The hydroxyapatite and copper-doped hydroxyapatite coatings (Ca_10−xCu_x(PO₄)₆(OH)₂; x_Cu = 0, 0.03; HAp and 3CuHAp) were obtained by the vacuum deposition technique. Then, both coatings were analyzed by the X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and water contact angle techniques. Information regarding the in vitro antibacterial activity and biological evaluation were obtained. The XRD studies confirmed that the obtained thin films consist of a single phase associated with hydroxyapatite (HAp). The obtained 2D and 3D SEM images did not show cracks or other types of surface defects. The FTIR studies’ results proved the presence of vibrational bands characteristic of the hydroxyapatite structure in the studied coating. Moreover, information regarding the HAp and 3CuHAp surface wettability was obtained by water contact angle measurements. The biocompatibility of the HAp and 3CuHAp coatings was evaluated using the HeLa and MG63 cell lines. The cytotoxicity evaluation of the coatings was performed by assessing the cell viability through the MTT assay after incubation with the HAp and 3CuHAp coatings for 24, 48, and 72 h. The results proved that the 3CuHAp coatings exhibited good biocompatible activity for all the tested intervals. The ability of Pseudomonas aeruginosa 27853 ATCC (P. aeruginosa) cells to adhere to and develop on the surface of the HAp and 3CuHAp coatings was investigated using AFM studies. The AFM studies revealed that the 3CuHAp coatings inhibited the formation of P. aeruginosa biofilms. The AFM data indicated that P. aeruginosa’s attachment and development on the 3CuHAp coatings were significantly inhibited within the first 24 h. Both the 2D and 3D topographies showed a rapid decrease in attached bacterial cells over time, with a significant reduction observed after 72 h of exposure. Our studies suggest that 3CuHAp coatings could be suitable candidates for biomedical uses such as the development of new antimicrobial agents.

Phosphoric acid (H3PO4), commonly derived from phosphate rock, is vital in industry as it could be employed in numerous processes. Several techniques were used to purify H3PO4. In the current work, natural and H2SO4-activated clays were used to reduce cadmium (Cd) and magnesium (Mg) ions from the H3PO4 solution through the adsorption method. The solid materials were characterized using several analytical methods including Elemental analysis, Scanning Electron Microscopy (SEM), Fourier Transform

Waste regenerated after washing of rock phosphate and phosphogypsum has been proposed as removal agents of Acid Red 88 (AR 88)) from artificially contaminated solution. Natural phosphate (PN) was also studied for comparison. These materials were characterized beforehand, as is intended for the removal tests, by chemical analysis, powder X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis– differential thermal analysis, scanning electron microscopy, and N2 adsorption isotherms. The conducted experiments show that among the different materials, the PWR has the highest retention capacity of the dye (123.4 mg g−1) of AR-88. Upon calcinations, the removal capacities reduced by 60 to 70%. We take note also that a decrease in the amount of removed AR 88 dye occurs with an increase in pH. The kinetics data on the reaction between AR 88 and the materials are described well by a pseudo -second-order model. The Langmuir model is successfully applied to the experimental data of the removal of acid red 88. The removal process is exothermic.

Hydroxyapatite (HAp) is a promising biomaterial with potential environmental and biomedical applications; however, its surface properties and functional performance can be improved through polymer modification. In this study, a novel hydroxyapatite xanthan (HAp-XAn) composite was developed and investigated for both environmental and biomedical applications. Comprehensive structural and surface analyses were carried out using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and atomic force microscopy (AFM) measurements. The biocompatibility of HAp and the HAp-XAn composite was assessed with the aid of the MG63 cell line using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. The findings indicate that both HAp and HAp-XAn exhibit good in vitro cytocompatibility and favorable interactions with osteoblast-like cells, supporting their potential for use in bone-related biomedical applications. The antibacterial properties of HAp and HAp-XAn composites were studied in vitro against Staphylococcus aureus ATCC 25923 (S. aureus) and Escherichia coli ATCC 25922 (E. coli) bacterial strains. The results of the antibacterial assay revealed that HAp-XAn exhibited an improved antibacterial activity compared with HAp. The antibacterial assay highlighted that the inhibitory effect of HAp-XAn increased with the increase in incubation period. The HAp-XAn composite exhibited enhanced methylene blue (MB) adsorption compared with HAp, with the adsorption performance strongly dependent on pH, contact time, and initial dye concentration. Kinetic and equilibrium analyses indicated that the adsorption process was best described by the pseudo-second-order kinetic model and Langmuir isotherm. Overall, the incorporation of xanthan gum improved the adsorption and biological properties of HAp, demonstrating the potential of HAp-XAn as a multifunctional material for dye removal and biomedical applications.