In North China,iodine-rich groundwater has been extensively studied,but few in South China.This study aimed to investigate the characteristics of iodine-rich groundwater in South China and identify potential contamina...In North China,iodine-rich groundwater has been extensively studied,but few in South China.This study aimed to investigate the characteristics of iodine-rich groundwater in South China and identify potential contamination sources.The results revealed that the average concentration of iodine in groundwater was 890μg/L,with a maximumconcentration of 6350μg/L,exceeding the permitted levels recommended by the World Health Organization(5–300μg/L).Notably,the enrichment of iodide occurred in acidic conditions(pH=6.6)and a relatively low Eh environment(Eh=198.4 mV).Pearson correlation and cluster analyses suggested that the enrichment of iodide could be attributed to the intensified redox process involving Mn(II),iodine(I_(2)),or iodate(IO_(3)^(−))in the soil.The strong affinity between Mn(II)and I_(2)/IO_(3)^(−)facilitated their interaction,resulting in the formation and mobilization of I^(−)from the soil to the groundwater.Leaching experiments further confirmed that reducing substances(such as sodium sulfides,ascorbic acids,and fulvic acids)in the soil with low dissolved oxygen(DO)levels(<1.0 mg/L)enhanced the dissolution of iodine species.Conversely,higher DO content(>3.8 mg/L)promoted the oxidation of I^(−)into I_(2)or IO_(3)^(−),leading to its stabilization.This research provides new insights into the characteristics and mechanisms of I^(−)enrichment in groundwater in South China,and emphasizes the significance of the redox reactions involving Mn(II)and I_(2)/IO_(3)^(−),as well as the influence of soil properties in regulating the occurrence and transportation of iodine species within groundwater systems.展开更多
There is a pressing demand for the development of novel birefringent crystals tailored for compact optical components,especially for crystals exhibiting large birefringence across a range of temperatures.This has comm...There is a pressing demand for the development of novel birefringent crystals tailored for compact optical components,especially for crystals exhibiting large birefringence across a range of temperatures.This has commonly been achieved by introducing various deformable groups with high polarizability anisotropy.In this study,we combined both rigid and deformable groups to synthesise a new birefringent crystal,Al_(2)Te_(2)MoO_(10),which demonstrates an exceptional birefringence value of 0.29@550 nm at room temperature.Not only is this higher birefringence than that of commercial crystals,but Al_(2)Te_(2)MoO_(10)exhibits excellent birefringence stability over a wide temperature range,from 123 to 503 K.In addition,the first-principles theory calculations and structural analyses suggest that although the rigid AlO_(6)groups do not make much contribution to the prominent birefringence,they nonetheless played a role in maintaining the structural anisotropy at elevated temperatures.Based on these findings,this paper proposes a novel structural design strategy to complement conventional approaches for developing optimal birefringent crystals under various environmental conditions.展开更多
基金supported by the National Key Research and Development Program of China(No.2019YFC1803900)and the 111 Project(No.B18060)as well as Shenzhen Municipal Science and Technology Plan Project(No.JCYJ20160519095007940).
文摘In North China,iodine-rich groundwater has been extensively studied,but few in South China.This study aimed to investigate the characteristics of iodine-rich groundwater in South China and identify potential contamination sources.The results revealed that the average concentration of iodine in groundwater was 890μg/L,with a maximumconcentration of 6350μg/L,exceeding the permitted levels recommended by the World Health Organization(5–300μg/L).Notably,the enrichment of iodide occurred in acidic conditions(pH=6.6)and a relatively low Eh environment(Eh=198.4 mV).Pearson correlation and cluster analyses suggested that the enrichment of iodide could be attributed to the intensified redox process involving Mn(II),iodine(I_(2)),or iodate(IO_(3)^(−))in the soil.The strong affinity between Mn(II)and I_(2)/IO_(3)^(−)facilitated their interaction,resulting in the formation and mobilization of I^(−)from the soil to the groundwater.Leaching experiments further confirmed that reducing substances(such as sodium sulfides,ascorbic acids,and fulvic acids)in the soil with low dissolved oxygen(DO)levels(<1.0 mg/L)enhanced the dissolution of iodine species.Conversely,higher DO content(>3.8 mg/L)promoted the oxidation of I^(−)into I_(2)or IO_(3)^(−),leading to its stabilization.This research provides new insights into the characteristics and mechanisms of I^(−)enrichment in groundwater in South China,and emphasizes the significance of the redox reactions involving Mn(II)and I_(2)/IO_(3)^(−),as well as the influence of soil properties in regulating the occurrence and transportation of iodine species within groundwater systems.
基金This work was financially supported by the National Natural Science Foundation of China(22122507,21833010,61975207,22193042,and 21921001)the Natural Science Foundation of Fujian Province(2022J02012)+2 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Y202069)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(ZDBS-LY-SLH024)as well as Fujian Institute of Innovation(FJCXY18010201)in the Chinese Academy of Sciences.
基金supported by the National Natural Science Foundation of China(22122507,61975207,22193042,21833010,and 21921001)the Natural Science Foundation of Fujian Province(2022J02012)+2 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Y202069)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(ZDBS-LYSLH024)the China Postdoctoral Science Foundation(2023M743498)。
文摘There is a pressing demand for the development of novel birefringent crystals tailored for compact optical components,especially for crystals exhibiting large birefringence across a range of temperatures.This has commonly been achieved by introducing various deformable groups with high polarizability anisotropy.In this study,we combined both rigid and deformable groups to synthesise a new birefringent crystal,Al_(2)Te_(2)MoO_(10),which demonstrates an exceptional birefringence value of 0.29@550 nm at room temperature.Not only is this higher birefringence than that of commercial crystals,but Al_(2)Te_(2)MoO_(10)exhibits excellent birefringence stability over a wide temperature range,from 123 to 503 K.In addition,the first-principles theory calculations and structural analyses suggest that although the rigid AlO_(6)groups do not make much contribution to the prominent birefringence,they nonetheless played a role in maintaining the structural anisotropy at elevated temperatures.Based on these findings,this paper proposes a novel structural design strategy to complement conventional approaches for developing optimal birefringent crystals under various environmental conditions.
