Surface enhanced Raman scattering (SERS) is a trace detection technique that extends even to single molecule detection. Its potential application to the noninvasive recognition of lung malignancies by detecting volatile organic compounds (VOCs) that serve as biomarkers would be a breakthrough in early cancer diagnostics. This application, however, is currently limited by two main factors: (1) most VOC biomarkers exhibit only weak Raman scattering; and (2) the high mobility of gaseous molecules results in a low adsorptivity on solid substrates. To enhance the adsorption of gaseous molecules, a ZIF-8 layer is coated onto a self-assembly of gold superparticles (GSPs) in order to slow the flow rate of gaseous biomarkers and depress the exponential decay of the electromagnetic field around the GSP surfaces. Gaseous aldehydes that are released as a result of tumor-specific tissue composition and metabolism, thereby acting as indicators of lung cancer, are guided onto SERS-active GSPs substrates through a ZIF-8 channel. Through a Schiff base reaction with 4-aminothiophenol pregrafted onto gold GSPs, gaseous aldehydes are captured with a 10 ppb limit of detection, demonstrating tremendous prospects for in vitro diagnoses of early stage lung cancer.
An effective approach for control of internal nutrient loading and sediment hypoxia remains a longstanding challenge to the restoration of aquatic ecosystems. In order to simultaneously tackle these issues, a MultiFunction Geoengineering material (MFG) was developed for sediment remediation through the synergistic functions of physical capping, nutrient adsorption and delivery of O2 nanobubbles. The MFG, derived from natural zeolite, exhibited superior (1.5-4 times higher) adsorption capabilities for both phosphate (PO4 3--P) and ammonium (NH4 + -N), than pristine zeolite. The O2 adsorption capacity was also enhanced from 46, observed in the natural zeolite, to 121 mg O2/g for the MFG. An in-situ sediment capping experiment in a eutrophic lake demonstrated that the application of MFG dramatically reversed sediment hypoxia (ORP -200 mV) to an aerobic status (ORP 175 mV) and, furthermore, stimulated sediment microbial activity, particularly nitrifying bacteria. The MFG treatment resulted the sediment changing from a nutrient source to a sink through decreasing the cumulative PO4 3--P and NH4 + -N fluxes from the sediment by 124.6% and 131.1%, respectively. Moreover, the comprehensive functionalities of the material have been, for the first time, quantified, from which data O2 nanobubble delivery was determined to be the largest contributor, reducing the fluxes of PO4 3--P and NH4 + -N by 57.3% and 56.1% of, respectively. Our findings highlight the viability of such multifunctional material for the remediation of internal nutrient loads in lacustrine environments, towards sustainable eutrophication control.
Advanced and optimized textile wastewater treatment by catalytic ozonation and activated carbon (AC) adsorption was investigated. Scanning electron microscopy, X‐ray diffraction, and X‐ray photoelectron spectroscopy indicated that Mn and Ce oxides were successfully loaded on the γ‐Al2O3 support, and MnO2, Mn2O3, CeO2, and Ce2O3 were the main components of the catalyst. Actual textile wastewater from biochemical effluent was used as experiment wastewater. The removal efficiencies of chemical oxygen demand (COD) and chromaticity were approximately 30.6% (414–287 mg/L on average) and 99.3% (4,033 times to 27 times on average), respectively during the 30‐day on‐site continuous‐flow test with an ozone dosage, contact time, and gas–liquid ratio of 100 mg/L, 15.7 min, and 2.9, respectively. Following 1 g/L AC adsorption, the effluent COD concentration was reduced to 40 mg/L. By contrast, AC adsorption without catalytic ozonation as pretreatment required 10 g/L AC dosage to achieve similar treatment results. Gas chromatography–mass spectrometry analyses indicated that volatile phenols, sulfides, and aniline in wastewater were completely removed after treatment. Inductively coupled plasma results further showed that the active components of MnOx–CeOx in the catalyst were stable after continuous use for 60 days.Practitioner points
Mesoporous catalyst synthesized by impregnating MnOx–CeOx on γ‐Al2O3 support.
Catalytic ozonation and AC adsorption were combined to degrade organics.
Maximum degradation of COD and chromaticity by optimizing process variables.
The efficiency of the method was compared to that of single AC adsorption.
Dissolved organic matter (DOM) obtained from three leachates with different landfill ages was fractionated, and its compositional variation based on hydrophobicity and polarity was characterized by synchronous fluorescence spectra combined with principal component analysis (PCA) and two-dimensional correlation technique. The results showed that the bulk DOM and its fractions were comprised of tryosine-, tryptophan-, fulvic-, and humic-like substances. Tyrosine-like matter was dominant in the young leachate DOM and its fractions, while tryptophan-, fulvic-, and humic-like substances were the main components in the intermediate and old leachate DOMs and their fractions. Tryosine-, tryptophan-, fulvic-, and humic-like substances varied concurrently with the hydrophobicity and polarity. However, the change ratio of these substances was different for the three leachates. Tyrosine-like matter, humic-like materials, and fulvic-like substances were the most sensitive to the hydrophobicity and polarity in the young, intermediate, and old leachates, respectively. Such an integrated approach jointly enhances the characterization of the hydrophobicity- and polarity-dependent DOM fractions and provides a promising way to elucidate the environmental behaviors of different DOM species.
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