Search

The study of modern pollen, and vegetation can improve the accuracy of paleoenvironmental reconstruction based on fossil pollen data. A total of 188 pollen surface samples were collected from Southern Xinjiang (34°00′–43°00′N, 74°00′–94°00′E) in China, with an elevation range of 888–1530 m. Surface pollen and vegetation were studied in the northern region of the Kunlun Mountains and the southern region of the Tianshan Mountains. The results showed that the surface pollen assemblages on the southern slope of the Tianshan Mountains (3530–1124 m) were divided into three pollen zones, namely, montane steppe, montane desert steppe, and montane desert. These zones were dominated by Artemisia, Chenopodiaceae, and Ephedra pollen. The surface pollen assemblages in the eastern Pamir Plateau (4530–1287 m) could be divided into alpine meadow, montane desert steppe, and montane desert zones, which were predominantly characterized by Artemisia, Chenopodiaceae, and Asteraceae pollen. However, the Southern Tarim Basin (3548–888 m) comprised montane desert steppe and montane desert zones, which was dominated by Artemisia and Chenopodiaceae pollen. The geographic distribution of the surface pollen sites obtained using ArcGIS, the R-value, and Pearson correlation analyses indicated that the over-represented Picea and Pinus pollen were of external origin and were transported by wind, water (rivers), and ice (glacier movement). Over-representation of Ephedra and Nitraria pollen was mainly distributed in the montane desert and desert steppe zones, respectively. Pollen from Chenopodiaceae and Artemisia were over-represented and broadly distributed across Southern Xinjiang. Juglans pollen was concentrated in areas with walnut trees, strongly indicating the presence of local parent plants. According to the Hybrid Single-particle Lagrangian Integrated Trajectory model, more Pinus pollen was transported to the Pamir region by external airflows during spring and summer, resulting in its higher surface pollen content. Research elucidating the relationship between modern pollen and vegetation in southern Xinjiang could provide data describing the surface palynological database of Xinjiang for use in large-scale paleoenvironmental reconstructions. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Self-organized hierarchical separation. • Liquid-liquid phase separation in super-gravity field. • Efficient recycling of overall metals in WPCBs. • Green strategy for the treatment of toxic heavy metals. Abstract Waste electrical and electronic equipment is rapidly increasing worldwide, resulting in a large quantity of waste printed circuit boards (WPCBs). There is a great challenge on how to efficiently separate mixed metals in WPCBs, which consists of more than 10 elements including hazardous Cr, Pb and Cd. In this work, based on atomic interactions, a method of liquid-liquid hierarchical separation is developed to separate the mixed metals dissociated from the pyrolyzed WPCBs of mobile phones. The hierarchical separation of L→L Fe-rich + L Cu,Pb-rich , L Cu,Pb-rich →L Cu-rich + L Pb-rich and L Pb-rich →S Cu-dendritical + L' Pb-rich produces four immiscible Fe-rich, Cu-rich, Cu-dendritical and Pb-rich substances. The separation rate between these substances can reach more than 96% in a super-gravity field of G = 1000 g. Other metals selectively distribute in the four substances. The Fe-rich substance collects Cr, Co, Ni and Si. Almost all of Au and Ag are trapped in the Cu-rich and Cu-dendritical substances. The low-melting-point metals, i.e. Bi, Cd, In and Sn, are located in the Pb-rich substance. This work provides a green shortcut for efficiently separating and recycling overall metals in WPCBs. [ABSTRACT FROM AUTHOR]