A simple method for removal of toxic dyes such as Brilliant Green and Acid Red from the aquatic environment using Halloysite nanoclay

This project explains an easy, simple and eco-friendly method to remove some toxic dyes like Brilliant Green and Acid Red from aquatic solution by technique of solid-phase extraction that uses Halloysite nanoclay eco-friendly solid phase as absorbent surface for adsorption of dye. The physical properties of the HNC such as scanning electron microscopy, transmission electron microscope, X-ray diffraction, Fourier transform infrared spectroscopy, and surface area analysis were studied. The best conditions like pH of the solution, HNC weight, contact shaking time, the temperature of the solution, and ionic strength were investigated for removal effectiveness. The experimental data of the adsorption process showed that HNC can remove most of the dyes within 30 min, with an adsorption capacity of 12.5 mg/g for A.R dye and 13.9 mg/g for B.G dye on HNC solid phase at optimum conditions. The removal process of dyes on HNC was studied kinetically and thermodynamically, and the data confirms that the pseudo-second-order kinetic model was able to describe the adsorption process. Thermodynamic data confirms the process was spontaneous andexothermic in nature for A.R dye, while was spontaneous and endothermic in nature for B.G dye. Finally, the effectiveness of HNC was inspected by removing dyes from three various real samples, and the results showed high performance in removing dyes on HNC for four consecutive cycles. (c) 2022 The Authors. Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This project presents an easy and eco-friendly method using solid-phase extraction with Halloysite nanoclay as the absorbent surface to remove toxic dyes from aquatic solutions. The study investigates the physical properties of HNC and identifies the optimal conditions for effective removal. The experimental data confirms the high adsorption capacity of HNC and its ability to remove dyes within 30 minutes. Kinetic and thermodynamic analyses support the efficiency of HNC in removing dyes, and real sample tests demonstrate its consistent performance over multiple cycles.