Synthesis and evaluation of chitosan/essential oil nanoemulsion beads for water treatment

ABSTRACT Water treatment receives wide attention due to its close relationship with the environment and its protection from pollutants. This study investigates the effectiveness of applying chitosan/essential oil/nanoemulsion (NE) hydrogel beads in water treatment, which were produced by combining chitosan and various NEs containing different fractions of mixed surfactants of tween 80 and span 20, oils of either clove or peppermint, and distilled water. The physicochemical properties were determined using the scanning electron microscope (SEM), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR). SEM images exhibited that the clove beads presented sharp edges with parallel lines of networks and uniform pores (6.947 ± 1.45 μm, coefficient of variation (CV) = 20%), whereas peppermint beads displayed a spongy surface with spherical pores (11.203 ± 3.34 μm, CV = 29%). DSC analysis revealed that both clove and peppermint beads were thermally stable until 100 °C. The FTIR curve of the beads displayed new peaks confirming chemical interactions between the chitosan and the constituents of the NE. The adsorption capacity of the beads for the copper sulfate and bromophenol blue was more than 50% achieved within 1 h at 25 °C. In conclusion, chitosan–NE hydrogel beads have promising potential for use in water treatment.