Synthesis Of Novel Adsorption Materials And Their Separation Properties For Trace Components

The rapid development of proceeding industrialization and economic technology leads to the draining of heavy metals. It has been a new challenge to determinate the metal ions exactly for analytical chemists.Direct determination of trace elements at low concentrations by modern atomic spectrometric techniques is often difficult, and various pre-treatment procedures are necessary before the more accurate measurement of solution so that reach to high precision and accuracy.The pre-concentration and analysis of trace elements have to depend on different adsorption materials with higher selectivity and bigger adsorption capacity and appropriate separation methods.This paper mainly described the preparation of several adsorption materials based on the pre-concentration and separation of trace components. At the same time,the adsorption selectivity characteristics for trace heavy metals have been investigated systematically.1. A new sorbent 1-acylthiosemicarbazide-modified activated carbon (AC-ATSC) was prepared as a solid phase extractant and applied for adsorbing of trace Cu(Ⅱ), Hg(Ⅱ) and Pb(Ⅱ) prior to their determination by inductively coupled plasma atom emission spectrometry (ICP-AES). The separation/preconcentration conditions of analytes were investigated, including effects of pH, the shaking time, the sample flow rate and volume, the elution condition and the interfering ions. At pH 3, the maximum static adsorption capacity of Cu(Ⅱ), Hg(Ⅱ) and Pb(Ⅱ) onto the AC-ATSC was 78.20,67.80 and 48.56 mg g-1, respectively. The adsorbed metal ions could be quantitatively eluted by 3.0 mL of 2% CS(NH2)2 and 2.0 mol L-1 HCl solution. Common coexisting ions did not interfere with the separation. According to the definition of IUPAC, the detection limit (3a) of this method for Cu(Ⅱ), Hg(Ⅱ) and Pb(Ⅱ) was 0.20,0.12 and 0.45 ng mL-1,respectively. The relative standard deviation under optimum conditions was less than 4.0%(n=8). The prepared sorbent was applied for the preconcentration of trace Cu(Ⅱ), Hg(Ⅱ) and Pb(Ⅱ) in certified and water samples with satisfactory results.2. In this study, a new sorbent 4-hydroxy salicylic acid (AZO) anthraquinone modified silica gel (SG-HSAA) sorbent was prepared as a solid phase extractant and applied for adsorbing of trace Pb(II) and Fe(III) prior to their determination by inductively coupled plasma atom emission spectrometry (ICP-AES). The separation/preconcentr-ation conditions of analytes were investigated, including effects of pH, the shaking time, the elution condition and the interfering ions. At pH 2, the maximum static adsorption capacity of Pb(Ⅱ) and Fe(Ⅲ) onto the SG-HSAA was 65.0 and 58.3 mg g-1. The adsorbed metal ions were quantitatively eluted by 2.0 mL 0.1 mol L-1 HCl solution. Common coexisting ions did not interfere with the separation. According to the definition of IUPAC, the detection limits (3σ) of this method for Pb(Ⅱ) and Fe(Ⅲ) was 4.03 and 3.19 ng mL-1. The relative standard deviation under optimum conditions is less than 4.0%(n=8). The prepared sorbent was applied for the preconcentration of trace Pb(Ⅱ) and Fe(Ⅲ) in certified and water samples with satisfactory results.3. A new sorbent benzyl carbazate-modified activated carbon AC-CBZH was synthesisedas a solid phase extractant, and applied for adsorbing of trace Pb(Ⅱ) prior to their determination by inductively coupled plasma atom emission spectrometry (ICP-OES). The experiments showed that the percentage extraction of Pb(Ⅱ) was achieved within 10 min. At pH 3, the maximum static adsorption capacity of Pb(Ⅱ) onto the AC-CBZH were 48.64μmol g-1. According to the definition of IUPAC, the detection limits (3a) of this method for Pb(Ⅱ) was 1.04 ng mL-1. The relative standard deviation under optimum conditions was 2.5%(n=8). The prepared sorbent was applied for the preconcentration of trace Pb(Ⅱ) in certified and water samples with satisfactory results.