Search

The preparation of heterogeneous Fenton catalysts with both adsorption and catalytic properties has become an effective strategy for the treatment of refractory organic wastewater. In this work, 4A-Fe@Cu bimetallic Fenton catalysts with a three-dimensional core-shell structure were prepared by a simple, template-free, and surfactant-free methodology and used in the adsorption and degradation of Congo red (CR). The results showed that the open three-dimensional network structure and the positive charge of the surface of the 4A-Fe@Cu catalyst could endow a high adsorption capacity for CR, reaching 432.9 mg/g. The good adsorption property of 4A-Fe@Cu for CR not only did not inactivate the catalytic site on 4A-Fe@Cu but also could promote the contact between CR and the active sites on the catalyst surface and accelerate the degradation process. The 4A-Fe@Cu bimetallic catalyst exhibited higher catalytic activity than monometallic 4A@Cu and/or 4A-Fe catalysts due to low work function value. The effects of different pH, H2O2 dosages, and catalyst dosages on the catalytic performance of 4A-Fe@Cu were explored. In the conditions of 7.2 mM H2O2, 2 g/L 4A-Fe@Cu, and 1 g/L CR solution, the degradation ratio of CR by 4A-Fe@Cu could reach 99.2% at pH 8. This strategy provided guidance to the design of high-performance Fenton-like catalysts with both adsorption and catalysis properties for dye wastewater treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Surface acetates exchange of 2D acetate-based light lanthanide fluoride nanomaterials is evidenced for the first time; • The maximum Langmuir adsorption capacity of these nanosheets for Congo red and Coomassie brilliant blue G-250 is 4334 mg/g and 2827 mg/g, respectively; • These nanosheets show an ultrahigh salt-tolerance in high-salinity wastewater treatment; • Surface acetates exchange is responsible for the ultrahigh adsorption capacity and salt-tolerance. To develop an excellent two-dimensional (2D) adsorbent with an ultrahigh adsorption capacity and salt-tolerance is much of importance in actual wastewater treatment. In this work, 2D acetate-based light lanthanide fluoride nanomaterials (F–Ln nanosheets) are identified as high-efficient adsorbents for anionic dye decoloration. F–Ln nanosheets are prepared through a hydrothermal synthetic methodology at room temperature and pressure. Multiple characterizations demonstrate that surface acetates exchange with exogenous anions is the prominent characteristic of these nanosheets. Adsorption experiments infer that adsorption processes obey a pseudo-second-order kinetics model and a Langmuir isotherm model. The maximum Langmuir adsorption capacity for Congo red and Coomassie brilliant blue G-250 is 4334 mg/g and 2827 mg/g, respectively. The mechanism analysis suggests that surface acetates exchange of F–Ln nanosheets is responsible for their ultrahigh adsorption capacity. Besides, F–Ln nanosheets present an ultrahigh salt-tolerance in saturated NaCl or high-concentration Na 2 SO 4 , K 2 CO 3 and NaNO 3 solution. Computational studies claim that surface acetates exchange with dye anions, which has a higher binding strength than common salts, is the key to induce an ultrahigh salt-tolerance. With an ultrahigh adsorption capacity and salt-tolerance, we believe that F–Ln nanosheets promise an outstanding platform to develop excellent adsorbents for environment remediation. [ABSTRACT FROM AUTHOR]

• Core-shell hierarchical Cu@4A filler was prepared via in situ growth method. • Cu@4A as filler was used to fabricate mixed matrix membrane contactor. • Cu@4A loaded MMMC exhibited 10 times higher SO 2 adsorption capacity than PVDF. • Cu@4A facilitated SO 2 transport and decreased membrane mass transfer resistance. • Cu@4A enhanced both SO 2 absorption flux and SO 2 removal efficiency in MMMC. Achieving high flux membrane contactor is significantly important for hazardous gas removal. In this study, we prepared poly(vinylidene fluoride) (PVDF)-based mixed matrix membrane contactor (MMMC) that contained a core-shell hirarchical Cu@4A composite filler (Cu@4A). On one hand, the Cu@4A regulated the physical structure of MMMC, which enhanced gas permeation and thus resulted in the increment of physical SO 2 absorption flux. On the other hand, Cu@4A changed the chemical environment of MMMC by remarkably increased SO 2 facilitated transport sites, which elevated SO 2 concentration around Cu@4A by the enhancement of adsorption and oxidation of SO 2 , resulting in the increase of chemical SO 2 absorption flux. Moreover, the copper nanosheets on 4A helped to construct facilitated transport pathways along the Cu@4A fillers at polymer-filler interface. The results showed that Cu@4A loaded MMMC exhibited increased SO 2 removal efficiency and SO 2 absorption flux compared with PVDF control membrane. Specifically, the M 10 40 MMMC loaded with 40 wt% Cu@4A and PVDF concentration 10 wt% exhibited the highest SO 2 removal efficiency and SO 2 absorption flux, which was up to 73.6% and 9.1 × 10−4 mol·m-2·s-1 at the liquid flow rate of 30 L/h. Besides, the overall SO 2 mass transfer coefficient (K o) and membrane mass transfer resistance (H / K m) were investigated. [ABSTRACT FROM AUTHOR]