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In the Earth's ecological environment, humic acid substances (including HA, FA) is the most widely distributed natural organic matter, because it contains many functional groups, and the component of the soil and water, and organic and inorganic pollutants interaction, which attributed an important impact on the behavior of pollutants. Mercury is a great environmental hazards of heavy metals, gaseous Hg0 migration in the environment interface is a of mercury difference and other heavy metal elements, important biogeochemical processes. So far, although carried out some of humic acid, and Hg2 interaction research, but most are concentrated in and Hg2 ligand complexation and adsorption and desorption, and redox properties of humic acid on Hg2 reduction and its influencing factors, there are very few. To this end, this paper studied under different electron acceptor conditions, several humic acid reducing capacity on this basis of humic acid of Hg2 reduction reaction process influencing factors, the following important results: Fe3 reduction derived humic acid reduction capacity between the three kinds of humic acid, the Jinyun humic acid (JY) reduction capacity (RC) were greater than the Shanghai of humic acid (SH), humic acid Tianjin (TJ), JY restore ability. Humic acid reduction capacity by the impact of the type of electron acceptor, Fe (NO3) 3 electron acceptor humic acid (HA) RC RC greater than to FeCit as electron acceptor HA. To restore the capacity of the initial form of the three kinds of humic acid (solid and liquid) comparison solution humic acid reducing capacity than solid humic acid reduction capacity, but the difference reached a significant level (P lt; 0.05). Three reduction indicators show that the humic acid significantly enhanced after H2 and soil solution processing of RC chemical reduction capacity (CRC) and the microbial reduction of capacity (MRC) is greater than the background restore capacity (NRC), but no obvious pattern between CRC and MRC. The actual reduction capacity of heavy metals - mercury (Hg) as an electron acceptor, humic acid, indicating that between three kinds of humic acid, divalent mercury ion (Hg2) explore humic acid restore the capacity of the pollutants, the results showed that between the three kinds of humic acid of HgCl2 and Hg (NO3) 2 receptor, reducing capacity reached significant difference (p lt; 0.05), the largest of which JY, SH Secondly, TJ minimum. Hg (NO3) 2 as the electron acceptor HA's RC are greater than HgCl2 as electron acceptor HA RC. Three humic acid reduction of mercury ion reduction capacity indicators (NRC, CRC, MRC) is the order of the results obtained by the reduction of the size of the order and traditional Fe3 consistent, but the absolute values ??are lower than the latter, indicating that Fe3 reduction reduction capacity qualitative characterization of humic acid reduction capacity size, but not quantitative characterization of pollutants Hg2 reducing power. Solution system, the reduction of humic acid Hg2 significant. Restore Hg2 kinetics of humic acid, indicating that the a Hg0 generation in reaction to about 600min within a larger increase, followed by the slowdown in the rate of increase; reaction equilibrium state when the reaction time is greater than 1200min. Using commonly used to fit the kinetic equation of the reaction process, a kinetic equation fitting better, three kinds of humic acid to restore the the Hg2 initial rate constant K of order JY (9.6-3min-1) gt; SH (8.8 × 10-3min-1) gt; TJ (6.2 × 10-3min-1). Influencing factors on the reaction process and direction of research, such as the initial concentration of mercury, HA concentration, reaction temperature of the solution, pH, light, indicating that the initial concentration with mercury and the increase of the concentration of humic acid, humic acid Hg2 reduction rate was reduced after the first increase; natural light irradiation and temperature increases can increase amount of Hg0 the generated; under strong acid (pH3.6) and strong base (pH8, 1) conditions, humic acid The Hg2 reduction inhibition; through the different initial form of humic acid Hg2 reduction comparison, liquid, the HA than solid-state HA the Hg2 reduction is more, and the difference was significant (P lt; 0.05). Further, by the analysis of three kinds of HA solid and liquid active group, show that adding a variety of reactive groups of the content of the HA solution is higher than the added solid HA. By comparison to Hg2 reducing effect of three types of HA (TJ, SH, JY), there exists a significant difference (P LT; 0.05), wherein JY's strongest reducing ability, SH Secondly, TJ weakest. HA in natural environment, particularly in the water, of Hg2 both chelation also restore the role, so it can not only Sorption by chelation mercury in its existence media, can also impact through reduction of mercury interface migration.
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