Xiaoxia Ye,Zhihong Zheng,Jinwei Zhu,Jie Chen,Jianfei Zhou,Bi Shi
Adsorptive removal of mercury ion from wastewater has become a hot topic due to the toxicity and persistence; acquiring adsorbent materials with high-capacity, rapid-kinetic, super-selective while low-cost features are highly demanded. Herein, based on the full functionality of collagen fiber (CF) from the leather waste, we proposed an innovative synthetic approach through exploiting amino-functionalized ZIF-7 (ZIF-7-NH 2 ) as functional groups to facilely in-situ incorporate with CF, affording low-cost but effective adsorbent materials of CF/ZIF-7-NH 2 composite maximizing both functions of CF and ZIF-7-NH 2 in the Hg(II) capture. Remarkably, it exhibits an ultra-high capacity as high as 909.09 mg g - 1 , fast kinetics that could remove 99.01 % of 200 mg·L -1 within 20 min, and significant selectivity of S Hg/M ( K d Hg / K d M ) as large as 522–1017 over Mg 2+ , K + , Ca 2+ , Cd 2+ , and Mn 2+ . We understand such an impressive adsorption is contributed by the synergistic action between functional groups including on the CF and ZIF-7-NH 2 . This study offers an effective method for removing heavy metal ions, achieving efficient removal of Hg(II) ions for pollution control, and promoting the reuse of waste CF to reduce waste accumulation in various aspects.
Junfeng Qian,Tingting Wu,Jianqun Shi,Hao Chang,Donghui Liu,Yichang Pan
Membrane-based technology is an attractive alternative in terms of CO 2 separation. Pebax-based membranes are regarded as potential candidates for CO 2 separation due to the favorable interaction between its poly (ethylene oxide) chains with CO 2 molecules and inorganic fillers. However, the separation performance for CO 2 /CH 4 mixture is still suffered from the moderate gas permeability and selectivity. To overcome this problem, in this work, amino-functionalized zeolite imidazolate framework (ZIF-7-NH 2 ) nanocrystals were used as fillers to blend with Pebax 1657 for fabricating mixed-matrix membranes (MMMs). XRD, Brunauer–Emmett–Teller (BET), scanning electron microscope, and 1 H nuclear magnetic resonance characterization indicated that ZIF-7-NH 2 with the highest crystallinity was synthesized. Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry (DSC), and Young's modulus showed that it has good interfacial interaction. Gas separation test results showed that both the CO 2 permeability and CO 2 /CH 4 selectivity of the 31 wt% ZIF-7-NH 2 /Pebax MMMs increased by 80 and 170%, respectively. The improved performance is attributed to the addition of ZIF-7-NH 2 nanocrystals and the favorable interfacial interactions between the polymer and ZIF-7-NH 2 nanocrystals. Furthermore, the polyvinylidene fluoride supported hollow fiber composite membranes also exhibit the long-term stability for CO 2 /CH 4 separation.
Yang Gao,Yuyang Wang,Yanlin Jiang,Chaojie Bai,Zuoqun Zhang,Yawen Zhao,Congjie Gao,Lixin Xue
To improve interface compatibility between ZIF-7 particles (PTs) and polyamide (PA) and reverse osmosis (RO) performance of thin film nano-composite (TFN) membranes, ZIF-7-NH 2 (x) particles (PTs) with different levels of -NH 2 substitution were synthesized by reacting Zn(NO 3 ) 2 with mixed ligand under different preparation conditions. The impact of their residual surface functional groups (SFGs) on the formation of inter-phase covalent bonds (ICBs) in PA separating layers were investigated relating to the inter-phase compatibility and salt rejection performance of the formed composite RO membranes. Doping ZIF-7-NH 2 PTs with ICBs could avoid the expansion of PA in acidic condition. Surprisingly high chemical stability was observed for ZIF-7-NH 2 PTs wrapped in the PA separating layers in TN membranes in the pH range of 2–13. TN(50)-0.15 membranes with strong ICBs showed 3 times higher water flux of 76 L·m −2 ·h −1 under 5.5 MPa at a high salt rejection of 98.7 %.
A novel hybrid material (ZIF-7-NH 2 @MIP) combining high adsorption capacity of amino-functional zeolitic imidazolate framework and specific recognition ability of dual-template molecular imprinted polymer was synthesized. The prepared ZIF-7-NH 2 @MIP was characterized by a range of instrumental techniques and combined with high performance liquid chromatography for the detection of four phthalate esters. The limits of detection of the four PAEs were below the maximum residue limit of GB 3838-2002 in China, ranging from 0.04 to 0.08 μg L −1 . The recoveries of the three real samples of mineral water , carbonated drinks and pulpy juices spiked at 10 μg L −1 were 88.68–98.58% and the relative standard deviations was 1.19–3.40%. The above results showed that the obtained absorbent exhibited many advantages for extracting analytes in aqueous solution especially complex environment due to the combination of the superior hydrothermal and large specific surface area of the amino-functionalized ZIF-7-NH 2 and the specific identification of the dual-template molecular imprinted polymer.
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