By using multivariate strategy, a series of multivariate UiO-66-type metal−organic frameworks with mixed 1,4-benzendicarboxylic acid (BDC) and 1,2,4,5- benzentetracarboxylic acid (BTC) ligands in different ratio, namely UiO-66-n (COOH)₂ (n = 0, 0.25, 0.50, 0.75 and 1), had been successfully prepared. The products were characterized by ¹H NMR, powder X-ray diffraction, field emission scanning electron microscopy, thermogravimetric analysis, N₂ adsorption-desorption, and zeta potential. It can be observed that with the increase of BTC ratio, the surface area decreases from 1620 to 179 cm³/g, and the zeta potential decreases from 36.11 to −29.78 mV. Therefore, this strategy can effectively regulate the surface area and charge of the frameworks, thereby regulate their adsorption behaviors towards selected dye molecules. In contrast to the pristine UiO-66 that only adsorption anionic dyes, the multivariate MOFs shows an excellent selective dye adsorption to cationic dyes, where the adsorption capacities of MB and RhB on UiO-66-0.25(COOH)₂, UiO-66-0.50(COOH)₂, and UiO-66-0.75(COOH)₂ are 87, 90, 94 mg/g and 84, 47, 46 mg/g, respectively. In addition, the selective adsorption to mixed cationic and anionic dyes (MB and MO) and cationic dyes with different size (MB and RhB) were also achieved by UiO-66-0.25(COOH)₂ and UiO-66-0.75(COOH)₂, respectively. This adsorption selectively is attribute to the electrostatic attraction between the charged surface of MOFs and the dyes, as well as the surface area of the MOFs.

通过使用多元策略，一系列多元UiO-66型金属有机骨架具有不同比例的混合的1,4-苯二甲酸（BDC）和1,2,4,5-苯并四羧酸（BTC）配体，即UiO已成功制备了-66-n（COOH）₂（n = 0、0.25、0.50、0.75和1）。产物通过¹ H NMR，粉末X射线衍射，场发射扫描电子显微镜，热重分析，N ₂吸附-解吸和Zeta电位进行表征。可以观察到，随着BTC比的增加，表面积从1620减少到179 cm ^3。/ g，并且zeta电位从36.11降低到-29.78 mV。因此，该策略可以有效地调节框架的表面积和电荷，从而调节它们对所选染料分子的吸附行为。与仅吸附阴离子染料的原始UiO-66相比，多元MOF在阳离子染料上表现出优异的选择性染料吸附能力，其中MB和RhB在UiO-66-0.25（COOH）₂，UiO-66-上的吸附能力0.50（COOH）₂和UiO-66-0.75（COOH）₂分别为87、90、94 mg / g和84、47、46 mg / g。此外，UiO-66-0.25（COOH）₂还可选择性吸附于混合的阳离子和阴离子染料（MB和MO）以及大小不同的阳离子染料（MB和RhB）。和UiO-66-0.75（COOH）₂。该吸附选择性地归因于MOF的带电表面和染料之间的静电吸引以及MOF的表面积。