Optimization of toxic dye removal from contaminated water using chitosan-grafted novel nanocomposite adsorbent

The prevalence of dyes in aquatic environments raises severe concerns on a global scale. Methyl orange (MO) is a typical anionic organic dye, which is widely used in industrial wastewater such as textile and paper making. Then the treatment of water contaminated with dyes is an important aspect. The recent decade has witnessed adsorption technology emerging as an advanced dye wastewater treatment with great potential and a grand blueprint, in which the specific surface area and active sites of the adsorbent are considered to be the two most important characteristics largely impacting the adsorption performance. In this study, chitosan-treated nanocomposite was prepared as an effective adsorbent for the removal of MO from contaminated water. The dye removal parameter was performed according to the solution acidity, reaction time, initial concentration, competing for ion affinity, maximum adsorption capacity, and reuse with potential use. The solution pH played a key role in MO dye removal and a suitable pH of 7.0 was selected according to high adsorption ability. The adsorption results were highly fitted with the Langmuir adsorption isotherm model and the maximum adsorption was 172.17 mg/g. The results revealed that introducing chitosan could improve the adsorption capacity and rate effectively even though sacrificing part of specific surface areas of the cotton, indicating that active sites might play a dominant role during the MO adsorption. In addition, the fabricated nanocomposite adsorbent was recycled rapidly by the eluent and regenerated simultaneously, which exhibited the advantages of easy operation as a potentially cost-effective material. The chitosan-based nanocomposite displayed high reusability based on the elution and simultaneous regeneration ability. Therefore, as a cheap green nanocomposite adsorbent with high adsorption performance for MO, chitosan-based fibrous nanocomposite adsorbent is expected to become one of the best candidate materials for future industrial wastewater treatment.