Removal of Toxic Metal Cr ( VI ) from Industrial Wastewater Using Sawdust as Adsorbent : Equilibrium , Kinetics and Regeneration Studies
Removal of Toxic Metal Cr ( VI ) from Industrial Wastewater Using Sawdust as Adsorbent : Equilibrium , Kinetics and Regeneration Studies
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使用锯末作为吸附剂去除工业废水中的有毒金属Cr(VI):平衡、动力学和再生研究
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
B. Babu
中科院分区：
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作者：
Suresh Gupta;B. Babu
铬在自然界中是丰富的，并且与其他重金属离子相比，在大多数流出物流中占主导地位。高毒性和致癌性六价铬（Cr（VI））在废水中的存在是一个主要的环境问题。电镀和制革工业废水是废水流中Cr（VI）生产的主要来源。本文研究了用低成本吸附剂木屑对电镀和制革工业废水中Cr（VI）的去除能力。在本研究中，批量实验进行初始Cr（VI）浓度范围从50 - 500毫克l-1。实验结果表明，木屑吸附剂具有显着的吸附能力的Cr（VI）从废水流。考察了pH值、接触时间、吸附剂用量、Cr（VI）初始浓度等参数对锯末吸附Cr（VI）的影响。木屑对Cr（VI）的最大吸附量在pH 1时达到。木屑对Cr（VI）的吸附平衡时间为1050 min。采用多种吸附等温线模型（例如Langmuir、Freundlich、Redlich-Peterson、Koble-Corrigan、Tempkin、DubininRadushkevich和广义方程）测试了锯末对Cr（VI）的吸附平衡数据。Langmuir等温模型被认为是最适合的Cr（VI）吸附木屑。在pH = 1时，采用Langmuir等温吸附模型得到的最大吸附量为41.5mg g-1。无因次平衡参数RL在0.00453 ~ 0.0435之间（0 < RL < 1），表明木屑吸附剂对Cr（VI）具有良好的吸附性能。采用拟一级动力学模型、二级动力学模型和Elovich模型对木屑吸附Cr（VI）的机理进行了研究。在Cr（VI）初始浓度为100 ~ 400 mg/l范围内，吸附过程符合二级动力学，相应的速率常数为3.39 × 10 - 3 ~ 4.3 × 10 - 4g mg-1（min-1）.采用酸碱处理对木屑中的Cr（VI）进行解吸，解吸率可达95%以上。提出了一种可行的解决方案，为处理污染物（酸和碱溶液）含有高浓度的Cr（VI）在解吸过程中获得。目前的工作还包括影响
Chromium is abundant in nature and has a dominant presence in most of the effluent streams as compared to other heavy metal ions. The presence of highly toxic and carcinogenic hexavalent chromium (Cr(VI)) in effluent streams is a major environmental issue. The electroplating and tannery industry effluents are the major source for the Cr(VI) production in wastewater streams. The present work deals with the determination of Cr(VI) removal capacity from synthetically prepared industrial effluent of electroplating and tannery industries using sawdust which is a low cost adsorbent. In the present study, batch experiments are carried out for an initial Cr(VI) concentration ranging from 50 – 500 mg l -1 . Experimental results demonstrate that the sawdust adsorbent has a significant capacity for adsorption of Cr(VI) from wastewater streams. The effect of various parameters such as pH, contact time, adsorbent amount, and initial Cr(VI) concentration for the adsorption of Cr(VI) on sawdust is investigated. The maximum adsorption of Cr(VI) on sawdust is obtained at pH 1. The equilibrium time obtained is 1050 min for Cr(VI) adsorption on sawdust. The equilibrium data for the adsorption of Cr(VI) on sawdust is being tested with various adsorption isotherm models such as Langmuir, Freundlich, Redlich-Peterson, Koble-Corrigan, Tempkin, DubininRadushkevich and Generalized equation. The Langmuir isotherm model is found to be most suitable for the Cr(VI) adsorption using sawdust. The maximum adsorption capacity obtained using the Langmuir isotherm model is 41.5 mg g -1 at pH 1. The dimensionless equilibrium parameter, RL, signifies a favorable adsorption of Cr(VI) on sawdust adsorbent and is found to be between 0.00453 and 0.0435 (0 < RL < 1). Various kinetic models such as pseudo first-order, second order and Elovich model are used to evaluate the mechanism of adsorption of Cr(VI) on sawdust. The adsorption process follows second order kinetics and the corresponding rate constants, for initial Cr(VI) concentration ranging from 100 – 400 mg/l, is found to be 3.39 × 10 -3 to 4.3 × 10 -4 g mg -1 (min -1 . Desorption of Cr(VI) from sawdust using acid and base treatment exhibit higher desorption efficiency by more than 95%. A feasible solution is proposed, for the disposal of contaminant (acid and base solutions) containing high concentration of Cr(VI) obtained during desorption process. The present work also includes the effect of