氧化镁改性生物炭的制备及其对阿魏酸的吸附作用

Preparation of Magnesium Oxide Modified Biochar and Its Adsorption of Ferulic Acid

摘要:

该文以甘蔗渣为原料，通过优化煅烧条件制得吸附性能较好的生物炭，并引入镁盐制备氧化镁改性生物炭。采用电子扫描电镜（Scanning Electron Microscope, SEM）、能谱仪（Energy Dispersive Spectrometer，EDS）、X射线衍射（X-ray Diffraction, XRD）和红外光谱（Infrared Spectroscopy, FT-IR）和比表面积和空隙度分析仪（Specific Surface area and Porosity Analyzer，BET）表征。以对阿魏酸蔗糖溶液的吸附率为评价指标，探讨溶液pH值、吸附温度、吸附时间、吸附剂用量四个单因素最佳吸附条件。采用吸附动力学模型和热力学模型实验对数据进行拟合，探究其吸附行为。结果表明：在炭化温度600℃、炭化时间2 h下制得的生物炭吸附性能最佳；通过SEM、EDS、XRD、FT-IR和BET可知生物炭表面成功负载镁元素且孔结构发生了较大的变化，比表面积和空隙率大，吸附能力强；单因素实验测得的最佳条件为pH值为5.5、温度75℃、搅拌时间120 min、吸附剂用量150.00 mg；改性后生物炭对阿魏酸蔗糖溶液的吸附率为42.01%，相较于未改性生物炭29.01%及大孔树脂22.09%的吸附率有较大提升且吸附行为以多分子层的化学吸附为主。由此可见，氧化镁改性生物炭作为清净剂在糖汁澄清工艺中具有一定的应用前景。

Abstract:

In this paper, bagasse was used as raw material to produce biochar with adsorption properties by optimizing the calcination conditions, and magnesium oxide-modified biochar was prepared by introducing magnesium salt. The biochar was characterized by Scanning Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS), X-ray Diffraction (XRD), Infrared Spectroscopy (FT-IR) and Specific Surface area and Porosity Analyzer(BET).The adsorption rate on ferulic acid sucrose solution was used as the evaluation index to explore the four one-factor adsorption conditions: solution pH, adsorption temperature, adsorption time, and adsorbent dosage. Adsorption kinetic model and thermodynamic model experiments were used to fit the data and explore the adsorption behavior. The results showed that the best adsorption performance of the biochar produced at a carbonization temperature of 600℃ and a carbonization time of 2 h; SEM; EDS, XRD, FT-IR and BET showed that the surface of the biochar was successfully loaded with magnesium and the pore structure has changed greatly, with large specific surface area and void ratio, and strong adsorption capacity; the best conditions measured in the one-way experiment were pH 5.5, temperature 75℃, stirring time 120 min, and adsorbent dosage 150.00 mg; the adsorption rate of modified biochar on ferulic acid sucrose solution was 42.01%, which is a big improvement compared with the adsorption rate of unmodified biochar 29.01% and that of the macroporous resin 22.09%, and the adsorption behavior was dominated by the chemical adsorption of the multimolecular layer. Thus, magnesium oxide-modified biochar has a certain application prospect as a scavenger in the sugar juice clarification process.