Zhang Shuzhen

Influence of organic amendments on the sorption of pentachlorophenol on soils

The influence of pH on the sorption of pentachlorophenol (PCP) onto three organic amendments, char, humic acid (HA) and peat, and the effect of organic amendments on PCP sorption to three kinds of soils were evaluated. The sorption of PCP on these sorbents fitted the Freundlich model well, suggesting that PCP sorption isotherms were nonlinear with exponential coefficient (N) value lower than 1. The PCP sorption capacity on three organic amendments and the N values increased with decreasing pH. The sorption capacities were in the order: char > HA > peat. Organic amendments resulted in an enhancement of sorption capacities of soils. The N values of PCP sorption on soils were decreased by char amendment and increased by HA and peat amendments. This study demonstrated that application of traditional organic amendments led to the enhancement of PCP sorption by soils. This information may aid both in predicting environmental fates of hydrophobic ionizable organic compounds and in developing remediation strategies for them.

Analysis of hydroxylated polybrominated diphenyl ethers in plant samples using ultra performance liquid chromatography-mass spectrometry

A method was developed for the analysis of hydroxylated brominated diphenyl ethers (OH-PBDEs) in plant samples using an ultra performance liquid chromatography-triple quadrupole mass spectrometer (UPLC-ESI-MS/MS) in negative mode. Plant samples were extracted and cleaned up through florisil column, resolved on a 100 mm C18 column with linear gradient elution and detected by mass spectrometry in multiple reaction monitoring (MRM) mode. The method provided good recoveries ranging from 68.2% to 94.6%, relative standard deviation (RSD) in the range of 3.2%–9.1%, and limits of quantification (LOQ) defined as the signal-to-noise ratio of 10 of 0.3–2.1 ng/g. It allowed a fast separation and sensitive quantification of the isomers and homologues of seven OH-PBDE congeners 2′-OH-BDE-3, 3′-OH-BDE-7, 4′-OH-BDE-17, 3′-OH-BDE-28, 3-OH-BDE-47, 5-OH-BDE-47 and 6-OH-BDE-47. The method was successfully applied to identify and quantify the formation of hydroxylated metabolites in alfalfa exposed to BDE-209. Five OH-PBDEs were detected in plant tissues, and more congeners were found in roots than in shoots. To our knowledge, this work represents the first attempt to validate UPLC-MS/MS method to quantify OH-PBDEs in plant samples without derivatization.

Applications of synchrotron-based X-ray techniques in environmental science

Synchrotron-based X-ray techniques have been widely applied to the fields of environmental science due to their element-specific and nondestructive properties and unique spectral and spatial resolution advantages. The techniques are capable of in situ investigating chemical speciation, microstructure and mapping of elements in question at the molecular or nanometer scale, and thus provide direct evidence for reaction mechanisms for various environmental processes. In this contribution, the applications of three types of the techniques commonly used in the fields of environmental research are reviewed, namely X-ray absorption spectroscopy (XAS), X-ray fluorescence (XRF) spectroscopy and scanning transmission X-ray microscopy (STXM). In particular, the recent advances of the techniques in China are elaborated, and a selection of the applied examples are provided in the field of environmental science. Finally, the perspectives of synchrotron-based X-ray techniques are discussed. With their great progress and wide application, the techniques have revolutionized our understanding of significant geo- and bio-chemical processes. It is anticipatable that synchrotron-based X-ray techniques will continue to play a significant role in the fields and significant advances will be obtained in decades ahead.