Browsing by Author "Li, Xi"
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- Electron beam treatment for the removal of 1,4-dioxane in water and wastewaterPearce, Robert; Li, Xi; Vennekate, John; Ciovati, Gianluigi; Bott, Charles (IWA Publishing, 2023-01)Electron beam (e-beam) treatment uses accelerated electrons to form oxidizing and reducing radicals when applied to water without the useof external chemicals. In this study, electron beam treatment was used to degrade 1,4-dioxane in several water matrices. Removal improvedin the progressively cleaner water matrices and removals as high as 94% to 99% were observed at a dose of 2.3 kGy in secondary effluent.1,4-dioxane removal was confirmed to be primarily through hydroxyl radical oxidation. The calculated electrical energy per order was foundto be 0.53, 0.26, and 0.08 kWh/m(3)/order for secondary effluent (Avg. TOC 9.25 mg/L), granular activated carbon effluent (TOC 3.46 mg/L), andultrapure water, respectively, with a 70% generation and transfer efficiency applied.
- Phylotranscriptomic insights into a Mesoproterozoic-Neoproterozoic origin and early radiation of green seaweeds (Ulvophyceae)Hou, Zheng; Ma, Xiaoya; Shi, Xuan; Li, Xi; Yang, Lingxiao; Xiao, Shuhai; De Clerck, Olivier; Leliaert, Frederik; Zhong, Bojian (Nature Portfolio, 2022-03-22)The Ulvophyceae, a major group of green algae, is of particular evolutionary interest because of its remarkable morphological and ecological diversity. Its phylogenetic relationships and diversification timeline, however, are still not fully resolved. In this study, using an extensive nuclear gene dataset, we apply coalescent- and concatenation-based approaches to reconstruct the phylogeny of the Ulvophyceae and to explore the sources of conflict in previous phylogenomic studies. The Ulvophyceae is recovered as a paraphyletic group, with the Bryopsidales being a sister group to the Chlorophyceae, and the remaining taxa forming a clade (Ulvophyceae sensu stricto). Molecular clock analyses with different calibration strategies emphasize the large impact of fossil calibrations, and indicate a Meso-Neoproterozoic origin of the Ulvophyceae (sensu stricto), earlier than previous estimates. The results imply that ulvophyceans may have had a profound influence on oceanic redox structures and global biogeochemical cycles at the Mesoproterozoic-Neoproterozoic transition.