Norfloxacin adsorption by activated carbon from turmeric waste

Abstract

In recent years, extensive use of modern medicines and incompetency of conventional wastewater treatment systems have led to contamination of antibiotics in the environment especially in lower income countries. Antibiotics could interact with bacteria in the environment forming resistance to the medicine. Antibiotics also disrupt the balance of ecosystems affecting various lifeforms. Norfloxacin is a common antibiotic in Thailand with reported levels of contamination in Bang Pakong River. Adsorption process is a cheap and effective approach to remove antibiotics from wastewater effluent. Activated carbon is a common adsorbent in adsorption process due to its porous properties. Agricultural waste presents as an inexpensive and renewable precursor for activated carbons. Turmeric waste is an abundant and clean agricultural waste that is a novel activated carbon precursor. Turmeric waste activated carbon was prepared by the environmentally friendly CaCl2 under nitrogen atmosphere at 500-900 °C (TWAC500-900). The optimal carbonization temperature was 700 °C. TWAC700 was partly graphitized, and the surface contained C ≡ C, C = O, and C – H functional groups. Porosity of TWAC700 included BET surface area 334 m2/g, considerably high mesopore volume 0.362 cm3/g, and micropore volume 0.0954 cm3/g. TWAC700 showed high Norfloxacin removal efficiency (96.1%) with maximum monolayer adsorption capacity at 41.7 mg/g. The adsorption isotherm was in accordance with the Langmuir adsorption model which describes the monolayer adsorption on homogeneous surface. Turmeric waste activated carbon supports bio-circular-green economy model by adding value to agricultural waste, at the same time providing a new activated carbon for antibiotic residue removal in wastewater through adsorption process.