软水中EPS对铜管/磷酸盐体系溶解性铜释放的影响

以海藻酸钠模拟水体中的细胞外高聚物(EPS)，研究软水体系中海藻酸钠对铜管／磷酸盐缓蚀行为的影响，结果表明：低浓度海藻酸钠能明显提高软水一铜管一磷酸盐体系中溶解性铜的释放，从而降低磷酸盐对铜管的缓蚀效果，而且从新管释放的溶解性铜远高于老化6个月、12个月和10年的铜管，释放溶解铜的顺序为Cnew＞C6m＞C12m＞C10y；随着海藻酸钠含量的增加，溶解性铜的释放浓度降低，但仍高于对照试验．在低pH条件下，海藻酸钠对溶解性铜的释放影响显著，从新管释放的溶解性铜浓度低于老化6个月、12个月和10年的铜管，这可能是由于不同老化时间的铜管其腐蚀表面的组成不同，水质pH值明显影响这些腐蚀副产物的溶解性铜释放；在不同停留时间内，随着水体组成的变化，溶解性铜的释放浓度不断发生变化，表明海藻酸钠与铜离子形成的络合物影响磷酸与铜的相互作用，从而影响磷酸盐对铜管的缓蚀效果．

INFLUENCE OF EPS ON ORTHOPHOSPHATE CORROSION INHIBITION FOR COPPER PIPE IN SOFT WATER

The effects of sodium alginate on orthophosphate corrosion inhibition for copper pipe in simulated soft water were investigated. The results showed that more soluble copper release was occurred in low levels for so- dium alginate. The 2-week aged copper pipe released more soluble copper than the 6, 12-month and 10-year aged copper pipe. The sequence of concentration of soluble copper release was C new>C 6m>C 12m>C 10y. When the initial pH value was low, compared to the system of no sodium alginate, the soluble copper release distinctly increased in the presence of sodium alginate. The amount of soluble copper released from new copper pipe is lower than that from 6, 12-month and 10-year aged copper pipe, which due to the different components of copper corrosion by-products on the surface of different aged copper pipes and the different solubility of different corrosion by-products. The effects of different stagnation times on the concentration of soluble copper release were highly variable which due to the absorption of sodium alginate on the surface of copper surface and the complex between sodium alginate and copper ions.