Eggshell waste materials-supported metal oxide nanocomposites for the efficient photocatalytic degradation of organic dyes in water and wastewater: A review

IntroductionTribocatalysis, an emerging cutting‐edge technique that uses frictional mechanical energy to activate the catalytic operation of a reaction or material including nanomaterials has garnered the interest of the research community in recent times.AimThis study aimed to critically review original research works directed toward tribocatalytic degradation of various hazardous dye pollutants. Notably, in this review, various nanomaterials and their composites with outstanding tailored degradation profiles are explored for their tribocatalytic degradation efficiency for various dye pollutants. In addition, the effect of various operating factors that are of importance to engineers, industries, and investors for optimization purposes was pragmatically discussed. Also, the effect of electron trapping and radical scavengers alongside the mechanism of tribocatalytic degradation was empirically analyzed.ResultsFrom this work, it was found that the maximum tribocatalytic degradation efficiency was >80% in most cases at an optimum temperature of 20–40°C, time taken of 0.5‐48 hours, and stirring speed of 500‐1000rmp. It was discovered that magnetic stirring enhances the production of •OH, O2•, and h+ by the nanomaterials that are mechanistically responsible for the degradation of the dye pollutants. Also, it was revealed that expended tribocatalyst can be eluted mostly using H2O and can be reused up to 3–10 times while still sustaining degradation efficiency of >80% in most cases and this suggests the industrial scalability and eco‐friendliness potential of this approach.ConclusionIn the end, challenges and research gaps that can pave the way for method improvement and also serve as future research hotspots for researchers were presented.

Harvesting surface (interfacial) energy for tribocatalytic degradation of hazardous dye pollutants using nanostructured materials: A review

Emmanuel,

Adesibikan

2024

Covalent organic frameworks and metal–organic frameworks for sustainable adsorptive removal/extraction of dirty dozen chemicals: A review

Emmanuel,

Aniekezie,

Adesibikan

2024

Dirty dozen chemicals (DDCs) are a group of 12 extremely toxic chemicals that were recognized at the Stockholm convention in 2001 for their severe impact on the ecosystem and human health. Despite the embargo and restraint placed on DDCs usage, these chemicals continue to find their way into the ecosystem because they are still secretly or openly applied by many nations, especially in African regions. Moreover, DDCs can still be perceived where they have been employed previously before the Stockholm convention treaty due to their persistent profile. This study aimed to critically review original works directed toward the removal of various dirty dozen chemicals using covalent and metal–organic frameworks (COFs and MOFs). Specifically, in this study, various COFs/MOFs and their composites with remarkably tailored adsorptive profiles are evaluated for their adsorption efficiency for different DDCs. In addition, the effect of various operating parameters that are of importance to environmentalists and various stakeholders for optimization purposes was empirically discussed. This review also fills knowledge vacuums about the COF/MOF‐DDCs adsorption process, offers insights into their reusability potential, fundamental mechanism, isotherm, and kinetic modeling, and offers a framework for future studies. Findings from this study revealed that COF and MOF have high DDC removal capacity and reusability potential attributed to their admirable porosity and the existence of a plethora of oxygen‐rich functional groups that allow for better interactions with DDCs through chelation, halogen bonding, H‐bonding, and π‐π interactions and stacking. This points to the upscaling potential of this remediation technique. Future researchers need to direct more efforts to the use of density functional theory for mechanism interpretation, exploration of hybrid technology, cost analysis, scalability, isotherm, thermodynamics, adsorption, and desorption kinetic modeling.

A review on photocatalytic degradation of aromatic organoarsenic compounds in aqueous environment using nanomaterials

Emmanuel,

Adesibikan

2024

Aromatic organoarsenic compounds (AOCs) have proven to be both a boon and a curse by boosting profit maximization in livestock production and at the same time contributing to the pollution of water bodies, the chief cornerstone of the ecosystem. Interestingly, photocatalytic degradation using nanomaterials has emerged as an effective method to mitigate AOC pollution. Thus, this study aims to review and analyze original research works directed toward the photocatalytic degradation of AOC in the aqueous environment. In this study, the photocatalytic degradation efficiency of various nanomaterials is investigated for different aromatic organoarsenic compounds. In addition, an empirical analysis was conducted on the impact of electron trapping and radical scavengers. Furthermore, photocatalytic degradation kinetics and mechanisms were pragmatically discussed. Also, recyclability, stability, and real‐life applicability were empirically evaluated. According to this review, most nanomaterial materials had maximal photocatalytic degradation efficiencies of >75% for most AOCs within an average time of 6–330 min. The radical scavenging study revealed that ●OH and O2● mechanistically play a major role in AOC degradation than electrons and holes. Additionally, it was shown that expended photocatalysts can be eluted mostly with H2O/NaOH and recycled up to 3–6 rounds with a degradation efficiency of >80% in most cases while maintaining their original structural integrity. This indicates that the method has the potential to be both environmentally friendly and industrially scalable. Ultimately, research gaps were highlighted, which can help researchers identify future research hotspots and open doors for technique advancement.