Adsorption of Diclofenac onto Activated Carbon

Prisutnost farmaceutika u vodenom okolišu i njihov potencijalni negativni utjecaj na ekosustav privukla je veliku pozornost znanstvenika. Upotreba farmaceutskih spojeva kod potrošača je u porastu, a njihovo nepotpuno uklanjanje tijekom pročišćavanja otpadnih voda dovodi do onečišćenja vodenih sustava. Metode koje se koriste za uklanjanje diklofenaka iz vode, između ostalog, uključuju i adsorpciju. Stoga je u ovom radu ispitana učinkovitost uklanjanja diklofenaka adsorpcijom na modificirani aktivni ugljen dobiven iz ljuske lješnjaka i modificiranog i nemodificiranog Cullara (komercijalni proizvod) iz vodenih otopina u šaržnim procesima. Karakterizacija adsorbensa provedena je FTIR-om i izmjeren je zeta-potencijal te određen \(pH_{pzc}\). Utjecaj pH vrijednosti na adsorpcijski kapacitet ispitan je u rasponu pH 2-10, a adsorpcijski mehanizam opisan je izotermnim i kinetičkim modelima. Prema dobivenim podacima, maksimalni adsorpcijski kapacitet od 48,7 mg/g postignut je s modificiranim Cullarom. Eksperimentalni podaci dobro opisuju Freundlichov i Langmuirov model izoterme. Dodatno je mehanizam adsorpcije ispitan kinetičkim modelima pseudo-prvog i pseudo-drugog reda. Aktivni ugljen iz ljuske lješnjaka kao alternativa komercijalnim aktivnim ugljenima, pokazao se učinkovitim adsorbensom za uklanjanje diklofenaka iz vodenih otopina.Recently, the presence of pharmaceutical contaminants in water bodies and their potential negative impact on the ecosystem gained much attention. The usage of pharmaceutical compounds by consumers follows an increasing trend, and their incomplete removal during wastewater treatment results in contamination of water surfaces. The methods used to remove DCF from water, among others, include adsorption. Therefore, the adsorption of diclofenac on modified activated carbon produced from hazelnut shells and modified and unmodified Cullar (a commercial product) from water solutions in batch processes was investigated. The adsorbent material was characterised by FTIR and the zeta-potential was measured, as well as the pH pzc was determined. The effect of pH on the adsorption capacity was evaluated in the range of 2-10 and the adsorption mechanism was described by isothermal and kinetic studies. According to obtained data, the maximum adsorption uptake of 48.7 mg/g was achieved with modified Cullar. The isotherm data were in good agreement with both, Freundlich and Langmuir isotherm models. In order to describe adsorption mechanisms, kinetic models were also calculated. Adsorption kinetics followed the pseudo-second-order model closely. Activated carbon from hazelnut shells proved to be an effective adsorbent for diclofenac removal