Cement-based solidification of nuclear waste: Mechanisms, formulations and regulatory considerations.

This review paper provides a comprehensive analysis of cement-based solidification and immobilisation of nuclear waste. It covers various aspects including mechanisms, formulations, testing and regulatory considerations. The paper begins by emphasizing the importance of nuclear waste management and the associated challenges. It explores the mechanisms and principles in cement-based solidification, with a particular focus on the interaction between cement and nuclear waste components. Different formulation considerations are discussed, encompassing factors such as cement types, the role of additives and modifiers. The review paper also examines testing and characterisation methods used to assess the physical, chemical and mechanical properties of solidified waste forms. Then the paper addresses the regulatory considerations and compliance requirements for cement-based solidification. The paper concludes by critically elaborating on the current challenges, emerging trends and future research needs in the field. Overall, this review paper offers a comprehensive overview of cement-based solidification, providing valuable insights for researchers, practitioners and regulatory bodies involved in nuclear waste management.

Ultrasonic-assisted synthesis of graphene oxide - fungal hyphae: An efficient and reclaimable adsorbent for chromium(VI) removal from aqueous solution.

In this study, a hybrid film bio-nanocomposite material was developed based on the graphene oxide/fungal hyphae (GO-FH) interaction. The developed GO-FH bio-nanocomposite material was used for the removal of hexavalent chromium from aqueous solution. The GO-FH bio-nanocomposite material was prepared by ultrasonic irradiation technique. The synthesized GO-FH bio-nanocomposite material was characterized by XRD, FT-IR, SEM, TEM and TGA. The adsorption experiments were carried out in batch mode to optimize parameters such as pH, adsorbent dosage, initial Cr(VI) ion concentration, contact time and shaking speed. The results indicated that the adsorption of Cr(VI) onto GO-FH bio-nanocomposite material was pH dependant, with the maximum adsorption capacity of 212.76 mg/g occurred at pH 2.0. The adsorption studies followed, Langmuir isotherm and pseudo second order kinetic model. Findings demonstrates that GO-FH bio-nanocomposite material exhibited excellent regeneration performance.

Preparation of graphene oxide/chitosan/ferrite nanocomposite for Chromium(VI) removal from aqueous solution.

A magnetically modified graphene oxide/chitosan/ferrite (GCF) nanocomposite material was synthesized and exploited for removal of Chromium(VI) from aqueous solution. The GCF nanocomposite material was characterized by powder-X-ray diffraction (powder-XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope- energy dispersive X-ray (SEM-EDX) analysis, transmission electron microscopy (TEM) thermogravimetric analysis (TGA), UV-vis diffusive reflectance spectra and Brunauer-Emmett-Teller (BET) analysis. The effect of pH, adsorbent dose, contact time and initial Cr(VI) metal ion concentration were studied in batch process. The GCF nanocomposite material showed an adsorption capacity of 270.27 mg g-1 for Cr(VI) at pH 2.0. The adsorption mechanism of GCF adsorbent material was well described by Langmuir isotherm and pseudo second order kinetic model, with a high regression coefficient (<0.99). The results have shown that GCF nanocomposite material can be used as a suitable adsorbent for removal of Cr(VI) from wastewater.