Co-reporter:Wei Wang, Ying Jing, Shihai He, Jian-Ping Wang, Jian-Ping Zhai
Colloids and Surfaces B: Biointerfaces 2014 Volume 117() pp:449-456
Publication Date(Web):1 May 2014
DOI:10.1016/j.colsurfb.2013.11.050
•Magnetic Fe70Co30 nanoparticles were fabricated by a magnetron–sputtering-based gas phase condensation deposition method.•The nanoparticles were modified by 3-aminopropyltriethoxy silane and were subsequently activated by glutaraldehyde.•Three proteins (streptavidin, PAPP-A antibody and Nectin-4 antibody) were immobilized on glutaraldehyde activated FeCo nanoparticle.•The immobilized proteins retain their binding bioactivities.Magnetic Fe70Co30 nanoparticles with a cubic shape and a mean size of 15 ± 1.5 nm were fabricated using a magnetron–sputtering-based gas phase condensation deposition method. The particles had a high saturation magnetization of 220 emu/g, which is much higher than that of commercially available iron oxide nanoparticles. The FeCo nanoparticles were modified by 3-aminopropyltriethoxy silane and subsequently activated by glutaraldehyde, leading to successful attachment of aldehyde groups onto nanoparticle surfaces. Three proteins, namely streptavidin, PAPP-A antibody and Nectin-4 antibody, were immobilized on glutaraldehyde activated FeCo nanoparticles, and their loading levels were quantitatively evaluated. Our results show that loading capabilities are 95 μg of streptavidin, 128 μg of PAPP-A, and 125 μg of Nectin-4 antibody per milligram of FeCo nanoparticles, and that the three immobilized proteins retain their binding bioactivity. The protein–FeCo conjugates may find valuable applications involving magnetic separation and purification of proteins and cells, and the magnetic detection of biomolecules.
Co-reporter:Jianfeng Pang, Qin Li, Bing Wang, Dejing Tao, Xiaotian Xu, Wei Wang, Jianping Zhai
Powder Technology 2012 Volume 226() pp:246-252
Publication Date(Web):August 2012
DOI:10.1016/j.powtec.2012.04.055
The process of depositing Ni-Fe-P alloy films on fly ash cenospheres (FACs) through modified electroless plating is documented. A coupling procedure was used with γ-aminopropyltriethoxy silane (APS) as coupling agent and silver nitrate as activator. The resultant Ni-Fe-P/FACs composites were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), X-ray diffractometry (XRD) and vibrating sample magnetometry (VSM). The results show that continuous and uniform films of Ni-Fe-P alloy were obtained on the surfaces of the FACs. DSC traces indicated that two distinct exothermic peaks appeared during the heat treatment, which moved to higher temperature with decrease in mole ratios of Ni2+/Fe2+ in the coating. XRD spectra confirmed that electroless Ni-Fe-P alloy deposits were amorphous in the as-plated condition, which transformed from the amorphous to crystalline phase with increase in calcining temperature. In addition, VSM data revealed that the resulting sample exhibited characteristics of soft magnetic materials at room temperature. The magnetic performances of the composites would be ameliorated with an increase in iron content in the coating and calcining temperature.Fig. 1. Flow chart of preparation procedure for Ni-Fe-P/FACs composites.Highlights► A coupling agent (APS) promotes the adhesion between Ni-Fe-P alloy films and FACs surface. ► Ag atoms renders active sites on coating Ni-Fe-P alloy films on the surface of FACs. ► A new kind of composite material of Ni-Fe-P alloy films coated on FACs was obtained by modified electroless plating method. ► The formation mechanism of the composite material was discussed in detail.
Co-reporter:Liang Ding, Qin Li, Dandan Zhou, Hao Cui, Hao An, Jianping Zhai
Journal of Electroanalytical Chemistry 2012 Volume 668() pp:44-50
Publication Date(Web):1 March 2012
DOI:10.1016/j.jelechem.2011.12.018
Bromate is recognized as an oxyhalid disinfection byproduct in drinking water. Polyaniline/multi-walled carbon nanotubes composite (PANI/CNT) was synthesized by in situ chemical oxidation and employed to investigate the electrocatalytic reduction of bromate. The introduction of CNT into PANI was proven by X-ray diffraction and transition electron microscopy. The prepared PANI/CNT composite presented better electrochemical performances than pure PANI. The electrochemical reduction of bromate occurred while polyaniline transformed from emeraldine into leucoemeraldine in acid solution. Besides, peak current of bromate reduction increased linearly with bromate concentration, indicating an analyte diffusion process. The activation energy for bromate reduction was calculated to be 10.98 kJ mol−1. Various initial bromate concentrations had different removal rates. The maximum removal rate of BrO3- at 10 mg L−1 (48.9%) was better than those at 50 mg L−1 (30.1%) and 100 mg L−1 (13.2%). Due to the persistent doping of bromide ions into polyaniline, the electrocatalytic performance of PANI/CNT decreased as the electrochemical reaction progressing.Highlights► Polyaniline/multi-walled carbon nanotubes composite was simply synthesized by in situ chemical oxidation. ► The prepared PANI/CNT composite presented better electrochemical performance than PANI. ► PANI/CNT was employed to investigate the electrocatalytic reduction of bromate in acid solution theoretically. ► The reduction of bromate occurred while polyaniline transformed from emeraldine into leucoemeraldine. ► The efficiency of bromate reduction and stability of the modified electrode were investigated.
Co-reporter:Guanghong Sheng, Qin Li, Jianping Zhai
Fuel 2012 Volume 98() pp:61-66
Publication Date(Web):August 2012
DOI:10.1016/j.fuel.2012.02.008
Self-cementitious properties of fly ash from circulating fluidized bed combustion boiler (CFBC) with limestone addition were investigated, especially the effect of lime on self-cementing process. The CFBC fly ash is self-cementitious and its main hydration products are ettringite (AFt), hydrated calcium silicate (CSH), portlandite, and gypsum. Slaking of free lime has a great effect on the self-cementing process of CFBC fly ash, accelerating the setting process. The self-cementing process of CFBC fly ash paste is based on three main reactions: (1) generation of Ca(OH)2 micelles by quick slaking of lime, (2) generation of AFt by active alumina reacting with CaSO4 and Ca(OH)2, and (3) generation of CSH by active silica reacting with Ca(OH)2.Highlights► The CFBC fly ash is self-cementitious and its main hydration products are AFt, CSH, portlandite, and gypsum. ► Slaking of free lime accelerates the setting process of CFBC fly ash paste. ► The self-cementing process of CFBC fly ash paste is based on the generation of Ca(OH)2 micelle, AFt and CSH.
Co-reporter:Qin Li, Hui Xu, Feihu Li, Peiming Li, Lifeng Shen, Jianping Zhai
Fuel 2012 Volume 97() pp:366-372
Publication Date(Web):July 2012
DOI:10.1016/j.fuel.2012.02.059
Blends of circulating fluidized bed combustion (CFBC) fly and bottom ashes of the same coal origin were investigated as raw materials for geopolymer synthesis. Reactivity of the low-reactive CFBC fly ash (CFA) was enhanced by an alkali-fusion pretreatment, which was optimized by an L16 (44) orthogonal array. It was found that, at a relatively low sodium hydroxide to CFA mass ratio of 0.5, effective alkali fusion could be achieved at 350 °C for 0.5 h. The fused CFA was blended with ground CFBC bottom ash (CBA) at mass ratios of 2.00, 1.00, 0.55, 0.29, and 0.12, and activated by two sodium silicate solutions (21.6 wt% and 34.5 wt%). Geopolymer pastes were cured at 40 °C for 7 days, reaching a highest compressive strength of 34.0 MPa. Characterization of the raw materials and geopolymer products was also conducted by an alkaline dissolution test, thermogravimetric–differential thermal analysis (TG–DTA), X-ray diffractography (XRD), scanning electron microscopy (SEM), as well as Fourier transform infrared spectroscopy (FTIR). The results of this study suggest that, by a moderate alkali-fusion pretreatment at temperatures slightly higher than the melting point for sodium hydroxide (318 °C), low-reactive CFA can be recycled together with CBA for production of value-added geopolymer composites.Highlights► Simultaneous recycling of CFBC fly and bottom ashes by geopolymerization. ► No natural kaolinitic resource (raw or calcined kaolinite) involved. ► Modified alkali-fusion pretreatment for enhancing the reactivity of CFBC fly ash. ► An L16 (44) orthogonal array designed for optimization of the alkali fusion. ► High 7-day compressive strength of 32.7 MPa for recommended geopolymer sample.
Co-reporter:Bing Wang, Qin Li, Wei Wang, Ying Li, Jianping Zhai
Applied Surface Science 2011 Volume 257(Issue 8) pp:3473-3479
Publication Date(Web):1 February 2011
DOI:10.1016/j.apsusc.2010.11.050
Abstract
Fe3+-doped TiO2 film deposited on fly ash cenosphere (Fe–TiO2/FAC) was successfully synthesized by the sol–gel method. These fresh photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analyses (TGA). The XRD results showed that Fe element can maintain metastable anatase phase of TiO2, and effect of temperature showed rutile phase appears in 650 °C for 0.01% Fe–TiO2/FAC. The SEM analysis revealed the Fe–TiO2 films on the surface of a fly ash cenosphere with a thickness of 2 μm. The absorption threshold of Fe–TiO2/FACs shifted to a longer wavelength compared to the photocatalyst without Fe3+-doping in the UV–vis absorption spectra. The photocatalytic activity and kinetics of Fe–TiO2/FAC with varying the iron content and the calcination temperatures were investigated by measuring the photodegradation of methyl blue (MB) during visible light irradiation. Compared with TiO2/FAC and Fe3+-doped TiO2 powder (Fe–TiO2), the degradation ratio using Fe–TiO2/FAC increased by 33% and 30%, respectively, and the best calcined temperature was 450 °C and the optimum doping of Fe/Ti molar ratio was 0.01%. The Fe–TiO2/FAC particles can float in water due to the low density of FAC in favor of phase separation to recover these photocatalyst after the reaction, and the recovery test shows that calcination contributes to regaining photocatalytic activity of Fe–TiO2/FAC photocatalyst.
Co-reporter:Hao An, Qin Li, Dejing Tao, Hao Cui, Xiaotian Xu, Liang Ding, Li Sun, Jianping Zhai
Applied Surface Science 2011 Volume 258(Issue 1) pp:218-224
Publication Date(Web):15 October 2011
DOI:10.1016/j.apsusc.2011.08.034
Abstract
For the electrochemical oxidative degradation of wastewater, it is crucial for electrodes to be highly catalytic active, stable in performance and inexpensive in price. This study focuses on the preparation of the Ti/SnO2–Sb2O3/PbO2 anodes by anodic deposition under galvanostatic conditions and their electrocatalytic activity affected by crystal structure and surface roughness under different electrochemical deposition time, with phenol taken as the model pollutant to evaluate the electrocatalytic activity. The electrode surface morphology is characterized by XRD and SEM-EDX. The treatment effect of phenol is reflected by electrochemical analysis like CV and LSV. An important conclusion from experiment is that electrochemical deposition time has a major impact on electrocatalytic activity with the optimal deposition time observed around 30 min. At both deposition time beyond this optimal time window, electrocatalytic activity of phenol is substantially lowered. Increasing in electrochemical deposition time leads to a more uniform and smooth electrode surface, which enjoys a more compact structure than the “cracked-mud” one but lower specific surface area and catalytic activity. On the contrary, the “cracked-mud” structure means potentially a unique porous structure, which makes morphology at 30 min a perfect one for high electrocatalytic activity.
Co-reporter:Rong Tang;Qin Li;Hao Cui;Ya Zhang
Polymers for Advanced Technologies 2011 Volume 22( Issue 12) pp:2231-2236
Publication Date(Web):
DOI:10.1002/pat.1750
Abstract
A novel poly(aniline-co-o-aminophenol) (PAOA)/mesoporous silica SBA-15 nanocomposite was synthesized and investigated for adsorption of Hg (II) from aqueous solutions of wide pH range. A chemical oxidation method was employed for polymerization of aniline and o-aminophenol on an ordered SBA-15 template to obtain a significantly enlarged BET surface area of the adsorbent. Efficiency study revealed that the PAOA/SBA-15 could reach a maximum Hg (II) adsorption capacity of over 400 mg/g. Kinetic study showed that the Hg (II) adsorption by the PAOA/SBA-15 fitted a pseudo-second-order kinetic model, indicating that the mercury adsorption process was predominantly controlled by chemical process. The results of this study also proved that the adsorbed Hg (II) could be effectively desorbed from the PAOA/SBA-15 in 0.1M HCl and 5% sulfocarbonide solutions. Associated adsorption mechanism was also investigated by means of Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) techniques. Copyright © 2010 John Wiley & Sons, Ltd.
Co-reporter:Jianfeng Pang, Qin Li, Wei Wang, Xiaotian Xu, Jianping Zhai
Surface and Coatings Technology 2011 205(17–18) pp: 4237-4242
Publication Date(Web):
DOI:10.1016/j.surfcoat.2011.03.020
Co-reporter:Liang Ding, Qin Li, Hao Cui, Rong Tang, Hui Xu, Xianchuan Xie, Jianping Zhai
Electrochimica Acta 2010 Volume 55(Issue 28) pp:8471-8475
Publication Date(Web):1 December 2010
DOI:10.1016/j.electacta.2010.07.062
The electrocatalytic reduction of bromate ion (BrO3−) was investigated in a three-electrode system using polyaniline (PANI) as the electrode material. Bromate ion reduction and Br− removal were observed during electrochemical treatment because of the catalytic and doping capabilities of the PANI film. BrO3− removal efficiency in the 0.10 mol L−1 Na2SO4 supporting electrolyte achieved 99% at pH 7 in 25 min, with no bromide ion detected in the solution. Optimal removal was found in pH range 6–7, and the pH of the solution had a significant impact on bromate reduction. A reduction mechanism was also discussed by analyzing the cyclic voltammograms of the reduction process and X-ray photoelectron spectra of the main elements (N 1s and Br 3d) on the PANI surface. We propose that during the electrocatalytic reduction process, bromate is reduced to bromide because of the loss of electrons from the nitrogen atoms on the PANI chains. The doping of the resultant Br− ions in the PANI film has an important role in avoiding further oxidation of Br− to BrO3−. The used PANI film can be regenerated by de-doping the Br− ions with a 0.5 mol L−1 H2SO4 solution. Thus the process can be considered efficient and green.
Co-reporter:Ya Zhang, Qin Li, Hao Cui, Jianping Zhai
Electrochimica Acta 2010 Volume 55(Issue 24) pp:7219-7224
Publication Date(Web):1 October 2010
DOI:10.1016/j.electacta.2010.07.002
Phenol and 3-nitrophenol in a aqueous solution of NaCl with pH 4.0 can be polymerized on the polyaniline electrode to form polyaniline/polyphenol and polyaniline/poly(3-nitrophenol) composites, respectively, using potential cycling between −0.20 and 1.00 V (vs. SCE). Polyaniline played an important role in lowering passivation of the electrode, which made the consecutive electrochemical polymerization of phenol and 3-nitrophenol become possible. The growth of the polyaniline/polyphenol and polyaniline/poly(3-nitrophenol) films in the electrolytic process was proved by the increasing area of the cyclic voltammograms as the electrolysis proceeded. The SEM images and IR spectra of polyaniline and phenolic polymers demonstrated the formation of the phenolic polymers on the polyaniline electrode. Therefore, the removal of both phenolic compounds is based on the formation of their polymers on the polyaniline film.
Co-reporter:Ya Zhang, Qin Li, Li Sun, Jianping Zhai
Journal of Electroanalytical Chemistry 2009 Volume 636(1–2) pp:47-52
Publication Date(Web):15 November 2009
DOI:10.1016/j.jelechem.2009.09.009
Poly(aniline-co-o-aminophenol) (PANOA) deposited on the glassy carbon (GC) electrode was first used to investigate the electrocatalytic reduction of arsenate in a NaCl solution. The electrocatalytic evidence came from the pronounced increase in the current of arsenate reduction at the PANOA/GC electrode compared to the bare GC electrode under the same conditions. In the latter case the reduction current was small, indicating that arsenate is electrochemically inactive at the bare GC electrode. The catalytic activity of PANOA depended on the pH in the range 5.6–7.0, which is related to the effect of pH on the redox activity of PANOA and the dissociated form of arsenate in the solution. In addition, the electrochemical activity of PANOA was found to increase in a solution containing arsenate, which was caused by the increase in both the unpaired spin density of PANOA and the pH buffer capacity of the solution due to the presence of arsenate. The XPS data indicated that PANOA can be used to remove arsenate from the solution.
Co-reporter:Feihu Li, Hao Fu, Jianping Zhai, Qin Li
Microporous and Mesoporous Materials 2009 Volume 123(1–3) pp:177-184
Publication Date(Web):1 July 2009
DOI:10.1016/j.micromeso.2009.03.044
Co-reporter:Ya Zhang, Shaolin Mu, Jianping Zhai
Synthetic Metals 2009 Volume 159(17–18) pp:1844-1851
Publication Date(Web):September 2009
DOI:10.1016/j.synthmet.2009.06.004
A conducting copolymer poly(aniline-co-2,4-diaminophenol) (PADAP) with two kinds of functional groups was first synthesized via the chemical copolymerization of aniline and 2,4-diaminophenol (DAP) in the acidic medium. The fast copolymerization rate resulted in the formation of PADAP copolymer nanostructures in the absence of templates. The spectra of FTIR and 1H NMR demonstrate that there is DAP unit in the polymer chain. The ΔHpp of the ESR signal and unpaired spin density of PADAP are very sensitive to the copolymer composition that is a function of monomer concentration ratio in the mixture. The properties of PADAP are affected by several polymerization factors, but the most important one among them is the monomer concentration ratio in the mixture used for the copolymerization. PADAP synthesized under the optimal copolymerization conditions has good redox activity from highly acidic solution to pH 12.0 in a wider potential range and has a conductivity very close to that of polyaniline. However, the pH dependence of the conductivity of PADAP is improved compared to that of polyaniline. The fast copolymerization rate and novel electrical properties of the copolymer are attributed to the synergistic effect of –NH2 and –OH functional groups in the copolymer chain.
Co-reporter:Xiaoru Fu, Qin Li, Jianping Zhai, Guanghong Sheng, Feihu Li
Cement and Concrete Composites 2008 Volume 30(Issue 3) pp:220-226
Publication Date(Web):March 2008
DOI:10.1016/j.cemconcomp.2007.08.006
The physical–chemical characteristics of mechanically-treated circulating fluidized bed combustion (CFBC) fly ash, such as 45 μm sieve residue, granulometric distribution, water requirement, specific gravity, pH value, and mineralogical phases, were investigated. It was found that the grinding process can be divided into three stages. The increase in fineness of ground CFBC fly ash is very sharp in the first stage, then slows down in the second stage, and in the last stage it becomes almost invary. The water requirement decreases with prolonged grinding time, and slightly increases during the last stage of grinding. Ground CFBC fly ash shows a higher specific gravity due to the crushing of coarse particles and carbon particles. The pH of ground CFBC fly ash is greater than that of the original CFBC fly ash, indicating that ground samples react more rapidly with water. The mineralogical compositions remain unchanged with grinding, although the intensity of the crystalline phases decreases and the half peak width increases.
Co-reporter:Guanghong Sheng, Jianping Zhai, Qin Li, Feihu Li
Fuel 2007 Volume 86(Issue 16) pp:2625-2631
Publication Date(Web):November 2007
DOI:10.1016/j.fuel.2007.02.018
Fly ash coming from a circulating fluidized bed combustion (CFBC) boiler co-firing coal and petroleum coke (CFBC fly ash) is very different from coal ash from traditional pulverized fuel firing due to many differences in their combustion processes, and thus they have different effects on the properties of Portland cement. The influences of CFBC fly ash on the strength, setting time, volume stability, water requirement for normal consistency, and hydration products of Portland cement were investigated. The results showed that CFBC fly ash had a little effect on the strength of the Portland cement when its content was below 20%, but the strength decreased significantly if the ash content was over 20%. The water requirement for normal consistency of cement increased from 1.8% to 3.2% (absolute increment value) with an addition of 10% CFBC fly ash; and the free lime (f-CaO) content of CFBC fly ash affected the value of increasing. The setting time decreased with an increase of CFBC fly ash content. The volume stability of the cement was qualified even when the content of SO3 and f-CaO reached 4.48% and 3.0% in cement, respectively. The main hydration productions of cement with CFBC fly ash were C–S–H (hydrated calcium silicate), AFt (ettringite), and portlandite.
Co-reporter:Hao Cui, Yan Qian, Qin Li, Zhongbo Wei, Jianping Zhai
Applied Clay Science (February 2013) Volume 72() pp:84-90
Publication Date(Web):February 2013
DOI:10.1016/j.clay.2013.01.003
Co-reporter:Ya Zhang, Qin Li, Rong Tang, Qiuchan Hu, Li Sun, Jianping Zhai
Applied Catalysis B: Environmental (9 November 2009) Volume 92(Issues 3–4) pp:351-356
Publication Date(Web):9 November 2009
DOI:10.1016/j.apcatb.2009.08.014
Co-reporter:Qin Li, XiaoTian Xu, Hao Cui, Jianfeng Pang, ZhongBo Wei, Zengqing Sun, Jianping Zhai
Journal of Environmental Management (15 May 2012) Volume 98() pp:98-106
Publication Date(Web):15 May 2012
DOI:10.1016/j.jenvman.2011.12.018
Two adsorbents, magnesia-loaded fly ash cenospheres (MGLC) and manganese-loaded fly ash cenospheres (MNLC), were prepared by wet impregnation of fly ash cenospheres with MgCl2 solution or a mixed solution of MnCl2 and KMnO4, respectively. Their physicochemical properties were characterized by scanning electron microscopy, X-ray diffractometry, X-ray fluorescence spectrometry, and Fourier transform infrared spectrometry. Sorption experiments were conducted to examine the effects of adsorbent dosage, pH, time, temperature, ionic strength and competing anions on As(V) removal by MGLC and MNLC. Both MGLC and MNLC had greater pH buffering capacity and were less affected by changes in ionic strength. Competing anions (carbonate and dihydric phosphate) had a larger impact on As(V) removal by MNLC than by MGLC. Adsorption on MNLC reached equilibrium at 60 min, while adsorption on MGLC reached equilibrium at 120 min. The Langmuir adsorption isotherm was a good fit for the experimental data of As(V) adsorption on MGLC and MNLC, and the adsorption kinetics for both followed the pseudo-second-order rate equation. MGLC and MNLC had a larger removal capacity for As(V) than the cenospheres. Compared with MNLC, MGLC is a better absorbent.Highlights► Two adsorbents, MGLC and MNLC were prepared for As(V) removal. ► Both MGLC and MNLC were less affected by changes in pH value and ionic strength. ► Competing anions (CO32− and HCO3−) had a larger impact on As(V) removal by MNLC than by MGLC. ► The Langmuir adsorption isotherm was a good fit for As(V) adsorption on MGLC and MNLC. ► The adsorption kinetics for both MGLC and MNLC followed the pseudo-second-order rate equation.
