scholarly journals Synthesis of Calcium Silicate Hydrate from Coal Gangue for Cr(VI) and Cu(II) Removal from Aqueous Solution

Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6192
Author(s):  
Qing Zhang ◽  
Guijian Liu ◽  
Shuchuan Peng ◽  
Chuncai Zhou
Keyword(s):  
Aqueous Solution ◽  
Reaction Time ◽  
Calcium Silicate ◽  
Calcium Silicate Hydrate ◽  
Variable Temperature ◽  
Coal Gangue ◽  
Molar Ratio ◽  
Solution Temperature ◽  
Solution Ph ◽  
Adsorption Temperature

Both the accumulation of coal gangue and potentially toxic elements in aqueous solution have caused biological damage to the surrounding ecosystem of the Huainan coal mining field. In this study, coal gangue was used to synthesize calcium silicate hydrate (C-S-H) to remove Cr(VI) and Cu(II)from aqueous solutions and aqueous solution. The optimum parameters for C-S-H synthesis were 700 °C for 1 h and a Ca/Si molar ratio of 1.0. Quantitative sorption analysis was done at variable temperature, C-S-H dosages, solution pH, initial concentrations of metals, and reaction time. The solution pH was precisely controlled by a pH meter. The adsorption temperature was controlled by a thermostatic gas bath oscillator. The error of solution temperature was controlled at ± 0.3, compared with the adsorption temperature. For Cr(VI) and Cu(II), the optimum initial concentration, temperature, and reaction time were 200 mg/L, 40 °C and 90 min, pH 2 and 0.1 g C-S-H for Cr(VI), pH 6 and 0.07 g C-S-H for Cu(II), respectively. The maximum adsorption capacities of Cr(VI) and Cu(II) were 68.03 and 70.42 mg·g−1, respectively. Furthermore, the concentrations of Cu(II) and Cr(VI) in aqueous solution could meet the surface water quality standards in China. The adsorption mechanism of Cu(II) and Cr(VI) onto C-S-H were reduction, electrostatic interaction, chelation interaction, and surface complexation. It was found that C-S-H is an environmentally friendly adsorbent for effective removal of metals from aqueous solution through different mechanisms.

Heterogeneous Fenton Catalytic Removal of Organic Pollutant in Aqueous Solution by using Coal Gangue as a Catalyst

2019 ◽  
Vol 12 (4) ◽  
pp. 312-325
Author(s):  
Jiwei Zhang ◽  
Jingjing Xu ◽  
Shuaixia Liu ◽  
Baoxiang Gu ◽  
Feng Chen ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Hydroxyl Radical ◽  
Removal Rate ◽  
Organic Pollutant ◽  
Coal Gangue ◽  
Ion Leakage ◽  
Heterogeneous Fenton ◽  
Solution Ph ◽  
X Ray

Background: Coal gangue was used as a catalyst in heterogeneous Fenton process for the degradation of azo dye and phenol. The influencing factors, such as solution pH gangue concentration and hydrogen peroxide dosage were investigated, and the reaction mechanism between coal gangue and hydrogen peroxide was also discussed. Methods: Experimental results showed that coal gangue has the ability to activate hydrogen peroxide to degrade environmental pollutants in aqueous solution. Under optimal conditions, after 60 minutes of treatment, more than 90.57% of reactive red dye was removed, and the removal efficiency of Chemical Oxygen Demand (COD) up to 72.83%. Results: Both hydroxyl radical and superoxide radical anion participated in the degradation of organic pollutant but hydroxyl radical predominated. Stability tests for coal gangue were also carried out via the continuous degradation experiment and ion leakage analysis. After five times continuous degradation, dye removal rate decreased slightly and the leached Fe was still at very low level (2.24-3.02 mg L-1). The results of Scanning Electron Microscope (SEM), energy dispersive X-Ray Spectrometer (EDS) and X-Ray Powder Diffraction (XRD) indicated that coal gangue catalyst is stable after five times continuous reuse. Conclusion: The progress in this research suggested that coal gangue is a potential nature catalyst for the efficient degradation of organic pollutant in water and wastewater via the Fenton reaction.

scholarly journals Crystal structure of the new hybrid material bis(1,4-diazoniabicyclo[2.2.2]octane) di-μ-chlorido-bis[tetrachloridobismuthate(III)] dihydrate

2015 ◽  
Vol 71 (11) ◽  
pp. 1384-1387
Author(s):  
Marwen Chouri ◽  
Habib Boughzala
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Hydrogen Bonds ◽  
Room Temperature ◽  
Molar Ratio ◽  
Water Molecules ◽  
Site Symmetry ◽  
Two Dimensional ◽  
Slow Evaporation ◽  
Solution Ph

The title compound bis(1,4-diazoniabicyclo[2.2.2]octane) di-μ-chlorido-bis[tetrachloridobismuthate(III)] dihydrate, (C6H14N2)2[Bi2Cl10]·2H2O, was obtained by slow evaporation at room temperature of a hydrochloric aqueous solution (pH = 1) containing bismuth(III) nitrate and 1,4-diazabicyclo[2.2.2]octane (DABCO) in a 1:2 molar ratio. The structure displays a two-dimensional arrangement parallel to (100) of isolated [Bi2Cl10]4−bioctahedra (site symmetry -1) separated by layers of organic 1,4-diazoniabicyclo[2.2.2]octane dications [(DABCOH2)2+] and water molecules. O—H...Cl, N—H...O and N—H...Cl hydrogen bonds lead to additional cohesion of the structure.

scholarly journals Municipal Leachate Treatment by Fenton Process: Effect of Some Variable and Kinetics

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Mohammad Ahmadian ◽  
Sohyla Reshadat ◽  
Nader Yousefi ◽  
Seyed Hamed Mirhossieni ◽  
Mohammad Reza Zare ◽  
...  
Keyword(s):  
Reaction Time ◽  
Color Removal ◽  
Molar Ratio ◽  
Order Kinetic ◽  
Fenton Process ◽  
Solution Ph ◽  
Leachate Treatment ◽  
First Order ◽  
Order Kinetic Model ◽  
Better Than

Due to complex composition of leachate, the comprehensive leachate treatment methods have been not demonstrated. Moreover, the improper management of leachate can lead to many environmental problems. The aim of this study was application of Fenton process for decreasing the major pollutants of landfill leachate on Kermanshah city. The leachate was collected from Kermanshah landfill site and treated by Fenton process. The effect of various parameters including solution pH, Fe2+and H2O2dosage, Fe2+/H2O2molar ratio, and reaction time was investigated. The result showed that with increasing Fe2+and H2O2dosage, Fe2+/H2O2molar ratio, and reaction time, the COD, TOC, TSS, and color removal increased. The maximum COD, TOC, TSS, and color removal were obtained at low pH (pH: 3). The kinetic data were analyzed in term of zero-order, first-order, and second-order expressions. First-order kinetic model described the removal of COD, TOC, TSS, and color from leachate better than two other kinetic models. In spite of extremely difficulty of leachate treatment, the previous results seem rather encouraging on the application of Fenton’s oxidation.

scholarly journals ESR and Optical Studies on the Interaction between Cu(II) and Pepsin

1978 ◽  
Vol 33 (5-6) ◽  
pp. 321-325 ◽  
Author(s):  
L. Sportelli ◽  
H. Neubacher ◽  
W. Lohmann
Keyword(s):  
Aqueous Solution ◽  
Electron Spin Resonance ◽  
Reaction Time ◽  
Conformational Change ◽  
Optical Spectroscopy ◽  
Electron Spin ◽  
Molar Ratio ◽  
Optical Studies ◽  
Spin Resonance

Abstract The interaction of Cu (II) with the protein pepsin has been investigated by means of electron spin resonance (ESR) and optical spectroscopy. Depending on the molar ratio of Cu(II) and pepsin in aqueous solution two different complexes are formed. A third complex can be detected after a reaction time of several days, attributed to a complex with a conformationally changed pepsin. The presence of inhibitors 1,2-epoxy-3-phenoxypropane (EPP) or diazoacetyl-ethylester (DAE) seems to hinder the conformational change. The structure of the three complexes is discussed.

scholarly journals Characterization, Dissolution, and Solubility of Zn-Substituted Hydroxylapatites [(ZnxCa1−x)5(PO4)3OH] at 25°C

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Xin Zhao ◽  
Yinian Zhu ◽  
Zongqiang Zhu ◽  
Yanpeng Liang ◽  
Yanlong Niu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Lattice Parameter ◽  
Batch Experiment ◽  
Molar Ratio ◽  
Final Solution ◽  
Free Energies ◽  
Solution Ph ◽  
Initial Ph ◽  
Zinc Concentrations ◽  
The Mean

A series of Zn-substituted hydroxylapatites [(ZnxCa1−x)5(PO4)3OH, Zn-Ca-HA] with the Zn/(Zn + Ca) molar ratio (XZn) of 0~0.16 was prepared and characterized, and then the dissolution of the synthesized solids in aqueous solution was investigated by batch experiment. The results indicated that the aqueous zinc, calcium, and phosphate concentrations greatly depended on the Zn/(Zn + Ca) molar ratio of the Zn-Ca-HA solids (XZn). For the Zn-Ca-HA dissolution at 25°C with an initial pH of 2.00, the final solution pH increased, while the final solution calcium and phosphate concentrations decreased with the increasing XZn. The final solution zinc concentrations increased with the increasing XZn when XZn≤0.08 and decreased with the increasing XZn when XZn = 0.08~0.16. The mean Ksp values for (ZnxCa1−x)5(PO4)3OH at 25°C decreased from 10−57.75 to 10−58.59 with the increasing XZn from 0.00 to 0.08 and then increased from 10–58.59 to 10–56.63 with the increasing XZn from 0.08 to 0.16. This tendency was consistent with the dependency of the lattice parameter a on XZn. The corresponding free energies of formation (ΔGfo) increased lineally from −6310.45 kJ/mol to −5979.39 kJ/mol with the increasing XZn from 0.00 to 0.16.

scholarly journals Aqueous solution behavior of stimulus-responsive poly(methacrylic acid)-poly(2-hydroxypropyl methacrylate) diblock copolymer nanoparticles

2020 ◽  
Vol 11 (12) ◽  
pp. 2147-2156 ◽  
Author(s):  
Shannon M. North ◽  
Steven P. Armes
Keyword(s):  
Aqueous Solution ◽  
Methacrylic Acid ◽  
Diblock Copolymer ◽  
Dispersion Polymerization ◽  
Aqueous Dispersion ◽  
Solution Temperature ◽  
Solution Ph ◽  
Solution Behavior ◽  
Hydroxypropyl Methacrylate ◽  
Stimulus Responsive

RAFT aqueous dispersion polymerization is used to prepare poly(methacrylic acid)-poly(2-hydroxypropyl methacrylate) diblock copolymer nanoparticles, which exhibit stimulus-responsive behaviour on adjusting the solution temperature and/or solution pH.

scholarly journals Preparation and characterization of iron-copper binary oxide and its effective removal of antimony(III) from aqueous solution

2016 ◽  
Vol 74 (2) ◽  
pp. 393-401 ◽  
Author(s):  
Yongchao Li ◽  
Bing Geng ◽  
Xiaoxian Hu ◽  
Bozhi Ren ◽  
Andrew S. Hursthouse
Keyword(s):  
Aqueous Solution ◽  
Photoelectron Spectroscopy ◽  
Binary Oxide ◽  
Molar Ratio ◽  
Precipitation Process ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
X Ray ◽  
Freundlich Adsorption Isotherm ◽  
Co Precipitation

An Fe-Cu binary oxide was fabricated through a simple co-precipitation process, and was used to remove Sb(III) from aqueous solution. X-ray diffraction, scanning electron microscopy, energy dispersive X-ray and N2 adsorption–desorption measurements demonstrated that the Fe-Cu binary oxide consisted of poorly ordered ferrihydrite and CuO, and its specific surface area was higher than both iron oxide and copper oxide. A comparative test indicated that Fe/Cu molar ratio of prepared binary oxide greatly influenced Sb(III) removal and the optimum Fe/Cu molar ratio was about 3/1. Moreover, a maximum adsorption capacity of 209.23 mg Sb(III)/g Fe-Cu binary oxide at pH 5.0 was obtained. The removal of Sb(III) by Fe-Cu binary oxide followed the Freundlich adsorption isotherm and the pseudo-second-order kinetics in the batch study. The removal of Sb(III) was not sensitive to solution pH. In addition, the release of Fe and Cu ions to water was very low when the pH was greater than 6.0. X-ray photoelectron spectroscopy analysis confirmed that the Sb(III) adsorbed on the surface was not oxidized to Sb(V).

Sign in / Sign up

Export Citation Format

Share Document