Sythesis Of Novel Sorbents And Applications In Separation And Preconcentration Of Trace Ions

With the development of industrial production,heavy metal residues in theenvironment is getting more and more serious,which is known to cause severedamage to human health and aquatic life.To solve these problems,we must improvethe sensitivity of detection in order to strengthen the control,or find suitableadsorbent to recovery heavy metal ions in environment.Solid-phase extraction (SPE) method is currently being widely used inpreconcentration and separation of trace elements because it can provide moreflexible working conditions and simple operation.The trend of SPE method is to findnew adsorbent,especially of which has good performance in achieving ablity ofpreconcentration and separation analyte from complex matrices.Based on the research works of reference literature reported,some creativeworks were carried out in this dissertation as follows:(1) A new solid-phase extractant,poly-allylthiourea was prepared for selectiveseparation and enrichment of trace Au³⁺ and Pd⁴⁺ from aqueous solution.Thedetermination of metal ions in aqueous solutions was carried out by inductivelycoupled plasma optical emission spectrometry (ICP-AES).Several parameters,suchas distribution coefficient and adsorption capacity of the chelating resin,pH and timeof uptake and striping,volume of sample and eluent,were evaluated using modelsolutions.The effects of electrolytes and cations on the enrichment were alsoinvestigated.At optimal conditions,the maximum extraction capacity of new sorbentwas 3.23 and 3.84 mmol g^-1 for Au³⁺ and Pd⁴⁺,respectively.The adsorption behaviorof target ions on the sorbent could be described by Langmuir adsorption isothermequation.The developed method was applied to the separation and enrichment oftrace Au³⁺ and Pd⁴⁺ in synthetic samples with satisfactory results.(2) A new chelating matrix was prepared by immobilizing sulfanilamide (SA) onsilica gel (SG) surface modified with 3-chloropropyltrimethoxysilane as a sorbent forthe solid-phase extraction (SPE) of Cu²⁺,Zn²⁺ and Ni²⁺.The determination of metalions in aqueous solutions was carried out by inductively coupled plasma opticalemission spectrometry (ICP-AES).Experimental conditions for effective sorption of trace levels of Cu²⁺,Zn²⁺ and Ni²⁺ were optimized with respect to differentexperimental parameters.The maximum sorption capacity of the sorbent at optimumconditions was found to be 34.91,19.07 and 23.62 mg g^-1 for Cu²⁺,Zn²⁺ and Ni²⁺,respectively.The detection limit of the method was found to be 1.60,0.50 and 0.61 ngmL^-1 for Cu²⁺,Zn²⁺ and Ni²⁺,respectively.The method was applied to the recovery ofCu²⁺,Zn²⁺ and Ni²⁺ from the certified reference material (GBW 08301,river sediment)and to the simultaneous determination of these cations in different water samples withsatisfactory results.(3) A new method that utilizes 1-pyrrolidine dithio carboxylic acid ammoniumsalt-modified activated carbon (AC-PDCA) as a solid phase extractant has beendeveloped for simultaneous preconcentration of trace Cr³⁺ and Pb²⁺ prior to themeasurement by inductively coupled plasma optical emission spectrometry(ICP-AES).Experimental conditions for effective adsorption of trace levels of Cr³⁺and Pb²⁺ were optimized with respect to different experimental parameters.Themaximum static adsorption capacity of the sorbent at optimum conditions was foundto be 39.4 and 49.9 mg g^-1 for Cr³⁺ and Pb²⁺,respectively.The prepared sorbent assolid-phase extractants were successfully applied for the preconcentration of traceCr³⁺ and Pb²⁺ in natural and certified samples with satisfactory results.(4) Morin was successfully used as a chemical modifier to improve the reactivityof the nanometer SiO₂ surface in terms of selective binding and extraction of heavymetal ions.This new functionalized nanometer SiO₂ (nanometer SiO₂-morin) wasused as an effective sorbent for the solid phase extraction (SPE) of Cd²⁺,Cu²⁺,Ni²⁺,Pb²⁺,Zn²⁺ in solutions prior to its determination by inductively coupled plasmaatomic emission spectrometry (ICP-AES).Experimental conditions for effectiveadsorption of trace levels of metal ions were optimized with respect to differentexperimental parameters.The maximum static adsorption capacity of the sorbent atoptimum conditions was found to be 22.36,36.8,40.37,33.21 and 25.99 mg g^-1 forCd²⁺,Cu²⁺,Ni²⁺,Pb²⁺,Zn²⁺,respectively.The procedure was validated by analyzingthe certified reference river sediment material (GBW 08301,China).The resultsobtained were in good agreement with standard values.The prepared sorbent assolid-phase extractants were successfully employed in the separation andpreconcentration of trace Cd²⁺,Cu²⁺,Ni²⁺,Pb²⁺,Zn²⁺ from the biological and naturalwater samples. In addition,an extract of Polymyxin B was analyzed by a validated highperformance liquid chromatography (HPLC) method based on reverse phase (RP)column separations.The components were separated preparatively on a C₁₈ stationaryphase by using 215nm detection.The mobile phase comprises acetonitrile-sodiumsulphate (dissolve 4.46 g of anhydrous sodium sulphate in 900 ml of water,adjust topH 2.3 with dilute phosphoric acid and dilute to 1000 mL with water) (20:80).Tenpolymyxin B components were isolated and characterized using Accurate-MassQ-TOF.These were investigated and characterized by a number of instrumentaltechniques including:HPLC spectrometry;high resolution mass spectrometry;isolation of compounds by preparative scale HPLC,etc.