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Niu F.,Guangxi University | Yao S.,Guangxi University | Nie S.,Guangxi University | Nie S.,University of New Brunswick | And 4 more authors.
BioResources | Year: 2014

The aims of this study were response surface modeling and optimization of Cr(VI) removal from solution using formaldehyde-modified eucalyptus bark. A high removal rate of Cr(VI) was achieved under the conditions of low adsorbent dosing quantity and high initial concentration of Cr(VI). Analysis of variance showed a high multiple coefficient of determination (R2=0.9875), adjusted determination coefficient (R2 Adj=0.9714), and the good second order regression equation. The initial concentration of Cr(VI) was 40.15 mg/L, adsorbent dosing quantity 3.40 g/L, and initial reaction pH 2.78, and the largest removal rate was 99.998% under the optimum reaction conditions. Langmuir and Freundlich isothermal models described well adsorption of Cr(VI) by the modified stringy bark. Adsorption kinetics studies showed that the adsorption was controlled by multiple factors, dominated by chemical adsorption. The adsorption was found to be spontaneous and endothermic, with ΔG0 < 0, ΔH0 > 0, and ΔS0 > 0. Adsorption of Cr(VI) by formaldehyde-modified stringy bark was partly controlled by REDOX reactions. The adsorbents were characterized by SEM and FTIR. Source

Wei M.-R.,The Guangxi Key Laboratory of Environmental Engineering | Wei M.-R.,Wuhan University of Technology | Wei M.-R.,China Institute of Technology | Jiang Y.-H.,Wuhan University of Technology | And 3 more authors.
Wuhan Ligong Daxue Xuebao/Journal of Wuhan University of Technology | Year: 2010

Five samples of sediment columns in Nanhu Lake of Wuhan were collected and analyzed, the results showed that the concentration of Organic Matter (OM), Total Nitrogen (TN) and Total Phosphorus (TP) decreased along depth and stabilized gradually under 40 cm, with the maximum appearing in the top sediment; the contaminants content in the sediment column near Xingfucun sewage outlet were the highest. The value of pH, TN, TP and Ammonium-Nitrogen (NH4 +-N) in overlying water and pore water were tested. The results showed that in horizontal distribution the concentrations of TN and NH4 +-N were similar but TP varied distinctively for overlying water, TN, TP and NH4 +-N content in pore water near Xingfucun sewage outlet are the highest; the concentrations of TN and NH4 +-N are higher and TP are less in pore water than that in overlying water, which mean that TN and NH4 +-N in sediment could release into water and TP couldn't. Source

Lin Q.,University of Sichuan | Lin Q.,Hezhou University | Wang Q.,University of Sichuan | Duan Y.,University of Sichuan | And 5 more authors.
Separation Science and Technology (Philadelphia) | Year: 2013

A novel adsorbent, chufa corm peels (CCP), is used for removing Cu(II), Cr(III), and Cr(VI) from aqueous solutions. The adsorption ability and characteristics of the CCP are thoroughly investigated. The adsorption capability for three heavy metal ions is in the order of Cu(II) > Cr(III) > Cr(VI). The morphology and elemental distribution on the biomass of CCP were evaluated by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). Fourier-transform infrared spectroscopy (FTIR) analysis revealed that oxygen-containing functional groups, especially carboxylic and hydroxyl groups were responsible for chemical coordination between ionizable functional groups and metal ions. The adsorption features were evaluated based on the batch biosorption experiment. The results showed that the adsorption well meets the Freundlich adsorption isotherm models and pseudo-second-order kinetics model. In summary, this work demonstrated that CCP is an attractive, efficient, and low-cost adsorbent biomaterial that can be used for the removal of heavy metals from environmental contaminations. © 2013 Copyright Taylor and Francis Group, LLC. Source

Dai Y.,Guangxi University | Dai Y.,Guangxi Key Laboratory of Clean Pulp and Papermaking and Pollution Control | Song X.,Guangxi University | Gao C.,Guangxi University | And 6 more authors.
BioResources | Year: 2016

Xylanase pretreatment was used to improve the chlorine dioxide bleaching of bagasse pulp. The pulp was pretreated with xylanase, which was followed by a chlorine dioxide bleaching stage. The HexA content of the pulp and the AOX content of the bleaching effluent were measured using UV-Vis and GC-MS methods, respectively. The results showed that a good correlation occurred between HexA and kappa number. HexA content of the pulp decreased significantly after the xylanase pretreatment. The AOX content of the bleaching effluent decreased as HexA was removed from the pulp. It was found that AOX could be reduced by up to 29.8%, comparing XD0 with a D0 stage. Fourier transform infrared spectroscopy (FTIR) was employed to determine the breakage of chemical bonds in the pulp. It revealed that some lignin and hemicellulose were removed after xylanase treatment. The GC-MS results showed that some toxic chloride such as 2,4,6-Trichlorophenol could be completely removed after xylanase pretreatment. Source

Lin Y.,Guangxi Normal University | Lin Y.,The Guangxi Key Laboratory of Environmental Engineering | Zeng L.,CAS East China Sea Fisheries Research Institute | Zhang Q.,Guangxi Normal University | And 3 more authors.
American Journal of Botany | Year: 2011

Premise of the study: Microsatellite markers were developed in an endangered plant, Kmeria septentrionalis, to investigate its population genetic structure, gene flow, and mating systems. Methods and Results: Using the combined biotin capture method, 14 microsatellite primer sets were isolated and characterized. All of these markers showed polymorphism, and the number of alleles per locus ranged from 3 to 15 across 60 individuals from two populations. The observed and expected heterozygosities ranged from 0.2692 to 0.9667 and from 0.3271 to 0.8881, respectively. Conclusions: These markers will facilitate further studies on the genetic diversity and mating systems of K. septentrionalis. © 2011 Botanical Society of America. Source

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