The Optimal Concentration of Nanoclay Hydrotalcite for Recovery of Reactive and Direct Textile Colorants

Abstract

Concerns about the health of the planet have grown dramatically, and the dyeing sector of the textile industry is one of the most polluting of all industries. Nanoclays can clean dyeing wastewater using their adsorption capacities. In this study, as a new finding, it was possible to analyze and quantify the amount of metal ions substituted by anionic dyes when adsorbed, and to determine the optimal amount of nanoclay to be used to adsorb all the dye. The tests demonstrated the specific amount of nanoclay that must be used and how to optimize the subsequent processes of separation and processing of the nanoclay. Hydrotalcite was used as the adsorbent material. Direct dyes were used in this research. X-ray diffraction (XRD) patterns allowed the shape recovery of the hydrotalcite to be checked and confirmed the adsorption of the dyes. An FTIR analysis was used to check the presence of characteristic groups of the dyes in the resulting hybrids. The thermogravimetric (TGA) tests corroborated the dye adsorption and the thermal fastness improvement. Total solar reflectance (TSR) showed increased radiation protection for UV-VIS-NIR. Through the work carried out, it has been possible to establish the maximum adsorption point of hydrotalcite.

Dyeing with Hydrotalcite Hybrid Nanoclays and Disperse, Basic and Direct Dyes

“…Continuing with the analysis, Figure 5 shows the spectra offered by the three dyes and each of their hybrids after adsorption and after the dyeing process. Analysing these spectra, it can be seen that in all the hybrids the characteristic bands of the hydrotalcite are shown, as at 1361 cm −1 and there is the band corresponding to CO 3 2− and in the range of 3200-3600 cm −1 with the peak centred at 3408 cm −1 which corresponds to the hydroxyl group -OH [46,47]. Once again, the appearance of these bands, which had disappeared during calcination, shows that the nanoclay has shape memory and reconstructs itself after rehydration.…”

“…After a dyeing process by depletion, the dye remains in the dye bath; just as after the adsorption effect, the dye that has not been adsorbed may remain [47,70]. In order to determine the amount of dye in the form of g•L −1 concentration in each of these cases, simple regression models by Lambert-Beer [71] are used beforehand.…”

Complete Desorption of Hybrid Nanoclays Composed of Hydrotalcite and Disperse Dye

“…Adsorption studies were carried out with real dye wastewater, and the effectiveness of the adsorption method was proven. However, certain conditions were simulated in the laboratory, which are detailed below [ 63 , 64 ]. Five litres of dye bath were prepared with only the dye, without adding any type of salt, dispersant, or any other product, since the initial objective was to load the clay with only the dye.…”