Agro-Environmental Protection Institute, Ministry of Agriculture and Rural Affairs, Tianjin 300191, China.
Erhai Watershed Ecological Environment Quality Testing Engineering Research Center of Yunnan Provincial Universities, West Yunnan University of Applied Sciences, Dali 671004, China.
Int J Environ Res Public Health. 2022 Jun 13;19(12):7227. doi: 10.3390/ijerph19127227.
In order to improve the phosphate adsorption capacity of Ca-loaded biochar at a wide range of pH values, Ca (oyster shell) was loaded as Ca(OH) on the tobacco stalk biochar (Ca-BC), which was prepared by high-temperature calcination, ultrasonic treatment, and stirring impregnation method. The phosphorus removal performance of Ca-BC adsorption was studied by batch adsorption experiments, and the mechanism of Ca-BC adsorption and phosphorus removal was investigated by SEM-EDS, FTIR, and XRD. The results showed that after high-temperature calcination, oyster shells became CaO, then converted into Ca(OH) in the process of stirring impregnation and had activated the pore expansion effect of biochar. According to the Langmuir model, the adsorption capacity of Ca-BC for phosphate was 88.64 mg P/g, and the adsorption process followed pseudo-second-order kinetics. The Ca(OH) on the surface of biochar under the initial pH acidic condition preferentially neutralizes with H acid-base in solution, so that Ca-BC chemically precipitates with phosphate under alkaline conditions, which increases the adsorption capacity by 3-15 times compared with other Ca-loaded biochar. Ca-BC phosphate removal rate of livestock wastewater (pig and cattle farms) is 91~95%, whereas pond and domestic wastewater can be quantitatively removed. This study provides an experimental basis for efficient phosphorus removal by Ca-modified biochar and suggesting possible applications in real wastewater.
为了提高 Ca 负载生物炭在较宽 pH 值范围内的磷酸盐吸附能力，将 Ca（牡蛎壳）负载在高温煅烧、超声处理和搅拌浸渍法制备的烟草秸秆生物炭（Ca-BC）上，作为 Ca(OH)。通过批量吸附实验研究了 Ca-BC 吸附的除磷性能，并通过 SEM-EDS、FTIR 和 XRD 研究了 Ca-BC 吸附和除磷的机理。结果表明，高温煅烧后，牡蛎壳变成了 CaO，然后在搅拌浸渍过程中转化为 Ca(OH)，从而激活了生物炭的孔扩张效应。根据 Langmuir 模型，Ca-BC 对磷酸盐的吸附容量为 88.64 mg P/g，吸附过程遵循拟二级动力学。在初始 pH 值为酸性的条件下，生物炭表面的 Ca(OH)优先与溶液中的 H 酸碱中和，从而使 Ca-BC 在碱性条件下与磷酸盐发生化学沉淀，与其他 Ca 负载生物炭相比，吸附容量增加了 3-15 倍。对猪和牛养殖场的牲畜废水的 Ca-BC 除磷率为 91%~95%，而池塘和生活污水则可以定量去除。本研究为 Ca 改性生物炭高效除磷提供了实验基础，并为实际废水处理中的应用提供了可能。
