The management of large amounts of eggshell waste annually produced in the world is problematic as generally this material is only disposed at landfills with odor production and microbial growth. On the contrary, significant environmental and economic advantages could be obtained transforming this biowaste into new value-added products. Eggshell biowaste was the starting material for the synthesis of hydroxyapatite by a simple and sustainable procedure and applied for the removal of Co²⁺ from aqueous solutions. The effects of contact time and initial metal concentration were investigated in batch experiments. Eggshell-based hydroxyapatite (ESHAP) before and after Co²⁺ removal was characterized by X-ray diffraction and scanning electron microscopy. The process was rapid and reached equilibrium within 80 min. The removal efficiency was in the range 70–80% which is generally higher than other waste-derived adsorbents. Adsorption of Co²⁺ on the surface of ESHAP particles and ion exchange with Ca²⁺ resulting in the formation of a Co-phosphate are the main mechanisms of the metal removal. The conversion of eggshell waste to a low-cost adsorbent for the treatment of metal contaminated waters could contribute to a more sustainable and effective management of this biowaste.

The restoration of one of the most famous masterpieces of the Renaissance, the wall paintings regarding the Assumption of the Virgin Mary painted inside the dome of the Cathedral of Parma by Antonio Allegri called Correggio (1489-1534) between 1526 and 1530, allowed an in-depth chemical-physical study of materials. Non-invasive infrared imaging and spectroscopic techniques (reflectance spectrometry in the visible range and in-situ X-ray fluorescence) and micro-invasive analytical techniques (optical microscopy, scanning electron microscopy with energy dispersive X-ray microanalysis, powder X-ray diffraction, micro-FTIR spectroscopy, micro-Raman spectroscopy, and gas chromatography coupled with mass spectrometry) were chosen in order to provide the higher set of significant data, limiting as much as possible sampling. The joined use of different techniques allowed to deeply explore Correggio's palette, on the use of a fresco and/or a secco technique, to study as well degradation products and the diffused and old restoration materials like consolidants. The study allowed the characterization of a wide range of pigments, the identification of the binding media, mainly egg and animal glue, the restoration materials (acrylic resins, paraffin waxes, various pigments) and the degradation products (calcium sulfate dihydrate and calcium oxalate). © 2013 Elsevier B.V