Photodegradation of Sulfadiazine in Aqueous Solution and the Affecting Factors

Xuesen Bian,Jibing Zhang

doi:10.1155/2016/8358960

Abstract

Knowledge about photochemical behavior of sulfonamides under UV light is limited. In this study, photodegradation of sulfadiazine in water by ultraviolet (UV) light was studied using a 300 W, 365 nm UV lamp. The degradation process followed well the first-order kinetics, with a half-life of 9.76 min in water with air saturation. The photodegradation was slower at acidic pH 4.52 than at pH 6.98 and pH 8.90. Addition of H2O2and nitrate enhanced the photodegradation rate, while addition of ethanol, nitrite, sulfate, and bicarbonate depressed the reaction rate. This study suggested that sulfadiazine photodegradation under UV light is generally favored by the attack of hydroxyl radicals.

Highlights

Antibiotics are a sort of organic compounds synthesized by industry or generated by organisms including microorganisms, plants, and animals, in their life activities, which could selectively depress or influence functions of other organisms at low or even micro level concentrations
Control experiment under dark conditions showed ignorable disappearance of sulfadiazine in the solution, indicating that the compound was stable in the dark; that is, hydrolysis of sulfadiazine was not significant, which is in agreement with the observations of Boreen et al [18], who found that most sulfa drugs were stable in solutions of various pH values
Sulfadiazine in pure water was degraded by 99 percent in one hour with a half-life of 9.76 min (Figure 1)

Summary

Introduction

Antibiotics are a sort of organic compounds synthesized by industry or generated by organisms including microorganisms, plants, and animals, in their life activities, which could selectively depress or influence functions of other organisms at low or even micro level concentrations. Photodegradation is one important degradation process in natural environment. Photodegradation, both direct (reaction between substrates and photons) and indirect (reaction between substrates and reactive species formed by photons), of sulfadiazine under natural or simulated sunlight was investigated by previous studies [15, 16]. Results from UV photodegradation study will be useful to learn the behavior of photolysis by ultraviolet in water environment and will be helpful to the design of the artificial wastewater treatment system through UV photolysis of such chemicals. This work is designed to study kinetics and possible mechanisms of sulfadiazine photodecomposition under pure UV, by investigating the influences of some common affecting factors

Experimental

Results and Discussion

Conclusions