化工进展 ›› 2020, Vol. 39 ›› Issue (2): 776-789.DOI: 10.16085/j.issn.1000-6613.2019-0788

• 资源与环境化工 • 上一篇    下一篇

FeCl3和十六烷基三甲基溴化铵改性赤泥对水中铜离子的吸附性能和机理

刘江龙(),郭焱(),席艺慧   

  1. 西安交通大学环境科学与工程系,陕西 西安 710049
  • 收稿日期:2019-05-14 出版日期:2020-02-05 发布日期:2020-03-12
  • 通讯作者: 郭焱
  • 作者简介:刘江龙(1995—),男,硕士研究生,研究方向为废水处理及固体废弃物资源化处理技术。E-mail:245650606@qq.com

Adsorption and mechanism of copper ions in water by red mud modified with FeCl3 and hexadecyl trimethyl ammonium bromide (CTAB)

Jianglong LIU(),Yan GUO(),Yihui XI   

  1. Department of Environmental Engineering and Technology, Xi’an Jiaotong University, Xi’an 710049, Shaanxi, China
  • Received:2019-05-14 Online:2020-02-05 Published:2020-03-12
  • Contact: Yan GUO

摘要:

含铜废水主要来自电镀、有色冶炼、有色金属矿山开采、染料生产等过程。因Cu(Ⅱ)具有高毒性和生物富集性,严重威胁生态环境和人类健康。利用浓盐酸、三氯化铁(FeCl3)、十六烷基三甲基溴化铵(CTAB)依次对拜耳法赤泥(RM)进行处理、改性,制备出了一种去除率高、吸附量大、吸附效果好的重金属离子吸附剂。通过SEM、TEM、XRD、BET、元素分析、FTIR、热重分析等手段对其进行表征,并探究溶液pH、吸附剂投加量以及吸附温度等条件对水溶液中Cu(Ⅱ)吸附效果的影响。结果表明:酸浸赤泥(RM-HCl)比表面积比RM增大20倍,经过FeCl3和CTAB改性后赤泥表面负载了大量羟基氧化铁(FeOOH)并且改善了吸附材料的表面性质,提高了吸附材料与Cu(Ⅱ)之间的亲和力和单层吸附能力。综合改性赤泥(FeCl3/CTAB/RM)对铜的吸附时间在100min达到平衡,其最佳吸附pH为6、最佳吸附剂投加量为2g/L、饱和吸附量为221mg/g。吸附过程较好地符合准二级动力学模型和Langmuir吸附等温模型,热力学数据说明该吸附是吸热、自发的过程。吸附机理主要是FeCl3/CTAB/RM表面的羟基(Si-OH、α-FeOOH和β-FeOOH)以及掺杂的氯原子和表面活性剂,通过物理吸附(微胶束、静电引力)和化学吸附(离子交换、氢键)有效地去除Cu(Ⅱ)离子。

关键词: 重金属, 赤泥, 吸附, 综合改性, 羟基氧化铁, 表面活性剂

Abstract:

Copper-containing wastewater mainly comes from electroplating, non-ferrous smelting, non-ferrous metal mining, dye production and other processes. Due to its high toxicity and bioaccumulation, Cu(Ⅱ) is a serious threat to the ecological environment and human health. In this paper, concentrated red hydrochloric acid, ferric chloride (FeCl3), hexadecyl trimethyl ammonium bromide (CTAB) were used to treat and modify Bayer red mud (RM), and a high removal rate was prepared. It was characterized by SEM, TEM, XRD, BET, elemental analysis, FTIR, thermogravimetric analysis, etc., and the effects of solution pH, adsorbent dosage and adsorption temperature on the adsorption of Cu(Ⅱ) in aqueous solution were investigated. The results showed that the specific surface area ratio of acid-immersed red mud (RM-HCl) was increased by 20 times. After modification by FeCl3 and CTAB, the surface of red mud was combined with a large amount of hydroxyl oxidize iron (FeOOH) and improved the surface properties of the adsorbent as well as affinity and single layer adsorption capacity between adsorbent material and Cu(II). The adsorption time of copper by comprehensive modified red mud (FeCl3/CTAB/RM) reached equilibrium at 100min, the optimum adsorption pH was 6, the optimal adsorbent dosage was 2g/L, and the saturated adsorption amount was 221mg/g. The adsorption process was in good agreement with the quasi-secondary kinetic model and the Langmuir adsorption isotherm model. The thermodynamic data indicated that the adsorption is an endothermic and spontaneous process. The adsorption mechanism is mainly the grafting of hydroxyl groups (Si-OH, α-FeOOH and β-FeOOH) on FeCl3/CTAB/RM surface and doped chlorine atoms and surfactants. It effectively removed Cu(Ⅱ) by physical adsorption (chelation, electrostatic attraction) and chemical adsorption (ion exchange, hydrogen bonding).

Key words: heavy metal, red mud, adsorption, comprehensive modification, hydroxyl oxidize iron, surfactant

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