Determination of Trace Amounts of Pb, Cd, Cu and Ag in High Salinity Water by ICP-AES with Sulfhydryl Cotton Separation and Preconcentration

Wastewater from mining enterprises contains a variety of heavy metals, and therefore requires treatment before discharge to render it non-toxic. After treatment by chemical precipitation, the content of metal is extremely low but has a large amount of salt introduced, which increases the difficulty of metal analysis in wastewater. A method for enrichment of trace elements from high salinity wastewater is described in this paper. Pb, Cd, Cu and Ag were determined by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) after separating and enriching with sulfhydryl cotton. Optimization experiment results showed that sulthydryl cotton could effectively separate a large number of sulfate ions and sodium ions, and could obviously enrich trace elements in the actual samples. The recovery rates of sulfate ion and sodium ion were all less than 0.05%, and the recovery rates of test target elements were at the rate of 88.7%-113.0%. Moreover, the effect of pH, flow rate of solution and the concentration of hydrochloric acid were investigated. Under optimal instrument conditions, the recoveries of these elements were 95.0%-102.0% and RSDs were 3.1%-9.4%, respectively. The method is rapid and convenient, with high accuracy and good precision, and should satisfy the analysis of metallurgical wastewater.