REMOVAL OF CHROMIUM FROM AQUEOUS SOLUTION USING LOCALLY AVAILABLE INEXPENSIVE TARO AND WATER HYACINTH AS BIOSORBENT

Shahjalal Khandaker,Ganesh Chandra Saha,Mohammad Al Mamun Miah

doi:10.31436/iiumej.v17i1.568

Shahjalal Khandaker, Ganesh Chandra Saha + Show 1 more

Open Access

https://doi.org/10.31436/iiumej.v17i1.568

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Abstract

In this investigation, locally available and inexpensive Taro and Water Hyacinth were used as biosorbents to remove chromium from synthetic wastewater. The removal of this metal ion from water in the batch and column method have been studied and discussed. Adsorption kinetics and equilibrium isotherm studies were also carried out. The material exhibits good adsorption capacity and the data follow both Freundlich and Langmuir models. Scanning Electronic Microscopic image was also used to understand the surface characteristics of biosorbent before and after biosorption studies. Effects of various factors such as pH, adsorbent dose, adsorbate initial concentration, particle size etc. were analyzed. The initial concentrations of chromium were considered 5-30mgL-1 in batch method and only 4mgL-1 in column method. The maximum chromium adsorbed was 1.64 mgg-1 and 4.44 mgg-1 in Batch method and 1.15 mgg-1 and 0.75 mgg-1 in Column method. Batch and Column desorption and regeneration studies were conducted. Column desorption studies indicated that both of these biosorbents could be reused for removing heavy metals. Results of the laboratory experiments show that the performance of Taro and Water Hyacinth prove that they can effectively be used as low cost biosorbents for the removal of chromium from wastewater.KEYWORDS: Â adsorption; chromium removal; Taro; water hyacinth; batch method; column studies

Highlights

Water pollution due to toxic heavy metals has been a major cause of concern for environmental engineers
The specific gravity of Taro was 0.70, whereas in water hyacinth this was 0.35. pH was measured in water hyacinth and Taro were 4.80 and 3.90 and leaching as chemical oxygen demand (COD) was 2094 mgL-1 and 5262 mgL-1 respectively
The scanning electronic microscope (SEM) pictures of biosorbent Taro and water hyacinth before and after chromium uptake are shown in Fig. 1(a), 1(b), 2(a), and 2(b)

Summary

Introduction

Water pollution due to toxic heavy metals has been a major cause of concern for environmental engineers. The availability of non-biodegradable heavy metals in wastewater may lead to bioaccumulation with living organisms and may cause health complications to animals, plants and human beings [1]. Chromium can be severely poisonous to both plants and animals. It is considered one of the acute toxic metal ions for its carcinogenic nature [2]. Some industries discharge wastewater which contain two forms of chromium such as hexavalent and trivalent. Nowadays, like other harmful heavy metals, removal of chromium from wastewater following suitable approaches is being seriously considered. A wide range of technologies have been established for removal of chromium from wastewater such as reverse osmosis, ion exchange, precipitation, electrolysis, adsorption, etc. Adsorption is a surface phenomenon in which materials are extracted from one phase and concentrated at the surface of a second phase [34]

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