Designing, modelling, and optimising amido black and Eosin B dyes adsorption on MWCNT/ZrO2/Pb nanocomposites from aqueous solution by response surface methodology

Abstract

ABSTRACT This research illustrates the modification of multi-walled carbon nanotube (MWCNT) by ZrO2/Pb to construct a nanocomposite (MWCNT/ZrO2/Pb-NC) using a simple precipitation technique, as well as to examine the ability of this NC for the adsorption of two dyes, amido black (AB) and Eosin B (EB), in binary systems. FESEM, XRD, FTIR, and EDX were utilised to investigate the MWCNT/ZrO2/Pb-NC. The results suggested that MWCNT/ZrO2/Pb-NCs possessed as-synthesised crystalline nature with a cubic morphology and the average particle size of 30–50 nm. The nano-adsorbent represented herein showed high adsorption efficiency towards AB and EB. The influence of experimental parameters, i.e. pH, initial concentration of dyes, contact time, and MWCNT/ZrO2/Pb-NCs mass, were analysed by central composite design (CCD). The removal percentages more than 95% for AB and EB dyes were obtained by the adjustment of operational conditions at pH 6.0, 0.05 g of MWCNT/ZrO2/Pb-NCs, 15 min stirring, and 15 mg L−1 of each dye. The binding behaviour of the two dyes on the proposed NC was precisely modelled by the Langmuir isotherm. The adsorption capacities for AB and EB were 15.46 and 16.92 mg g−1, respectively. Pseudo-first order model, owing to its high correlation coefficient and closeness of experimental and theoretical data, well represented the behaviour of the corresponding adsorption system. Mechanism examination strongly affirmed the high contribution of external mass transference as the main rate-controlling step. The successful regeneration of MWCNT/ZrO2/Pb-NC signified the usefulness of the NC in wastewater treatment and its capability of environmental management.