Carbon dots (CDs) are zero-dimensional nanomaterials composed of carbon and surface groups attached to their surface. CDs have a size smaller than 10 nm and have potential applications in different fields such as metal ion detection, photodegradation of pollutants, and bio-imaging, in this review, the capabilities of CDs in metal ion detection will be described. Quantum confinement is generally viewed as the key factor contributing to the uniqueness of CDs characteristics due to their small size and the lack of attention on the surface functional groups and their roles is given, however, in this review paper, the focus will be on the functional group and the composition of CDs. The surface functional groups depend on two parameters: (i) the oxidation of precursors and (ii) their composition. The mechanism of metal ion detection is still being studied and is not fully understood. This review article emphasizes the current development and progress of CDs, focusing on metal ion detection based on a new perspective.

Ceramizable (ceramifiable) silicone rubber-based composites are modern elastomeric materials for fire protection application. The most important sector of economy using such materials is cable industry because there are special types of electric circuits that have to keep working in the case of fire. These kinds of composites can create ceramic phase protecting copper wire from melting under high temperature. When temperature increases, polymer matrix degrades (creating silica residue as one of the products) and mineral particles dispersed in silicone rubber matrix stick together creating stiff, durable, insulating and porous ceramic skin. In this paper, the influence of surface modification of montmorillonite with quaternary ammonium salts on ceramization of their silicone rubber composites is presented. Filler modification was studied, determining changes to its surface energy and thermal stability. Mechanical properties, flammability and thermal stability of composites were determined. Ceramization of the composites was discussed from the point of view of their mechanical properties and structure of ceramic phase after heat treatment, determined by compression stress tests, porosimetry and scanning electron microscopy adequately. Results show that type of modifier applied strongly affects properties of silicone rubber-based ceramizable composites before and after ceramization. Samples containing surface-modified montmorillonite produce significantly less heat during their thermal decomposition than composite filled with unmodified montmorillonite. Moreover, incorporation of montmorillonite modified with ammonium salt of linear organic chain causes the creation of nano-porous structure after ceramization. On the one hand, it facilitates heat insulation, but on the other hand, high total volume of pores adversely affects mechanical endurance of the ceramic phase.

The process of palladium(II) chloride complex ion adsorption on activated carbon was investigated. The influence of variable parameters such as the initial concentration of the Pd(II) complex (from 0.04 to 2.25 mmol·kg^–1) and temperature (from 294 to 348 K) was determined. Experiments were conducted in the solution with pH equal to 0 and 1. It was found that the Freundlich adsorption isotherm describes the process better than the Langmuir model. The observed sorption capacity as high as q_294K = 42.4 mg·g^–1 and q_323K = 67 mg·g^–1 for activated carbon was found at 294 and 323 K, and it is increasing with temperature increase. The obtained results showed that the palladium(II) complex may react with functional groups present on the surface of activated carbon. The thermodynamic parameters such as the equilibrium constant and heat and entropy of adsorption were derived. The enthalpy value is equal to −6.7 kJ·mol^–1, and the entropy is equal to −23 J·mol^–1·K^–1. It is suggested that, during chemisorption of palladium(II) chloride complex ions, the palladium dichloro-oxide or PdCl₂ is formed on the surface of activated carbon.