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Huang R.,South China Normal University | Fang Z.,South China Normal University | Fang Z.,Guangdong Technology Research Center for Ecological Management | Fang X.,South China Normal University | And 3 more authors.
Journal of Colloid and Interface Science | Year: 2014

In this study, Fe3O4 NPs (named as Fe3O4 NPs-PO) were prepared by steel pickling waste liquor to reduce the cost of preparation, and were compared with those obtained by the common co-precipitation method (named as Fe3O4 NPs-CP) which prepared from chemical reagent using BET, XRD, XPS, TEM and SEM techniques. The results indicated that Fe3O4 NPs-PO nanoparticles mainly existed in the form of Fe3O4 and appeared to be roughly spherical in shape with a size range of 20-50nm. The heterogeneous Fenton-like catalytic capacity of Fe3O4 NPs-PO in US+Fe3O4+H2O2 system was comprehensively investigated. BPA could be degraded within a wide pH range of 7-10. The removal efficiencies of BPA were close to 100% and about 45% total organic carbon (TOC) in solution was eliminated at the optimized conditions. It was found that·OH radicals which mainly caused the degradation of BPA were promptly generated due to the catalysis of the Fe3O4 NPs-PO. Furthermore, the comparative study of catalytic activity, stability and reusability between Fe3O4 NPs-PO and Fe3O4 NPs-CP showed that the two catalysts both remained good activity after several reaction cycles and no significant change in composition and structure was observed, the loss of catalyst was negligible, which demonstrated that Fe3O4 NPs-PO were promising in ultrasonic Fenton-like process to treat refractory organics. © 2014 Elsevier Inc.


Chen Y.,South China Normal University | Fang J.,South China Normal University | Fang J.,Guangdong Technology Research Center for Ecological Management | Lu S.,U.S. Center for Disease Control and Prevention | And 5 more authors.
Journal of Chemical Technology and Biotechnology | Year: 2015

Chlorophenols (CPs) are organic pollutants and are most widespread in the aqueous environment. Photocatalytic degradation of organic compounds has been extensively studied as a potential technology for water treatment. In this study, BiOI/Bi2WO6 hierarchical heterostructure with flower-like morphology was synthesized by a facile method using a one-step hydrothermal approach. The catalytic activities of the photocatalysts were tested by the degradation of 2,4-DCP under visible-light irradiation and the photocatalysis mechanism of BiOI/Bi2WO6 was investigated. RESULTS: The as-prepared catalysts exhibited the characteristic peaks of BiOI and Bi2WO6. The photocatalytic activities, which were evaluated by degradation of 2,4-DCP under visible light irradiation, were enhanced significantly by BiOI/Bi2WO6 hierarchical heterostructures with different molar ratios of BiOI to Bi2WO6. CONCLUSIONS: BiOI/Bi2WO6 hierarchical heterostructure significantly enhanced the photocatalytic activity. The optimum percentage of BiOI was 10%. The optimal initial pH value of 2,4-DCP was determined to be pH 8. The possible reaction mechanisms were discussed on the basis of the calculated energy band positions. © 2014 Society of Chemical Industry.


Su H.,South China Normal University | Su H.,Guangdong Technology Research Center for Ecological Management | Fang Z.,South China Normal University | Fang Z.,Guangdong Technology Research Center for Ecological Management | And 5 more authors.
Environmental Pollution | Year: 2016

In this study, a biochar-supported nanoscale zero-valent iron (nZVI@BC) material was used for in situ remediation of hexavalent chromium-contaminated soil. Sedimentation tests and column experiments were used to compare the stability and mobility of nZVI@BC and bare-nZVI. The immobilisation efficiency of chromium, toxic effect of chromium and the content of iron were assessed through leaching tests and pot experiments. Sedimentation tests and transport experiments indicated that nZVI@BC with nZVI to BC mass ratio of 1:1 exhibited better stability and mobility than that of bare-nZVI. The immobilisation efficiency of Cr(VI) and Crtotal was 100% and 92.9%, respectively, when the soil was treated with 8 g/kg of nZVI@BC for 15 days. Moreover, such remediation effectively reduced the leachability of Fe caused by bare-nZVI. In addition, pot experiments showed that such remediation reduced the phytotoxicity of Cr and the leachable Fe and was favourable for plant growth. © 2016 Elsevier Ltd. All rights reserved.


Xie Y.,South China Normal University | Xie Y.,Guangdong Technology Research Center for Ecological Management | Cheng W.,South China Normal University | Cheng W.,Guangdong Technology Research Center for Ecological Management | And 4 more authors.
Journal of Environmental Management | Year: 2016

Polybrominated diphenyl ethers (PBDEs) are a new class of environmental pollutants which easily accumulated in the soil, especially at e-waste sites. However, knowledge about their phytotoxicity after degradation is not well understood. Nano zero valent iron (nZVI) immobilized in mesoporous silica microspheres covered with FeOOH (SiO2@FeOOH@Fe) synthesized in this study was utilized to remove decabromodiphenyl ether (BDE209) from soil. Results revealed that the removal efficiency of BDE209 can be achieved 78% within 120 h using a dosage of 0.165 g g-1 and a pH of 5.42. Furthermore, the removal efficiency enhanced with increasing soil moisture content and the decreasing of initial BDE209 concentration. Phytotoxicity assays (biomass and germination rate, shoots and roots elongation of Chinese cabbage) were carried out to provide a preliminary risk assessment of treated soil for the application of SiO2@FeOOH@Fe. © 2015 Elsevier Ltd.


Lin J.,South China Normal University | Pang S.,South China Normal University | Wang Q.,South China Normal University | Wang Q.,Guangdong Technology Research Center for Ecological Management
Materials Letters | Year: 2013

We used ultrasonic-assisted microwave technique to synthesize V 2O5/MgF2:Eu3+ with characteristic red emissions. Phototocatalytic performances and emission properties were improved compared to the traditional route. Further investigation indicates that 9% V2O5 (molar ratio V/Mg=9%) gave the best result for decomposing methylene blue (91% in 1 h). © 2013 Elsevier B.V.


Wang Y.,South China Normal University | Wang Y.,Guangdong Technology Research Center for Ecological Management | Fang Z.,South China Normal University | Fang Z.,Guangdong Technology Research Center for Ecological Management | And 4 more authors.
Chemical Engineering Journal | Year: 2014

The removal of Cr(VI) from contaminated soil using sodium carboxymethyl cellulose (CMC)-stabilized nanoscale zero-valent iron prepared from steel pickling waste liquor was systematically investigated. Laboratory batch experiments indicated that 0.09gL-1 of Fe0 nanoparticles at a soil to solution ratio of 1g: 10mL completely reduced the aqueous-bound Cr(VI), which contributed about 46% of the pre-sorbed Cr(VI) in the soil (Cr(VI)=102mgkg-1). Furthermore, the addition of Fe0 nanoparticles only removed a portion of the soil-bound Cr(VI). When the soil was treated with 0.3gL-1 of Fe0 nanoparticles for 72h, 80% of the loaded Cr(VI) was reduced to Cr(III), which resulted in a residual Cr(VI) concentration of 20mgkg-1. Based on the studies of elemental distributions and XPS analysis, it is proposed that reduction and immobilization may be equally important removal mechanisms for Cr(VI) by CMC-nZVI. Following the treatment by CMC-nZVI, the TCLP leachability of the Cr(VI) and Crtotal was significantly reduced by 100% and 82%, respectively. This study sheds new light on the remediation of Cr(VI)-contaminated soil by CMC-nZVI. © 2014 Elsevier B.V.


Xie Y.,South China Normal University | Xie Y.,Guangdong Technology Research Center for Ecological Management | Fang Z.,South China Normal University | Fang Z.,Guangdong Technology Research Center for Ecological Management | And 6 more authors.
Chemosphere | Year: 2014

Our previous reports showed that nano zero-valent iron (nZVI), steel pickle liquor for the synthesis of nZVI (S-nZVI), nZVI immobilised in mesoporous silica microspheres (SiO2@FeOOH@Fe) and nano Ni/Fe bimetallic particles (Ni/Fe) have been proved to show good property for elimination of polybrominated diphenyl ethers (PBDEs). However, it is necessary to compare their reactivity, reusability and stability when applied to in situ remediation. In this study, the performances of different iron-based nanoparticles were compared through reusability, sedimentation and iron dissolution experiments. The SiO2@FeOOH@Fe and Ni/Fe nanoparticles were shown to have higher reusability and stability, as they could be reused more than seven times, and that the SiO2@FeOOH@Fe can effectively avoid leaching iron ions into the solution and causing secondary pollution in the reaction. This study may serve as a reference for PBDE remediation in the future. © 2014 Elsevier Ltd.


Wang Y.,South China Normal University | Wang Y.,Guangdong Technology Research Center for Ecological Management | Fang Z.,South China Normal University | Fang Z.,Guangdong Technology Research Center for Ecological Management | And 4 more authors.
Journal of Hazardous Materials | Year: 2014

The toxic effect of Cr(VI)-contaminated soil remediated by sodium carboxymethyl cellulose stabilized nanoscale zero-valent iron (CMC-stabilized nZVI) was assessed through in vitro toxicity and phytotoxicity tests. In vitro tests showed that 0.09gL-1 of Fe0 nanoparticles (soil-to-solution ratio was 1g:5mL) significantly reduced the toxicity characteristic leaching procedure (TCLP) leachability and physiological based extraction test (PBET) bioaccessibility of Cr by 82% and 58%, respectively. Sequential extraction procedures (SEP) revealed that exchangeable (EX) Cr was completely converted to Fe-Mn oxides (OX) and organic matter (OM). Accordingly, phytotoxicity tests indicated that after 72-h remediation, Cr uptakes by edible rape and Chinese cabbage were suppressed by 61% and 36%, respectively. Moreover, no significant increase in Cr uptake was observed for either species after a 1-month static period for the amended soil. Regarding Fe absorption, germination and seedling growth, both plant species were significantly affected by CMC-nZVI-exposed soils. However, similar phytotoxicity tests conducted after 1 month showed an improvement in cultivation for both plants. Overall, this study demonstrated that CMC-nZVI could significantly enhance Cr immobilization, which reduced its leachability, bioavailability and bioaccumulation by plants. From a detoxification perspective, such remediation is technologically feasible and shows great potential in field applications. © 2014 Elsevier B.V.

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