Zhaoxue Zhang,Yi Lu,Haipu Li,Nan Zhang,Junfei Cao,Bo Qiu,Zhaoguang Yang
The simultaneous separation and determination of inorganic trivalent antimony Sb(III) and pentavalent antimony Sb(V) in plant, soil, and sediment samples was carried out by high performance liquid chromatography – inductively coupled plasma – mass spectrometry (HPLC-ICP-MS). The chromatographic conditions (composition and concentration of competing ion, pH value and flow rate of mobile phase) and the operating parameters for inductively coupled plasma – mass spectrometry were optimized by single factor experiments. The separation of the Sb species was achieved within 6 min using the optimized chromatographic conditions. The detection limits of the method were 0.016 μg/L and 0.021 μg/L for Sb(III) and Sb(V), respectively. The retention times of Sb(V) and Sb(III) were 2.7 min and 4.5 min, respectively. The relative standard deviations for replicate measurements (n = 6) of low (5 μg/L), medium (20 μg/L), and high (40 μg/L) concentrations of Sb(III) and Sb(V) were less than 4%. The results of spiking and recovery experiments for the extracting solutions of soil, sediments, and plants showed that the spiked recoveries of the two species ranged from 92% to 103%. This method has been used to determine the antimony species in extracts of environmental samples.
Li Jingxin,Zhang Yuxiao,Wang Xing,Walk Seth T.,Wang Gejiao
Antimony (Sb)-resistant bacteria have potential applications in the remediation of Sb-contaminated sites. However, the effect of Sb(III) exposure on whole-cell metabolic change has not been studied. Herein, we combined untargeted metabolomics with a previous proteomics dataset and confirmatory gene transcription analysis to identify metabolic responses to Sb(III) exposure in Agrobacterium tumefaciens GW4. Dynamic changes in metabolism between control and Sb(III)-exposed groups were clearly shown. KEGG pathway analysis suggested that with Sb(III) exposure: (1) the branching pathway of gluconeogenesis is down-regulated, resulting in the up-regulation of pentose phosphate pathway to provide precursors of anabolism and NADPH; (2) glycerophospholipid and arachidonic acid metabolisms are down-regulated, resulting in more acetyl-CoA entry into the TCA cycle and increased capacity to produce energy and macromolecular synthesis; (3) nucleotide and fatty acid synthesis pathways are all increased perhaps to protect cells from DNA and lipid peroxidation; (4) nicotinate metabolism increases which likely leads to increased production of co-enzymes (e.g., NAD+ and NADP+) for the maintenance of cellular redox and Sb(III) oxidation. Expectedly, the total NADP+/NADPH content, total glutathione, and reduced glutathione contents were all increased after Sb(III) exposure in strain GW4, which contribute to maintaining the reduced state of the cytoplasm. Our results provide novel information regarding global bacterial responses to Sb(III) exposure from a single gene level to the entire metabolome and provide specific hypotheses regarding the metabolic change to be addressed in future research.
As a toxic element, antimony (Sb) often exists in contaminated water in the form of Sb(III) and Sb(V), and poses a threat to the environment and human health. To remove Sb from water efficiently, the novel cerium hydroxide loaded Y-tape molecular sieve adsorbent (NaY@Ce) was successfully prepared by co-precipitation method. Adsorption capacity of the adsorbent showed up the increasing trend with the increase of cerium species. With 0.4 % loading of cerium trichloride, the maximum adsorption capacity of Sb(III) and Sb(V) on NaY@Ce was 24.65 mg/g and 7.28 mg/g at pH = 7.0, respectively. The results of batch experiments showed that the Langmuir isotherm well described the Sb(III) adsorption experiments, while Sb(V) better fitted the Freundlich model. Both adsorption behaviors fitted the pseudo-second-order kinetic model. The adsorbent exhibited excellent Sb removal performance in the wide range of pH = 2–10 and co-existing anions such as Cl − , NO 3 − , HCO 3 − and SO 4 2- almost have no effect on the adsorption process. And there was almost no release of Ce at pH＞2. The SEM, EDS, XRD, FTIR and XPS analysis confirmed the successful loading of Ce, and explained the possible mechanism of Sb on the adsorbent. Abundant hydroxyl groups and the presence of Ce(Ⅳ) were the basis of adsorption. The adsorption mechanisms for antimony included partial Sb(III) oxidized to Sb(V) and simultaneously adsorbed on NaY@Ce, formed Ce–O–Sb inner-sphere surface complexes between metal hydroxyl groups and antimony and electrostatic attraction. The above results confirmed that NaY@Ce can be used as a promising adsorbent to efficiently remove Sb from aqueous solution.
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