Adsorption of Acid Orange Ⅱ with Two Step Modified Sepiolite: Optimization, Adsorption Performance, Kinetics, Thermodynamics and Regeneration.

Jian Yu,Bin Liu,Wenting He

doi:10.3390/ijerph17051732

Abstract

In this study, a two-step modification of sepiolite for adsorption enhancement was investigated. The cetyltrimethylammonium bromide (CTAB) was utilized for the organic modification process after a heat modification. To develop the optimal modification condition, adsorption of Acid Orange II onto modified sepiolite was investigated with respect to heat temperature and adsorbent dosage. The temperature of 200 °C and 100% cation exchange capacity (CEC) was deemed as the optimal condition. The impacts of operation conditions on adsorption procedure, including pH, adsorbent dosage and adsorption duration, were comprehensively discussed. The adsorption of Acid Orange II by sepiolite is in accordance with the quasi-secondary kinetic model. Moreover, the results of intraparticle diffusion indicate that the intraparticle diffusion was the dominant adsorption force in the initial adsorption period. The adsorption process was obeyed with the Langmiur adsorption model. The results from regeneration procedure suggest that the superior regeneration obtained with 0.8 mol/L NaOH concentration.

Highlights

A dye is an organic compound which stains the substance in an aqueous solution or other medium
The surface charge of sepiolite tends to be more positive when introducing the Cetyltrimethylammonium bromide (CTAB) which could improve the adsorption of negatively charged Acid Orange II
On the sepiolite surface by van der Waals force when CTAB is over 100% cation exchange capacity (CEC), which could lead to the outward hydrophilic group forming the outer “dual layer” [37]

Summary

Introduction

A dye is an organic compound which stains the substance in an aqueous solution or other medium.The dyestuff is employed with a dispersed state or dissolved in a water solvent to form a solution to dye the material [1,2]. A dye is an organic compound which stains the substance in an aqueous solution or other medium. Acid Orange II is a commonly used acidic water-soluble dye and has strong carcinogenicity [3]. It is mainly used in the wool, leather, silk and paper industry. The composition of dye wastewater mainly consists of refractory organic molecules [4]. These organic compounds have the characteristics of being difficult to biodegrade and stable under light, heat and oxidant [5,6,7]

Methods

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Discussion

Conclusion