化学修饰甘薯渣对碱性品红的吸附特性

Adsorption Characteristics of Alkali Fuchsia by Sweet Potato Dregs by Chemical Modification

摘要:

以废弃甘薯渣为原料，经化学修饰处理得到了改性甘薯废渣生物吸附剂，并将用于对水溶液中印染物质碱性品红的吸附。针对改性甘薯渣加入量、粒径、碱性品红溶液初始浓度、溶液pH、吸附温度、吸附时间各因素对吸附率的影响进行实验，对影响显著的碱性品红初始浓度、改性甘薯渣加入量、吸附时间采用二次正交旋转组合设计优化，得碱性品红初始浓度200 mg/L、改性甘薯渣加入量0.8 g、吸附时间140 min时模拟预测最大吸附率97.66%，同条件下实测97.38%，二者吻合。吸附平衡试验表明甘薯渣吸附剂对碱性品红吸附符合Langmuir和Frundlich模型，其最大吸附量为37.17 mg/g。吸附动力学可用准二级动力学方程描述。BET及SEM表征分析可知改性甘薯渣优化后表面疏松多孔，且褶皱增多，有利于吸附过程进行。经FT-IR与EDS得知，羟基(-OH)、羧基(-COOH)在吸附过程中起到主要作用。

Abstract:

The modified sweet potato residue biosorbent was obtained by chemically modifying the waste sweet potato residue as raw material, and it was used for the adsorption of the basic fuchsin of the printed matter in the aqueous solution. Effects of modified sweet potato slag addition amount, particle size, initial concentration of basic fuchsin solution, solution pH, adsorption temperature and adsorption time on the adsorption rate were investigated. The initial concentration, addition amount and time showed significant effects. By using quadratic orthogonal rotating combination design, the optimum initial concentration, addition amount and time were determined as 200 mg/L, 0.8 g and 140 min, respectively. The measured adsorption rate was 97.38%, which is similar to the predicted maximum value of 97.66%. The adsorption equilibrium test showed that the adsorption of sweet potato residues on basic fuchsin was consistent with Langmuir and Frundlich model, and the maximum adsorption capacity was 37.17 mg/g. The adsorption kinetics can be described by quasi - second order kinetic equations. BET test and SEM observation showed that the modified sweet potato residue was optimized for porous surface and increased wrinkles, which was beneficial to the adsorption process. According to FTIR and EDS, hydroxyl and carboxyl groups play major roles in the adsorption process.