petroleum contaminants. Catalytic ozonation of PRW using this sludge biochar (SBC) doubles the total organic carbon removal (53.5%) relative to single ozonation (26.9%). Oxygen (Ox)-, nitrogen (NOx)- and sulfur (OxS)-containing contaminants were decreased by 33.4% (989 vs 659), 58.2% (912 vs 384) and 12.5% (384 vs 336). The present study shows the potential of a "wastes-treat-wastes" process for wastewater treatment.