title: Pb and Cd binding to natural freshwater biofilms developed at different pH: the important role of culture pH.
abstract: The effects of solution pH on adsorption of trace metals to different types of natural aquatic solid materials have been studied extensively, but few studies have been carried out to investigate the effect of pH at which the solid materials were formed on the adsorption. The purpose of present study is to examine this effect of culture pH on metal adsorption to natural freshwater biofilms. The adsorption of Pb and Cd to biofilms which were developed at different culture pH values (ranging from 6.5 to 9.0) was measured at the same adsorption pH value (6.5). The culture pH had considerable effects on both composition and metal adsorption ability of the biofilms. Higher culture pH usually promoted the accumulation of organic material and Fe oxides in the biofilms. The culture pH also affected the quantity and species of algae in the biofilms. The adsorption of Pb and Cd to the biofilms generally increased with the increase of culture pH. This increase was minor at lower pH range and significant at higher pH range and was more remarkable for Cd adsorption than for Pb adsorption. The notable contribution of organic material to the adsorption at higher culture pH values was also observed. The profound impacts of culture pH on adsorption behavior of biofilms mainly resulted from the variation of total contents of the biofilm components and were also affected by the alteration of composition and properties of the components.
authors.affiliation: Key Lab of Groundwater Resources and Environment of Ministry of Education, Key Lab of Water Resources and Aquatic Environment of Jilin Province, College of Environment and Resources, Jilin University, Changchun 130012, China. huaxy@jlu.edu.cn
authors.forename: Xiuyi
authors.initials: X
authors.lastname: Hua
authors.forename: Deming
authors.initials: D
authors.lastname: Dong
authors.forename: Xiaoou
authors.initials: X
authors.lastname: Ding
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.forename: Xu
authors.initials: X
authors.lastname: Jiang
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Guo
mesh_terms: D000327:Adsorption; D018441:Biofilms; D002104:Cadmium / Q000032:analysis / Q000378:metabolism*; D004784:Environmental Monitoring; D005618:Fresh Water / Q000737:chemistry* / Q000382:microbiology; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000032:analysis / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*
chemical_list: D014874:Water Pollutants, Chemical; D002104:Cadmium; D007854:Lead