title: Physical pretreatments of wastewater algae to reduce ash content and improve thermal decomposition characteristics.
abstract: Previous study showed high ash content in wastewater algae (WA) has a negative effect on bio-crude oil formation in hydrothermal liquefaction (HTL). This study explored the effect of different pretreatments on ash reduction and the thermal decomposition of WA. Single-stage (e.g. centrifugation) and two-stage pretreatments (e.g. centrifugation followed by ultrasonication, C+U) were used. The apparent activation energy of the thermal decomposition (E(a)) of pretreated algae was determined. HTL was conducted to study how different pretreatments may impact on bio-crude oil formation. Compared to untreated samples, the ash content of algae with centrifugation was reduced from 28.6% to 18.6%. With C+U pretreatments, E(a) was decreased from 50.2 kJ/mol to 35.9 kJ/mol and the bio-crude oil yield was increased from 30% to 55%. These results demonstrate that pretreatments of C+U can improve the thermal decomposition behavior of WA and enhance the bio-crude oil conversion efficiency.
authors.affiliation: Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
authors.forename: Wan-Ting
authors.initials: WT
authors.lastname: Chen
authors.affiliation: Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310027, China.
authors.forename: Junchao
authors.initials: J
authors.lastname: Ma
authors.affiliation: Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. Electronic address: yzhang1@illinois.edu.
authors.forename: Yuanhui
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Department of Mechanical Engineering, Shandong University, Jinan 250061, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Gai
authors.affiliation: Department of Agricultural and Biological Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
authors.forename: Wanyi
authors.initials: W
authors.lastname: Qian
mesh_terms: D018533:Biomass; D001709:Biotechnology / Q000379:methods*; D002498:Centrifugation; D056890:Eukaryota / Q000378:metabolism*; D013696:Temperature; D013818:Thermogravimetry; D062065:Wastewater / Q000737:chemistry*; D014867:Water
chemical_list: D062065:Wastewater; D014867:Water
keywords: Activation energy; Algae; Hydrothermal liquefaction (HTL); Physical pretreatment; Wastewater