In this study, porous biochar (PvBC) was obtained by the pyrolysis of bean (phaseolus vulgaris) plant at 600 °C, and then activated biochar (PvBCZn) was synthesized by ZnCl₂ activation at an equal biomass ratio (1.0:1.0). Some analytical techniques (SEM-EDX (scanning electron microscopy–energy dispersive X-ray spectroscopy), TGA/DTA (Thermogravimetric/Differential Thermal Analysis), BET (Brunauer–Emmett–Teller), FTIR (Fourier Transform Infrared Spectroscopy) and XRD (X-ray diffraction)) were used to characterize both PvBC and PvBCZn. In addition, their antibiotic sensitivity, water solubility, moisture content and swelling behavior were investigated in detail. Furthermore, both PvBC and PvBCZn were used for the adsorption of primamycin la, an anti-inflammatory drug used in veterinary medicine whose active ingredient is oxytetracycline, in a milk sample. The effect of both pH and adsorbent dosage on the adsorption capacity was investigated. Based on adsorption studies, while the maximum adsorption capacity (q_max) of PvBCZn was found to be 188.48 mg/g, that of PvBC was found to be 122.49 mg/g. According to these results, PvBCZn is an excellent adsorbent for the removal of primamycin la from milk samples. The Langmuir isotherm model and the pseudo-second-order kinetic model were more suitable to describe the adsorption behavior of primamycin la. The PvBCZn adsorbent exhibited rapid removal exceeding 75% in the first 20 min and reached equilibrium after about 50 min. In addition, studies on the desorption and reusability of PvBCZn were carried out under the same optimum experimental conditions. The q_max value of PvBCZn was found to be 171.40 mg/g even in the fifth cycle, confirming the idea that it is a potential adsorbent for the removal of primamycin la. At the same time, the antimicrobial activity of PvBCZn against Escherichia coli bacteria increases its potential to be used in both purification systems and hygiene products.

Nowadays, there is an increasing interest in the development of novel bioresorbable membranes for Guided Bone Regeneration (GBR), and for this purpose, hydroxyapatite, from different sources, has been tested in combination with chitosan. This work details the production and the characterization of membranes of chitosan reinforced with hydroxyapatite derived from the bone of armoured catfish (Pterygoplichthys spp.), which is a widely available natural resource. The hydroxyapatite was characterized morphologically and chemically after the particles of hydroxyapatite were incorporated into a chitosan matrix. Then, the impact of adding hydroxyapatite particles into a matrix of chitosan on the roughness, mechanical properties, degradation, and cytotoxicity was evaluated. Subsequently, an in vivo test was carried out with the purpose of elucidating its guided bone regeneration activity, where the newly developed chitosan–hydroxyapatite membranes were implanted in rabbits with calvarial bone defects. The membranes of chitosan–hydroxyapatite presented a very rough surface morphology compared to the membranes of chitosan; moreover, the membranes of chitosan–hydroxyapatite showed superior mechanical tensile properties. The Masson’s trichrome staining analysis histologically demonstrated that the membranes of chitosan–hydroxyapatite enhanced the formation of a complete mineralized bone matrix in the calvarial bone defects. Finally, these findings confirm that the bone of armoured catfish (Pterygoplichthys spp.) is a viable, economic, and environmentally friendly source for isolating hydroxyapatite, which, combined with a matrix of chitosan, can be a suitable alternative to develop biocompatible GBR membranes.