The present COVID-19 emergency has dramatically increased the demand for pharmaceutical containers, especially vials. End-of-life containers, however, cannot be easily recycled in the manufacturing of new articles. This paper presents some strategies for upcycling of pharmaceutical glass into various porous ceramics. Suspensions of a fine glass powder (70 vol%) are used as a starting material. Highly uniform cellular structures may be easily prepared by vigorous mechanical stirring of partially gelified suspensions with added surfactant, followed by drying and firing at 550–650 °C. Stabilization of the cellular structures at temperatures as low as the glass transition temperature (T_g) of the used glass is facilitated by thermal decomposition of the gel phase, instead of viscous flow sintering of glass. This finding enabled the preparation of glass membranes (∼78 vol% open porosity), by direct firing of hardened suspensions, avoiding any surfactant addition and mechanical stirring. The powders obtained by crushing of hardened suspensions, even in unfired state, may be used as a low-cost sorbent for dye removal.

A sustainable nexus between renewable energy production and plastic abatement is imperative for overall sustainable development. In this regard, this study aims to develop a cheaper and environmentally friendly nexus between plastic waste management, wastewater treatment, and renewable hydrogen production. Fluorescent carbon (FCs) were synthesized from commonly used LDPE (low-density polyethylene) by a facile hydrothermal approach. Optical absorption study revealed an absorption edge around 300 nm and two emission bands at 430 and 470 nm. The morphological analysis showed two different patterns of FCs, a thin sheet with 2D morphology and elongated particles. The sheet-shaped particles are 0.5 μm in size, while as for elongated structures, the size varies from 0.5 to 1 μm. The as-synthesized FCs were used for the detection of metal ions (reference as Cu²⁺ ions) in water. The fluorescence intensity of FCs versus Cu²⁺ ions depicts its upright analytical ability with a limit of detection (LOD) reaching 86.5 nM, which is considerably lesser than earlier reported fluorescence probes derived from waste. After the sensing of Cu²⁺, the as-obtained FCs@Cu²⁺ was mixed with TiO₂ to form a ternary FCs@CuO@TiO₂ composite. This ternary composite was utilized for photocatalytic hydrogen production from water under 1.5 AM solar light irradiation. The H₂ evolution rate was found to be ~1800 μmolg⁻¹, which is many folds compared to the bare FCs. Moreover, the optimized FCs@CuO@TiO₂ ternary composite showed a photocurrent density of ~2.40 mA/cm² at 1 V vs. Ag/AgCl, in 1 M Na₂SO₄ solution under the illumination of simulated solar light. The achieved photocurrent density corresponds to the solar-to-hydrogen (STH) efficiency of ~0.95%. The efficiency is due to the fluorescence nature of FCs and the synergistic effect of CuO embedded in TiO₂, which enhances the optical absorption of the composite by reaching the bandgap of 2.44 eV, apparently reducing the recombination rate, which was confirmed by optoelectronic, structural, and spectroscopic characterizations.