photodegradation of the antibiotic penicillin g in the aqueous solution using uv-a radiation

background and purpose: highly consumption of antibiotics and their entrance into the environment has increased concerns all over the world. these compounds enter to the environment through an incomplete metabolism and a considerable amount of them cannot be removed using usual waste filtration systems. therefore, the present study aimed to investigate the feasibility of using ultraviolet radiation (uv-a) to remove penicillin g (peng) from aqueous phase and determining its removal efficiency. materials and methods: the experiments were carried out in the batch mode. the samples were assessed in a 2-liter reactor. in order to investigate the effect of uv-a radiation on the removal rate of antibiotic penicillin g (peng), the following parameters were studied. three concentration levels of peng antibiotic (10,25,and 45 mg/l) were exposed to uv-a at three ph levels (3,7,11) and were evaluated at four reaction times (30,60,90, and 120 min). antibiotic penicillin g (peng) was determined using hplc instrument (waters yl9100,usa) and results analyzed using factorial design software. results: the finding demonstrated that antibiotic removal rate increased by decreasing ph and decreasing the initial concentration of antibiotic and increasing contact time. the maximum rate of penicillin g removal occurred in acidic ph (ph=3) is as much as 38%. all of the variables in the process have been statistically significant effect (p<0.001). conclusion: results showed that by reducing the ph, increasing contact time and reducing the antibiotic concentration, the removal rate increases. in conclusion, photodegradation process using uv-a may enhance the rate of penicillin g degradation in polluted water and could be used as a complementary step for other chemical and biological processes to remove penicillin g from the aqueous solution. therefore, uv-a process in conjugate with the other processes is an appropriate method for reducing antibiotic penicillin g in polluted water resources.