| This paper studies the environmental effects of tetracycline and enrofloxacincombined with two different adsorbents in the soil media - aluminum hydrous oxideand iron hydrous oxide. The adsorptions of two types of antibiotics onto aluminumhydroxide and iron hydroxide were investigated by batch sorption experiments whenthe affecting response to environmental factors, such as ionic strength, pH, wasstudied too. The adsorption behaviors and regulations in different environmentalmedia were ascertained. Focusing on the surface complexation sorption mechanismsand ligand-promoted dissolution of antibiotic substance sorption to the hydrous oxides,the study was in approach to reveal the possible reactions of the antibiotics that mightoccur in the soil environment, and finally to predict the pathways for the migrationand transformation. The results could be utilized for the further sufficient evaluationof chemical behavior of antibiotics reacted with the oxides in soil matrix and thepossibly produced environmental issues. To some extent, the study also could providethe theoretical evidence for the remediation and restoration of antibioticscontaminated soil.This paper consists of five ChaptersChapter 1. Tendency and Development of Behaviors Study onAntibiotic Contaminants in Water-Soil EnvironmentThis chapter describes the effects of antibiotics and development procedures inrecent years, and exact usage. An overview on researches of their produced pollutionand environmental behaviors and ecological risk assessment in water, soil andsediment are summarized based on the international and internal publications. Thispaper also reviews the detection technologies of antibiotics in the circumstances.Chapter 2. Interaction of Tetracycline with Aluminum HydroxideThe adsorptions of tetracycline (TC) onto aluminum hydroxide (HAO) at thedifferent pH and ionic strengths were investigated by the batch sorption experiments.The results proved that the adsorption of TC on HAO could be described by Freundlich isotherms when a complex reaction was involved in the adsorption process.At a pH range between 4 and 10, adsorption of TC on HAO increased with increasingpH at beginning, and then reached the relatively stable maximum at the pH rangebetween 5.5-8.5. If pH above the latter range, adsorption would decrease gently. Atthe low concentration of TC, the alternative of sodium chloride concentrations wouldnot obviously influence adsorption of TC, which indicated that the adsorption of TCon HAO were mainly affected by surface complexation mechanism. However, theincrease of sodium ion might weaken the adsorption of TC under a condition with thehigher concentration of TC.Chapter 3. Adsorption Behaviors of Enrofloxacin on AluminumHydroxide and Iron HydroxideBatch equilibrium experiments were used to reveal enrofloxacin (ENR)adsorption on two different hydrous oxides- aluminum hydroxide and iron hydroxide.The experimental results showed that the adsorption isotherms were well described byLangmuir model, but KL(HFO) > KL(HAO). The NaCl concentration changes at a rangebetween 0.01 - 0.5 mol ? L-1 with a variation of ion strengths in the solution did notcause the significant alternative of enrofloxacin adsorption, which indicated thatadsorption of enrofloxacin on two different hydrous oxides was essentially based onligand reaction. However, the adsorption efficiency was apparently reduced in thestrong acidic or alkaline environment. The coordination adsorption mainly occurred atpH5 ~ 8 in the envir onment.Chapter 4. Surface complexation sorption and Ligand-promoteddissolution of Tetracycline and Enrofloxacin on Hydrous OxidesBy using Fourier transform infrared analysis, UV spectrophotometry, atomicabsorption spectrophotometry, and other modern instruments, the Surfacecomplexation sorption ligand-promoted dissolutions of tetracycline and enrofloxacinon hydrous oxides were analyzed, and then the coordinative effects and efficiencywere discussed. Was found that the soluble complexes of 1:2 TC:Al3+ were formed inthe solution, and soluble complexes 1: 1 = ENR : M(Metal ions) were formed in thesolution too. However, the complex of antibiotics with iron and aluminum that was dissolved in water could produce the environmental issues, which might increaseecological toxicity of antibiotics in the environment.
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