Implementation of ferric hydroxide-based media for removal of toxic metalloids

Małgorzata Szlachta,Patryk Wójtowicz,B Kaźmierczak,J Danielewicz,M Kutyłowska,K Piekarska,H Jouhara

doi:10.1051/e3sconf/20172200175

Abstract

Effective removal of inorganic arsenic species is possible by application of the sorption technique with the use of iron-based sorbents. This study investigates the removal of arsenic(III) and arsenic(V) from an aqueous solution by application of a granular ferric hydroxide-based sorbent. The performance of tested media was evaluated based on the batch and fixed-bed adsorption studies. The efficiency of the process was determined with various treatment times, adsorbent doses, initial concentrations of arsenic and various solution temperatures. The obtained adsorption data were fitted with pseudo-first and second-order kinetic models and Langmuir and Freundlich isotherm equations. It was observed that the overall arsenite removal was lower when compared to the arsenate, and all tested operating parameters influenced the process efficiency. The experiments under dynamic conditions showed high treatment capacity and stability of tested adsorbent over a long period of time.

Highlights

The pollution of the aquatic ecosystem is a global long-term environmental problem due to the rapid industrial development and urbanisation
This study investigated the removal of arsenic(III) and arsenic(V) from an aqueous solution by using iron-based sorbent – a granular ferric hydroxide-based material
Qq = qqee(1 − ee−kk1tt) kk2qqe2e tt 1+kk2qqeett where q and qe is the amount of arsenic adsorbed at time t and equilibrium state(mg/g), respectively; t is the contact time; k1 is the rate constant of the pseudo-first-order adsorption; k2 is the rate constant of the pseudo-second-order adsorption (g/mg min)

Summary

Introduction

The pollution of the aquatic ecosystem is a global long-term environmental problem due to the rapid industrial development and urbanisation. Toxic heavy metals or metalloids are widespread and their discharging through air and industrial effluents or leaching from the soil by acid rain into natural waters often is a reason of their severe degradation. Many unwanted contaminants in an excessive concentration in the aquatic environment cause a detrimental effect on human and animals. Cases of severe arsenic poisoning in humans have been reported in many places around the world, including Bangladesh, India, Vietnam, China, Chile, Mexico, Argentina and USA [3,4]. This element occurs as a natural constituent of rock, soil, water and atmosphere as well as may originate from the anthropogenic sources. Trivalent arsenite As(III) is dominant in more reducing conditions, whereas pentavalent arsenate As(V) is mostly present in an oxidizing environment [5,6]

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Results

Conclusion