Heavy Metal Adsorption onto Kappaphycus sp. from Aqueous Solutions: The Use of Error Functions for Validation of Isotherm and Kinetics Models.

Md Sayedur Rahman,Kathiresan V Sathasivam

doi:10.1155/2015/126298

Md Sayedur Rahman, Kathiresan V Sathasivam

Open Access

https://doi.org/10.1155/2015/126298

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Abstract

Biosorption process is a promising technology for the removal of heavy metals from industrial wastes and effluents using low-cost and effective biosorbents. In the present study, adsorption of Pb2+, Cu2+, Fe2+, and Zn2+ onto dried biomass of red seaweed Kappaphycus sp. was investigated as a function of pH, contact time, initial metal ion concentration, and temperature. The experimental data were evaluated by four isotherm models (Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich) and four kinetic models (pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models). The adsorption process was feasible, spontaneous, and endothermic in nature. Functional groups in the biomass involved in metal adsorption process were revealed as carboxylic and sulfonic acids and sulfonate by Fourier transform infrared analysis. A total of nine error functions were applied to validate the models. We strongly suggest the analysis of error functions for validating adsorption isotherm and kinetic models using linear methods. The present work shows that the red seaweed Kappaphycus sp. can be used as a potentially low-cost biosorbent for the removal of heavy metal ions from aqueous solutions. Further study is warranted to evaluate its feasibility for the removal of heavy metals from the real environment.

Highlights

Heavy metal pollution due to rapid urbanization and industrialization is one of the most significant environmental problems
We examined adsorption of four heavy metal ions such as Pb2+, Cu2+, Fe2+, and Zn2+ onto the dried biomass of the red seaweed Kappaphycus sp. from Malaysia
Kinetic data for all the metal ions can be best described by the intraparticle diffusion model

Summary

Introduction

Heavy metal pollution due to rapid urbanization and industrialization is one of the most significant environmental problems. Heavy metals are released into the aquatic environment from several domestic (automobile exhaust, smelting processes, burning of fossil fuels, incineration of wastes, landfill leaches, use of sewage sludge, municipal wastewater, and urban runoff) and industrial processes (electroplating, refining ore, mining, electronic and metal-finishing industries, fertilizer industry, tanneries, painting, paper industries, and pesticides) [1]. Heavy metals have become a global issue of environment and public health concern due to their toxicities, bioaccumulation in human body and food chain, carcinogenicities, and mutagenesis in various living organisms [2,3,4]

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