Investigation of Na2SO4 removal from a supercritical aqueous solution in a dip-tube salt separator

Analysis of Iron Anchor Diseases Unearthed from Gudu Ruins in Xianyang City, Shaanxi Province, China

Iron cultural relics are easily affected by environmental factors and can completely rust away. As early as the Qin Dynasty in ancient China, Xianyang Gudu was part of the most important transportation route to the West from ancient Chang’an; research into Xianyang Gudu has provided important information for understanding the historical changes in ancient China, East–West trade, and ancient boating technology. In this research, we use the iron anchors unearthed from the Gudu ruins in Xianyang City, Shaanxi Province, China as the research object; then, we used a scanning electron microscope–energy dispersive spectrometer (SEM-EDS), a high-resolution X-ray diffractometer (XRD), ion chromatography, and other methods to detect the corroded products of the iron anchors, and analyzed the iron anchor diseases in different preservation environments to explore the relationship between iron anchor disease and the preservation environment. This research found that the corroded products of the iron anchors contained the harmful tetragonal lepidocrocite (β-FeOOH) and that a high concentration of salt ions in the river channel accelerated the corrosion of the anchors; this analysis, based on the disease results, can provide a basis for the subsequent scientific restoration of iron anchors.

Sub- and Supercritical Water Liquefaction of Kraft Lignin and Black Liquor Derived Lignin

To mitigate global warming, humankind has been forced to develop new efficient energy solutions based on renewable energy sources. Hydrothermal liquefaction (HTL) is a promising technology that can efficiently produce bio-oil from several biomass sources. The HTL process uses sub- or supercritical water for producing bio-oil, water-soluble organics, gaseous products and char. Black liquor mainly contains cooking chemicals (mainly alkali salts) lignin and the hemicellulose parts of the wood chips used for cellulose digestion. This review explores the effects of different process parameters, solvents and catalysts for the HTL of black liquor or black liquor-derived lignin. Using short residence times under near- or supercritical water conditions may improve both the quality and the quantity of the bio-oil yield. The quality and yield of bio-oil can be further improved by using solvents (e.g., phenol) and catalysts (e.g., alkali salts, zirconia). However, the solubility of alkali salts present in black liquor can lead to clogging problem in the HTL reactor and process tubes when approaching supercritical water conditions.