This review addresses the growing need for the efficient recycling of crystalline silicon photovoltaic modules (PVMs), in the context of global solar energy adoption and the impending surge in end-of-life (EoL) panel waste. It examines current recycling methodologies and associated challenges, given PVMs’ finite lifespan and the anticipated rise in solar panel waste. The study explores various recycling methods—mechanical, thermal, and chemical—each with unique advantages and limitations. Mechanical recycling, while efficient, faces economic and environmental constraints. Thermal methods, particularly pyrolysis, effectively break down organic materials but are energy-intensive. Chemical processes are adept at recovering high-purity materials but struggle with ecological and cost considerations. The review also highlights multifaceted challenges in recycling, including hazardous by-product generation, environmental impact, and the economic feasibility of recycling infrastructures. The conclusion emphasizes the need for innovative, sustainable, and economically viable recycling technologies. Such advancements, alongside global standards and policy development, are crucial for the long-term sustainability of solar energy and effective management of PVM waste.

Bismuth vanadate (BiVO₄) is a narrow-bandgap semiconductor (~2.41 Ev) that responds to visible light. The efficiency of degradation of organic dyes is indexed by methylene blue (MB). After 150 min, the efficiency of MB degradation by pure BiVO₄ was about 20%. Its adsorption performance and electron–hole pair migration ability are weak, and the photocatalytic activity of pure BiVO₄ needs to be improved. BiVO₄ doped with rare earth ions can facilitate the separation of photogenerated electron–hole pairs, thereby enhancing photocatalytic activity in the visible light range. This study investigates changes in the structure and morphology of BiVO₄ doped with different atomic percentages of terbium (Tb). BiVO₄ powders were prepared by the hydrothermal method with different atomic percentages of Tb (at% = 0, 1, 3, and 5). Doping Tb benefits the coexistence of monoclinic/tetragonal heterostructures, which changes the band gap and improves degradation efficiency. After 150 min of visible light irradiation, the photocatalyst doped with 3 atomic percent of Tb exhibited 98.2% degradation of methylene blue. The degradation percentage of MB remained stable in the presence of 3at%Tb-doped BiVO₄ composite. The optimal parameters for the amount of photocatalyst added were studied. Real-field simulations of metal ions and inorganic salts both retain high levels of degradation efficiency.

This study introduces a novel two-stage circular economy model to transform organic waste materials—bean dregs and coffee grounds—into functional products: eco-friendly cat litter and organic fertilizer. The hypothesis was that integrating vermicompost and diatomaceous earth with these waste materials would enhance the functional properties of cat litter while ensuring its recyclability into high-quality fertilizer. In the first stage, a combination of bean dregs, coffee grounds, vermicompost, and diatomaceous earth was optimized using the Taguchi method, achieving cat litter with superior water absorption and clumping performance. In the second stage, the spent cat litter was rapidly composted, producing a nutrient-rich organic fertilizer. The fertilizer’s efficacy was validated through a potting experiment with lettuce, where a 10% application rate promoted optimal growth without causing nutrient toxicity. This innovative approach offers a sustainable solution to waste management challenges while contributing to environmentally friendly agricultural practices. Future research could investigate incorporating additional waste streams and enhancing composting efficiency for broader implementation.