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

The selective separation and enrichment of metal ions are two important foreland field in analytical chemistry.Because of high complexity of classification and concentration of pollutants and samples,extreme low concentration of analytes and severe interference caused by matrix effects,traditional analytical methods weren't competent for the challenging.Pre-concentration and analysis of trace elements is still necessary before the more accurate measurement by analytical instruments in reality.The pre-concentration and analysis of trace elements will depend on different adsorption materials with higher selectivity and bigger adsorption and appropriate separation methods.Therefore,in this research paper,new adsorption materials are synthesized in order to establish new methods by which the pre-concentration and separation of trace metal ions can be separated completely.The new enrichment methods of adsorption and selectivity characteristics for trace metal ions have been investigated systematically.The more detailed novelty of this research can be categorized as following:1.SiO₂ was modified with 4-(8-Hydroxy-5-quinolyl azo)naphthalenesulfonic acid (HQANSA)and used for preconcentration and separation of trace amounts of Cu(â…¡),Zn(â…¡),Cd(â…¡),Cr(â…¢)and Ni(â…¡)from sample solutions with reliable and satisfactory results.The adsorption behavior of Cu(â…¡),Zn(â…¡),Cd(â…¡),Cr(â…¢)and Ni(â…¡)on the HQANSA-modified SiO₂(HQANSA-SG)at low concentration was studied using inductively coupled plasma atomic emission spectrometry(ICP-AES).The optimum conditions for adsorption were discussed in detail,and under the condition that the analytes could be adsorbed and recovered quantitatively.The HQANSA-SG show the higher adsorption capacities for preconcentration and separation of trace metal ions,and the dsorption capacities of Cu(â…¡),Zn(â…¡),Cd(â…¡),Cr(â…¢)and Ni(â…¡)were found to be 33.47,36.43,88.2,18.35 and 19.90 mg g^-1,respectively.The accuracy of the proposed each method was checked by analyzing standard reference material with satisfactory results.2.SiO₂ was modified using a new method,the Salicylaldehyde-modified SiO₂(SA-SG) and the Ammonium pyrrolidine dithiocarbamate-modified SiO₂(APDC-SG)as solid-phase extractant have been developed for the simultaneously on line separation and preconcentration of trace noble metal ions from sample solutions.The optimum conditions for adsorption were discussed in detail,and under the condition that the analytes could be adsorbed and recovered quantitatively.The adsorption behavior of Au (â…¢),Pd(â…¡)and Pt(â…£)on the SA-SG and APDC-SG at low concentration was studied using inductively coupled plasma atomic emission spectrometry(ICP-AES).The acidity, rate,desorbed conditions,adsorption capacity and interference on the adsorption of ions on these sorbents were investigated in detail.The precision and the accuracy of the proposed method were applied for the determination of trace analytes in water samples with satisfactory results.3.A molecularly polymer was prepared using the product of Mateic anhydride(MA) and Diethylenetriamine as monomer,a large excess of Trihydroxymethylpropyl trimethylacrylate(TMPTMA)as the cross-linking agent and 2,2-Azobisisobutyronitrile (AIBN)as the initiator.The bulk polymer obtained was investigated in equilibrium binding experiments.The results showed that the polymer exhibited much higher affinity for Hg(â…¡)among the tested metal ions.The separation/preconcentration conditions of analytes,which include the effects of the pH,the sample flow rate and volume,the elution condition,detection limits,precision and the interfering ions on the recovery of the analytes were discussed in detail.It is possible to be a good adsorption and binding material in the selective enrichment and determination of trace Hg(â…¡)in water samples.