Department of Civil and Environmental Engineering , University of Sharjah, United Arab Emirates.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2013;48(2):223-31. doi: 10.1080/10934529.2012.717820.
This study was part of a larger effort that involves evaluating alternatives to upgrading secondary treatment systems in the United Arab Emirates for the removal of nutrients. In this study, six modified bentonite (BNT) phosphate adsorbents were prepared using solutions that contained hydroxy-polycations of aluminum (Al-BNT), iron (Fe-BNT), and mixtures of aluminum and iron (Al-Fe-BNT). The adsorption kinetics and capacities of the six adsorbents were evaluated, and the adsorbents were used to remove phosphorus from synthetic phosphate solutions and from treated wastewater. The experimental adsorption kinetics results were well represented by the pseudo-second-order kinetic model, with R(2) values ranging from 0.99 to 1.00. Similarly, the experimental equilibrium adsorption results were well represented by the Freundlich and Langmuir isotherms, with R(2) values ranging from 0.98 to 1.00. The adsorption capacities of the adsorbents were dependent on the BNT preparation conditions; the types, quantities and combination of metals used; BNT particle size; and adsorption pH. The Langmuir maximum adsorption capacities of the six adsorbents ranged from 8.9-14.5 mg P/g-BNT. The results suggested that the BNT preparations containing Fe alone or in combination with Al achieved higher adsorption capacities than the preparations containing only Al. However, the Al-BNT preparations exhibited higher adsorption rates than the Fe-BNT preparation. Three of the six adsorbents were used to remove phosphate from secondarily treated wastewater samples, and the removal results were comparable to those obtained using synthetic phosphate solutions. The BNT adsorbents also exhibited adequate settling characteristics and significant regeneration potential.
本研究是评估阿拉伯联合酋长国升级二级处理系统以去除营养物替代方案的更大努力的一部分。在本研究中，使用含有羟基多阳离子的溶液制备了六种改性膨润土（BNT）磷酸盐吸附剂，所述溶液包含铝（Al-BNT）、铁（Fe-BNT）和铝和铁的混合物（Al-Fe-BNT）。评估了六种吸附剂的吸附动力学和容量，并使用吸附剂从合成磷酸盐溶液和处理后的废水中去除磷。实验吸附动力学结果很好地由伪二阶动力学模型表示，R(2)值范围从 0.99 到 1.00。同样，实验平衡吸附结果很好地由 Freundlich 和 Langmuir 等温线表示，R(2)值范围从 0.98 到 1.00。吸附剂的吸附容量取决于 BNT 的制备条件、使用的金属的类型、数量和组合、BNT 粒径和吸附 pH 值。六种吸附剂的 Langmuir 最大吸附容量范围为 8.9-14.5 mg P/g-BNT。结果表明，单独含有 Fe 或与 Al 结合的 BNT 制备物比仅含有 Al 的制备物具有更高的吸附容量。然而，Al-BNT 制剂的吸附速率高于 Fe-BNT 制剂。六种吸附剂中的三种被用于去除二级处理废水样品中的磷酸盐，去除结果与使用合成磷酸盐溶液获得的结果相当。BNT 吸附剂还表现出足够的沉降特性和显著的再生潜力。
