Studies on castor seed shell as a sorbent in basic dye contaminated wastewater remediation
Studies on castor seed shell as a sorbent in basic dye contaminated wastewater remediation
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DOI：
10.1016/j.desal.2007.06.025
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发表时间：
2008-07
期刊：
影响因子：
9.9
通讯作者：
N. A. Oladoja;C. Aboluwoye;Y. Oladimeji;A. O. Ashogbon;I. Otemuyiwa
中科院分区：
文献类型：
--
作者：
N. A. Oladoja;C. Aboluwoye;Y. Oladimeji;A. O. Ashogbon;I. Otemuyiwa
研究了蓖麻籽壳（CSS）对碱性染料亚甲基蓝（MB）污染水体的修复潜力。将CSS研磨并彻底清洗，以去除任何可水提取的成分。将干燥后的CSS重新研磨、筛分，并进行了一系列的搅拌批量吸附实验。通过实验考察了初始MB浓度和CSS投加量对吸附过程的影响。采用Freundlich和Langmuir两种常用的等温线模型研究了平衡吸附等温线。等温线研究结果表明，吸附过程发生在CSS的非均相表面。Langmuir图显示，CSS的吸附量为158 mg/g。采用拉格伦准一级动力学模型和化学吸附准二级动力学模型研究了吸附过程的传质特性。吸附过程更符合准二级动力学模型，而非准一级动力学模型；利用该动力学模型进一步分析了吸附过程的机理。应用颗粒内扩散模型确定的速率限制步骤表明，颗粒内扩散并不是MB吸附到CSS上的单一速率限制步骤。通过拟二级速率常数K与初始MB浓度之间的经验关系，确定了化学吸附在吸附机理中的作用。这一关系的结果表明，伪二级化学吸附在吸附过程中起着重要作用。
The potentialities of castor seed shell (CSS), a waste agricultural by-product, in the remediation of water, contaminated with Methylene Blue (MB), a basic dye, were investigated in the present study. The CSS was ground and washed, thoroughly, to remove any water extractable constituents. The dried CSS was reground, sieved and used in series of agitated batch adsorption experiments. The experiments were conducted to assess the effect of two process variables i.e. initial MB concentration and CSS dosage on the sorption process. The equilibrium sorption isotherm was studied using the two widely used isotherm models (i.e. Freundlich and Langmuir isotherm models). The results from the isotherm studies showed that the process of sorption of MB occurred on a heterogeneous surface of the CSS. The sorption capacity of the CSS, as obtained from the Langmuir plot was 158 mg/g. The mass transfer property of the sorption process was studied using Lagergren pseudo-first-order and chemisorptions pseudo-secondorder kinetic models. The sorption process obeyed the pseudo-second-order kinetic model more than the pseudo-first order; hence the mechanism of the sorption process was analysed further using this kinetic model. The application of the intraparticle diffusion model to determine the rate limiting step showed that intraparticle diffusion is not the singular rate limiting step in the sorption of MB onto CSS. The role of chemisorptions in the mechanism of sorption was established by an empirical relationship between the pseudo-second-order rate constant, K, and the initial MB concentration. The results of this relationship showed that pseudo-second-order chemisorptions are important in the sorption process.