Soil contaminated with typical heavy metals (Pb,Cd,Cu,and Zn) was remedied by using the polymeric aluminum salt coagulants including polyaluminum chloride (PAC) and polyaluminum sulfate (PAS).The remediation efficienc...Soil contaminated with typical heavy metals (Pb,Cd,Cu,and Zn) was remedied by using the polymeric aluminum salt coagulants including polyaluminum chloride (PAC) and polyaluminum sulfate (PAS).The remediation efficiencies are influenced by reaction time,water amount,and dosage of remediation agent.The optimal remediation conditions are as follows:6 h of reaction time,1 kg/kg of water addition amount,and 0.25 kg/kg of remediation agent dosage.After PAC addition,the remediation efficiencies of diethylenetriamine-pentaacetic acid (DTPA)-extractable Pb,Cd,Cu,and Zn reach 88.3%,85.1%,85.4%,and 73.7%,respectively;and those for PAS are 89.7%,88.7%,83.5%,and 72.6%,respectively.The main remediation mechanism of the polymeric aluminum salt may contribute to the ionization and hydrolysis of PAC and PAS.H + released from ionization of polymeric aluminum salt can cause the leaching of heavy metals,while the multinuclear complex produced from hydrolysis may result in the immobilization of heavy metals.For PAC,the immobilization of heavy metals is the main remediation process.For PAS,both leaching and immobilization are involved in the remediation process of heavy metals.展开更多
The Middle-Late Jurassic Cu-Pb-Zn-bearing and W-bearing granites in the Nanling Range have distinctly different mineralogical and geochemical signatures. The Cu-Pb-Zn-bearing granites are dominated by metaluminous amp...The Middle-Late Jurassic Cu-Pb-Zn-bearing and W-bearing granites in the Nanling Range have distinctly different mineralogical and geochemical signatures. The Cu-Pb-Zn-bearing granites are dominated by metaluminous amphibole-bearing granodiorites, which have higher CaO/(Na2O+K2O) ratios, light/heavy rare earth element(LREE/HREE) ratios, and δEu values,lower Rb/Sr ratios, and weak Ba, Sr, P, and Ti depletions, exhibiting low degrees of fractionation. The W-bearing granites are highly differentiated and peraluminous, and they have lower CaO/(Na2O+K2O) ratios, LREE/HREE ratios, and δEu values,higher Rb/Sr ratios, and strong Ba, Sr, P, and Ti depletions. The Cu-Pb-Zn-bearing granites were formed predominantly between155.2 and 167.0 Ma with a peak value of 160.6 Ma, whereas the W-bearing granites were formed mainly from 151.1 to 161.8Ma with a peak value of 155.5 Ma. There is a time gap of about 5 Ma between the two different types of ore-bearing granites.Based on detailed geochronological and geochemical studies of both the Tongshanling Cu-Pb-Zn-bearing and Weijia W-bearing granites in southern Hunan Province and combined with the other Middle-Late Jurassic Cu-Pb-Zn-bearing and W-bearing granites in the Nanling Range, a genetic model of the two different types of ore-bearing granites has been proposed. Asthenosphere upwelling and basaltic magma underplating were induced by the subduction of the palaeo-Pacific plate. The underplated basaltic magmas provided heat to cause a partial melting of the mafic amphibolitic basement in the lower crust, resulting in the formation of Cu-Pb-Zn mineralization related granodioritic magmas. With the development of basaltic magma underplating,the muscovite-rich metasedimentary basement in the upper-middle crust was partially melted to generate W-bearing granitic magmas. The compositional difference of granite sources accounted for the metallogenic specialization, and the non-simultaneous partial melting of one source followed by the other brought about a time gap of about 5 Ma between the Cu-Pb-Zn-bearing and W-bearing granites.展开更多
基金Project(K1201010-61)supported by the Science and Technology Program of Changsha,ChinaProject(51074191)supported by the National Natural Science Foundation of ChinaProject(2012BAC09B04)supported by National Key Technology Research and Development Program,China
文摘Soil contaminated with typical heavy metals (Pb,Cd,Cu,and Zn) was remedied by using the polymeric aluminum salt coagulants including polyaluminum chloride (PAC) and polyaluminum sulfate (PAS).The remediation efficiencies are influenced by reaction time,water amount,and dosage of remediation agent.The optimal remediation conditions are as follows:6 h of reaction time,1 kg/kg of water addition amount,and 0.25 kg/kg of remediation agent dosage.After PAC addition,the remediation efficiencies of diethylenetriamine-pentaacetic acid (DTPA)-extractable Pb,Cd,Cu,and Zn reach 88.3%,85.1%,85.4%,and 73.7%,respectively;and those for PAS are 89.7%,88.7%,83.5%,and 72.6%,respectively.The main remediation mechanism of the polymeric aluminum salt may contribute to the ionization and hydrolysis of PAC and PAS.H + released from ionization of polymeric aluminum salt can cause the leaching of heavy metals,while the multinuclear complex produced from hydrolysis may result in the immobilization of heavy metals.For PAC,the immobilization of heavy metals is the main remediation process.For PAS,both leaching and immobilization are involved in the remediation process of heavy metals.
基金supported by the National Natural Science Foundation of China (Grant No. 41273053)the National Key Basic Research Program of China (Grant No. 2012CB416702)the Sino-French Cai Yuanpei Program of China Scholarship Council
文摘The Middle-Late Jurassic Cu-Pb-Zn-bearing and W-bearing granites in the Nanling Range have distinctly different mineralogical and geochemical signatures. The Cu-Pb-Zn-bearing granites are dominated by metaluminous amphibole-bearing granodiorites, which have higher CaO/(Na2O+K2O) ratios, light/heavy rare earth element(LREE/HREE) ratios, and δEu values,lower Rb/Sr ratios, and weak Ba, Sr, P, and Ti depletions, exhibiting low degrees of fractionation. The W-bearing granites are highly differentiated and peraluminous, and they have lower CaO/(Na2O+K2O) ratios, LREE/HREE ratios, and δEu values,higher Rb/Sr ratios, and strong Ba, Sr, P, and Ti depletions. The Cu-Pb-Zn-bearing granites were formed predominantly between155.2 and 167.0 Ma with a peak value of 160.6 Ma, whereas the W-bearing granites were formed mainly from 151.1 to 161.8Ma with a peak value of 155.5 Ma. There is a time gap of about 5 Ma between the two different types of ore-bearing granites.Based on detailed geochronological and geochemical studies of both the Tongshanling Cu-Pb-Zn-bearing and Weijia W-bearing granites in southern Hunan Province and combined with the other Middle-Late Jurassic Cu-Pb-Zn-bearing and W-bearing granites in the Nanling Range, a genetic model of the two different types of ore-bearing granites has been proposed. Asthenosphere upwelling and basaltic magma underplating were induced by the subduction of the palaeo-Pacific plate. The underplated basaltic magmas provided heat to cause a partial melting of the mafic amphibolitic basement in the lower crust, resulting in the formation of Cu-Pb-Zn mineralization related granodioritic magmas. With the development of basaltic magma underplating,the muscovite-rich metasedimentary basement in the upper-middle crust was partially melted to generate W-bearing granitic magmas. The compositional difference of granite sources accounted for the metallogenic specialization, and the non-simultaneous partial melting of one source followed by the other brought about a time gap of about 5 Ma between the Cu-Pb-Zn-bearing and W-bearing granites.
