Adsorptive removal of phenol and aniline by modified bentonite: adsorption isotherm and kinetics study

Shahin Ahmadi,Chinenye Adaobi Igwegbe

doi:10.1007/s13201-018-0826-3

Shahin Ahmadi, Chinenye Adaobi Igwegbe

Open Access

https://doi.org/10.1007/s13201-018-0826-3

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Abstract

In the present study, the adsorptive potential of modified bentonite in a batch system for the removal of aniline and phenol from aqueous solutions was investigated. The effect of various parameters including contact time (10–120 min), pH (2–10), adsorbent dosage (0.4–1.5 g/L) and initial concentration of aniline and phenol (50–200 mg/L) was investigated in this experimental laboratory study. Maximum removal of aniline and phenol was achieved at contact time of 30 and 45 min for aniline and phenol, respectively, and at the lowest studied initial concentration of 50 mg/L. Optimum bentonite dosage of 1 and 0.4 g/L was obtained for phenol and aniline, respectively. The adsorption process was better at the pH of 6 for aniline and pH of 4 for phenol. It was found that the equilibrium data was best followed by the Langmuir and Freundlich isotherms. Also, the pseudo-second-order kinetic model was best applicable for phenol and aniline adsorption. It was defined that bentonite not only was an inexpensive absorbent, but also a quite effective adsorbent for the removal of aniline and phenol from water and wastewater.

Highlights

Organic compounds are used as intermediates for the manufacture of various synthetic compounds such as dyestuffs, rubbers, pesticides, plastics and paints (Ahmadi and Kord Mostafapour 2017a)
The results showed that aniline on bentonite fits best into the Freundlich isotherm model (R2 = 0.99), but phenol on bentonite fits best into the Langmuir model isotherm model (R2 = 0.997)
Highest removal was achieved at contact time of 30 and 45 min for aniline and phenol, respectively; it was found to decrease as the initial concentration was increased for both adsorbates

Summary

Introduction

Organic compounds are used as intermediates for the manufacture of various synthetic compounds such as dyestuffs, rubbers, pesticides, plastics and paints (Ahmadi and Kord Mostafapour 2017a). The aniline can transform the hemoglobin into methaemoglobin causing anorexia, erythrocyte damage and spleen effect (Han et al 2006; Matsushita et al 2005). Phenol is considered as the priority pollutant since it is harmful to organisms even at a low concentration (Rahmani et al 2008) due to its toxicity and carcinogenicity properties. It is fully recommended to remove phenol and aniline from industrial effluents before discharge to the water stream (Kord Mostafapoor et al 2017). Several treatment methods have been proposed for the removal of aniline and phenol from contaminated waters, including The highly used adsorbing materials are the active granulated carbons, but they are very expensive and not revived (Ciambelli et al 1984)

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Results

Conclusion