Wastewater recovery is one of the most pressing contaminant-related subjects in the textile industry. Many cleaning and recovery techniques have been applied in recent decades, from physical separation to chemical separation. This work reviews textile wastewater recovery by focusing on natural or synthetic nanoclays in order to compare their capabilities. Presently, a wide variety of nanoclays are available that can adsorb substances dissolved in water. This review summarizes and describes nanoclay modifications for different structures (laminar, tubular, etc.) to compare adsorption performance under the best conditions. This adsorbent capacity can be used in contaminant industries to recover water that can be used and be recontaminated during a second use to close the production circle. It explores and proposes future perspectives for the nanoclay hybrid compounds generated after certain cleaning steps. This is a critical review of works that have studied adsorption or desorption procedures for different nanoclay structures. Finally, it makes a future application proposal by taking into account the summarized pros and cons of each nanoclay. This work addresses contaminant reuse, where part of the employed dyes can be reused in printing or even dyeing processes, depending on the fixing capacity of the dye in the nanoclay, which is herein discussed.
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.
Growing environmental conservation concerns have led researchers to seek the means to treat and recover wastewater. The textile industry dumps vast quantities of wastewater from textile dyes. By means of clays, dye waste can be separated and reused for other industrial processes. Clay absorption varies depending on the type of dye employed because factors like the reactivity of the dye molecule and its size are very important during the absorption process. The absorption capacity of calcined hydrotalcite at several concentrations was compared in a 0.05 g • L-1 solution of four distinct dyes: Direct Blue 199, Direct Red 23, Direct Blue 71 and Reactive Yellow. Dyes have different molecular weights because the weight of reactive dyes is considerably lighter than that of direct dyes, which is why the Lambert-Beer lines of each dye are previously considered. We worked with a 5 g • L-1 clay concentration to introduce the dye into the clay by stirring for 24 h in 100 ml of each dye solution before filtering it and leaving it to dry. In all cases, the dye absorption by nanoclay was nearly absolute and the initial solution was very clean, which are excellent results from the wastewater treatment point of view. Color measurement was performed by a Jasco V-670, double-beam spectrophotometre between 190-2700 nm. Differences in color were calculated and represented in CIE-Lab* color space diagrams. Finally, thermogravimetric (TGA) and X-ray diffraction (XRD) analyses were carried out to ensure both nanoclay-dye interactions and hydrotalcite structure recovery. No large differences were observed under these conditions, which reinforces the idea of using low nanoclay concentrations.
Textile effluents are among the most polluting industrial effluents in the world. Textile finishing processes, especially dyeing, discharge large quantities of waste that is difficult to treat, such as dyes. By recovering this material from the water, in addition to cleaning and the possibility of reusing the water, there is the opportunity to reuse this waste as a raw material for dyeing different textile substrates. One of the lines of reuse is the use of hybrid nanoclays obtained from the adsorption of dyes, which allow dye baths to be made for textile substrates. This study analyses how, through the use of the nanoadsorbent hydrotalcite, dyes classified by their charge as anionic, cationic and non-ionic can be adsorbed and recovered for successful reuse in new dye baths. The obtained hybrids were characterised by X-ray diffraction and infrared spectroscopy. In addition, the colour was analysed by spectrophotometer in the UV-VIS range. The dyes made on cotton, polyester and acrylic fabrics are subjected to different colour degradation tests to assess their viability as final products, using reflection spectroscopy to measure the colour attribute before and after the tests, showing results consistent with those of a conventional dye.
Clays are considered great nanoadsorbents for many materials, including textile dyes. The use of these materials for cleaning textile wastewater is well known; however, it is not at all common to find applications for the hybrid materials formed from the clay and dye. In this work, a dye-loaded clay material was used to make new dye baths and colour a polyester textile substrate. The same hybrid could be used several times as it did not use all the adsorbed dye in a single dyeing. The hybrid obtained from hydrotalcite (nanoclay) and the dispersed red 1 dye was analysed by measuring the colour obtained, carrying out an X-ray diffraction analysis that provided information after each desorption–dyeing process, and using infrared spectroscopy to analyse the specific bands of each characteristic group. Both analyses showed that the amount of dye present in the hybrid decreases. Thermogravimetry (TGA), surface area and porosity measurements (BET), and X-ray photoelectron spectroscopy (XPS) tests were conducted. Chemical stability was assessed by subjecting the hybrid to the actions of different reagents. In addition, colour fastness tests were carried out after dyeing and washing the polyester test tubes to check for the correct fixing of the dye to the fibre. These fastness results showed that the dyeing was carried out correctly and as if it was a conventional dyeing process.
The scientific community is continuously developing new methods for the recovery and purification of water, since the precious resources of our planet are increasingly scarce and we must work to save and clean our waters. One of the methods used is the use of adsorbent and absorbent materials that remove from the water those substances that are harmful to the environment are nanoclays. In this work, the effect of a nanoclay, specifically Halloysite, to adsorb reactive dyes has been used as an example of a technique. As an example of this type of coloring substances, Reactive Yellow 2 has been used, which has been subjected to the adsorbent action of the mineral, having an adsorption of 78% in the proposed experiment. Subsequently, it has undergone a desorption process by applying temperature to the dye-clay hybrid, so that later, thanks to the effect of solvents (HCL and / or NaOH), the desorption process in aqueous solution can be completed, obtaining a recovery from the dye. up to 17.67% adsorbed, which is interpreted as a very good result. At the same time, the ability to stamp the HNT has been tested once the dye has been adsorbed and used on a PES / CO textile, demonstrating the viability of this process and evaluating its results by rubbing and washing fastness tests.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.