Selective, Rapid and Perfect Removals of Diluted Heavy Metal Ions in Waste Waters.

采用沉淀法处理采矿和炼油厂废水时，会产生大量的氢氧化物污泥，可共沉淀出Cd、As、Pb、Se等有毒物质。本实验室的研究结果表明，柱床中的镍铁矿渣纤维(FS)是快速分离悬浮低浓度超细污泥颗粒(SS)的良好介质(2 mm/S线速度)。这可以用基于FS纤维与超细颗粒之间的互凝现象的DLVO理论来解释。在分离废水中的低浓度有毒物质如Cd、Se和Pb时，也应用了上述机理，但需要对FS纤维进行表面改性。在低浓度的Cd溶液(1 mg/L)中，加入10~10 mg/L的铁或锌，加入硫离子，快速将Cd沉淀分离成超细的硫化镉颗粒。通过对FS纤维进行硫化亚铁表面改性，实现了1 mg/Lt；2+-Gt；的快速分离。用硫酸盐还原菌生物反应器在FS床上对含铅溶液(1 mg/L)也进行了沉淀。在SeO_4~(2-)的快速分离中，对FS纤维表面进行了碱性氢氧化亚铁和氢氧化铁的表面改性。获得了良好的快速分离效果，可以选择性地去除低浓度的有毒物质，这预示着未来废水处理工艺可能发生重大变化。

Treatment of wastewater from mining operations and refineries by precipitation which generates large volume of hydroxide sludge can coprecipitate toxic substances such as Cd, As, Pb, Se, etc. Results in our laboratory works showed that Ferro-Nickel Slag fibers(FS) in column bed served as excellent media in the rapid separation (2 mm/s linear velocity) of suspended low concentrated ultra fine sludge particles (SS) from precipitation. This can be explained by the DLVO theory based on the heterocoagulation phenomena between the FS fibers in column bed and the ultra fine particles.In the separation of low concentrated toxic substances such as Cd, Se and Pb in the wastewater, the above mechanisms were also applied but with FS fiber surface modifications. This was carried-out to low concentrated Cd solution (1 mg/L), which was rapidly separated by precipitation of Cd to ultra fine CdS particles by the addition of sulfide ions in the presence of 10^0-10^2 mg/L Fe or Zn. Rapid separation of 1 mg/L Cd^<2+> was also carried-out by application of ferrous sulfide surface modification to FS fibers. Other precipitation method was also applied to Pb solution (1mg/L) using bioreactor with Sulfate Reducing Bacteria (SRB) on FS bed. In the rapid separation of SeO_4^<2->, the basic ferrous and ferric hydroxide surface modification on the surface of FS fibers was conducted. Favorable rapid separation results were obtained and as a conclusion, low concentrated toxic substances can be selectively removed suggesting that potential drastic change in wastewater treatment processes in the future.