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With the growing concern of biofilm-associated infections and drug-resistant bacteria, an increasing interest in developing novel antibacterial agents is an urgent priority. Metal oxide-based polymeric materials are able to distinguish mammalian cells from bacterial cells and thus provide long-term antibacterial growth inhibition. Herein, we report the preparation of MgO, NiO and chitosan-coated metal oxide (CS–MO) nanocomposites via a simple in situ chemistry approach. Fourier transform infrared spectroscopy, X-ray diffraction patterns and X-ray photoelectron spectra results proved the formation of CS–MgO and CS–NiO nanocomposites. Also, the particle sizes were observed to be 18.3 and 25.5 nm for CS–NiO and CS–MgO, respectively. All the samples exhibited antibacterial activities against the Escherichia coli and Staphylococcus aureus strains; however, more effective against S. aureus compared to E. coli. Noticeably, 5 μg/mL CS–NiO comparatively exhibited highest bactericidal capability where E. coli and S. aureus viabilities were reduced to 25–47% after 12 h incubation. After treatment with 15 μg/mL of CS–NiO, ∼98% of S. aureus and 92.3% of E. coli cells were inhibited. [ABSTRACT FROM AUTHOR]

Alginate encapsulated nano-hydroxyapatite beads were synthesized and characterized by Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller surface analysis, and X-ray diffraction. Their adsorptive potential for Ni2+and rhodamine B was explored in batch mode and by fixed-bed column passage. In the batch system, maximum uptake capacity for Ni2+was 360 mg g−1and 480 mg g−1for rhodamine B. In the presence of humic acid, sorption was enhanced. For the continuous-flow system, adsorption was effective at low flow rate. For both pollutants, mass transport resistance increased during adsorption. The overall rates of rhodamine B and Ni2+uptake were found to be controlled by external mass transfer. [ABSTRACT FROM AUTHOR]