Removal of Direct Red Dye Using Neem Leaf Litter

Author Name(s): Prasana Manikanda Kartik J, Swathik H, Udaya Baskar S, Sivamani S*
Author Email: sivman.sel@gmail.com

Abstract

The adsorption of Congo red (CR) onto carbon prepared from Neem leaf litter (NLLC) and Raw Neem Leaf Litter (RNLL) was investigated. The CR adsorption increased with an increase in pH of the CR solution in high acidic region and then decreased for NLLC, and for RNLL it slightly increased but rapidly decreased in neutral pH region but with further increase in pH, increased rapidly again. The Langmuir isotherm model showed a good fit with the equilibrium experimental data and the values of the heterogeneity factor (n) indicated heterogeneous adsorption of CR onto both RNLL and NLLC. The kinetic data showed better fit to the pseudo second-order rate model than to the pseudo first-order rate model in both cases. The adsorption of Neem leaf litter carbon (NLLC) showed the higher adsorption capacities of CR compared to Raw Neem Leaf Litter (RNLL) and any other adsorbents and would be a good method to increase adsorption efficiency for the removal of anionic dyes in a wastewater treatment process.

Keywords

Adsorption, Azadirachta indica (Neem), Carbonization, Congo red.

Introduction

Wastewater effluents from different industries such as textiles, rubber, paper and plastics, contain several kinds of synthetic dyestuffs [1]. Further, discharging even a small amount of dye into water can affect aquatic life and food webs due to the carcinogenic and mutagenic effects of synthetic dyes [2]. Congo red [1-naphthalene sulfonic acid, 3, 30-(4, 40-biphenylenebis (azo)) bis (4-amino-) disodium salt] is a benzidine-based dye. This dye has been known to cause an allergic reaction and to be metabolized to benzidine, a human carcinogen.
Adsorption is quite popular due to simplicity and high efficiency, as well as the availability of a wide range of adsorbents. It has proved to be an effective method for removal of dye from wastewater [3].

Conclusion

The adsorption of Congo red (CR) onto carbon prepared from Neem leaf litter was investigated. The Langmuir isotherm model showed a good fit with the equilibrium experimental data. The kinetic data showed better fit to the pseudo second-order rate model. The adsorption of Neem leaf litter showed the highest adsorption capacities of CR compared to any other adsorbents and would be a good method to increase adsorption efficiency for the removal of anionic dyes in a wastewater treatment process

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