The influence of peracetic acid on the degradation of pharmaceuticals in water

U posljednjem desetljeću, posebice rezultatom proizvodnog procesa ili odlaganjem neupotrijebljenih farmaceutskih proizvoda, zabilježen je kontinuiran unos farmaceutika u okoliš. Glavni izvor farmaceutika su neadekvatno obrađene otpadne vode u kojima su pronađeni tragovi farmaceutika u rasponu koncentracija od ng L^-1 do μg L^-1, ovisno o efikasnosti uklanjanja te predstavljaju potencijalnu opasnost za ljude i okoliš. Tek nedavno su farmaceutici prepoznati kao onečišćivala okoliša te zahtijevaju daljnja istraživanja. Odlukom Europske unije, brojni farmaceutici su stavljeni na listu prioritetnih tvari za koje je potrebno praćenje i uklanjanje kao što je diklofenak (DCF). Moguća alternativa ili nadopuna postojećih metoda obrade voda je pomoću peroctene kiseline koja je postala atraktivna u novije vrijeme. Zbog svojih poznatih svojstava i uspješnosti kod dezinfekcije vode, peroctena kiselina je prepoznata kao moguće sredstvo koje bi se upotrebljavalo i za uklanjanje farmaceutika iz vode. Ovim radom željelo se istražiti utjecaj peroctene kiseline na učinkovitost razgradnje diklofenaka u otpadnim vodama. Ispitan je utjecaj odabranih parametara – pH i koncentracije peroctene kiseline, u prisutnosti iona klorida i nitrata te potom klorida, nitrata i željeza. Ustanovljeno je kako je brzina razgradnje DCF-a u odsustvu željeza mala. Utjecaj parametara na učinkovitost razgradnje DCF-a u prisutnosti željeza određen je analizom varijance i modelom odzivne površine. Eksperimentom je pokazano da peroctena kiselina i pH vrijednost utječu na brzinu razgradnje diklofenaka te je ostvarena razgradnja DCF-a u svim eksperimentima velika. Optimalni uvjeti koji su određeni su vrijednosti pH 2 i koncentracija peroctene kiseline 3,74 mM.In the last decades, especially with the result of the production process or the disposal of unused pharmaceuticals, continued input of pharmaceuticals into the environment has been recorded. The main source of pharmaceuticals are inadequately treated wastewaters in which traces of pharmaceuticals in the range of ng L^-1 to μg^-1 are found, depending on the effectivness of removal and pose a potential hazard to humans and the environment. Only recently pharmaceuticals are recognized as the environmental pollutants and require further research. By the directive of the European Union, numerous drugs are placed on a list of priority substances for which monitoring and removal is required, amongst them is diclofenac (DCF). A possible alternative or supplement to the existing processes in wastewater treatment is by using peracetic acid which has become attractive in recent times. Because of its known properties and performance in water disinfection, peractic acid has been recognized as a possible solution for removing pharmaceuticals from wastewaters. This work aims to investigate the effect of peracetic acid on the efficiency of degradation of DCF in waste water. The influence of selected parameters - pH and peracetic acid concentrations in the presence of chloride and nitrate ions along with chloride, nitrate and iron was investigated. It was found that the rate of degradation of DCF in the absence of iron is small. The influence of parameters on the efficiency of DCF degradation in the presence of iron was determined by the analysis of variance and the response surface model. The experiments have shown that peracetic acid and pH value affect the rate of degradation of diclofenac. Optimal conditions were determined to be pH values 2 and peracetic acid concentrations 3.74 mM