Design of functionalized adsorbents for simultaneous removal of fluoride and arsenite from waters

合成了一种以苯甲酸(BA)为调节剂的富马酸锆系金属有机骨架材料(MOF)，并详细研究了它们对水中砷氧阴离子(AsO43-和AsO33-)的吸附机理及其吸附前后的稳定性。AsO_4~(3-)和AsO_3~(3-)在Zr-MOF上的相互作用机理为配位交换，由朗缪尔吸附等温式得到AsO_4~(3-)和AsO_3~(3-)的吸附性能最大，分别为1.159和1.121 mm o/g。同样，以苯甲酸(BA)、1，4-苯二元酸(BDC)和1，3，5-苯三甲酸(BTC)为交联剂合成了La基MOF。有趣的是，BA的配体通过酸催化酰胺-水解机理接近La金属生成了La(HCOO)3而不是La-BA MOF，其中La-BDC和La-BTC是MOF，PXRD图谱证实了这一点。这是首次用不同的光谱方法详细研究了AsO43-在La-BA、La-BDC和La-BTC上的吸附及其溶解行为。用Langmuir等温线模型计算得到AsO_4~(3-)对La-BA、La-BDC和La-BTC的最大吸附容量分别为2.623、3.891和0.280 mmoL/g。La-BDC的值被记录为远高于UIO-66的值之一，而不是先前报道的AsO43-TURE DATE的吸附剂。此外，还制备了氧化锆纳米颗粒包埋石墨烯树枝状大分子，并将其用于去除水中有毒的AsO33-。

It was aimed to synthesize a modulator (benzoic acid (BA))-driven zirconium-fumaric acid (Zr-fum) metal-organic frameworks (MOF) and investigated in detail the adsorption mechanism of arsenic oxyanions (AsO43- and AsO33-) and their stability before and after the adsorption from water. The mechanism of AsO43- and AsO33- interaction on Zr-MOF was ligand-exchange and found to be the maximum uptake performance of AsO43- (1.159 mmol/g) and AsO33- (1.121 mmol/g) was obtained by the Langmuir adsorption isotherm. Likewise, it is also synthesized La-based MOFs with the linkers of benzoic acid (BA), 1,4-benzene dicarboxylic acid (BDC) and 1,3,5-benzenetricarboxylic acid (BTC). Interestingly, the ligand of BA approached La metal to form lanthanum methanoate (La(HCOO)3 instead of La-BA MOF through acid catalyst amide-hydrolysis mechanism, where, La-BDC and La-BTC as MOFs, confirmed by PXRD patterns. This is the first report to investigate the AsO43- adsorption and their dissolution behavior over La-BA, La-BDC and La-BTC in detail using the different spectroscopic methods. The maximum adsorption capacities of AsO43- obtained from the Langmuir isotherm model were found to be 2.623 mmol/g, 3.891 mmol/g and 0.280 mmol/g for La-BA, La-BDC and La-BTC, respectively. The value for La-BDC was recorded as one of the much superior, next to UiO-66, to the previously reported adsorbents for AsO43- till date. In addition, the zirconia nanoparticles (ZrO2) embedded graphene oxide dendrimer was prepared and utilized for removal of toxic AsO33- removal from water.