Abstract
Experimental studies were carried out to adsorb Acid Blue 113 (AB113), an azo dye that is probably a mutagen, from aqueous environments using commercially available, inexpensive halloysite nanoclay (HNC). Water footprint management in the remediation of dye from aqueous medium and textile industrial effluent (TIE) was the focus of a laboratory-scale experiment planned and carried out to align with the guidelines of sustainability and valorization. One interesting feature of this study is that the adsorption process is almost independent of the temperature (27-50 °C) and pH (2-12) range studied, which aligns with sustainability and valorization necessities. We conducted a laboratory-scale experiment to assess the water footprint of textile industrial effluent (TIE). To determine how operational factors affected the effectiveness of dye removal, we looked into initial dye concentration (25-200 mg L(-1)), contact time (15-180 min), adsorbent dosage (0.500-6.000 g L(-1)), initial pH (2-12), and temperature (30-50 °C). The findings showed that higher initial dye concentration, a 60-min contact time, and a pH range of 2-12 provide dye removal efficiency (q(e) = 95.00 mg g(-1)). A two-level fractional factorial experimental design (FFED) was employed to determine the factors influencing HNC's adsorption capacity and evaluate the feasibility and effectiveness of the approach. The optimal values of the variables were determined using interaction factors derived from multiple regression studies based on FFED to maximize the second-order polynomial equation. Under optimal conditions of pH 1, the adsorbent dosage of 0.500 g L(-1), beginning dye concentration of 623 mg L(-1), adsorption time of 139 min with orbital shaking of 165 rpm at 49 °C, the maximum adsorption value achieved by statistical optimization was 329 mg g(-1). Four two-parameter and six three-parameter isotherm models were used to analyze equilibrium data. The pseudo-first-order and pseudo-second-order models were applied in our adsorption kinetic investigations. Webber-Morris, Dumwald-Wagner, and film diffusion models were used to examine the diffusion effects. The adsorption system's thermodynamic parameters, Gibbs free energy (ΔG(0)), entropy (ΔS(0)), and change in enthalpy (ΔH(0)) were also measured and assessed. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterize the dye, the adsorbent, and the dye-adsorbed HNC. The experiments showed that HNC is an economical and efficient adsorbent for eliminating AB113 dye from aqueous solutions and effluent from the textile industry. It is possible to use the dye-adsorbed HNC, known as "sludge", as a strengthening material for creating composites from waste plastic. Preliminary research examined and contrasted the physico-mechanical and chemical characteristics of dye-adsorbed HNC thermoplastic and thermoset composites with those of HNC composites.