| Summary: | Study on the influence of addition of oxalic and malonic acids on Hg(II) photoreduction has been carried out. The photoreduction of Hg(II) ion was carried out by irradiating 50 mL the solution that consisted of 5 ppm Hg(II) ion using either oxalic acid or malonic acid in a batch reactor equipped with UV lamp tipe Black Light Blue (BLB) 40 Watt 220 Volt with wave length 340-390 nm with stirring. Photoreduction effectiveness found expression in % m/m Hg(II) ion culated based on the difference between the weight of Hg (II) with initial weight of Hg (II) residual. The concentration of Hg(II) ion that was not reduced was determined by using CV-AAS (Cold Vapor-Atomic Absorption Spectrophotometry) by standard curve technique. In this study the effect of irradiation time and concentration of organic acids on the effectiveness Hg(II) photoreduction ion were also evaluated.
The results of this research show that the addition of oxalic and malonic acids on Hg(II) solution with and without irradiation decrease concentration of Hg(II) ion by reduction and photoreduction reaction that is from 10,71% to 43,33% (addition of oxalic acid) and 35,00% (addition of malonic acid). Hg(II) photoreduction in the presence of oxalic acid reaches a maximum value at time irradiation of 2 hours and those containing of malonic acid reaches a maxium at 3 hours at ratio of mole 1:1 the of Hg(II) to acid. Increasing the number of moles of oxalic acid and malonic acid can provide increasing effectiveness of Hg(II) photoreduction and reaches a maximum result at ratio of mole 1:2 of Hg(II) to acid.
Key words: photoreduction, Hg(II), oxalic acid, malonic acid
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