IMPROVED REMOVAL OF TARGET PHARMACEUTICALS FROM WASTEWATER USING MODIFIED BIOCHAR

摘要

Latest wood waste survey conducted in 2012 concluded that around 9.6 million tonnes (including non-residential sources such as woods) are being disposed of yearly in Ontario, with a diversion rate of only 22.2% (Statistics Canada, 2012). Biochar, produced from the pyrolysis of agricultural waste and forest industry by-products as feedstock, can be used in several applications, including: (1) soil amendment (Hunt et al., 2010), (2) carbon sequestration (IBI, 2016), (3) pollution prevention through better management of agricultural waste and run-off control, and (4) reuse potential as bio-oil. Biochar has been traditionally used for the removal of heavy metals from wastewater (Mohan et al., 2007), but it also received increased interest in recent years for its capacity to adsorb emerging contaminants such as pharmaceuticals (Kyzas et al., 2015; vom Eyser et al., 2015; Jung et al., 2015). Biochar physico-chemical properties are highly influenced by the pyrolysis process (e.g. slow or fast). Biochar produced at high temperatures yields higher surface area and micro-porosity that can improve its adsorption potential (Ahmad et al., 2012). Substrate composition also dictates the physical and chemical properties of biochar, and current biochar production is focused on advanced pyrolysis processes that allow higher yield and adsorptive characteristics (Lima et al., 2010; Ok et al., 2015). Slow and fast pyrolysis processes of biochar generate varying impact on its surface area. Generally, fast pyrolysis at higher temperatures results in higher yield, whereas slow pyrolysis at high temperature was found to significantly improve surface area. For example, Yao et al. (2012) found that Brazilian pepper woods, bamboo, sugarcane bagasse, and hickory wood slowly pyrolyzed at 600°C produced biochar with surface areas of 234.7, 375.5, 388.3 and 401.0 m~2/g, respectively, while biochars produced at 450°C had only areas in the range of 0.7 to 13.6 m~2/g. Feedstock composition and production technology also play an important role in the improvement of surface area. In the present study, we investigate a cost effective biochar treatment mechanism that yields high removal efficiency of selected pharmaceuticals including Carbamazepine and other pharmaceuticals of similar physicochemical properties such as Ibuprofen, Clofibric acid, and Ciprofloxacin, using High Performance Liquid Chromatography and Brunauer-Emmett-Teller for detection and analysis. Other natural soil amendments, such as synthesized zeolite, are also considered, and will be compared to treated biochar.