研究报告

  • 饶本强,张少丽,李勇,郭秀梅,李慧娟,王婷婷,陈玉平.PVA-膨润土包埋固定化荒漠丝状蓝藻复合体的制备及其对Cu(Ⅱ)的吸附特性[J].环境科学学报,2020,40(11):3939-3949

  • PVA-膨润土包埋固定化荒漠丝状蓝藻复合体的制备及其对Cu(Ⅱ)的吸附特性
  • Preparation and characterization of bio-composite by immobilizing desert cyanobacteria with PVA-bentonite for Cu(Ⅱ) sorption
  • 基金项目:国家自然科学基金(No.U1404305);国家大学生创新训练项目(No.201610477009);信阳师范学院大学生科研基金重点项目(No.2014-DXS-139);信阳师范学院大学生科研基金项目(No.2017-DXS-143)
  • 作者
  • 单位
  • 饶本强
  • 信阳师范学院生命科学学院, 信阳 464000
  • 张少丽
  • 信阳师范学院生命科学学院, 信阳 464000
  • 李勇
  • 信阳师范学院化学化工学院, 信阳 464000
  • 郭秀梅
  • 信阳师范学院生命科学学院, 信阳 464000
  • 李慧娟
  • 信阳师范学院生命科学学院, 信阳 464000
  • 王婷婷
  • 信阳师范学院生命科学学院, 信阳 464000
  • 陈玉平
  • 信阳师范学院生命科学学院, 信阳 464000
  • 摘要:利用聚乙烯醇、膨润土包埋固定一种广泛分布的荒漠丝状蓝藻——具鞘微鞘藻,通过正交试验考察了聚乙烯醇(PVA)、膨润土、蓝藻藻粉和交联时间等用于复合材料制备的最佳参数配比,并研究了这种复合材料对Cu2+的吸附特性.结果表明,PVA-膨润土-蓝藻复合固定化小球(MIBB)最佳制备条件为PVA 8%、膨润土2%、蓝藻3 g·L-1、交联时间12 h,此条件下吸附率高达99.12%.单因素吸附实验表明,MIBB吸附Cu2+的最佳条件为投加量4%、pH 5.5、温度30℃,MIBB对Cu2+的吸附率随着Cu2+初始浓度的增加而降低,吸附量则随Cu2+初始浓度的增加而升高;整个吸附过程可分为快速吸附(前8 h)和慢速积累与吸附平衡(8~24 h)两个阶段.相比于蓝藻小球(CB)、膨润土小球(BB)和空白对照小球(CKB),MIBB对Cu2+具有更好的吸附性能.吸附等温模型拟合发现,MIBB对Cu2+的吸附符合Langmuir、Freundlich和Temkin等温方程,Langmuir方程拟合最好,说明吸附过程是典型的单分子层吸附,最大拟合吸附量为125.313 mg·g-1.吸附动力学模型拟合表明,MIBB对Cu2+的吸附过程可用Lagergren准二级动力学方程描述,而颗粒内扩散动力学曲线表明吸附过程经过弯曲、线性和平衡3个阶段.表征分析表明,MIBB吸附反应改变了固定化小球的超微结构,并发生了基团的化学位移和结合能变化.吸附-解吸附表明,MIBB重复利用率高、可有效回收利用.
  • Abstract:This study aimed to investigate the ability of Microcoleus Vaginatus (one species of desert cyanobacteria) immobilized into bentonite beads (MIBB) to remove Cu(Ⅱ) in aqueous solution. Polyvinyl alcohol (PVA) and calcium-based bentonite were used to immobilize the desert cyanobacterial powder to prepare bio-composite sorbents. We used orthogonal experiment to investigate the optimum matching ratios of PVA concentration, algal powder dosage, bentonite content and cross-linking time on adsorption of copper ions by the immobilized beads. The optimal preparation conditions were as follows: PVA mass fraction of 8%, bentonite mass fraction of 2%, algal powder dosage of 3 g·L-1, cross-linking time of 12 h, respectively. Under the preparation condition, the adsorption rate could reach to 99.12%. The effects of adsorbent dosage, pH, temperature, contact time and initial Cu(Ⅱ) concentration on the removal of Cu(Ⅱ) were studied by using batch adsorption experiments. The results showed that the best adsorption conditions of MIBB were: bead dosage mass fraction 4%, pH 5.5 and temperature 30 ℃. Cu2+ adsorption rates by MIBB decreased with the increasing initial concentration of Cu2+, but adsorption capacities of Cu2+ increased with the increasing initial concentration of Cu2+. The whole adsorption process included rapid adsorption (before 8 h) and slow accumulation and equilibrium (within 8~24 h). Compared to cyanobacterial beads (CB), bentonite beads (BB) and control check beads (CKB), MIBB had higher efficiency on Cu (II) removal. Based on the isothermal adsorption properties, it showed that the equilibrium curve could be described by Langmuir model, Freundlich model and Temkin model, but the Langmuir isotherm model was proved to better fit the equilibrium data than other two isotherm models. The maximum adsorption capacity was 125.313 mg·g-1. The kinetic process of Cu2+ adsorption on MIBB was well fitted by the Lagergren pseudo-second-order model, and results showed that there were chemical reactions occurring during the adsorption of Cu(Ⅱ) by MIBB. Moreover, intraparticle diffusion model showed that the whole adsorption process had an initial curve portion, followed by a linear portion and an equilibrium region. Characterization analysis results showed that there were structure changes after Cu2+ adsorption by MIBB and meanwhile there were some chemical shifts of groups and binding energy changes during adsorption process. Finally, the desorption result showed that MIBB could be recycled effectively.

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