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飞灰和煤混合吸附剂从水溶液去除铬染料的研究
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作者 G.S.Gupta g.prasad +1 位作者 V.N.Singh 薛大明 《环境保护科学》 CAS 1992年第4期76-81,62,共7页
对不同比例的飞灰和煤的均匀混合物吸附去除水溶液中的Ω铬红 ME(一种普通的铬染料)进行了研究.注意到低浓度吸附物质、小颗粒吸附剂、低温及酸性介质有利于染料的去除.当飞灰和煤的此例为1:1,颗粒粒径为53μm、pH=2.0、30℃,吸附质浓度... 对不同比例的飞灰和煤的均匀混合物吸附去除水溶液中的Ω铬红 ME(一种普通的铬染料)进行了研究.注意到低浓度吸附物质、小颗粒吸附剂、低温及酸性介质有利于染料的去除.当飞灰和煤的此例为1:1,颗粒粒径为53μm、pH=2.0、30℃,吸附质浓度为10mg/1时,上述染料的去除率达到1005.分别采用 Lagergren 和 Mekay 等提出的模型进行动力学和传质研究,平衡数据与 Langmuir 吸附模型相吻合,表明吸附剂外表面形成了染料分子的单分子覆盖层.根据吸附质的溶解度和化学势解释了温度的影响.用固液界面的各种物理化学性质解释研究结果进行了尝试. 展开更多
关键词 吸附剂 染料 废水处理 除铬
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SYNTHESIS,CHARACTERIZATION AND ELECTRICAL PROPERTIES OF Nd/Zr CO-DOPED NANO BaTiO_(3) CERAMICS
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作者 CH.SAMEERA DEVI M.B.SURESH +1 位作者 G.S.KUMAR g.prasad 《Journal of Advanced Dielectrics》 CAS 2012年第1期34-47,共14页
Ceramic samples of composition Ba_(1-3)xNd_(2x)Ti_(1-y)ZryO_(3)(x=0.025;y=0.025 and 0.05)were synthesized by modified sol-gel technique.Phase confirmation,surface morphology and electrical properties of the samples we... Ceramic samples of composition Ba_(1-3)xNd_(2x)Ti_(1-y)ZryO_(3)(x=0.025;y=0.025 and 0.05)were synthesized by modified sol-gel technique.Phase confirmation,surface morphology and electrical properties of the samples were studied using XRD,FESEM,impedance spectroscopy and DC conductivity.Impedance,AC and DC conductivities of the samples were recorded in the temperature range room temperature(RT)-500℃.From impedance data,various parameters like bulk resistance(R_(b)),bulk capacitance(C_(b)),grain resistance(R_(g)),grain boundary resistance(R_(gb)),grain capacitance(C_(g))and grain boundary capacitance(Cgb)T were determined.These parameters were found to be function of both temperature and frequency.Grain and grain boundary relaxation times(τ_(g),τ_(gb))were also evaluated as a function of temperature.From AC and DC conductivity plots activation energies for conduction were obtained.Results obtained lead to improved understanding of conductivity and charge transportation kinetics in the present system of samples. 展开更多
关键词 Sol-gel method BaTiO_(3) impedance spectroscopy DC conductivity AC conductivity
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Studies of phase transition and impedance behavior of Ba(Zr,Ti)O_(3)ceramics
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作者 P.Sateesh J.Omprakash +1 位作者 G.S.Kumar g.prasad 《Journal of Advanced Dielectrics》 CAS 2015年第1期8-20,共13页
Ceramic samples of Barium Zirconium Titanate(BaZr_(x)Ti_(1-x)O_(3)(BZT))were synthesized by conventional solid-state reaction method with different concentrations of x(=0.05(BZT1),0.10(BZT2),0.15(BZT3),0.20(BZT4),0.25... Ceramic samples of Barium Zirconium Titanate(BaZr_(x)Ti_(1-x)O_(3)(BZT))were synthesized by conventional solid-state reaction method with different concentrations of x(=0.05(BZT1),0.10(BZT2),0.15(BZT3),0.20(BZT4),0.25(BZT5),0.30(BZT6)).Phase confirmation of the samples was done by X-ray diffraction(XRD)technique.All the compositions are in cubic structure.XRD pattern was recorded for samples sintered at different sintering temperatures.Lattice parameters increased with addition of Zr^(+4).Doping with Zr^(+4)into Barium titanate resulted in interesting changes of electrical properties(dielectric,impedance and ferroelectiricity).The strong influence of Zr doping on the phase transition characteristics of the BZT ceramics was studied from the dielectric response of the samples.Diffusivity of phase transition of the BZT ceramic samples increase with Zr^(+4)concentration,indicating changes from normal to diffuse transition to relaxor phase transition behavior.Impedance spectroscopy reveals the presence of temperature-dependent grain,grain boundary effects.Polarization-Electricfield(PE)loop measurements are also done on the samples. 展开更多
关键词 Ferroelectric properties diffuse phase transition impedance spectroscopy
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