Effective removal of Rose Bengal using Ni-Co-Zn layered triple hydroxide: Studies on batch adsorption, mechanism, selectivity, co-ions, and reusability

Abstract

The simple co-precipitation approach was used to produce Ni-Co-Zn layered triple hydroxide (NCZ), and its batch adsorption removal of Rose Bengal (RB) was investigated. The batch adsorption experiments demonstrated that the maximal RB removal efficiency of NCZ at natural pH was 99.9%. The maximum adsorption capacities (qmax) of NCZ were determined to be 29.8 mg g−1, indicating excellent adsorption capabilities. The selectivity studies revealed that NCZ could completely remove all types of anionic dyes (Trypan blue, Congo red, Methyl orange, Amido black 10b, and Eriochrome Black T) when combined with RB and selectively remove RB when combined with cationic dyes (Rhodamine 6 G, Safranin O, Rhodamine 6B, Crystal violet, Methylene blue and Brilliant green). The effect of salts with increasing concentration reveals that SO3− and SO4− had a higher impact on the removal of RB by NCZ than Cl−. NCZ's recyclability investigation indicated that RB was removed after five cycles of desorbing it with 0.1 M NaOH (98.4–91.7%), ethanol (98.8–92.7%), and methanol (98.9–96.6%). Therefore, the synthetic adsorbent exhibits considerable efficacy in removing RB from water and may prove valuable in the remediation of dye-based wastewater.