Sustainable technology for mass production of Ag nanoparticles and Al microparticles from damaged solar cell wafers

Recent advances in nanoantibiotics against multidrug-resistant bacteria

Multidrug-resistant (MDR) bacteria-caused infections have been a major threat to human health. The abuse of conventional antibiotics accelerates the generation of MDR bacteria and makes the situation worse. The emergence of nanomaterials holds great promise for solving this tricky problem due to their multiple antibacterial mechanisms, tunable antibacterial spectra, and low probabilities of inducing drug resistance. In this review, we summarize the mechanism of the generation of drug resistance, and introduce the recently developed nanomaterials for dealing with MDR bacteria via various antibacterial mechanisms. Considering that biosafety and mass production are the major bottlenecks hurdling the commercialization of nanoantibiotics, we introduce the related development in these two aspects. We discuss urgent challenges in this field and future perspectives to promote the development and translation of nanoantibiotics as alternatives against MDR pathogens to traditional antibiotics-based approaches.

A facile crush-and-sieve treatment for recycling end-of-life photovoltaics

The shift towards renewable energy mix has resulted in an exponential growth of the photovoltaic (PV) industry over the past few decades. Parallelly, new recycling technology developments are required to address the incoming volume of waste as they gradually approach their end-of-life (EoL) to realize the concept of a circular economy. Typical recycling processes involve high-temperature burning for separation and release of the PV cells for metal recovery processes. However, this thermal process generates gaseous by-products that cause serious health and environmental issues. Eschewing the need for burning, we demonstrate a simple crush-and-sieve methodology to strategically aids the separation of polymeric and metallic contents. The proposed approach showcased the efficient size-selective separation and generated polymer- and metal-rich fractions. More than 90 % of the total polymer present within the studied wastes was found to be retained in larger sized-particle fractions (F1 and F2). Metal content analysis highlighted the enrichment of highly valuable silver into the smallest sized-particle fraction (F4), accounting up to 70 % and 80 % of total silver present respectively for EVAc and MP. The benefits ripe through this simple crush-and-sieve method offers an attractive pathway for PV recycling process to obtain metal-rich fractions and allow focused recovery of valuable materials through an environmentally friendlier manner.

End-of-Life Photovoltaic Modules

More than 78 million tons of photovoltaic modules (PVMs) will reach their end of life (EOL) by 2050. If they are not responsibly managed, they can (a) pollute our terrestrial ecosystem, (b) indirectly encourage continuous mining and extraction of Earth’s finite resources, and (c) diminish the net environmental benefit of harvesting solar energy. Conversely, successfully recovering them could reduce resource extraction and waste and generate sufficient economic return and value to finance the production of another 2 billion PVMs by 2050. Therefore, EOL PVMs must participate in the circular economy, and business and political leaders are actively devising strategies to enable their participation. This article aims to facilitate and expedite their efforts by comprehensively reviewing and presenting the latest progress and developments in EOL PVM recovery methods and processes. It also identifies and thoroughly discusses several interrelated observations that impede or accelerate their efforts. Overall, our approach to this article differs but synergistically complements and builds upon existing life cycle assessment-based (LCA-based) contributions.

Purification of silicon from waste photovoltaic cells and its value-added application in lithium-ion batteries

A facile and promising method was proposed to make full use of waste photovoltaic cell natural characteristics by fabricating the PSi/Li/N@C composite as high-performance LIB anode material.

Metal dissolution from end-of-life solar photovoltaics in real landfill leachate versus synthetic solutions: One-year study

To investigate the after end-of-life concerns of solar panels, four commercially available photovoltaics (reduced to 15×15 cm² size) in broken and unbroken conditions were exposed to three synthetic solutions of pH 4, 7, 10 and one real municipal solid waste landfill leachate for one year. Metals leaching, encapsulant degradation and release, probability of leached metals exceeding their surface water limits, and change in pollution index of leachate after dumping of solar panels were investigated. Rainwater simulating solution was found to be predominant for metal release from silicon-based photovoltaics, with silver, lead and chromium being released up to 683.26 mg/L (26.9%), 23.37 mg/L (17.6%), and 14.96 mg/L (13.05%), respectively. Copper indium gallium (de) selenide (CIGS) photovoltaic was found to be least vulnerable in various conditions with negligible release of indium, molybdenum, selenium and gallium with values ranging between 0.2 and 1mg/L (0.30%-0.74%). In contrast, minimal metals were released in real landfill leachate compared to other leaching solutions for all photovoltaics. Positive correlation was observed between encapsulant release and metal dissolution with a maximum encapsulant release in silicon-based photovoltaics in rainwater conditions. The calcualtion of values of probability of exceedance of leached metals to their respective surface water limits for aluminium (multi- and mono- crystalline-silicon), silver (amorphous photovoltaic) and indium (CIGS) indicated maximum value to be 92.31%. The regression analysis indicated that conditions of the modules and pH of the leaching solution play significant roles in the metal leaching. The increase in leachate contamination potential after one-year of photovoltaics dumping was found to be 12.02%, 10.90%, 15.26%, 54.19% for amorphous, CIGS, mono and multi crystalline-silicon photovoltaics, respectively. Overall, the maximum metal release observed in the present study is 30% of the initial amount under the most stressful conditions, which suggests that short-term leaching studies with millimeter sized sample pieces do not represent the realistic dumping scenarios.

Recycling experimental investigation on end of life photovoltaic panels by application of high voltage fragmentation

With the rapid development of photovoltaic industry, the recycling of waste solar photovoltaic (PV) panels is becoming a critical and global challenge. Considering PV panels recycling is significantly effective and worthwhile to save natural resources and reduce the cost of production, how to selectively recycle valuable components of PV panels is the hot and dominant topic. Different from current mechanical crushing, heat treatment and chemical operation processes, novel and environment-friendly recycling approaches by using high voltage pulse discharge in water, called high voltage fragmentation (HVF), was discussed under different discharge conditions. The results showed that discharging across surface and interior of PV panels produced ablation round holes, sputter metal particles and dendritic channels. The average particle size decreased with the ascent of pulse number and voltage amplitude. Considering the energy consumption, the optimal condition of HVF in this paper was 160 kV for 300 pulses with the energy consumption of 192.99 J/g, crushing the PV panels into particles of 4.1 mm in average (13.7% of the initial size). More particle was distributed among the 0.1-2 mm size fractions as the energy increased. Selective fragmented products, such as Cu, Al, Pb, Ag and Sn, are concentrated on the fractions under 1 mm. Finally, hybrid crushing energy consumption model combined with fractal theory was discussed, which presented close relationship between energy and average particle size. Walker's model (n = 2.047 determined by fractal theory) had the best fitting effect.