MA Yuena1,2, LEE Xingqing1, LI Ling1, LIAN Guoqi1,2, ZHAO Chenxi1,2, WANG Bing3,4,5
(1. State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China
2. University of Chinese Academy of Sciences, Beijing 100049, China;
3. School of resources and environmental engineering, Guizhou University, Guiyang , 550025;
4. Key Laboratory of the Ministry of karst geological resources and environmental education, Guiyang 550025;
5. Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang, Guizhou 550025, China)
Abstract：The removal of phosphorus from water is very important for controlling eutrophication. In this study, the functionalized biochar composite was synthetized from solid waste coal gangue and straw and was applied to the phosphate adsorption in aqueous solution. The physical and chemical properties were characterized by SEM and Zeta potential measurement, and its optimum adsorption conditions, adsorption behavior and mechanism were studied. The results show that the use of coal gangue to modify straw biochar changed the properties of biochar, and the specific surface area, Zeta potential, conductivity, yield and adsorption capacity were significantly increased. The result of the screening experiment of adsorption conditions is that the unit adsorption capacity of 700℃ biochar is higher than 450℃ biochar, the unit adsorption capacity of modified biochar is higher than that of original biochar, and the unit adsorption capacity of rape biochar is greater than that of rice biochar. The unit adsorption capacity under acidic conditions is inversely proportional to the pH of the solution. Therefore, the adsorption conditions were selected as pyrolysis of modified rape biochar at 700 ℃, and the adsorption effect of phosphate with the solution of pH 4 using 2.5 g/L dosage was the best, the unit adsorption capacity is 7.08 mg/g. The adsorption process conforms to the quasi-second adsorption kinetic model and the Langmuir adsorption model. This adsorption process is mainly based on chemical adsorption, belongs to the monolayer, which is favorable for adsorption. In this study, a method for preparing a new type of bio-carbon-based composite material using solid waste has been developed. The material has the characteristics of low cost, simple operation and remarkable effect.
Keywords：biochar; modification; gangue; phosphate; solid waste
EARTH AND ENVIRONMENT Vol.49, No.3, Tot No.341, 2021, Page 315-324
