In this work the statistical experimental design was considered for optimizing the photosensitized degradation of sulfamerazine (SMR: 0.01-0.05 mmol L-1) in dissolved organic matter (SRNOM: 10-20 mgL-1) at pH ranging from 5 to 9. A 300-W Xenon lamp was used as energy source. Our studies showed the presence of SRNOM increased the SMR degradation rate. The pH was the factor that produced greater effect on the photosensitized process. In presence of 15 mg L-1SRNOM and at circumneutral pH, the photodegradation efficiency was more pronounced at low concentration of SMR. At pH 7, the DOM concentration was the factor that produced significant effect on the photosensitized processes only in high concentration of SMR. To qualitatively demonstrate the role of reactive species in photosensitized processes, the degradation sulfamerazine containing SRNOM solution was studied in four sets of condition (Figure 1). The SMR solution (containing SRNOM) in D2O (k1 = 5.19�10-3 � 0.0006 min-1) showed enhancement over that in H2O (k1 = 4.13�10-3 � 0.0003 min-1). The SMR degradation rate in presence of 2-propanol decreased to 3.05�10-3 � 0.0002 min-1. We observed increasing in the SMR degradation rate when the solution was saturated with nitrogen (7.49�10-3 � 0.0007 min-1). However, it was not observed significant decreasing in the SMR degradation rate in sorbic acid (3.72�10-3 � 0.0003 min-1). These results indicate that HO� appears to have great importance during photosensitized degradation of SMR in presence of SRNOM. Figure 1  : Degradation rate of 0.01 mmol L-1 sulfamerazine containing 15 mg L--1 SRNOM using solar simulator at pH 7.

Photosensitized degradation of antibiotic in aqueous solution of Suwannee River natural organic matter

248th National Meeting (2014)

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