天然有机物对铁锰复合氧化膜去除氨氮的影响

利用中试系统和静态试验,以富里酸为对象,研究天然有机物对石英砂滤料表面负载的铁锰复合氧化膜去除地表水中氨氮的影响。中试结果表明,当富里酸浓度在0～10 mg/L时,富里酸对氨氮的去除没有明显影响,氨氮去除率均高于95. 2%;当富里酸浓度在10～20 mg/L时,氨氮去除率降至65. 4%,甚至出水氨氮超标。静态试验结果表明,氨氮降解过程符合一级反应动力学,相关系数R2> 0. 9,ln(C_0/C_t)与反应时间t有很好的线性关系,随着富里酸浓度的增加,氨氮降解速率k_1值逐渐降低,其中空白的k_1值为0. 012 67 min^-1,富里酸浓度为5、10和20 mg/L时k_1值分别为空白的78. 6%、63. 4%和57. 6%,即富里酸对氨氮的氧化过程有不利的影响。FTIR光谱分析结果证实了富里酸在铁锰复合氧化膜的表面吸附,且富里酸的羧基离子和铁锰复合氧化膜的表面羟基在吸附过程中起着重要作用。

Effect of Natural Organic Matter on Ammonium Removal Performance of Iron-manganese Co-oxide Film in Surface Water Treatment

Iron-manganese co-oxide film coated quartz sands was used to treat surface water,and the effect of natural organic matter( the representative substance was fulvic acid) on the ammonium removal performance was investigated in a pilot-scale filtration system and static experiment. The pilotscale experiment results showed that the removal efficiency of ammonium stabilized over 95. 2% with fulvic acid concentrations ranging from 0 to 10 mg/L,while it fell to 65. 4% and even effluent ammonium concentration exceeded the standard with fulvic acid concentrations ranging from 10 mg/L to 20 mg/L. In static experiment,the degradation of ammonium fitted the first-order reaction kinetics,the related coefficient R^2> 0. 9,ln( C0/Ct) and the reaction time presented a good linear relation,that was to say,as fulvic acid concentration increasing,the degradation rate of ammonium k1 value would decrease gradually,among which the blank k1 was 0. 012 67 min^-1,while fulvic acid concentration was 5 mg/L,10 mg/L and 20 mg/L,the k1 values were 78. 6%,63. 4% and 57. 6% of the blank k1,respectively;fulvic acid played an adverse part in the ammonium oxidation process. FTIR spectra demonstrated the adsorption of fulvic acid on iron-manganese co-oxide film,showing that carboxyl ions in the fulvic acid and the surface hydroxyl of the iron-manganese co-oxide film played an important role in adsorption process.