Background As a hydrophilic two-dimensional material with oxygen-containing groups on its basal planes, graphene oxide (GO) has been used for the fabrication of GO-based membranes to purify/desalinate water. However, promoting salt rejection of GO-based membranes is challenging while maintaining high water permeability. Methods First, the mercaptoethylamine-modified Ag NWs (Ag-MA) were prepared by mixing Ag NWs and MA to form Ag—S bonds. Then, Ag-MA was deposited on the GO membrane under externally assisted filtration to achieve the GO/Ag-MA membrane, which ensures the well-stacking of GO sheets and the even coating of GO membrane. Therefore, the delicately fabricated membrane possesses great electropositive cations and high swelling-tolerance in water solution. Significant findings We found that a high electrostatic repulsive interaction between the amino group and metal cations in GO/Ag-MA membrane aided the promotion of rejection rates, which was up to 75 % for both K + and Mg 2+ , surpassing that of the previously reported values. This work highlights a new approach for enhancing the electrostatic repulsion with metal cations near the surface/interface of GO-based membranes and their application in the development of water desalination and purification.
Liang Zhao,Guoying Yao,Huai Chen,Tao Zeng,Zhenyu Yang
Hybrid metal halide perovskites have attracted significant attention due to their outstanding chemical and structural versatility. Incorporating additional building blocks, such as large organic groups and organometallic clusters, provides additional pathways to manipulate the optoelectronic properties of perovskites. However, the bulky building blocks often struggle to cocrystallize with the lead halide framework, leading to undesirable crystal phase segregation or component exchange during cocrystallization. Here, we introduce a new zwitterionic-ligand-driven method for incorporating Cu-based clusters into perovskites. Mercaptoethylamine (MEA) serves as the bifunctional ligand to bridge the Cu(I) tetrahedral moieties and the perovskite scaffold, yielding a new bimetallic structure (MEA)4Cu2Pb3Br12. Combined X-ray-based characterizations and charge analysis affirm the antiferromagnetic coupling between the [CuS2Br2] tetrahedra, where the spin density is localized on the S atoms in a diradical form. The inclusion of Cu-based clusters introduces new acceptor energy levels that facilitate photocarrier separation and enable near-infrared light absorption.
Xi Chen,Qian Huang,Shuyan Ruan,Feili Luo,Ruiyun You,Shangyuan Feng,Lanjin Zhu,Yang Wu,Yudong Lu
Hyaluronidase expression is known to be upregulated in various pathological conditions. A method based on a combination of ratiometric surface-enhanced Raman scattering (SERS) and magnetic separation is described for the determination of hyaluronidase (HAase) activity. Gold nanospheres (AuNPs) functionalized by 4-mercaptophenylboronic acid (4-MPBA) form stable cyclic esters with diol on hyaluronic acid (HA) by the boronic acid group, while Fe 3 O 4 @ [email protected] modified with mercaptoethylamine (MEA) was used as a capture substrate to bind to the carboxyl group on the surface of HA, forming the “ [email protected] @HA/Fe 3 O 4 @ [email protected] @MEA” “core-satellite” structure. When HAase is present, HA is enzymatically disrupted, resulting in the destruction of the “core-satellite” structure, the SERS signal of 4-MPBA is subsequently weakened. The gold shell in the substrate protects the 5,5′-Dithio bis-(2-nitrobenzoic acid) (DTNB) from the external environment, which makes it become an ideal internal standard (IS) molecule for subsequent calibration. Under optimal conditions, the I 1075 /I 1324 varied in the range of 10 −3 - 10 U‧mL −1 HAase activity, with a limit of detection (LOD) of 0.32 mU‧mL −1 ，below the level of HAase in normal human body fluids. This method has been successfully applied to the determination of HAase activity in urine and is expected to provide a new method in disease detection, especially in the non-invasive detection of bladder cancer.
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