Goel Jyotsna, Kadirvelu Krishna, Rajagopal Chitra, Kumar Garg Vinod
Centre for Fire, Explosives and Environment Safety (CFEES), Defence R&D Organisation (DRDO), Brig. S.K. Majumdar Marg, Timarpur, Delhi 110054, India.
J Hazard Mater. 2005 Oct 17;125(1-3):211-20. doi: 10.1016/j.jhazmat.2005.05.032.
In the present study, a deeper understanding of adsorption behavior of Pb(II) from aqueous systems onto activated carbon and treated activated carbon has been attempted via static and column mode studies under various conditions. It probes mainly two adsorbents that is, activated carbon (AC) and modified activated carbon (AC-S). Characterization of both the adsorbents was one of the key focal areas of the present study. This has shown a clear change or demarcation in the various physical and chemical properties of the modified adsorbent from its precursor activated carbon. Both the adsorbents are subjected to static mode adsorption studies and then after a comparison based on isotherm analysis; more efficient adsorbent is screened for column mode adsorption studies. The lead removal increased for sample of treated carbon. The extent of Pb(II) removal was found to be higher in the treated activated carbon. The aim of carrying out the continuous-flow studies was to assess the effect of various process variables, viz., of bed height, hydraulic loading rate and initial feed concentration on breakthrough time and adsorption capacity. This has helped in ascertaining the practical applicability of the adsorbent. Breakthrough curves were plotted for the adsorption of lead on the adsorbent using continuous-flow column operation by varying different operating parameters like hydraulic loading rate (3.0-10.5 m3/(hm2)), bed height (0.3-0.5 m) and feed concentrations (2.0-6.0 mg/l). At the end, an attempt has also been made to model the data generated from column studies using the empirical relationship based on Bohart-Adams model. This model has provided an objective framework to the subjective interpretation of the adsorption system and the model constant obtained here can be used to achieve the ultimate objective of our study that is, up scaling and designing of adsorption process at the pilot plant scale level. AC-S column regeneration using 0.5 and 1.0M concentration of HNO3 has been investigated. It has shown a regeneration efficiency of 52.0% with 0.5 M HNO3.
在本研究中，通过在各种条件下的静态和柱模式研究，试图更深入地了解水体系中Pb(II)在活性炭和处理后的活性炭上的吸附行为。主要研究了两种吸附剂，即活性炭（AC）和改性活性炭（AC-S）。两种吸附剂的表征是本研究的关键重点领域之一。这表明改性吸附剂与其前体活性炭相比，各种物理和化学性质发生了明显变化或界限。两种吸附剂都进行了静态模式吸附研究，然后基于等温线分析进行比较；筛选出更高效的吸附剂用于柱模式吸附研究。处理后的碳样品的铅去除率有所提高。发现处理后的活性炭中Pb(II)的去除程度更高。进行连续流研究的目的是评估各种工艺变量，即床层高度、水力负荷率和初始进料浓度对穿透时间和吸附容量的影响。这有助于确定吸附剂的实际适用性。通过改变不同的操作参数，如水力负荷率（3.0 - 10.5 m³/(hm²)）、床层高度（0.3 - 0.5 m）和进料浓度（2.0 - 6.0 mg/l），使用连续流柱操作绘制了铅在吸附剂上吸附的穿透曲线。最后，还尝试使用基于Bohart-Adams模型的经验关系对柱研究产生的数据进行建模。该模型为吸附系统的主观解释提供了一个客观框架，此处获得的模型常数可用于实现我们研究的最终目标，即在中试规模水平上扩大和设计吸附过程。研究了使用0.5和1.0M浓度的HNO₃对AC-S柱进行再生。结果表明，使用0.5M HNO₃时再生效率为52.0%。
