Study On The Characteristics Of Phenolic Compounds Adsorption To Natural Surface Coatings

Phenolic compounds are toxic organic pollutants that are ubiquitous in environment. A great amount of waste water containing phenolic compounds is let out to the natural environment, which has done great harm to human being and organisms. In natural water, solid surfaces are usually covered with kinds of composite solid things, which consist of ferromanganese oxides, microorganisms, natural organic matters and many other things. These solid things play important roles in the interfacial reactions and compose what we call surface coatings. Due to the high surface reactivity and large surface areas, the most important role of surface coatings in the aquatic environments is to adsorb or enrich pollutants in water. Besides, the adsorbed pollutants may be degraded or detoxified due to the bioactivity of microorganisms. The toxic organic pollutants which are let out to environment will do greater harm to human being by enriching or adsorbing. Researches concerning phenolic compounds adsorption to natural surface coatings will do great help to the understanding of the behavior of phenolic compounds and the mechanism of their removal spontaneously in aquatic environments, and will also be hopeful to the development of aquatic environmental chemistry practicably and theoretically. In this paper, the adsorption of phenol and p-nitrophenol to natural surface coatings was studied with an aim of better understanding its removal pattern in environment. The differences between the initial concentration and the equilibrium solution concentration of phenol and p-nitrophenol adsorption to surface coatings were analyzed using UV-2100 spectrophotometer to estimate the Langmuir adsorption parameters of phenol and p-nitrophenol. Meanwhile, the influence of pH to adsorption was estimated. The location for cultivating surface coatings was Nanhu River, in Changchun, Jilin Province. The organic materials of the surface coatings were qualified by measuring chemical oxygen demand (COD) using a standard method. The total contents of metal (Fe, Mn) oxides were analyzed by FAAS after extracted by 15% HNO3 for 24 h. 10 pieces of surface coatings were put into 600 mL solutions, which contain phenol and p-nitrophenol concentrations from 5-50mg/L, respectively. 0.01 M HNO3 and NaOH were used to adjusted pH to 6.0 ±0.1, under 25℃shaking for 12 h, the thermodynamic adsorption experiments were carried out. Meanwhile, the adsorption experiments with different pH were performed on. The solution pH were 6.0,6.5,7.0,8.0, respectively. The observed phenol and p-nitrophenol adsorption to surface coatings were calculated from the difference between the initial concentration and the equilibrium solution concentration. Blank sorption experiment proved that the amount of phenol adsorbed to glass wall was negligible. The results showed that at pH 7.0,6.0,7.5,8.0, Freundlich, Langmuir and linear models were all fit for describing the sorption behavior of phenol in natural surfaces coatings. Freundlich equation fit...