title: Study on water-dispersible colloids in saline-alkali soils by atomic force microscopy and spectrometric methods.
abstract: Recent studies have revealed that water-dispersible colloids play an important role in the transport of nutrients and contaminants in soils. In this study, water-dispersible colloids extracted from saline-alkali soils have been characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV absorption spectra. AFM observation indicated that the water-dispersible colloids contain some large plates and many small spherical particles. XRD, XPS, and UV absorption measurement revealed that the water-dispersible colloids are composed of kaolinite, illite, calcite, quartz and humic acid. In addition, UV absorption measurement demonstrated that the humic acids are associated with clay minerals. Water-dispersible colloids in the saline-alkali soils after hydrolyzed polymaleic anhydride treatment and an agricultural soil (nonsaline-alkali soil) were also investigated for comparison. The obtained results implied that the saline-alkali condition facilitates the formation of a large quantity of colloids. The use of AFM combined with spectrometric methods in the present study provides new knowledge on the colloid characteristics of saline-alkali soils. Microsc. Res. Tech. 79:525-531, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin, 150040, People's Republic of China.|State Engineering Laboratory of Bio-Resource Eco-Utilization, Harbin, 150040, People's Republic of China.
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin, 150040, People's Republic of China.|State Engineering Laboratory of Bio-Resource Eco-Utilization, Harbin, 150040, People's Republic of China.
authors.forename: Fengjie
authors.initials: F
authors.lastname: Xu
authors.affiliation: Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin, 150040, People's Republic of China.|State Engineering Laboratory of Bio-Resource Eco-Utilization, Harbin, 150040, People's Republic of China.
authors.forename: Yuangang
authors.initials: Y
authors.lastname: Zu
authors.affiliation: Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin, 150040, People's Republic of China.|State Engineering Laboratory of Bio-Resource Eco-Utilization, Harbin, 150040, People's Republic of China.
authors.forename: Ronghua
authors.initials: R
authors.lastname: Meng
authors.affiliation: Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin, 150040, People's Republic of China.|State Engineering Laboratory of Bio-Resource Eco-Utilization, Harbin, 150040, People's Republic of China.
authors.forename: Wenjie
authors.initials: W
authors.lastname: Wang
keywords: atomic force microscopy (AFM); hydrolyzed polymaleic anhydride (HPMA); saline-alkali soils; water-dispersible colloids