MOLECULES
·
2024
·Vol. 29
·期 7
·1560
·
IF 4.2
Yi Fang,Lang Yang,Feng Rao,Kaiming Zhang,Zhuolin Qin,Zhenguo Song,Zhihui Na
Geopolymers show great potential in complex wastewater treatment to improve water quality. In this work, general geopolymers, porous geopolymers and geopolymer microspheres were prepared by the suspension curing method using three solid waste products, coal gangue, fly ash and blast furnace slag. The microstructure, morphology and surface functional groups of the geopolymers were studied by SEM, XRD, XRF, MIP, FTIR and XPS. It was found that the geopolymers possess good adsorption capacities for both organic and inorganic pollutants. With methylene blue and potassium dichromate as the representative pollutants, in order to obtain the best removal rate, the effects of the adsorbent type, dosage of adsorbent, concentration of methylene blue and potassium dichromate and pH on the adsorption process were studied in detail. The results showed that the adsorption efficiency of the geopolymers for methylene blue and potassium dichromate was in the order of general geopolymers < porous geopolymers < geopolymer microspheres, and the removal rates were up to 94.56% and 79.46%, respectively. Additionally, the competitive adsorption of methylene blue and potassium dichromate in a binary system was also studied. The mechanism study showed that the adsorption of methylene blue was mainly through pore diffusion, hydrogen bond formation and electrostatic adsorption, and the adsorption of potassium dichromate was mainly through pore diffusion and redox reaction. These findings demonstrate the potential of geopolymer microspheres in adsorbing organic and inorganic pollutants, and, through five cycles of experiments, it is demonstrated that MGP exhibits excellent recyclability.
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高影响因子
FUEL
·
2024
·
IF 6.7
Fanjia Sun,Xueqing Tian,Jianbing Zang,Rui Zhu,Zhiwei Hou,Youbin Zheng,Yanhui Wang,Liang Dong
Transition metal sulfides, recognized for their platinum-like activity, were prominent in electrolytic water hydrogen production research. In this context, we reported a NiS/NiS 2 heterostructure composite active center electrocatalyst optimized by Cr doping (Cr-NiS/NiS 2 @NF) based on the dual regulation of defect engineering and interface engineering. The electronic structure of Ni and S could be adjusted by Cr doping, and the creation of defects exposed more active sites. Meanwhile, the resulting NiS/NiS 2 heterogeneous interface acted as a composite activity center, enhancing the alkaline HER process rate. The Cr-NiS/NiS 2 @NF achieved 100 mA cm −2 at an overpotential of 172.8 mV. Density functional theory analysis confirms the significant decrease in the water dissociation potential barrier, attributable to the electron redistribution caused by Cr doping. The optimized heterointerface functioned as a composite activity center. Here, the Cr-NiS component effectively facilitated water dissociation, while the NiS 2 component primarily enhanced H 2 generation and desorption. The introduction of Cr significantly improved the electronic coupling at the bi-phase interfaces, thereby accelerating the transport of hydrogen intermediates. This study revealed the modulation of electron distribution at the Cr-doped nickel sulfide heterointerface, offering deep atomic-scale insights. These findings provide novel perspectives for the field of hydrogen production via water electrolysis.
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CHEMICAL ENGINEERING JOURNAL
·
2016
·
IF 5.31
Lei Wang,Changbo Zhang,Feng Gao,Gilles Mailhot,Gang Pan
Algae as an abundant natural biomass, more attention has been paid to explore its potential application in environmental pollutants treatment. This work prepared the algae-TiO 2 /Ag bionano hybrid material by loading algae cells on the ultrafine TiO 2 /Ag chitosan hybrid nanofiber mat. For the first time, the synergistic photocatalytic effect of fresh algae and TiO 2 /Ag nanomaterial was investigated by removal of Cr(VI). The addition of algae significantly improved the photo-removal of Cr(VI) in the system with TiO 2 /Ag hybrid nanomaterial under visible light irradiation. Meanwhile, the photocatalytic mechanism was studied. The photogenerated reactive oxygen species were quantified and the addition of algae apparently decreased the yields of OH to 31.0 μM, while improved the yields of 1 O 2 and O 2 − in the reaction system with TiO 2 /Ag hybrid nanofiber mats. The change of superoxide dismutase activity and malondialdehyde content in algae indicated that TiO 2 /Ag could impose oxidative stress and cause lipid peroxidation in algae cells. During the course of irradiation, algae released substances could act as scavenger for holes, thus inhibited the recombination of hole/electron and enhanced the photocatalytic reduction of Cr(VI) by electrons on TiO 2 surface. Algae was simultaneously photodegraded in the system and the resulting O 2 − , organic free radicals could promote the reduction of Cr(VI). This functional hybrid nanofiber mat was easily recovered and maintained a great photocatalytic activity on the five successive cycles. This algae-photocatalyst hybrid material has promising applications potential in heavy metal removal and organic pollutants treatment.
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Analytical Methods
·
2016
·Vol. 8
·期 15
·3263-3269
·
IF 1.915
Yangjuan Wang,Kejing Du,Yifu Chen,Yijun Li,Xiwen He
Green octahedral crystals of MIL-101(Cr) were synthesized and used for the determination of Pb2+ at the trace level by differential pulse anodic stripping voltammetry (DPASV) because of their good adsorption capability for Pb2+. The synthesized MIL-101(Cr) was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Parameters affecting the electrochemical process, such as the pH of the electrolyte solution, the volume of the MIL-101(Cr) suspension, the potential and the time for accumulation, were investigated in detail. Under optimal conditions, the electrochemical sensor had a linear response over the concentration range of 1.0 × 10−9 to 1.0 × 10−6 mol L−1 (R2 = 0.999) with a detection limit of 5.0 × 10−10 mol L−1 (S/N = 3). The method was successfully applied to the determination in real samples and good recoveries are obtained from different spiked samples.
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ELECTROCHIMICA ACTA
·
2017
·
IF 4.798
Huan Zhang,Yi Tan,Jiayan Li,Bing Xue
The performances of rayon (RGF) and polyacrylonitrile (PGF) based graphite felts as electrodes are compared in the iron-chromium redox flow battery (ICRFB). The essential differences in structure between RGF and PGF are also characterized in this study. The results show that the RGF electrode displays excellent electrochemical performance for negative redox couple (Cr 3+ /Cr 2+ ), resulting in the cell with higher charge efficiency and slower capacity decay. However, due to the high degree of graphitization and electrochemical activity for positive redox couple (Fe 2+ /Fe 3+ ) in PGF, the cell using PGF has higher voltage efficiency and energy efficiency, as well as lower area surface resistance than the cell with RGF. The fundamental difference between RGF and PGF is the crystallites structure in radial direction and basal plane of the fiber. PGF with the core-rim structure has better graphitization stacked in radial direction of the fiber. Further, PGF has more defective carbons exposed in the basal planes, while the surface of RGF exhibits a higher concentration of oxygen functional groups. The role of catalysts in the ICRFB has also been studied by introducing bismuth (Bi) into RGF and PGF used as negative electrodes. The electrocatalytic activities of RGF and PGF before and after modification with Bi are investigated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). Bismuth deposition on the negative electrode is found to improve the negative reaction in ICRFB.
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JOURNAL OF HAZARDOUS MATERIALS
·
2017
·
IF 6.065
Sheng Luo,Fan Qin,Yin’an Ming,Huiping Zhao,Yunling Liu,Rong Chen
Hazardous hexavalent chromium removal from wastewater is an urgent issue in industry environmental pollution. In this work, hollow Bi 2 S 3 nanospheres have been successfully synthesized from unique Bi 2 O 3 porous nanospheres via Kirkendall effect through hydrothermal process. It was found that the sulfur source and the initial Bi 2 O 3 templates played key roles in the formation of the uniform morphologies and structures through an anion exchange process. Compared with other Bi 2 S 3 samples, the synthesized hollow Bi 2 S 3 nanospheres exhibited much enhanced photocatalytic ability for Cr(VI) photoreduction. XPS analysis demonstrated that Cr(VI) was reduced to less harmful Cr(III) species over hollow Bi 2 S 3 nanospheres under visible-light irradiation. More importantly, the hollow Bi 2 S 3 nanospheres remained high efficiency and good stability in the recycling Cr(VI) photoreduction, and exhibited remarkable Cr(VI) removal ability in actual electroplating industry wastewater treatment.
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高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2016
·
IF 3.138
Pan Hu,Jing Wang,Ruihua Huang
In this study, simultaneous removal of Cr(VI) and Amido Black 10B (AB10B) using quaternized chitosan coated bentonite was investigated by a batch method. The factors affecting adsorption process such as pH, adsorbent dosage, contact time and initial concentration and the interaction of two components in binary solutions have been studied. The results showed that the antagonism effect existed between Cr(VI) and AB10B in binary systems. The equilibrium time for Cr(VI) adsorption was less than the one for AB10B adsorption. The maximum adsorption capacities of the modified bentonite, according to the Langmuir isotherm model were 847.5 mg/g for AB10B and 66.6 mg/g for Cr(VI) at 298 K. The experimental results demonstrated that both Cr(VI) and AB10B were well described by the pseudo-second-order model. Thermodynamic study depicted that the adsorption of Cr(VI) and AB10B onto the modified bentonite was both spontaneous. The adsorption for Cr(VI) was exothermic while the one for AB10B was endoth- ermic in nature.
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RSC Advances
·
2017
·Vol. 7
·期 60
·37778-37786
·
IF 3.108
Shuibin Cen,Weiming Li,Rong He,Jiean Tan,Haishui Wang,Chaohai Wei,Youwen Tang
We developed an effective and selective method to remove Cr(III) ions in acidic effluents. This method used combined ion imprinted technology with mesoporous silica materials. Cr(III) ion imprinted mesoporous silica (CrIMS) was synthesized and used as an excellent adsorbent. Iminodiacetic acid (IDA) was silanized, and acted as a functional monomer. The chemical groups, thermal stability, porosity and highly ordered morphology of CrIMS were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Brunauer–Emmett–Teller (BET) isotherms, X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The Brunauer–Emmett–Teller (BET) surface area was 856.24 m2 g−1. The saturated adsorption capacity of CrIMS towards Cr(III) ions reached up to 63 mg g−1 at pH 4.5. At a concentration of 200 mg L−1, the adsorption of Cr(III) ions reached equilibrium within 5 min and 20 min at pH 4.5 and pH 3.0, respectively. The CrIMS showed highly specific adsorption capacity and the imprinting factor was up to 4.03 at pH 3.0. The adsorption capacity of Cr(III) ions was remarkably higher than other co-existing metal ions. After eight adsorption–regeneration cycles, the adsorption efficiency of CrIMS still reached above 94.1%. The CrIMS could effectively remove Cr(III) ions below the discharge standard of China in real sample treatment.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2017
·
IF 9.446
Yaru Li,Zhongmin Liu,Yongchuan Wu,Jitao Chen,Jingyu Zhao,Fengmin Jin,Ping Na
Carbon dots-TiO 2 nanosheets (CDs-TNs) composites were synthesized by hydrothermal method and applied for the first time in photoreduction of Cr(VI) under sunlight illumination. The materials were characterized by transmission electron microscope, X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectrometer, and X-ray photoelectron spectroscopy analysis. The results confirmed that CDs are successfully incorporated with TNs through Ti O C bonds. With the introduction of CDs, CDs-TNs composites exhibit excellent photoreduction performance of Cr(VI), which is higher than that of TNs, P25 and CDs-P25. The unique upconversion property and electron transfer property of CDs play essential roles on light harvesting and charge carriers transferring in the photoreduction process. Most importantly, CDs could facilitate the formation of H 2 O 2 , leading to the consumption of holes. As a result, the recombination of photoinduced electron-hole pairs is hindered and photoreduction activity of CDs-TNs is promoted.
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JOURNAL OF HAZARDOUS MATERIALS
·
2017
·
IF 6.065
Qinghua Xu,Yulu Wang,Liqiang Jin,Yu Wang,Menghua Qin
A novel nanocomposite based on black wattle (BW) tannin and nanocellulose was prepared and applied in heavy metal ions adsorptive removal from aqueous solutions. Firstly, nanocrystalline cellulose was oxidized by sodium periodate to get dialdehyde nanocellulose (DANC). BW tannin was then covalently immobilized onto DANC, which was used as both the matrix and crosslinker, to obtain tannin-nanocellulose (TNCC) composite. The resulting nanocomposite was characterized using FTIR, AFM, and TG. The successful immobilization was confirmed by the chromogenic reaction between FeCl 3 and TNCC and FT-IR analysis. AFM images revealed that TNCC was ellipsoidal particles with lengths ranging from 100–400 nm. Zeta potential measurement showed that TNCC was negative charged at a pH range from 1–12. Compared to the original tannin, the thermal stability of TNCC was slightly increased by the addition of nanocellulose. TNCC demonstrated the maximum adsorption efficiency at pH 2 for Cr(VI) and pH 6 for Cu(II) and Pb(II), respectively. The adsorption for these three metal ions followed pseudo second-order kinetics, indicating the chemisorption nature. The adsorption isotherms all fitted well with the Sips model, and the calculated maximum adsorption capacities were 51.846 mg g −1 , 53.371 mg g −1 and 104.592 mg g −1 for Cu(II), Pb(II) and Cr (VI), respectively.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2016
·
IF 3.299
Ning Zhuo,Yaqian Lan,Weiben Yang,Zhen Yang,Xiaomin Li,Xia Zhou,Yang Liu,Jiachun Shen,Xuntong Zhang
Porous metal-organic frameworks (MOFs) have great potential as high-effective adsorbents for water treatment. However, poor separability restricts their practical application. To overcome the drawback, both MIL-101(Cr)/sodium alginate (MIL-101(Cr)/SA) and MIL-101(Cr)/chitosan (MIL-101(Cr)/CS) composite beads were prepared and characterized. Adsorption of three selected pharmaceuticals and personal care products (PPCPs) (benzoic acid (BEN), ibuprofen (IBU) and ketoprofen (KET)) onto the two composite beads was investigated and compared with pristine SA and CS beads. Kinetic plots, pH dependence, isotherm data, and influences of ionic strength were reported. The MIL-101(Cr)/CS beads exhibit much higher adsorption capacity than SA, CS and MIL-101(Cr)/SA, and the adsorption amounts of three PPCPs onto MIL-101(Cr)/CS follow the order of KET > IBU > BEN. The adsorption amounts of the three PPCPs on the MIL-101(Cr)/CS increased quickly during the first 60 min of contact time and then achieved the adsorption equilibrium after ∼180 min. Not only the protonated amine groups but also the Cr center of the adsorbents exerted electrostatic attraction with the deprotonated carboxyl groups of contaminants, as elucidated by X-ray photoelectron spectroscopy (XPS). Based on the adsorption isotherms and π-energy analysis of three PPCPs, π-π interaction of aromatic groups between adsorbents and contaminants also contributed to the adsorption. The MIL-101(Cr)/CS beads exhibited good regenerability over several repeated adsorption/desorption cycles. Overall, this study is believed to enlarge the application of MOFs on the removal of emerging contaminants from waters.
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MICROCHIMICA ACTA
·
2016
·Vol. 183
·期 12
·3151-3157
·
IF 4.831
Yu Haili,Long Dengying
The authors describe a highly chemiluminescent metal-organic framework (MOF) that was obtained by loading the pores of MIL-101(Cr) with luminol. Immobilization is based on Lewis acid-base interactions between the coordinatively unsaturated metal sites of MIL-101(Cr) and the amino groups of luminol. The luminol-loaded MOF displays strong chemiluminescence (CL) in the presence of hydrogen peroxide (H 2 O 2 ) in alkaline solution. Pyrophosphate (PPi), in turn, acts as a quencher of this CL. These findings have been exploited in the design of a CL based method for the determination of either H 2 O 2 or PPi. The assays for H 2 O 2 works in the 3 to 100 μM concentration range and has a detection limit of 0.5 μM. The quenchometric assay for PPi works in the 5 to 70 μM concentration range and has a 1.2 μM detection limit.
Luminol-embedded metal-organic frameworks (MOFs) with high chemiluminescent activity were prepared and used for the sensitive determination of either H 2 O 2 or pyrophosphate ions.
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