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首页> 外文学位 >Adsorption characteristics and isotherm models for single and binary metal ion solutes in aqueous solutions onto activated carbon produced from pecan shells.
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Adsorption characteristics and isotherm models for single and binary metal ion solutes in aqueous solutions onto activated carbon produced from pecan shells.

机译：山核桃壳产生的活性炭对水溶液中的单一和二元金属离子溶质的吸附特性和等温线模型。

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Activated carbon with a high adsorption capacity for removal of metal ions from aqueous solution is produced from pecan shells by air/phosphoric acid activation. Based on the characterization results, it has been determined that the surface of the carbon is covered with a considerable concentration of phosphorus, present in the form of various functional groups. It is proposed that the acidic groups detected by using the Boehm titration method not only be considered as oxygen containing acidic groups, but also as oxygen/phosphorus groups. It is demonstrated that a minimum surface area is required, in addition to the proper surface functionalities, for a high metal ion uptake.; In the adsorption studies of single solute metal ions onto activated carbon, it is found that in most cases higher electronegativities and stability constants correspond to the higher adsorption levels. A correlation is developed that predicts the constants of Freundlich equation from the material parameters of the metal ions, and thus can predict the adsorption isotherms. A procedure is proposed for obtaining similar correlations for different conditions (temperature, pH, carbon type and dosage).; The ratio of equivalent metal ion adsorbed to proton released is calculated and it is found that in most cases, particularly at low concentrations, this ratio is close to one, suggesting the ion exchange of one proton with one equivalent metal ion as the dominant reaction mechanism.; The adsorption behavior of Cu(II) and Mn(II) in the presence of other metal ions that display strong or intermediate affinities for adsorption sites has been systematically investigated. In this investigation the following factors have been considered: (1) metal ion site competition; (2) charge accumulation near the carbon surface; and (3) speciation of the metal ions.; Two multicomponent adsorption models are proposed, and the results compared to two models presented in the literature. The performance of these models is evaluated by an analysis of error. It is found that models with three interaction parameters generally provide a better fit of the data. In most cases, the proposed two-parameter model gives acceptable results.
机译：从山核桃壳中通过空气/磷酸活化可生产出具有高吸附能力的活性炭，可从水溶液中去除金属离子。基于表征结果，已经确定碳的表面被相当大浓度的磷覆盖，磷以各种官能团的形式存在。提出通过Boehm滴定法检测的酸性基团不仅被认为是含氧酸性基团，而且被认为是氧/磷基团。已经证明，除了适当的表面功能性以外，还需要最小的表面积以实现高金属离子吸收。在单个溶质金属离子在活性炭上的吸附研究中，发现在大多数情况下，较高的电负性和稳定性常数对应于较高的吸附水平。建立了一种相关性，该相关性根据金属离子的材料参数来预测Freundlich方程的常数，从而可以预测吸附等温线。提出了一种在不同条件（温度，pH，碳类型和剂量）下获得相似相关性的程序。计算了吸附的当量金属离子与质子释放的比率，发现在大多数情况下，特别是在低浓度下，该比率接近于1，表明一个质子与一种当量金属离子的离子交换是主要的反应机理。;已经系统地研究了在显示强或中等亲和力的其他金属离子存在下，Cu（II）和Mn（II）的吸附行为。在这项调查中，考虑了以下因素：（1）金属离子位点竞争; （2）碳表面附近的电荷积聚; （3）金属离子的形态。提出了两种多组分吸附模型，并将结果与​​文献中提出的两种模型进行了比较。这些模型的性能通过误差分析进行评估。发现具有三个交互参数的模型通常可以更好地拟合数据。在大多数情况下，建议的两参数模型给出了可接受的结果。

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