Removal of Specific Pharmaceuticals from Water using Activated Carbon

Abstract

Many types of pharmaceutical substances have been detected with significant concentrations through various advanced instrumental techniques in surface water, ground water, partially treated water (with concentration typically less than 0,1 ug/L), drinking water (concentration bellow 0,05 ug/L) domestic wastewater, municipal wastewater and industrial effluents (concentration approximately 1 ug/L). Pharmaceutical compounds are found at much lower concentrations in drinking water sources then the normally prescribed doses, but there is concern that chronic exposure to numerous compounds could cause serious health problems and that compounds can act synergistically to cause adverse health effects. The effectiveness of removal the specific pharmaceuticals (paracetamol, carbamazepine, metronidazole and caffeine) from drinking water with adsorption using two types of granular activated carbon (Filtrasorb 400 and WG12) was monitored. Paracetamol is a medication used to treat fever and mild to moderate pain. Paracetamol significantly relieves pain in acute migraine and headache. Carbamazepine is an anticonvulsant medication used primarily in the treatment of epilepsy and neuropathic pain. It is used in schizophrenia along with other medications and as a second-line agent in bipolar disorder. Metronidazole is an antibiotic and antiprotozoal medication. It is used either alone or with other antibiotics to treat inflammatory disease. Caffeine is a central nervous system (CNS) stimulant of the methylxanthine class. It is the world’s most widely consumed psychoactive drug. The concentrations of caffeine in surface waters were detected in the range 0.1 - 6.9 μg/L. The experiments were performed in laboratory conditions with varying values of pH (7,8 or 6,5), stable temperature, and dose of adsorbent. The experiments were performed in the glass bottles with the volume of 400 mL stock model water (drinking water spiked with pharmaceutical standard) with concentration approximately 0.05 μg/L. On the analytical scales weighed out 400 mg GAC was used and then it was added to the bottles. Subsequently these bottles were regularly stirred at 400 rpm. Samples were taken at 30, 60, 120 and 240 minutes, after which they were analyzed. Analyses of target pharmaceutical were performed in laboratories of ALS Czech Republic in Prague. LC-MS methodology (method was validated according to ISO 17025 system) was used to determine pharmaceuticals in water samples. The adsorption efficiency of pharmaceutical removal and the adsorption capacity of granular activated carbon depends on the time of contact of water with the material. Adsorption efficiency for two types of granular activated carbon varies from 13 to more than 90%.