Determination of trace mercury(ii) in wastewater using on-line flow injection spectrophotometry coupled with supported liquid membrane enrichment

Abstract

An on-line flow-injection spectrophotometric method coupled with supported liquid membrane enrichment was developed to determine trace Hg(II) in water. Tributyl phosphate (TBP) dissolved in kerosene was used as the flow carrier in a supported liquid membrane extraction system. The effect of various parameters on Hg(II) measurement was investigated. The optimum conditions were determined as 20% TBP in the membrane phase, 0.02 mol L⁻¹ NaOH in the accepting phase, 0.8 mol L⁻¹ HCl in the feeding phase, 0.2 μm PTFE membrane in the enrichment process, and 20 min enrichment time. Under these optimum conditions, the linear range for Hg(II) measurement was from 0.2 to 30 μg L⁻¹ with a detection limit of 0.06 μg L⁻¹. Additionally, we demonstrated that this system can be used to determine trace Hg(II) in wastewater.