Synthesis Of Novel Adsorption Materials And Their Adsorption Properties For Trace Elements In Water And Biological Samples

With the rapid development in science and technology and proceeding industrialization,the consumption and draining of heavy metals and organic substance are increasing daily.The pollution caused by heavy metals and poisonous organic substance become more severe,which is also a dominant factor for jeopardizing the public health and preventing social economical development of our country.The accurate determination of trace element in geological,biological and environmental samples is an important and challenging task in analytical chemistry;especially heavy metals are often routinely monitored in environmental water.Direct determination of trace elements at low concentrations by modern atomic spectrometric techniques is often difficult,not only because of the insufficient sensitivity of the methods,but because of matrix effects.For this reason,the preliminary separation and preconcentration of trace elements from matrix is often required.There can be no doubt that solid-phase extraction(SPE)is today the most popular sample preparation method.It is a very active area in the field of separation science (such as environmental,pharmaceutical,clinical,food and industrial chemistry,etc.). SPE has several major advantages in separation and preconcentration of trace elements,including(i)simple to operate;(ii)high preconcentration factor;(iii)rapid phase separation;(â…³)and the ability to combine with different detection techniques. The methodology continues to evolve,through changes in format more than principle, in response to the desire to simplify the sampling process or facilitate automation. Advances are expected in sorbent chemistry,particularly class-specific sorbents for the isolation and clean-up of target analytes in complex matrices.Over time,various sampling formats and sorbents have been developed to facilitate the convenient processing of different sample types and to extend the scope of the method.At present, SPE is still an active area of research to develop new and more selective sorbents or procedures.The synthesis of new adsorption materials and their adsorption selectivity characteristics for trace heavy metals have been investigated systematically.The more detailed novelty of this research can be categorized as following:(1)Nanometer SiO₂ and silica gel was modified with p-dimethylaminobenzaldehyde(p-DMABD),5-sulfosalicylic acid(SSA),morin sulfanilamide and ofloxacinand under the silane coupling agent(APS,CPS)and used for preconcentration and separation of trace amounts of metal ions from solution samples prior to their determination by inductively coupled plasma optical emission spectrometry(ICP-OES).The separation/preconcentration conditions of analytes, which include the effects of the pH,the sample flow rate and volume,the elution condition,detection limits and precision and the interfering ions on the recovery of the analytes were investigated in detail.The accuracy of the proposed each method was checked by analyzing standard reference material with satisfactory results. Compared with untreated nanometer SiO₂ and silica gel,the modified nanometer SiO₂ and silica gel show the higher selectivity and adsorption capacities for pre-concentration and separation of trace heavy ions.(2)The new adsorbent was prepared using diethyldithiocarbamate(DDTC) Impregnated activated carbon(AC)followed by activating agent of NaOH.The modified activated carbon with diethyldithiocarbamate(DDTC)was used as an adsorbent for the solid-phase extraction(SPE)of trace amounts of Pb(â…¡)and Cr(â…¢) from solution samples prior to their determination by inductively coupled plasma optical emission spectrometry(ICP-OES).The separation/pre-concentration conditions of analytes,which include the effects of the pH,the sample flow rate and volume,the elution condition,detection limits and precision and the interfering ions on the recovery of the analytes were investigated in detail.The accuracy of the proposed each method was checked by analyzing standard reference material with satisfactory results.Compared with untreated activated carbon,the modified activated carbon show the higher activation of adsorption and selectivity for pre-concentration and separation of trace heavy ions.(3)The imprinted and non-imprinted copolymers for Pb(â…¡)was obtained by a surface imprinting technique for selective solid-phase extraction(SPE)of Pb(â…¡)and prior to its determination by ICP-OES.The separation/pre-concentration conditions of analytes,which include the effects of the pH,the sample flow rate and volume,the elution condition,detection limits and precision and the interfering ions on the recovery of the analytes were investigated in detail with reliable and satisfactory results.The substrate selectivity of imprinted polymer and non-imprinted polymer was investigated.The results showed that the imprinted polymer exhibited much higher affinity for Pb(â…¡).