Detection and selective sample clean-up of beryllium(ii) through {extractor-HOMO}(:){Be3O(OH)(2)}(2+) 'ion pair complexation' amidst aluminum(iii) and uranium(vi) by employing a fluorescent resin: the resin's HOMO amount is a quantitative descriptor of BTC

摘要

FSG-PAN, an effective extractor, has been synthesized by chemically immobilizing PAN (1-{2-prydylazo}-2-naphthol) on silica-gel using an efficient silane-coupling-reagent, dimethyldichlorosilane. The corresponding luminescent nanomaterial has been utilized for the selective detection of Be(ii) (LOD 0.75 x 10(-6) mol L-1) amidst natural contaminants. The extractor selectively sorbed beryllium and aluminum (both as aqua-tri-nuclear-species, {Be3O(OH)(2)}(2+) and {Al-3(OH)(3)(H2O)(2)}(6+)), and uranium (as a bi-nuclear-aqua-species, {(UO2)(2)(OH)(2)(H2O)(7)}(2+)) at its highest occupied molecular orbital (HOMO) through HOMO:metal-ion-species 1:1 ion-pair formation. The binding stability of this interaction (0.012 eV mol(-1)/0.28 kcal mol(-1)) lies well below the classical bond energy (104 kcal mol(-1)) of any kind of chemical bond. The HOMO (mol g(-1)) is thus an important quantitative part of the breakthrough capacity (BTC) and is expressed as BTC = {amount of HOMO (mol g(-1)) x x}, where HOMO = 218 mol g(-1) and x = degree of polymerization; here, x = 3 for Be(ii)/Al(iii) and 2 for U(vi). Along with its excellently high BTC and enrichment factor (PF) (BTCBe(II): 645, BTCAl(III): 640, BTCU(VI): 428 mol g(-1); PFBe(II): 93.6, PFAl(III): 90.5, PFU(VI): 91.6), the appreciable durability (reusability 1000 cycles) and remarkable chemical inertness (BTC4MHNO3/H2SO4/HCl 95% at 4 mol L-1 acid-treatment) of the material signify its stability. By exploiting sorption-desorption selectivity, Be(ii) has been sequentially separated (recovery 94.5 +/- 2.5%) from several real and synthetic multicomponent' samples comprising its congeners.