Facile fabrication of Fe/Zr binary MOFs for arsenic removal in water:High capacity,fast kinetics and good reusability

A water-stable bimetallic Fe/Zrmetal-organic framework[UiO-66(Fe/Zr)]for exceptional decontamination of arsenic in water was fabricated through a facile one-step strategy.The batch adsorption experiments revealed the excellent performances with ultrafast adsorption kinetics due to the synergistic effects of two functional centers and large surface area(498.33 m^(2)/g).The absorption capacity of UiO-66(Fe/Zr)for arsenate[As(V)]and arsenite[As(III)]reached as high as 204.1 mg/g and 101.7 mg/g,respectively.Langmuir model was suitable to describe the adsorption behaviors of arsenic on UiO-66(Fe/Zr).The fast kinetics(adsorption equilibrium in 30min,10mg/L As)and pseudo-second-ordermodel implied the strong chemisorption between arsenic ions and UiO-66(Fe/Zr),which was further confirmed by DFT theoretical calculations.The results of FT-IR,XPS analysis and TCLP test demonstrated that arsenic was immobilized on the surface of UiO-66(Fe/Zr)through Fe/Zr-O-As bonds,and the leaching rates of the adsorbed As(III)and As(V)from the spent adsorbent were only 5.6%and 1.4%,respectively.UiO-66(Fe/Zr)can be regenerated for five cycles without obvious removal efficiency decrease.The original arsenic(1.0mg/L)in lake and tapwater was effectively removed in 2.0 hr[99.0%of As(III)and 99.8%of As(V)].The bimetallic UiO-66(Fe/Zr)has great potentials in water deep purification of arsenic with fast kinetics and high capacity.

Microwave-assisted continuous flow phytosynthesis of silver nanoparticle/reduced graphene oxide composites and related visible light catalytic performance

The creation of an environmentally friendly synthesis method for silver nanomaterials(Ag-NPs)is an urgent concern for sustainable nanotechnology development.In the present study,a novel straightforward and green method for the preparation of silver nanoparti-cle/reduced graphene oxide(AgNP/rGO)composites was successfully developed through the combination of phytosynthesis,continuous flow synthesis and microwave-assistance.Oriental persimmon(Diospyros kaki Thunb.)extracts were used as both plant reducing and capping agents for fast online synthesis of AgNP/rGO composites.The experimental param-eters were optimized and the morphologies of the prepared materials were investigated.The characterization results reveal that spherical AgNPs were quickly synthesized and uni-formly dispersed on rGO sheets using the proposed online system.Fourier transform in-frared spectroscopy analysis confirmed that phenols,flavonoids,and other substances in the plant extracts played a decisive role in the synthesis of AgNP/rGO composites.Using sodium borohydride(NaBH4)degradation of p-nitrophenol(4-NP)as a model,the catalytic activity of the prepared AgNP/rGO materials was evaluated.The complete degradation of 4-NP was achieved within 12 min through the use of AgNP/rGO materials,and the compos-ite had a much better catalytic activity than the bare AgNPs and rGO had.Compared with the conventional chemical method,our online method is facile,fast,cost-efficient,and en-vironmentally friendly.