For applications involving water cleanup, metal oxide nanoparticles are exceptionally successful. They are useful for the adsorption and photocatalytic destruction of organic pollutants due to their distinctive qualities, which include their wide surface/volume area, high number of active sites, porous structure, stability, recovery, and low toxicity. Metal oxide nanomaterials have drawn a lot of attention from researchers in the past ten years because of their various production pathways, simplicity in surface modification, abundance, and inexpensive cost. A wide range of metal oxides, such as iron oxides, MgO, TiO2, ZnO, WO3, CuO, Cu2O, metal oxides composites, and graphene–metal oxides composites, with variable structural, crystalline, and morphological features, are reviewed, emphasizing the recent development, challenges, and opportunities for adsorptive removal and photocatalytic degradation of organic pollutants such as dyes, pesticides, phenolic compounds, and so on. In-depth study of the photocatalytic mechanism of metal oxides, their composites, and photocatalytically important characteristics is also covered in this paper. Metal oxides are particularly effective photocatalysts for the degradation of organic pollutants due to their high photodegradation efficiency, economically sound methods for producing photo-catalytic materials, and precise band-gap engineering. Due to their detrimental effects on human health, pesticides—one of the highly hazardous organic pollutants—play a significant part in environmental contamination. Depending on where they come from and who they are targeting, they are categorized in various ways. Researchers focusing on metal oxides and their composites for the adsorptive and photocatalytic degradation of pesticides would find the review to be a beneficial resource. Detailed information on many pesticides, difficulties associated with pesticides, environmental concentration, and the necessity of degradation has been presented.

Global warming and climate changes are among the biggest modern-day environmental problems, the main factor causing these problems is the greenhouse gas effect. The increased concentration of carbon dioxide in the atmosphere resulted in capturing increased amounts of reflected sunlight, causing serious acute and chronic environmental problems. The concentration of carbon dioxide in the atmosphere reached 421 ppm in 2022 as compared to 280 in the 1800s, this increase is attributed to the increased carbon dioxide emissions from the industrial revolution. The release of carbon dioxide into the atmosphere can be minimized by practicing carbon capture utilization and storage methods. Carbon capture utilization and storage (CCUS) has four major methods, namely, pre-combustion, post-combustion, oxyfuel combustion, and direct air capture. It has been reported that applying CCUS can capture up to 95% of the produced carbon dioxide in running power plants. However, a reported cost penalty and efficiency decrease hinder the wide applicability of CCUS. Advancements in the CCSU were made in increasing the efficiency and decreasing the cost of the sorbents. In this review, we highlight the recent developments in utilizing both physical and chemical sorbents to capture carbon. This includes amine-based sorbents, blended absorbents, ionic liquids, metal-organic framework (MOF) adsorbents, zeolites, mesoporous silica materials, alkali-metal adsorbents, carbonaceous materials, and metal oxide/metal oxide-based materials. In addition, a comparison between recently proposed kinetic and thermodynamic models was also introduced. It was concluded from the published studies that amine-based sorbents are considered assuperior carbon-capturing materials, which is attributed to their high stability, multifunctionality, rapid capture, and ability to achieve large sorption capacities. However, more work must be done to reduce their cost as it can be regarded as their main drawback.

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