Soltani Roozbeh, Pelalak Rasool, Pishnamazi Mahboubeh, Marjani Azam, Albadarin Ahmad B, Sarkar Shaheen M, Shirazian Saeed
Department of Chemistry, Arak Branch, Islamic Azad University, Arak, Iran.
Institute of Research and Development, Duy Tan University, Da Nang, 550000, Vietnam.
Sci Rep. 2021 Jan 15;11(1):1609. doi: 10.1038/s41598-021-81095-w.
To date, many nanoadsorbents have been developed and used to eliminate heavy metal contamination, however, one of the challenges ahead is the preparation of adsorbents from processes in which toxic organic solvents are used in the least possible amount. Herein, we have developed a new carboxylic acid-functionalized layered double hydroxide/metal-organic framework nanocomposite (LDH/MOF NC) using a simple, effective, and green in situ method. UiO-66-(Zr)-(COOH) MOF nanocrystals were grown uniformly over the whole surface of COOH-functionalized NiCo-LDH ultrathin nanosheets in a green water system under a normal solvothermal condition at 100 °C. The synthesized LDH/MOF NC was used as a potential adsorbent for removal of toxic Cd(II) and Pb(II) from water and the influence of important factors on the adsorption process was monitored. Various non-linear isotherm and kinetic models were used to find plausible mechanisms involved in the adsorption, and it was found that the Langmuir and pseudo-first-order models show the best agreement with isotherm and kinetic data, respectively. The calculated maximum adsorption capacities of Cd(II) and Pb(II) by the LDH/MOF NC were found to be 415.3 and 301.4 mg g, respectively, based on the Langmuir model (pH = 5.0, adsorbent dose = 0.02 g, solution volume = 20 mL, contact time = 120 min, temperature = 25 ℃, shaking speed 200 rpm).
迄今为止，人们已经开发并使用了许多纳米吸附剂来消除重金属污染，然而，未来面临的挑战之一是如何在尽可能少使用有毒有机溶剂的过程中制备吸附剂。在此，我们采用一种简单、有效且绿色的原位方法，开发了一种新型的羧酸官能化层状双氢氧化物/金属有机框架纳米复合材料（LDH/MOF NC）。在100℃的常规溶剂热条件下，在绿色水体系中，UiO-66-(Zr)-(COOH) MOF纳米晶体均匀地生长在COOH官能化的NiCo-LDH超薄纳米片的整个表面上。合成的LDH/MOF NC被用作从水中去除有毒Cd(II)和Pb(II)的潜在吸附剂，并监测了重要因素对吸附过程的影响。使用各种非线性等温线和动力学模型来寻找吸附过程中可能涉及的机制，发现Langmuir模型和准一级模型分别与等温线和动力学数据显示出最佳拟合。基于Langmuir模型（pH = 5.0，吸附剂剂量 = 0.02 g，溶液体积 = 20 mL，接触时间 = 120 min，温度 = 25℃，振荡速度200 rpm），计算得出LDH/MOF NC对Cd(II)和Pb(II)的最大吸附容量分别为415.3和301.4 mg/g。
