Abstract:
Heavy metals are well-known environmental pollutants. Today, it has become a serious
problem in most of the countries in the world including Sri Lanka. The industrial sector
can be considered as the major source of heavy metal pollution and in Sri Lanka, the
textile industry has received a significant place. The processes like dyeing and finishing
in textile manufacturing result in adding heavy metals into its wastewater. This generated
wastewater typically contains environmentally harmful heavy metals like Cadmium.
Failing to remove them properly will lead to accumulating them in surface water bodies
and ultimately causing severe problems for human and aquatic ecosystems. Different
methods have been tested for their suitability in removing heavy metals from wastewater
amongst adsorption that has received much attention. For a country like Sri Lanka
however, investigation of an economical, inexpensive, and safe method with having
higher removal efficiencies is an essential and timely matter. The grumusol soil which
can be easily found in Jaffna and Mannar districts in Sri Lanka has shown some special
characteristics of a good adsorbent. The high cation exchange capacity, high clay fraction,
high organic matter content, swelling and shrinkage properties, and the 2:1 clay mineral
type bear evidence that it is worth to investigate the adsorption ability of grumusol soil.
The primary objective of this study was to investigate the applicability of grumusol soil in
removing heavy metals from aqueous solutions. In this study, cadmium (2+
) ion was used
as the selected heavy metal and the textile wastewater was used to check the adsorption
ability of grumusol soil to remove Cd2+. The equilibrium time and effect of pH were
investigated using the batch method. The results indicated that grumusol soil can adsorb
cadmium ions with higher efficiency. The reaction is pH-dependent and the adsorption
capacity of the grumusol soil increases with the increment of pH from 2 to 7 and
maximizes at pH 10. The highest removal efficiency of 97.66% was recorded at pH 10
during the optimum equilibrium time of 6 hours.
Keywords: Grumusol soil, Heavy metal pollution, Cadmium, Adsorption, Textile
wastewater
