Study on a new treatment method for classic pollutant diclofenac from the pharmaceutical factory

Abstract

As a classic component of non-steroidal anti-inflammatory drug (NSAID), diclofenac has the anti-inflammatory, analgesic and antipyretic effects. As a result, the medical wastewater discharged from some diclofenac pharmaceutical factories may contain a certain amount of diclofenac. This pollutant is toxic and harmful to livestock, and if the livestock have digested diclofenac, it will affect their cellular metabolism process, cellular components and protein catalysis, which may even cause mass deaths under severe situation. An effective treatment method for this pollutant is to adopt composite aerogel adsorption. This paper briefly introduces the modification plan of cellulose and the process of using cellulose to adsorb diclofenac sodium (DCF), compares the adsorption effects before and after modification, and proposes a new direction to treat this kind of pollutant based on the comparison results. In this paper, by using cotton fiber as the material and polyvinylamine as the modifier, the hydrothermal synthesis method is employed to prepare the rGO/cellulose composite aerogel material, and the characterization analysis of its structure and performance is also conducted. The characterization results of SEM, EDS, XRD. FTIR etc. show that the composite aerogel material prepared in our experiment has maintained the crystal structure of cellulose, which has obvious 3D porous structure, and its specific surface area reaches 354.7m2/g. In addition, the material surface contains abundant amino, hydroxyl, C=N and other functional groups. Secondly, with diclofenac sodium as the targeted pollutant, this paper investigates the performance and mechanism of using rGO/cellulose composite aerogel to adsorb diclofenac sodium. The experimental results show that the rGO/cellulose composite aerogel presents outstanding performance in adsorption of DCF, which is significantly superior to the performance of cellulose aerogel material. When the rGO/cellulose composite aerogel and the cellulose aerogel are used to adsorb DCF, their maximum adsorption capacities are 242.94mgg-1 and 47.82mgg-1, respectively. In addition, the process of using composite aerogel to adsorb DCF satisfies the Langmuir isothermal adsorption model and the pseudo-second-order kinetic model, which indicates that this adsorption is chemical adsorption mainly consisting of monolayer adsorption. The thermomechanical analysis shows that the adsorption of DCF using composite aerogel is spontaneous exothermic reaction. In the meantime, the composite aerogel has wider pH adaptability, and it presents great adsorption efficiency of DCF within the pH range of 4-10.