title: Evaluation of the potentials of humic acid removal in water by gas phase surface discharge plasma.
abstract: Degradation of humic acid (HA), a predominant type of natural organic matter in ground water and surface waters, was conducted using a gas phase surface discharge plasma system. HA standard and two surface waters (Wetland, and Weihe River) were selected as the targets. The experimental results showed that about 90.9% of standard HA was smoothly removed within 40 min's discharge plasma treatment at discharge voltage 23.0 kV, and the removal process fitted the first-order kinetic model. Roles of some active species in HA removal were studied by evaluating the effects of solution pH and OH radical scavenger; and the results presented that O3 and OH radical played significant roles in HA removal. Scanning electron microscope (SEM) and FTIR analysis showed that HA surface topography and molecular structure were changed during discharge plasma process. The mineralization of HA was analyzed by UV-Vis spectrum, dissolved organic carbon (DOC), specific UV absorbance (SUVA), UV absorption ratios, and excitation-emission matrix (EEM) fluorescence. The formation of disinfection by-products during HA sample chlorination was also identified, and CHCl3 was detected as the main disinfection by-product, but discharge plasma treatment could suppress its formation to a certain extent. In addition, approximately 82.3% and 67.9% of UV254 were removed for the Weihe River water and the Wetland water after 40 min of discharge plasma treatment.
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi Province 712100, PR China; Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, PR China. Electronic address: wangtiecheng2008@126.com.
authors.forename: Tiecheng
authors.initials: T
authors.lastname: Wang
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi Province 712100, PR China; Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, PR China.
authors.forename: Guangzhou
authors.initials: G
authors.lastname: Qu
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi Province 712100, PR China; Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, PR China.
authors.forename: Jingyu
authors.initials: J
authors.lastname: Ren
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi Province 712100, PR China; Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, PR China.
authors.forename: Qiuhe
authors.initials: Q
authors.lastname: Yan
authors.affiliation: Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi Province 712100, PR China.
authors.forename: Qiuhong
authors.initials: Q
authors.lastname: Sun
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi Province 712100, PR China; Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, PR China.
authors.forename: Dongli
authors.initials: D
authors.lastname: Liang
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi Province 712100, PR China; Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Yangling, Shaanxi 712100, PR China.
authors.forename: Shibin
authors.initials: S
authors.lastname: Hu
mesh_terms: D004203:Disinfection; D005618:Fresh Water / Q000737:chemistry; D054879:Halogenation; D006812:Humic Substances; D006863:Hydrogen-Ion Concentration; D017665:Hydroxyl Radical; D008855:Microscopy, Electron, Scanning; D017550:Spectroscopy, Fourier Transform Infrared; D022882:Trihalomethanes / Q000737:chemistry; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D006812:Humic Substances; D022882:Trihalomethanes; D014874:Water Pollutants, Chemical; D017665:Hydroxyl Radical
keywords: Disinfection by-product; Humic acid; Natural organic matter; Surface discharge plasma