Gendel Youri, Levi No'omi, Lahav Ori
Faculty of Civil and Environmental Engineering, Technion, Haifa, 32000, Israel.
Environ Sci Technol. 2009 Nov 1;43(21):8315-9. doi: 10.1021/es901594j.
A modified pH 1.0 liquid redox sulfur recovery (LRSR) process, based on reactive absorption of H(2)S((g)) in an acidic (pH 1.0) iron solution ([Fe(III)] = 9-8 g L(-1), [Fe(II)] = 1-2 g L(-1)) and electrochemical regeneration of the Fe(III)/Fe(II) catalyst couple, is introduced. Fe(II) was oxidized in a flow-through electrolytic cell by Cl(2(aq)) formed on a Ti/RuO(2) anode. pH 1.0 was applied to retard the potential precipitation of predominantly jarosite group Fe(III) species. At pH 1.0, the presence of chloride ions at [Cl(-)] = 30 g L(-1) allows for both efficient (indirect) electrochemical oxidation of Fe(II) and efficient H(2)S((g)) reactive absorption. The latter observation was hypothesized to be associated with higher concentrations of Fe(III)-Cl complexes that are more highly reactive toward H(2)S((aq)) than are free Fe(III) ions and Fe-SO(4) complexes that otherwise dominate pH 1.0 Fe(III) solutions in the absence of a significant Cl(-) concentration. At the described operational conditions the rate of Fe(II) oxidation in the experimental system was 0.793 kg Fe h(-1) per m(2) anode surface area, at a current efficiency of 58%. Electricity cost within the electrochemical step was approximated at $0.9 per kg H(2)S((g)) removed.
介绍了一种改进的pH 1.0液体氧化还原硫回收（LRSR）工艺，该工艺基于在酸性（pH 1.0）铁溶液（[Fe(III)] = 9 - 8 g L⁻¹，[Fe(II)] = 1 - 2 g L⁻¹）中对H₂S(g)进行反应吸收以及Fe(III)/Fe(II)催化剂对的电化学再生。Fe(II)在流通式电解池中被Ti/RuO₂阳极上形成的Cl₂(aq)氧化。采用pH 1.0来抑制主要为黄钾铁矾族Fe(III)物种的潜在沉淀。在pH 1.0时，[Cl⁻] = 30 g L⁻¹的氯离子的存在既允许Fe(II)进行高效的（间接）电化学氧化，也允许H₂S(g)进行高效的反应吸收。据推测，后一种观察结果与较高浓度的Fe(III)-Cl络合物有关，这些络合物对H₂S(aq)的反应性比游离Fe(III)离子和Fe-SO₄络合物更高，否则在没有显著Cl⁻浓度的情况下，Fe-SO₄络合物在pH 1.0的Fe(III)溶液中占主导地位。在所描述的操作条件下，实验系统中Fe(II)的氧化速率为每平方米阳极表面积0.793 kg Fe h⁻¹，电流效率为58%。电化学步骤中的电费估计为每去除一千克H₂S(g) 0.9美元。
