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This review examines the technological surveillance of photovoltaic panel recycling through a bibliometric study of articles and patents. The analysis considered the number of articles and patents published per year, per country, and, in the case of patents, per applicant. This analysis revealed that panel recycling is an increasingly prominent research area. However, the number of patents filed annually has varied in recent years, averaging fewer than 200 per year. The state-of-the-art review identified three main types of treatment for photovoltaic panel recycling: mechanical, chemical, and thermal. Among these, mechanical treatment serves as a preliminary stage before the recovery of valuable elements, which is achieved through chemical or thermal processes. The articles reviewed cover a range of processes, including hydrometallurgical and pyrometallurgical methods, and explore various classification processes, solvents, and oxidizing agents. In contrast, patents predominantly focus on pyrometallurgical processes. This analysis is supplemented by a survey of market-ready technologies, many of which include stages such as size reduction or delamination followed by pyrometallurgical processes. Additionally, the review highlights the collection processes implemented by some companies, noting that the volume of panels considered waste is currently insufficient to maintain a continuous and year-round operational process. This study identifies key challenges such as (i) reducing solar panel size due to the EVA polymer complicating conventional machinery use, (ii) high process costs from the need for high temperatures and costly additives, (iii) the environmental impact of thermal treatments with high energy consumption and air pollution, and (iv) the necessity for environmentally friendly solvents in hydrometallurgical treatments to reduce contamination during recycling. Future directions include developing specific machinery for panel size reduction, either creating or modifying a polymer to replace EVA for easier treatment, adopting hydrometallurgical treatments with green solvents proven effective in recycling minerals and electronic waste, and addressing the lack of detailed information on industrial processes to make more precise recommendations. [ABSTRACT FROM AUTHOR]

Abstract: The densities and viscosities of unsaturated solutions of sodium perchlorate+poly(ethylene glycol)+water were experimentally measured at temperatures of 288.15, 298.15 and 308.15K. The solution concentrations of poly(ethylene glycol) with an average molecular weight of 4000 ranged from 0.25 to 33.91 (mass%) and from 10.12 to 37 (mass%) of NaClO4. The electrolyte and polymer non-random two liquid models were extended for representing of the excess molar volume and the dynamic viscosity of the above system. At these specific temperatures, the model correlations compared favorably with the experimental data for both the density and the viscosity. [Copyright &y& Elsevier]

Abstract: Phase diagram and (liquid+liquid) equilibrium (LLE) data for the (NaNO3 +polyethylene glycol 4000 (PEG 4000)+H2O) system have been determined experimentally at T =(288.15 and 308.15)K. The effects of temperature on the binodal curves and tie-lines have been studied and it was found that an increasing in temperature caused the expansion of two-phase region. The Chen-NRTL, modified Wilson and UNIQUAC models were used to correlate the experimental tie-line data. The results show that the quality of fitting is better with the UNIQUAC model. [Copyright &y& Elsevier]

Abstract: The cloud-point (CP) temperatures and phase separation of {H2O+poly(ethylene glycol)+NaNO3} ternary system is studied by the turbidimetry method using a reaction calorimeter. The phase separation was also observed by visual inspection. Differences between the CP measured using the turbidimetry method and visual inspection, was up ±0.5K. The Flory–Huggins model with a temperature and concentration-dependent interaction parameter was employed to correlate the phase diagram of the system. As a result of the correlation an average absolute deviation of 0.002 is obtained. [Copyright &y& Elsevier]