APPLICATION OF INORGANIC CATALYSTS IN THE UTILIZATION OF INDUSTRIAL WASTE

Аннотация

Industrial growth has led to a sharp rise in waste generation, posing serious environmental and health risks. Conventional disposal methods—such as landfilling and incineration—are often inefficient and harmful. In contrast, inorganic catalysts offer a sustainable and effective approach for treating and converting industrial waste into less harmful or valuable products. This article examines the types, mechanisms, and applications of inorganic catalysts, along with their benefits, challenges, and future prospects. Their use supports pollution reduction and promotes green chemistry and circular economy goals. Keywords: Inorganic catalysts, industrial waste, photocatalysis, waste valorization, green technology. Introduction. With rapid industrialization, managing industrial waste has become a major challenge due to the release of harmful pollutants like heavy metals and toxic gases. Sustainable and efficient treatment methods are urgently needed. Inorganic catalysts—such as metals, metal oxides, and zeolites—offer a promising solution, as they accelerate reactions without being consumed and remain stable under harsh conditions. Understanding their structure, mechanisms, and applications is key to advancing waste treatment in line with sustainable development and the circular economy. Inorganic catalysts are typically classified into three main types: transition metal catalysts, metal oxide catalysts, and zeolite-based catalysts, each with unique properties suited to specific waste treatment processes. Transition metals like Pt, Pd, Cu, Co, and Ni are widely used for their variable oxidation states, enabling hydrogenation, oxidation, and reduction reactions. For instance, nickel is used in treating pharmaceutical waste, while copper is effective in reducing nitrogen oxides in flue gases. Metal oxides such as TiO₂, ZnO, MnO₂, and Fe₂O₃ are prominent in photocatalytic and oxidative degradation due to their high surface area and redox potential. TiO₂, in particular, is effective under UV or visible light in breaking down pollutants through advanced oxidation processes. Meanwhile, zeolites—crystalline aluminosilicates with porous structures—serve both as adsorbents and catalysts. Zeolites like ZSM-5 and Y- zeolite are used for plastic waste cracking, heavy metal removal, and ammonia transformation, thanks to their acidity, stability, and ion-exchange capacity. 126 ACADEMIC RESEARCH IN MODERN SCIENCE International scientific-online conference Inorganic catalysts enhance industrial waste treatment by offering alternative reaction pathways with lower activation energy, thus accelerating transformations under mild conditions. In heterogeneous catalysis, reactions occur on the catalyst's surface, where active sites facilitate reactant adsorption and bond weakening. Transition metals, through their variable oxidation states, enable redox reactions like the oxidation of VOCs using manganese oxide, converting pollutants into CO₂ and H₂O. Photocatalysts such as TiO₂ and ZnO absorb light to generate electron-hole pairs, producing reactive radicals that break down persistent pollutants in wastewater. Zeolites, functioning via acid- base catalysis, use Brønsted and Lewis acid sites to convert long-chain hydrocarbons into lighter, reusable products through cracking and isomerization [3]. Inorganic catalysts play a vital role across various industrial waste treatment domains, including wastewater purification, air pollution control, solid waste valorization, and CO₂ conversion. In wastewater treatment, catalysts like TiO₂, ZnO, and Fe₂O₃ are effective in breaking down persistent organic pollutants, dyes, and pharmaceuticals, especially when integrated with membrane filtration systems. In air pollution control, metal oxide catalysts— such as copper, cerium, and manganese oxides—are used in the selective catalytic reduction (SCR) of NOx and VOCs in flue gases. For solid waste, zeolite- assisted pyrolysis converts plastic waste into fuel-grade hydrocarbons. Additionally, catalysts like copper-zinc oxide and ruthenium on zirconia are increasingly used to convert CO₂ into methanol or formic acid, supporting carbon recycling and emission reduction efforts [1, 10-15]. There are several compelling advantages associated with the use of inorganic catalysts in industrial waste treatment. First and foremost, their robust structural integrity enables them to withstand high temperatures and pressures common in industrial reactors. This feature ensures long-term operational stability and cost-effectiveness. Moreover, many inorganic catalysts are non-toxic, non-volatile, and environmentally benign, making them preferable over organic or enzymatic catalysts that may pose disposal or safety concerns. Their ability to operate under ambient conditions (especially in photocatalysis) further reduces energy consumption and operating costs. Another advantage lies in their reusability and regenerability. For instance, many metal oxide catalysts can be