College of Environment, Sichuan Agricultural University, Chengdu 61130, China E-mail:
College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130 Sichuan, China.
Water Sci Technol. 2020 Jun;81(12):2533-2544. doi: 10.2166/wst.2020.309.
We analyzed the effects of pyrolysis temperature and duration on the physiochemical properties and Cd(II) adsorption capacity of spent tea leaves (STL) biochar. The STL biochar was produced by pyrolysis at 300, 400, 500 and 600 °C for 1 and 2 h. The pyrolysis temperature was positively correlated to the ash content, pH, electrical conductivity, specific surface area (S), pore volume (PV) and C content, and negatively with the total yield, O, H and N content, and the O/C and H/C atomic ratios. Furthermore, the surface porosity of STL biochar increased, the density of oxygen-containing functional groups decreased, and the formation of aromatic structures was enhanced at higher pyrolysis temperatures. The adsorption of Cd(II) onto STL biochar fitted with the pseudo-second-order kinetics and Langmuir isotherms model. The STL biochar produced at 600 °C for 2 h showed the maximum Cd(II) adsorption capacity of 97.415 mg/g. In addition, Cd(II) adsorption was mainly physical and occurred in monolayers. Thus, STL biochar is a suitable low-cost adsorbent for wastewater treatment.
我们分析了热解温度和时间对废茶叶（STL）生物炭的物理化学性质和 Cd(II)吸附能力的影响。STL 生物炭是通过在 300、400、500 和 600°C 下热解 1 和 2 小时制得的。热解温度与灰分含量、pH 值、电导率、比表面积（S）、孔体积（PV）和 C 含量呈正相关，与总产率、O、H 和 N 含量以及 O/C 和 H/C 原子比呈负相关。此外，STL 生物炭的表面孔隙率增加，含氧官能团密度降低，芳香结构的形成在较高的热解温度下增强。Cd(II)在 STL 生物炭上的吸附符合准二级动力学和 Langmuir 等温线模型。在 600°C 下热解 2 小时制得的 STL 生物炭对 Cd(II)的最大吸附容量为 97.415mg/g。此外，Cd(II)的吸附主要是物理吸附，发生在单分子层上。因此，STL 生物炭是一种适合废水处理的低成本吸附剂。
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