No abstract

Methods for recovering raw materials from end-of-life solar panels were studied. A process for removing the hazardous element lead (Pb) in solar panels was also investigated. We achieved recovery rates of 80%, 79%, and 90% for Si, Cu, and Ag. We also achieved a removal rate of 93% for Pb. We immersed the cells in 5 M nitric acid solution under agitation at 200 rpm to dissolve the metals. We sequentially recovered Si, Cu, Ag, Al, and Pb. To recover Si, a process for removing the Al electrode and SiN x layer was required. LIX84-I and 150 g/L H 2 SO 4 solution were used to respectively extract and strip Cu. The purity of Ag powder after reduction Ag 2 O was 99.7%. An electrolytic refining process increased the Ag purity to 99.99%. We were able to achieve a removal rate of 93% for Pb through neutralization and sulfurization.

The three-dimensional (3D) printing of large-volume cells, printed in a clinically relevant size, is one of the most important challenges in the field of tissue engineering. However, few studies have reported the fabrication of large-volume cell-printed constructs (LCCs). To create LCCs, appropriate fabrication conditions should be established: Factors involved include fabrication time, residence time, and temperature control of the cell-laden hydrogel in the syringe to ensure high cell viability and functionality. The prolonged time required for 3D printing of LCCs can reduce cell viability and result in insufficient functionality of the construct, because the cells are exposed to a harsh environment during the printing process. In this regard, we present an advanced 3D cell-printing system composed of a clean air workstation, a humidifier, and a Peltier system, which provides a suitable printing environment for the production of LCCs with high cell viability. We confirmed that the advanced 3D cell-printing system was capable of providing enhanced printability of hydrogels and fabricating an ear-shaped LCC with high cell viability. In vivo results for the ear-shaped LCC also showed that printed chondrocytes proliferated sufficiently and differentiated into cartilage tissue. Thus, we conclude that the advanced 3D cell-printing system is a versatile tool to create cell-printed constructs for the generation of large-volume tissues.