This study aimed to explore the physical, mechanical, optical, and radiation-attenuation characteristics of borate-based glasses with the composition (70-x)B2O3-28Na2O-2Gd2O3-xBaO (where x = 0, 5, 10, 15, and 20 mol%). The glasses were fabricated via the melt-quenching approach, and their amorphous structures validated through X-ray diffraction analysis. The density of the glasses increased from 2.412 to 3.114 g/cm3 due to the effective incorporation of barium oxide (BaO). The mechanical properties, assessed using the Makishima–Mackenzie model, showed a decrease in the mechanical moduli as the BaO content in the fabricated glasses increased. Optical analysis revealed a 3.048 to 2.807 eV decline in the indirect optical band gap energy and a 2.384 to 2.449 elevation in the refractive index as the BaO loading rose from 0 to 20 mol%, resulting in structural changes within the glass network and the generation of non-bridging oxygens. Additionally, radiation-shielding studies were carried out to determine the mass attenuation coefficient (MAC), half-value layer (HVL), and mean free path (MFP) using the XCOM software, revealing that the incorporation of BaO significantly enhanced the radiation-shielding performance of the prepared glasses, among which the glass with 20 mol% BaO (B-20) was the most effective for gamma-ray shielding through exhibiting high MAC and low HVL and MFP values. Furthermore, the evaluated MAC values were compared with those of recognized shielding materials and other BaO-doped glasses at 0.662 MeV, whereby the comparison verified that the glass with the highest BaO concentration provided the optimum radiation-shielding effectiveness, and is thus appropriate for radiation-protection applications.

Organic waste from orange peels was synthesized into carbon nanodots (CDs) using a microwaveassisted method to serve as photocatalysts for purifying industrial liquid waste. The CDs were characterized using photoluminescence (PL), ultraviolet-visible (UV-Vis) spectroscopy, Fouriertransform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and time-resolved photoluminescence (TRPL). The characterization results revealed that the CDs exhibit fluorescence at a wavelength of 509 nm with a lifetime of 56 ns. Additionally, three absorption peaks were observed: one at 230 nm, attributed to C=C bonds in the core state, and two at 276 nm and 320 nm, associated with C-N and C-O bonds in the surface state. The photocatalyst solution was synthesized by combining CDs with TiO2 to enhance pollutant absorption. This photocatalyst was applied to the degradation of methylene blue in liquid waste. Significant degradation of the methylene blue dye was observed over varying exposure times (0, 6, 12, 18, and 24 hours) under direct sunlight. UV-Vis analysis revealed a wavelength shift, a decrease in the energy gap, and an increase in particle size, attributed to quantum effects. Furthermore, the dye degradation efficiency increased with longer exposure, rising from 56.6% to 83% over 18 hours of sunlight. These findings demonstrate that optimizing the optical properties of CDs in combination with TiO2 is an effective, economical, and environmentally friendly approach for industrial liquid waste purification.