Liu Jianrong, Valsaraj Kalliat T, Devai Istvan, DeLaune R D
Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA 70803, USA.
J Hazard Mater. 2008 Sep 15;157(2-3):432-40. doi: 10.1016/j.jhazmat.2008.01.006. Epub 2008 Jan 11.
As one of the major constituents of acid volatile sulfide (AVS) in anoxic sediments, mackinawite (FeS) is known for its ability to scavenge trace metals. The interaction between aqueous Hg(II) (added as HgCl(2)) and synthetic FeS was studied via batch sorption experiments conducted under anaerobic conditions. Due to the release of H(+) during formation of hydrolyzed Hg(II) species which is more reactive than Hg(2+) in surface adsorption, the equilibrium pH decreased with the increase in Hg(II)/FeS molar ratio. Counteracting the loss of FeS solids at lower pH, the maximum capacity for FeS to remove aqueous Hg(II) was approximately 0.75 mol Hg(II) (mol FeS)(-1). The comparison of X-ray power diffraction (XRPD) patterns of synthetic FeS sorbent before and after sorption showed that the major products formed from the interaction between FeS and the aqueous Hg(II) were metacinnabar, cinnabar, and mercury iron sulfides. With the addition of FeS at 0.4 g L(-1) to a 1 mM Hg(II) solution with an initial pH of 5.6, Fe(2+) release was approximately 0.77 mol Fe(2+) per mol Hg(II) removed, suggesting that 77% of Hg(II) was removed via precipitation reaction under these conditions, with 23% of Hg(II) removed by adsorption. Aeration does not cause significant release of Hg(II) into the water phase.
作为缺氧沉积物中酸挥发性硫化物（AVS）的主要成分之一，硫铁矿（FeS）以其清除痕量金属的能力而闻名。通过在厌氧条件下进行的批量吸附实验，研究了水溶液中的Hg(II)（以HgCl₂形式添加）与合成FeS之间的相互作用。由于在形成水解Hg(II)物种过程中会释放H⁺，而水解Hg(II)物种在表面吸附中比Hg²⁺更具反应性，平衡pH随Hg(II)/FeS摩尔比的增加而降低。为抵消较低pH下FeS固体的损失，FeS去除水溶液中Hg(II)的最大容量约为0.75 mol Hg(II) (mol FeS)⁻¹。吸附前后合成FeS吸附剂的X射线粉末衍射（XRPD）图谱比较表明，FeS与水溶液中Hg(II)相互作用形成的主要产物是黑辰砂、辰砂和汞铁硫化物。向初始pH为5.6的1 mM Hg(II)溶液中添加0.4 g L⁻¹的FeS，每去除1 mol Hg(II)，Fe²⁺的释放量约为0.77 mol Fe²⁺，这表明在这些条件下，77%的Hg(II)通过沉淀反应去除，23%的Hg(II)通过吸附去除。曝气不会导致Hg(II)大量释放到水相中。
