氨基功能化烟叶生物碳对废水中U(VI)的吸附行为

Adsorption Behavior of Amino-functionalized Tobacco Leaf Biochar on U(VI) in Wastewater

摘要:

以废弃卷烟烟叶为原材料，对其进行碳化处理后再引入氨基功能团制备氨化烟叶生物碳吸附剂(ATC)，研究pH、投加量、温度、吸附时间对ATC吸附U(VI)的影响。通过扫描电镜(SEM)、傅里叶红外光谱(FTIR)、X射线光电子能谱(XPS)等技术进行机理分析。结果表明：在初始浓度为250mg/L、pH=6、投加量为0.2 g/L、温度为40 ℃、吸附时间为210 min，ATC对U(VI)的最大吸附量为495.04mg/g。吸附动力学符合准二级动力学模型；Langmuir吸附等温模型能更好描述ATC对U(Ⅵ)的吸附行为。U(Ⅵ)吸附去除机理主要包括静电相互作用，与氨基(-NH2)、羟基 (-OH)、羧基 (-COOH)的配位络合,与 Si-O-Si的“π-π“相互作用。通过5次吸附-解吸试验发现，U(Ⅵ)去除率在86.71%以上。本研究表明氨化烟叶生物碳具备处理与修复弱酸性含U(Ⅵ)废水污染的潜力。

Abstract:

Using waste cigarettes as raw materials, carbonizing them and then introducing amino functional groups to prepare ammoniated tobacco biocarbon adsorbent (ATC), to study the effects of pH, dosage, temperature, and adsorption time on the adsorption of U(VI) by ATC . The mechanism is analyzed by scanning electron microscopy (SEM), Fourier infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and other techniques. The results show that: when the initial concentration is 250mg/L, pH=6, dosage is 0.2 g/L, temperature is 40 ℃, adsorption time is 210 min, the maximum adsorption capacity of ATC for U(VI) is 495.04mg/g . The adsorption kinetics conforms to the quasi-second-order kinetic model; the Langmuir adsorption isotherm model can better describe the adsorption behavior of ATC on U(Ⅵ). U(Ⅵ) adsorption removal mechanism mainly includes electrostatic interaction, coordination and complexation with amino (-NH2), hydroxyl (-OH), carboxyl (-COOH), and the "π-π" interaction of Si-O-Si effect. Through 5 adsorption-desorption tests, it is found that the U(Ⅵ) removal rate is above 86.71%. This study shows that ammoniated tobacco leaf biochar has the potential to treat and repair the pollution of weakly acidic wastewater containing U(Ⅵ).