Benzene is the typical volatile organic compound (VOC) of indoor and outdoor air pollution, which harms human health and the environment. Due to the stability of their aromatic structure, the catalytic oxidation of benzene rings in an environment without an external energy input is difficult. In this study, the efficient degradation of benzene at room temperature was achieved by constructing Ag and Ni bimetallic active site catalysts (AgNi/BCN) supported on boron-carbon-nitrogen aerogel.
View Article and Find Full Text PDFThe rapid development of the economy and society is causing an increase in the amount of municipal solid waste (MSW) produced by people's daily lives. With the strong support of the Chinese government, incineration power generation has steadily become the primary method of treating MSW, accounting for 79.86%.
View Article and Find Full Text PDFBenzene and its aromatic derivatives are typical volatile organic compounds for indoor and outdoor air pollution, harmful to human health and the environment. It has been considered extremely difficult to break down benzene rings at ambient conditions without external energy input, due to the extraordinary stability of the aromatic structure. Here, we show one such solution that can thoroughly degrade benzene to basically water and carbon dioxide at 25 °C in air using atomically dispersed Fe in N-doped porous carbon, with almost 100% benzene conversion.
View Article and Find Full Text PDFAs an important air pollutant, volatile organic compounds (VOCs) pose a serious threat to the ecological environment and human health. To achieve energy saving, carbon reduction, and safe and efficient degradation of VOCs, ambient temperature catalytic oxidation has become a hot topic for researchers. Firstly, this review systematically summarizes recent progress on the catalytic oxidation of VOCs with different types.
View Article and Find Full Text PDFForward osmosis (FO) membranes have the advantages of low energy consumption, high water recovery rate, and low membrane pollution trend, and they have been widely studied in many fields. However, the internal concentration polarization (ICP) caused by the accumulation of solutes in the porous support layer will reduce permeation efficiency, which is currently unavoidable. In this paper, we doped Graphene oxide (GO) nanoparticles (50~150 nm) to a polyamide (PA) active layer and/or polysulfone (PSF) support layer, investigating the influence of GO on the morphology and properties of thin-film composite forward osmosis (TFC-FO) membranes.
View Article and Find Full Text PDFCopper contamination of water is one of the most pressing environmental problems which has attracted extensive concern in recent decades. In this study, a series of magnetic adsorbents were synthesized by two-step modified cellulose with N-[3-(trimethoxysilyl)propyl]ethylenediamine (KH-792) and diethylenetriaminepentaacetic acid (DTPA) using for removal of Cu(II) from aqueous solutions. Adsorption performance of Cu(II) was systematically investigated under various treatment conditions as the effect of solution pH, contact time, initial concentration and temperature.
View Article and Find Full Text PDFPolymer materials have become one of the potential materials for remediation of heavy metal (HM) contamination in water and soil. However, the specific advantages of polymers are rarely studied. Water-soluble thiourea formaldehyde resin (WTF) is one of the effective polymer amendments.
View Article and Find Full Text PDFChromium pollution is a serious environmental problem given that like most heavy metals, Cr tends to persist and accumulate in the environment. In this study, diethylenetriaminepentaacetic acid-thiourea-modified magnetic chitosan (DTCS-FeO) was synthesized for use as an adsorbent for Cr(VI) removal from aqueous solutions. The effects of various treatment conditions on the Cr(VI) adsorption performance of DTCS-FeO composite as well as the kinetics were elucidated.
View Article and Find Full Text PDFIt is very important to seek a heavy metal soil stabilization/solidification (S/S) agent that has less risk of secondary release and has less impact on the soil. This study explored the repair effect of a new resin repair agent water-soluble thiourea-formaldehyde (WTF), and its stability under indigenous biodegradation and compared the repair effect with sodium sulfide (NaS) and hydroxyapatite (HAP). Diethylene triamine pentaacetic acid leaching experiments show that WTF can effectively solidify/stabilize 97.
View Article and Find Full Text PDFNormal temperature catalytic ozonation is an effective method for the removal of volatile organic compounds (VOCs). A series of TiO-supported noble metal catalysts were synthesized by a facile impregnation method. The as-prepared catalysts were evaluated for the catalytic oxidation of toluene.
View Article and Find Full Text PDFIt is vital for the development and application of heavy metal stabilization/solidification (S/S) agents to reveal the mechanism of the reaction between water-soluble thiourea formaldehyde (WTF) resin and heavy metal and evaluate its repairing effect. Based on the density functional theory analysis of the WTF resin structure, the mechanism analysis and scanning electron microscope (SEM) showed that the three-dimensional network structure with thiocarbonyl and hydroxyl groups is very conducive to the capture of Cd. The reduction rate of Cd in soil added WTF resin could reach 70.
View Article and Find Full Text PDFNormal temperature catalytic ozonation (NTCO) is a promising yet challenging method for the removal of volatile organic compounds (VOCs) because of limited activity of the catalysts at ambient temperature. Here, we report a series of Pt/FeO catalysts prepared by the co-precipitation method for NTCO of gaseous methanol. All samples were found to be active and among them, the Pt/FeO-400 (calcined at 400 °C) catalyst with a Pt cluster loading of 0.
View Article and Find Full Text PDFStabilization/Solidification (S/S) can be regarded as necessary for remediation of heavy metal contaminated soil. There is, however, solid agent is not very convenient to use. Water-soluble thiourea-formaldehyde (WTF) is a novel chelating agent, which has more practical applications.
View Article and Find Full Text PDFTetrachloroethylene (PCE) is among the most ubiquitous chlorinated compounds found in groundwater contamination. Its chlorinated degradation by-products remain highly toxic. In this study, an anaerobic/aerobic permeable reactive barrier system consisting of four different functional layers was designed to remediate PCE-contaminated groundwater.
View Article and Find Full Text PDFA large-scale process to extract flavonoids from Moringa oleifera leaf by subcritical ethanol was developed and HPLC-MS analysis was conducted to qualitatively identify the compounds in the extracts. To optimize the effects of process parameters on the yield of flavonoids, a Box-Behnken design combined with response surface methodology was conducted in the present work. The results indicated that the highest extraction yield of flavonoids by subcritical ethanol extraction could reach 2.
View Article and Find Full Text PDFBecause of the high concentrations of heavy metals, municipal solid waste incineration (MSWI) fly ash is classified as a hazardous waste, which need to be treated to avoid damaging the environment. A novel water-soluble thiourea-formaldehyde (WTF) resin was synthesized by two step reactions (hydroxymethylation reaction and condensation reaction) in the laboratory. Synthetic conditions, removal of free formaldehyde in the resin and the ability of immobilization heavy metals in the MSWI fly ash were studied.
View Article and Find Full Text PDFEnviron Sci Pollut Res Int
February 2016
Lanthanum-modified bentonite has potential for wide application in eutrophication control. We investigated P adsorption on a lanthanum-modified bentonite by analysis of adsorption kinetics, equilibrium, and the effect of environmental factors. P adsorption closely followed the pseudo-second-order kinetic model, and the isotherm was well described by the Langmuir model.
View Article and Find Full Text PDFThe harmfulness of carcinogenic hexavalent chromium (Cr(VI)) is dramatically decreased when Cr(VI) is reduced to trivalent chromium (Cr(III)). Rutin, a natural flavonoid, exhibits excellent antioxidant activity by coordinating metal ions. In this study, a complex containing rutin and Cr(III) (rutin-Cr(III)) was synthesized and characterized.
View Article and Find Full Text PDFIn this paper, an anaerobic two-layer permeable reactive biobarrier system consisting of an oxygen-capturing layer followed by a biodegradation layer was designed firstly for evaluating the remediation effectiveness of nitrate-contaminated groundwater. The first layer filling with granular oxygen-capturing materials is used to capture dissolved oxygen (DO) in groundwater in order to create an anaerobic condition for the microbial denitrification. Furthermore, it can also provide nutrition, such as carbon and phosphorus, for the normal metabolism of immobilized denitrifying bacteria filled in the second layer.
View Article and Find Full Text PDFIn this study, an in situ biological two-layer permeable reactive barrier system consisting of an oxygen-releasing material layer followed by a biodegradation layer was designed to evaluate the remediation effectiveness of MTBE-contaminated groundwater. The first layer containing calcium peroxide (CaO(2)) and other inorganic salts is to provide oxygen and nutrients for the immobilized microbes in the second layer in order to keep them in aerobic condition and maintain their normal metabolism. Furthermore, inorganic salts such as potassium dihydrogen phosphate (KH(2)PO(4)) and ammonium sulphate ((NH(4))(2)SO(4)) can also decrease the high pH caused by the alkali salt degraded from CaO(2).
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