Synthesis Of Novel Sorbents And Their Adsorption Properties For Trace Metal Ions

In recent years, with the development of technology and the advance of industrialization, environmental problems are increasingly serious, particularly pollution which is caused by metal ions seriously affect people's life and production, therefore, metal ions' accurate determination becomes one of the important problems need to solve for analytical chemistry workers. For complex samples, due to both the matrix effect and the presence of interfering substances, it's difficult to determine directly with the instruments, so a separation and preconcentration step is needed. The enrichment and analysis of trace substances will rely on sorbents with better selectivity and higher adsorption capacity and suitable separation methods. Thence, in order to design novel separation and preconcentration of trace elements and analysis method, new SPE sorbent materials were obtained by modifying silica gel and activated carbon, and their selective adsorption characteristics were investigated systematically.1. A new 2-(2-oxoethyl)hydrazine carbothioamide modified silica gel (SG-OHC) sorbent was prepared and applied for preconcentration of trace mercury(Ⅱ) prior to the measurement by inductively coupled plasma atomic emission spectrometry(ICP-AES). The factors, performances of separation and enrichment were studied specifically, including enrichment acid, adsorption time, the elution condition, the detection limits and precision,etc. At pH 3, the saturated adsorption amount of SG-OHC for Hg(Ⅱ) was 37.5 mg g-1, the detection limit of this method was 0.10 ng mL-1, and the relative standard deviation was less than 4.0%(n=8). The sorbent was used for the enrichment of trace Hg(Ⅱ) in environmental samples with satisfactory results.2. A new sorbent 4-aminoazobenzene chemically-modified activated carbon(AC-AAB) was synthesized, the adsorption properties of the materials for Au (Ⅲ) was analyzed, and new method of enrichment before determination of Au(Ⅲ) was established. This method showed good selectivity, high precision, fast adsorption equilibrium, was used to separate and preconcentrate trace Au(Ⅲ) in environmental samples with good results.3. A new solid phase extractant was prepared by using isonicotinic acid hydrazide modified activated carbon, and used it to enrichment of trace Sc(Ⅲ). At pH 4, the maximum static adsorption capacity of the sorbent for Sc3+ was 21.58 mg g-1, only adsorbing 2 min was needed for maximum recovery (>95%), and the detection limit of this method for Sc(Ⅲ) was 0.096μg g-1. The adsorption materials was used for the enrichment of trace Sc(Ⅲ) in environmental samples with satisfactory results.