title: Hydrothermal decomposition of liquid crystal in subcritical water.
abstract: Treatment of liquid crystal has important significance for the environment protection and human health. This study proposed a hydrothermal process to decompose the liquid crystal of 4-octoxy-4'-cyanobiphenyl. Experiments were conducted with a 5.7 mL stainless tube reactor and heated by a salt-bath. Factors affecting the decomposition rate of 4-octoxy-4'-cyanobiphenyl were evaluated with HPLC. The decomposed liquid products were characterized by GC-MS. Under optimized conditions i.e., 0.2 mL H2O2 supply, pH value 6, temperature 275°C and reaction time 5 min, 97.6% of 4-octoxy-4'-cyanobiphenyl was decomposed into simple and environment-friendly products. Based on the mechanism analysis and products characterization, a possible hydrothermal decomposition pathway was proposed. The results indicate that hydrothermal technology is a promising choice for liquid crystal treatment.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, No. 1239 Siping Road, Shanghai 200092, PR China; Shanghai Cooperative Centre for WEEE Recycling, Shanghai Second Polytechnic University, No. 2360 Jinhai Road, Shanghai 201209, PR China.
authors.forename: Xuning
authors.initials: X
authors.lastname: Zhuang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, No. 1239 Siping Road, Shanghai 200092, PR China. Electronic address: hithwz@163.com.
authors.forename: Wenzhi
authors.initials: W
authors.lastname: He
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, No. 1239 Siping Road, Shanghai 200092, PR China.
authors.forename: Guangming
authors.initials: G
authors.lastname: Li
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, No. 1239 Siping Road, Shanghai 200092, PR China.
authors.forename: Juwen
authors.initials: J
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, No. 1239 Siping Road, Shanghai 200092, PR China.
authors.forename: Shangming
authors.initials: S
authors.lastname: Lu
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, No. 1239 Siping Road, Shanghai 200092, PR China.
authors.forename: Lianjiao
authors.initials: L
authors.lastname: Hou
mesh_terms: D001713:Biphenyl Compounds / Q000737:chemistry*; D002384:Catalysis; D003300:Copper / Q000737:chemistry; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000737:chemistry; D050866:Liquid Crystals / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry; D009570:Nitriles / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry; D014867:Water
chemical_list: D001713:Biphenyl Compounds; D017895:Manganese Compounds; D009570:Nitriles; D010087:Oxides; D014867:Water; D003300:Copper; D006861:Hydrogen Peroxide; C016552:manganese dioxide; C030973:cupric oxide
keywords: 4-octoxy-4’-cyanobiphenyl; Decomposition; Hydrothermal technology; Liquid crystal; Waste LCDs