Liang Shen,Ming Yi,Lian Tian,Fangqian Wang,Chun Ding,Shipeng Sun,Ang Lu,Li Su,Yan Wang
Membrane-based forward osmosis (FO) technology has attracted increasing interest in the field of water treatment due to its high economical and separation efficiency. However, the availability of a FO membrane with superior separation and antifouling properties is still the critical issue for its real application in wastewater purification. In this work, novel thin-film composite (TFC) membranes are developed by surface ionization with various metal ions and subsequent metallization with the assistance of pre-grafted polyethyleneimine (PEI) and N -containing organic phosphonic acid (OPA), where the latter provides abundant and stable complexing sites. The grafting of hydrophilic PEI/OPA and the attachment of silver atoms endow the resulting membrane a dual defensive and offensive functionality associated with anti-adhesive property and antibacterial activity, respectively. Compared with the control TFC membrane, the surface-modified membranes show significantly improved anti-adhesive property against bovine serum albumin (BSA) and antibacterial property against S. aureus and E. coli bacteria, and thereby improved antifouling property towards the local lake water. Additionally, compared with the silver-metalized TFC membranes prepared by the direct method or indirect PEI binding, the silver-metalized membrane prepared by the indirect OPA binding exhibits a much higher silver loading (34.38 μg/cm 2 ), as well as better, more stable and long-term antibacterial property. Moreover, compared with the control membrane, the modified membranes also have much higher water fluxes (87–141% increase) and comparable or even lower reverse salt fluxes. The influences of the metal ion type used for ionization and the method used for metallization are systematically investigated.
Stimuli-responsive phosphorescence materials with dynamic color-changing properties are highly promising for advanced information security. Herein, we demonstrate a novel strategy that effectively induces tunable dynamic phosphorescence color from carbon dots (CDs) on papers via surface ionization engineering for multimode encryption and information storage. Alkali-induced phenolic hydroxyl ionization on CDs can boost intersystem crossing rates , while surface-ionized groups with negative charges significantly passivate the surface defects and reduce non-radiative transitions, which can activate surface state-related blue phosphorescence emission. Combined with the carbon core state-related yellow-green phosphorescence, excitation/time-dependent phosphorescence color-changing from yellow-green to blue are realized from alkali (Na 2 CO 3 ) treated CDs on paper. Furthermore, benefiting from the transition from NaHCO 3 to Na 2 CO 3 under thermal treatment, dynamic color-changing phosphorescence can also be activated by thermally stimulating NaHCO 3 -treated CDs on paper. Finally, multi-stimuli (alkali or thermal) and multi-modal dynamic phosphorescent colors from a single CDs system are realized for the first time. Based on these unique features, multimode encryption and smart 3D codes with anti-counterfeiting and monitoring functions for medicine during transport or storage are demonstrated by combining an inkjet printing technique using CD inks.
Rationale Exhaled breath can be used for early warning of disease, with organic nitrogen compounds, including triethylamine (TEA), being linked to various medical conditions. Surface ionization ion mobility spectrometry (SI-IMS) facilitates the direct detection of TEA in exhaled breath. However, the presence of multiple ionization products of TEA poses challenges for both quantitative and qualitative analyses. Methods A doped surface ionization (DSI) method consisting of surface ionization of dopants and gas-phase reaction of samples was proposed, and TEA was detected when combined with an ion mobility spectrometer. TEA at different concentrations and spiked by human breath was detected to evaluate the method's properties. Results TEA with concentrations from 5.99 to 30.50 ppb and a relative humidity of 80% was detected. The peak intensity of the protonated TEA ions demonstrated a linear correlation with concentration, yielding a fitted correlation coefficient of R 2 = 0.94. A standard deviation less than 0.066% was obtained with 10 replicate analyses of 29.92 ppb TEA, and the recovery rate of the sample was 93.57%. Conclusions The SI-IMS based on the DSI method has the advantages of excellent selective ionization, high accuracy and sensitivity, and remarkable repeatability for detecting TEA. It is a promising method for detecting specific organic nitrogen compounds in exhaled breath.
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