Nanotechnology is a scientific and engineering technology conducted at the Nano-scale, such as in the fields of compound fabric manufacturing, food processing, agricultural processing, and engineering, as well as in medical and medicinal application. In recent decade, nanomaterial applications for antimicrobial works have been interested by many researchers. Available reports show that some of the metal oxide Nanoparticles including; Al2O3, TiO2, ZnO, CuO, Co3O4, In2O3, MgO, SiO2, ZrO2, Cr2O3, Ni2O3, Mn2O3, CoO, and Nickel oxide have toxicity toward several microorganisms and they could successfully kill numerous bacteria. Based on our literature review there are some effective factors that can influence the ability of nanomaterial in reducing or killing the cells, and there are mechanisms for nanomaterial against bacteria, which are briefly listed as follows: surface charge of the metal nanomaterial, shape, type and material, concentration of nanomaterial, dispersion and contact of nanomaterial to the bacterial cell, presence of active oxygen, liberation of antimicrobial ions, medium components and pH, physicochemical properties, specific surface-area-to-volume ratios, size, role of growth rate, role of biofilm formation, cell wall of bacteria, and effect of UV illumination. It can be considered that in the use of nanomaterial as antimicrobial agents, consideration of the many factors is in principal. Antibacterial resistance to common chemical antibacterial agents can be due to long production–consumption cycle, thereby reducing their efficiency, and use of poor quality or fake medicines in undeveloped and developing countries. Nanoparticles as an antimicrobial agent have become the new approach against this challenge, which can establish an effective nanostructure to deliver the antimicrobial agent for targeting the bacterial community efficiently; in addition, they are so potent that microbial pathogens cannot develop resistance to them. On the other hand, most of the metal oxide nanoparticles have no toxicity toward humans at effective concentrations used to kill bacterial cells, which thus becomes an advantage for using them in a full scale. However, over the present decade, several studies have suggested that NPs are excellent antibacterial agents, at least at the research level.

Antimicrobial potential of synthesized zinc oxide (ZnO) nanoparticles against four bacteria strains (Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853, as gram negative bacteria, Staphylococcus epidermidis PTCC 1114 and Staphylococcus aureus ATCC 25923 as gram-positive bacteria) in liquid and solid phases was studied in this work. Firstly, nanoparticle ZnO was prepared by the chemical method with an organic chemical inhibitor. The detail characterization of the nanoparticles was carried out using UV–vis spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) analysis. From SEM image analysis, the average particle size was found to be 50 nm. Also, the mean surface area was determined as 90 m² g⁻¹ by Brauner–Emmet–Teller (BET) analysis. We studied the antibacterial assay, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and disk diffusion method as per CLSI recommendations and time–kill studies were performed. Disk diffusion studies revealed greater effectiveness for P. aeroginosa. In vitro time–kill studies were performed for one or two times; the MICs and its results showed that the efficiency of particles increases with rising particle dose in suspension and treatment time. From this work, it is possible to suggest that ZnO nanoparticles are excellent antibacterial agents.

The goal of this study was to survey the feasibility of the biosorption of two acid dyes (Acid Blue 113 and Acid Black 1) from aqueous solution using biomass prepared from potato peel waste. Adsorption isotherms were constructed and the kinetics of dye adsorption were studied. Langmuir and Freundlich isotherms, pseudo-first-order, and pseudo-second-order kinetic models were studied. The maximum biosorption was observed at a pH of 2 and 3 for Acid Blue 113 and Acid Black 1, respectively. The biosorption of two dyes increased with increasing contact time and reached equilibrium after two hours, approximately. Acid dye removal efficiency decreased with an increase in the initial dye concentration. The sum of squares due to error and the coefficient of determination (R2) analysis showed that the pseudo-second-order kinetic and the Langmuir isotherm model are better fit for the adsorption of Acid Blue 113 and Acid Black 1 on used potato peel waste.