Design of organically modified sepiolite and its use as adsorbent for hazardous Malachite Green dye removal from water

• Published in: Water, air, and soil pollution air, and soil pollution, 2023-03, Vol.234 (3), p.183-183, Article 183
• Main Authors: Largo, Fadwa, Haounati, Redouane, Ouachtak, Hassan, Hafid, Naima, Jada, Amane, Addi, Abdelaziz Ait
• Format: Article
• Language: English
• Subjects: Adsorbents; Adsorption; air; Analysis; Analytical methods; Atmospheric Protection/Air Quality Control/Air Pollution; Carbon; carbonization; Chemical Sciences; Climate Change/Climate Change Impacts; Color removal; Composite materials; Design; desorption; Dyes; Earth and Environmental Science; Electron microscopy; Endothermic reactions; endothermy; Environment; Environmental monitoring; Fourier transform infrared spectroscopy; Fourier transforms; Hydrogeology; Infrared analysis; Isotherms; Kinetics; Malachite green; Parameter modification; Recycling (Waste, etc.); Removal; Sepiolite; soil; Soil Science & Conservation; sorption isotherms; Surface chemistry; thermodynamics; Waste recycling; Water; Water Quality/Water Pollution
• ISSN: 0049-6979; 1573-2932
• DOI: 10.1007/s11270-023-06185-z

A novel adsorbent design method, based on organic surface modification and carbonization at 350–500 °C, of sepiolite, was used to prepare carbon@sepiolite composites which were used for hazardous malachite green dye removal from water. Prior to their use as adsorbent, the structure and the morphology of the carbon@sepiolite composites were assessed by various methods, such as Fourier transform infrared (FTIR) spectroscopy, scanning (SEM) and transmission (TEM) electron microscopy, energy-dispersive analysis of X-rays (EDAX), and N 2 adsorption/desorption isotherms (BET method). The designed adsorbents showed good adsorption properties for MG molecules, reaching a maximum dye adsorbed amount of 1198.67 mg/g at 25 °C for the carbon@sepiolite composites calcinated at 500 °C. Further, the kinetics and the equilibrium adsorption isotherms of the MG molecules from water onto the sepiolite-based composites were well fitted by, respectively, the pseudo-second-order model ( R 2  = 0.98) and the Langmuir isotherm ( R 2  = 0.94) models, indicating that the MG molecules were homogenously adsorbed and formed a monolayer on the organically modified sepiolite surface. Moreover, the values of the thermodynamic parameters, such as ∆ G , ∆ H , and ∆ S related to the adsorption process, indicated that the adsorption reaction was spontaneous, feasible, and endothermic. In the overall, the present work offers facile ways for the design of organically modified sepiolite which can be used at large scale as adsorbents for waste recycling.