Numerous adsorbent materials are developed and are able to face specific types of pollution, but none of them can manage the whole pollution. The purpose of this work is to develop a novel hybrid adsorbent, based on chitosan (CS) biopolymer, clay minerals and activated carbon (AC), having complementary adsorption properties and achieving a wide-spectrum water decontamination in a single treatment. Hybrid CS beads, containing dispersed clay and AC, were prepared from dispersions of solid adsorbents in a CS solution and its further coagulation in a basic medium. The porosity and the homogeneity of the hybrid beads were characterized by N₂ adsorption at 77 K and Cryo-Scanning Electron Microscopy respectively. The interaction between CS and clay was characterized using X-ray diffraction. Water content and the amount of each adsorbent in the hydrogel beads were determined by thermogravimetric analysis. Such a composite material was still porous and presented a wide adsorption spectrum. As shown by their adsorption kinetics, hydrophobic anionic clofibric acid (CBA) and cationic metoprolol (MTP) were well adsorbed on AC containing beads (21 and 26 mg/g), respectively. Clays containing beads showed interesting adsorption properties towards cationic Zn²⁺ and MTP. The obtained composite beads were able to adsorb all the pollutant types: Zinc cations, and hydrophobic-charged organic molecules, such as pharmaceutical derivatives (clofibric acid and MTP).

Glassy carbon particles (millimetric or micrometric sizes) dispersions in water were treated by ultrasound at 20 kHz, either in a cylindrical reactor, or in a “Rosette” type reactor, for various time lengths ranging from 3 h to 10 h. Further separations sedimentation allowed obtaining few nanoparticles of glassy carbon in the supernatant (diameter <200 nm). Thought the yield of nanoparticle increased together with the sonication time at high power, it tended to be nil after sonication in the cylindrical reactor. The sonication of glassy carbon micrometric particles in water using “Rosette” instead of cylindrical reactor, allowed preparing at highest yield (1–2 wt%), stable suspensions of carbon nanoparticles, easily separated from the sedimented particles. Both sediment and supernatant separated by decantation of the sonicated dispersions were characterized by laser granulometry, scanning electron microscopy, X-ray microanalysis, and Raman and infrared spectroscopies. Their multiscale organization was investigated by transmission electron microscopy as a function of the sonication time. For sonication longer than 10 h, these nanoparticles from supernatant (diameter <50 nm) are aggregated. Their structures are more disordered than the sediment particles showing typical nanometer-sized aromatic layer arrangement of glassy carbon, with closed mesopores (diameter ∼3 nm). Sonication time longer than 5 h has induced not only a strong amorphization (subnanometric and disoriented aromatic layer) but also a loss of the mesoporous network nanostructure. These multi-scale organizational changes took place because of both cavitation and shocks between particles, mainly at the particle surface. The sonication in water has induced also chemical effects, leading to an increase in the oxygen content of the irradiated material together with the sonication time.