| 原文摘要 | Tetracycline (TC) is used to treat human, animal and aquaculture diseases, becoming an interesting research topic in recent years because of its residues in the aquatic environment. This leads to adverse effects on ecosystem and human health. There are many treatment technologies applied to remove TC in water, such as oxidation, adsorption, membrane separation, and biodegradation. In which, adsorbents derived agricultural biomass (biochar) have been demonstrated to be effective for emerge organic contaminations. Spent coffee ground (SCG) has small particle size and high carbon content, which favor for pollutant adsorption. However, its use seems to be ignored. Therefore, in this study, biochar derived from spent ground coffee (SGC) under various pyrolysis temperatures (300 - 900 oC) was applied to absorb TC from aqueous solution. In order to improve and degrade TC completely, SCG biochar was modified as catalysts by impregnating iron and cobalt ions. Effects of parameters (pH, pyrolysis temperature, oxidant (persulfate - PS, peroxymonosulfate - PMS) dosage, initial TC concentration, and catalyst dosage) on TC degradation of biochar and PAH production in biochar and bio-oil were evaluated in this study. Moreover, TC adsorption isotherms and degradation mechanisms were also determined. Results showed that biochar synthesized at 500 oC (SCG 500) contained low PAHs (600 µg kg-1) and had the highest TC adsorption efficiency (at pH 7). The presence of ions in salinity solution significantly reduced the capacity of SCG 500. For SCG modified with magnetite (Fe3+), the highest removal efficiency (96%) was achieved by PS/Fe-SCG under the conditions of pH = 2.0, [Fe-SCG] = 2.5 g L-1, [PS] = 60 mM and [TC] = 1 mM. The maximum adsorption capacity of PS/Fe-SCG for TC was 18.73 mg g-1. For Cobalt-impregnated SCG, the highest removal efficiency was achieved by PMS/Co-SCG under the conditions of pH = 7.0, [Co-SCG] = 100 mg L-1, [PMS] = 0.6 mM and [TC] = 0.2 mM. TC was almost completely degraded in 25 min with a degradation rate constant of 0.1778 min-1. The maximum adsorption capacity of Co-SCG biochar for TC was 370.37 mg g-1. The concentration of 16 PAHs on Co-SCG biochar (715 µg kg-1) significantly was lower than those of other biochars prepared from different materials and was within the permissible limit according to the European Biochar Certificate and the International Biochar Initiative. Generally, results demonstrated that SCG was effective removal, safety PAHs level, low-cost and eco-friendly materials for tetracycline from water. |