Seasonal variation, spatial distribution, and sources of PAHs in surface seawater from Zhanjiang bay influenced by land-based inputs.

This study was carried out for a comprehensive understanding of the concentrations, seasonal variation, spatial distribution, sources, and land-based inputs of polycyclic aromatic hydrocarbons (PAHs) in surface seawater from Zhanjiang Bay (ZJB). Although the PAHs were ubiquitous, their concentrations were relatively low, and significant seasonal trends and spatial distributions were observed. Based on the diagnostic ratios and composition profiles, the PAHs found in this study mainly originated from coal/biomass burning, and petroleum and its combustion played an important role in the wet seasons. Furthermore, the PAHs from land-based inputs had seasonal variations, spatial distributions, sources, and composition profiles similar to those in ZJB seawater. By combining the cases of energy structure, residential and industrial layouts, maritime traffic, and activities related to ports and mariculture, this study concluded that PAHs in ZJB seawater are greatly influenced by land-based inputs, atmospheric deposition and human activities.

Preparation of Micro-Nano Material Composed of Oyster Shell/Fe3O4 Nanoparticles/Humic Acid and Its Application in Selective Removal of Hg(II).

Micro-nano composite material was prepared to adsorb Hg(II) ions via the co-precipitation method. Oyster shell (OS), Fe3O4 nanoparticles, and humic acid (HA) were used as the raw materials. The adhesion of nanoparticles to OS displayed by scanning electron microscopy (SEM), the appearance of the (311) plane of standard Fe3O4 derived from X-ray diffraction (XRD), and the transformation of pore sizes to 50 nm and 20 µm by mercury intrusion porosimetry (MIP) jointly revealed the successful grafting of HA-functionalized Fe3O4 onto the oyster shell surface. The vibrating sample magnetometer (VSM) results showed superparamagnetic properties of the novel adsorbent. The adsorption mechanism was investigated based on X-ray photoelectron spectroscopy (XPS) techniques, which showed the process of physicochemical adsorption while mercury was adsorbed as Hg(II). The effects of pH (3-7), initial solution concentration (2.5-30 mg·L-1), and contact time (0-5 h) on the adsorption of Hg(II) ions were studied in detail. The experimental data were well fitted to the Langmuir isotherm equation (R2 = 0.991) and were shown to follow a pseudo-second-order reaction model (R2 = 0.998). The maximum adsorption capacity of Hg(II) was shown to be 141.57 mg·g-1. In addition, this new adsorbent exhibited excellent selectivity.

Binding induced strand displacement amplification for homogeneous protein assay.

An ultrasensitive and homogenous strategy for protein assay was established based upon binding-induced strand displacement amplification (BI-SDA). Binding-Induced DNA strand-displacement occurred between Apt-T•signal DNA and Apt-C, and release of signal DNA upon addition of platelet-derived growth factor (PDGF BB). The released signal DNA further hybridized with multifunctional hairpin DNA probe and induced the strand-displacement amplification in the presence of Klenow Fragment (exo-) and dNTPs. The BI-SDA product contain G-quaruplex DNA, which could be recognized and reported by the fluorescence of fluorochrome N-methyl porphyrin propionic acid IX (NMM). The fluorescence intensity was proportional to the concentration of PDGF-BB over the range of 1.0×10-11mol/L -2.0×10-9mol/L, with a detection limit of 3.6pmol/L. This proposed strategy showed good selectivity and practicality, and might be applied to other proteins in the future.