More and more, waste generated in most parts of the Western world has been recycled and transformed into new circularity products. However, managing waste within Sub-Saharan Africa (SSA), such as in Ghana, has become a challenge due to the continued practice of the old traditional linear waste economy, that is, the taking, making and disposing methods of management, representing a threat to global environmental sustainability. Despite the need to revise current linear waste management (WM) in order to turn to the circular economy (CE) model, which consists of the concept of renew, remake and share, to advance sustainable development, a number of factors restrict the CE realization in practice, specifically in developing countries. An integrative methodology was used in this article to identify some of the challenges that hinder the achievement of CE in SSA countries. The results revealed the absence of educational programs and public awareness of waste management activities. The findings also highlight the lack of political will, funding and national policies on WM as some of the most significant issues. The study contributes to further encouraging policymakers and policy implementers, entrepreneurs and relevant interested groups to commit resources to sustainable WM services aiming to advancing CE in SSA countries.

The synthesis of photocatalysts with high charge separation and transfer efficiency are of immense significance in the process of using photocatalysis technology for wastewater treatment. In this study core shell g-C₃N₄@ZnO, and ZnO defects photocatalysts presented an improved morphology in its characterization using techniques such as SEM, DRS, PL, MS, EIS, and XRD, and enhanced photodegradation of sulfamethoxazole, Nitenpyram and Tetracycline. Different composites were obtained as confirmed by the various characterization techniques studied, including core shell g-C₃N₄@ZnO, and ZnO defects photocatalyst. The synthesized photocatalysts showed high visible light absorption efficiency within a range of ~655 to 420 nm. Core shell g-C₃N₄@ZnO, and ZnO defects photocatalysts demonstrated high photocatalytic activity ascribed to high load separation and transition as shown in PL, Photocurrent reaction and EIS. It is understandable that core shell g-C₃N₄@ZnO, and ZnO defects photocatalysts have been confirmed to be one of the ultimate promising entrants for photocatalyst scheming.

Graphene nanocrystals can utilize solar light and are valuable in cases where electricity is lacking due to their chemical stability during the photocatalytic process, low cost and non-toxicity. However, because of the large band gap, ultraviolet light irradiation can barely excite graphene, which limits its application in the environment. CO₂ photoreduction through the visible light-responsive photocatalytic performance of graphene nanocrystals has recently been the focus of research in nanoscience due to the ability to convert pollutants into CO₂ and H₂O for environmental applications such as energy, environmental purification and wastewater treatment. This paper highlights the present improvements in CO₂ photoreduction with H₂O through the visible light-responsive photocatalytic performance of graphene nanocrystals via the development of structural modification strategies, solar harvesting, methods of synthesis and solar light catalytic mechanisms.

With solar light, modified d-block metal photocatalysts are useful in areas where electricity is insufficient, with its chemical stability during the photocatalytic process, and its low-cost and nontoxicity. However, because of their large band gap for excitation, only biohazardous ultraviolet (UV) light irradiation can excite d-block metals, which limits its application in the living environment. Modified d-block metal photocatalyts such as TiO₂, ZnO, has recently been the center of research in Nano studies due to the ability of these metals to convert pollutants into CO₂ and H₂O for environmental applications such as energy, environmental purification and wastewater treatment. This paper highlights the present improvements on the photocatalytic activity of modified d-block metals through their developing structure modification strategies, solar harvest, methods of synthesis and solar light synthesis catalytic mechanisms of these photocatalysts. In this report, the full knowledge of the use of the remarkable solar light harvest potentials vis-à-vis the excellent structure of these metals are revealed. Also, this study on modified d-block metal Nano-based photocatalysts is expected to enlighten scientists on precise management and evaluating the environment, which may merit prospect research into developing suitable mechanism for energy, wastewater treatment and environmental purification.