Mercury removal from flue gas using nitrate as an electron acceptor in a membrane biofilm reactor

Membrane bioreactor achieved mercury removal using nitrate as an electron acceptor. The biological mercury oxidation increased with the increase of oxygen concentration. Ferrous sulfide could make both Hg²⁺ and MeHg transform into HgS-like substances. Nitrate drives mercury oxidation through katE, katG, nar, nir, nor, and nos. Mercury (Hg⁰) is a hazardous air pollutant for its toxicity, and bioaccumulation. This study reported that membrane biofilm reactor achieved mercury removal from flue gas using nitrate as the electron acceptor. Hg⁰ removal efficiency was up to 88.7% in 280 days of operation. Oxygen content in flue gas affected mercury redox reactions, mercury biooxidation and microbial methylation. The biological mercury oxidation increased with the increase of oxygen concentration (2%‒17%), methylation of mercury reduced with the increase of oxygen concentration. The dominant bacteria at oxygen concentration of 2%, 6%, 17%, 21% were Halomonas, Anaerobacillus, Halomonas and Pseudomonas, respectively. The addition of ferrous sulfide could immobilize Hg²⁺ effectively, and make both Hg²⁺ and MeHg transform into HgS-like substances, which could achieve the inhibition effect of methylation, and promote conversion of mercury. The dominant bacteria changed from Halomonas to Planctopirus after FeS addition. Nitrate drives mercury oxidation through katE, katG, nar, nir, nor, and nos for Hg⁰ removal in flue gas.     

顶空气相色谱分析原理与技术

系统讨论了静态顶空气相色谱的原理,包括多次相平衡法、改变相比法和标准加入定量法。测定了挥发性有机物在气液两相间的分配常数及其在水中的含量。提出了通过测定分配常数作为分析准确度的判据。研究了温度、相比、分配常数和无机盐对顶空分析灵敏度的影响。采用顶空色谱测定了河流底泥中的可酸挥发硫化物。     

酸化吹气-气相分子法测定固体废物中硫化物

采用酸化吹气装置结合气相分子吸收光谱仪对固体废物中硫化物进行测定.考察酸性试剂的选取、加入量及酸化吹气反应时间对测定结果的影响,得出最佳的前处理条件为加入10 mL体积比为1:1的磷酸,酸化吹气45 min.为确保吸收液中硫化物不被氧化,向吸收液中加入一定量抗氧化剂.结果表明:当抗氧化剂加入量为5 mL时,吸收液中硫化...