负载硝酸盐有机改性沸石抑制底泥氮磷释放的效果及机制研究

Efficiency and Mechanics of Surfactant Modified Zeolite with Nitrate Adsorbed to Control Nitrogen and Phosphorus Release from Sediments

通过摇床振荡试验研究,考察HDTMA有机改性沸石对硝态氮的吸附-解吸特性及对磷酸盐和氨氮的吸附特性,再通过模拟释放试验考察负载硝酸盐HDTMA有机改性沸石对底泥氮磷释放的影响.结果表明:①有机改性沸石吸附硝态氮的最佳HDTMA负载量为276%ECEC.Langmuir公式能较好地描述有机改性沸石对硝态氮的吸附行为,饱和单位吸附量达到1 724mg/kg,并且有机改性沸石对硝态氮的吸附速率较快.有机改性沸石吸附硝态氮之后一定条件下又会逐渐释放出来,并且吸附的硝态氮越多,硝态氮的解吸量越大.Langmuir公式能较好地描述负载硝态氮之后有机改性沸石对磷和氨氮的吸附行为,且对氨氮的理论吸附量为12.0 mg/g以及对磷的理论吸附量为0.597 mg/g.②采用有机改性沸石负载硝酸盐可以较长时间地向表层底泥提供硝态氮,并且大大减低了进入上覆水的硝态氮比例.硝酸盐负载型有机改性沸石不仅可以有效控制底泥磷的释放,而且可以控制底泥氨氮的释放.

Efficiency and mechanics of surfactant modified zeolite （SMZ） with nitrate adsorbed to control nitrogen and phosphorus release from sediments were researched. The results show that： ① The optimal level of HDTMA adsorbed on SMZ for nitrate sorption was 276% ECEC. The sorption of nitrate on SMZ can be well described by the Langmuir sorption isotherm, and the sorption capacity was 1 724 mg/kg. The nitrate sorption on SMZ was quick and the nitrate adsorbed on SMZ can be released. The sorption of ammonia and phosphorus on SMZ with nitrate adsorbed can also be well described by the Langmuir sorption isotherm, and the sorption capacity of ammonia and phosphorus are 12.0 mg/g and 0.597 mg/g respectively. ② The barrier of SMZ with nitrate adsorbed can provide nitrate for surface sediments for a long time, and the quantity of released nitrate in overlying water was much less than that of nitrate directly added. This barrier can not only efficiently control ammonia release from sediments, but also control phosphorus release from sediment efficiently.