Removal of sulfate from wet FGD wastewater by co-precipitation with calcium hydroxide and sodium aluminate

2018 ◽  
Vol 77 (5) ◽  
pp. 1336-1345 ◽  
Author(s):  
Jicheng Yu ◽  
Jia Lu ◽  
Yong Kang
Keyword(s):  
Ph Value ◽  
Sodium Aluminate ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Operation Condition ◽  
Sulfate Removal ◽  
Aluminum Hydroxides ◽  
Initial Ph ◽  
Co Precipitation

Abstract Chemical precipitation method was adopted to remove sulfate from wet flue gas desulfurization (FGD) wastewater and mixtures of Ca(OH)2 (CH) and NaAlO2 (SA) were used as precipitants. The mechanisms of sulfate removal were explored according to the experimental and simulated results. These showed that three kinds of precipitations, which were gypsum, ettringite and co-precipitation onto aluminum hydroxides, were formed when sulfate in water reacted with CH and SA. The optimum operation condition for removing sulfate was that the molar ratio of CH/SA was 2, the initial pH value 5, the precipitant dosage 15 g/L, the reaction time 20 min, and the reaction temperature 55 °C. The sulfate was reduced from 4,881 mg/L to 784 mg/L under the optimized condition. In addition, the heavy metals and fluoride were also mostly removed. The post treatments of the supernatant illustrated that removal of sulfate from wet FGD wastewater by co-precipitation with CH and SA was a better choice.

Perchlorate Removal Using the Calcination Products of Mg-Al-Fe Hydrotalcite-Like Compounds as Adsorbent

2013 ◽  
Vol 662 ◽  
pp. 520-523
Author(s):  
Ling Ling Niu ◽  
Fang He ◽  
Shang Zhen Zhao
Keyword(s):  
Ph Value ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Constant Ph ◽  
Initial Ph ◽  
Perchlorate Concentration ◽  
Perchlorate Removal ◽  
Co Precipitation ◽  
Calcined Temperature ◽  
Adsorbent Dose

The calcination products of Mg/(Al-Fe) hydrotalcite-like compounds (HMAF) were used as adsorbent to remove perchlorate in affected water. HMAF were synthesized by co-precipitation method at a constant pH value, the best calcined temperature is 500°C and the optimal Mg/Al/Fe molar ratio is 3:0.8:0.2 (CHMAF5%). Factors such as adsorbent dose, initial pH, initial perchlorate concentration affecting perchlorate adsorption were studied. Results showed that the best parameters of adsorbent dose, pH and perchlorate concentration are 0.2g, pH 4-10 and 2000µg/l, respectively. The calcination products of HMAF can be a promising adsorbent for perchlorate removal.

Catalytic Hydrolysis of Hydrogen Cyanide on Cu-Al Catalyst

2015 ◽  
Vol 1094 ◽  
pp. 15-19
Author(s):  
Lin Xia Yan ◽  
Sen Lin Tian ◽  
Qiu Lin Zhang
Keyword(s):  
Calcination Temperature ◽  
Hydrogen Cyanide ◽  
Influence Factor ◽  
Ph Value ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Cu Content ◽  
Co Precipitation ◽  
The Impact ◽  
Hydrolysis Of

Cu-Al catalysts were synthesized by the co-precipitation method to study hydrolysis of hydrogen cyanide. During the synthesis, the impact of Cu/Al molar ratio, pH value and calcination temperature was investigated and the best synthesis condition was found. The results indicate that the remove of hydrogen cyanide first increases and then decreases with increasing Cu/Al molar ratio, pH value and calcination temperature, which reaches the maxima and remains above 95% at 360 min when Cu/Al molar ratio is 2:1, pH value is approximately 8.0 and calcination temperature is 400°C around. The analysis of X-ray diffraction (XRD) shows that Cu content is the main influence factor at Cu/Al molar ratio below 2:1 whereas crystallinity of catalysts is the key factor at Cu/Al molar ratio above 2:1.

Process Study on Green Treatment of Waste Anolyte

2014 ◽  
Vol 1015 ◽  
pp. 350-354
Author(s):  
Li Na Chen ◽  
Wan Yi Liu ◽  
Qi Lin Hu
Keyword(s):  
Ph Value ◽  
Removal Rate ◽  
Chemical Precipitation ◽  
Environmental Benefits ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Dihydrogen Phosphate ◽  
Waste Solution ◽  
Hydrogen Carbonate ◽  
Ammonium Hydrogen

Contraposing the waste anolyte of industry, the paper proposed a new chemical precipitation method to recover Mn (II) ions and Mg (II) ions from the waste solution using ammonium hydrogen carbonate and ammonium dihydrogen phosphate as precipitants, respectively. The technological conditions of dealing procedure such as the molar ratio of reactants, pH value, reaction temperature and time, aging time were investigated. The results shown that the removal rate of Mn (II) ions and Mg (II) ions reached to 96 % and 98 %, and the yields of MnCO3 and NH4MgPO4·6H2O reached to 91 % and 94 %, respectively. The residual solution was recycled to realize the treatment greenly, which could meet the needs of production and increase environmental benefits.

Effect of pH Value on Synthesis of Calcium Phosphates

2008 ◽  
Vol 47-50 ◽  
pp. 1307-1310 ◽  
Author(s):  
Ya Qin Huang ◽  
Lu Jun Sun ◽  
Ai Hua He ◽  
Qin Qin Wang ◽  
Charles C. Han
Keyword(s):  
Chemical Analysis ◽  
Ph Value ◽  
Calcium Phosphates ◽  
Chemical Precipitation ◽  
Chemical Precipitation Method ◽  
Crystal Phase ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Effect Of Ph ◽  
Ph Values

The effect of pH value at different initial Ca/P molar ratio on the composition and crystal phase of the calcium phosphates synthesized through chemical precipitation method was studied in detail. After calcining at 900°C, the products were characterized by XRD and chemical analysis. The results showed that the composition and crystal phase of the resultant powders can be controlled by pH value at different initial Ca/P molar ratio. When Ca/P molar ratio was 1.667, pure HA was obtained at pH values of both 12.0 and 11.0. When initial Ca/P molar ratio was 1.500, pure β-TCP was obtained at pH value from 11.0 to 9.0. CPP was obtained at pH value from 6.0 to 4.0 when initial Ca/P molar ratio was 1.000.

scholarly journals Impact of Iron on the Fe–Co–Ni Ternary Nanocomposites Structural and Magnetic Features Obtained via Chemical Precipitation Followed by Reduction Process for Various Magnetically Coupled Devices Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 341
Author(s):  
Tien Hiep Nguyen ◽  
Gopalu Karunakaran ◽  
Yu.V. Konyukhov ◽  
Nguyen Van Minh ◽  
D.Yu. Karpenkov ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Reduction Process ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Magnetic Characteristics ◽  
Reduction Temperature ◽  
Fe Content ◽  
Magnetic Features ◽  
Co Precipitation

This paper presents the synthesis of Fe–Co–Ni nanocomposites by chemical precipitation, followed by a reduction process. It was found that the influence of the chemical composition and reduction temperature greatly alters the phase formation, its structures, particle size distribution, and magnetic properties of Fe–Co–Ni nanocomposites. The initial hydroxides of Fe–Co–Ni combinations were prepared by the co-precipitation method from nitrate precursors and precipitated using alkali. The reduction process was carried out by hydrogen in the temperature range of 300–500 °C under isothermal conditions. The nanocomposites had metallic and intermetallic phases with different lattice parameter values due to the increase in Fe content. In this paper, we showed that the values of the magnetic parameters of nanocomposites can be controlled in the ranges of MS = 7.6–192.5 Am2/kg, Mr = 0.4–39.7 Am2/kg, Mr/Ms = 0.02–0.32, and HcM = 4.72–60.68 kA/m by regulating the composition and reduction temperature of the Fe–Co–Ni composites. Due to the reduction process, drastic variations in the magnetic features result from the intermetallic and metallic face formation. The variation in magnetic characteristics is guided by the reduction degree, particle size growth, and crystallinity enhancement. Moreover, the reduction of the surface spins fraction of the nanocomposites under their growth induced an increase in the saturation magnetization. This is the first report where the influence of Fe content on the Fe–Co–Ni ternary system phase content and magnetic properties was evaluated. The Fe–Co–Ni ternary nanocomposites obtained by co-precipitation, followed by the hydrogen reduction led to the formation of better magnetic materials for various magnetically coupled device applications.

Effect of Fe and Co promoters on CO methanation activity of nickel catalyst prepared by impregnation – co-precipitation method

2020 ◽  
Vol 18 (5-6) ◽  
Author(s):  
Buyan-Ulzii Battulga ◽  
Tungalagtamir Bold ◽  
Enkhsaruul Byambajav
Keyword(s):  
Synergetic Effect ◽  
Space Velocity ◽  
Catalytic Performance ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Alumina Support ◽  
Co Methanation ◽  
Temperature Range ◽  
Co Precipitation ◽  
Catalyst Distribution

AbstractNi based catalysts supported on γ-Al2O3 that was unpromoted (Ni/γAl2O3) or promoted (Ni–Fe/γAl2O3, Ni–Co/γAl2O3, and Ni–Fe–Co/γAl2O3) were prepared using by the impregnation – co-precipitation method. Their catalytic performances for CO methanation were studied at 3 atm with a weight hourly space velocity (WHSV) of 3000 ml/g/h of syngas with a molar ratio of H2/CO = 3 and in the temperature range between 130 and 350 °C. All promoters could improve nickel distribution, and decreased its particle sizes. It was found that the Ni–Co/γAl2O3 catalyst showed the highest catalytic performance for CO methanation in a low temperature range (<250 °C). The temperatures for the 20% CO conversion over Ni–Co/γAl2O3, Ni–Fe/γAl2O3, Ni–Fe–Co/γAl2O3 and Ni/γAl2O3 catalysts were 205, 253, 263 and 270 °C, respectively. The improved catalyst distribution by the addition of cobalt promoter caused the formation of β type nickel species which had an appropriate interacting strength with alumina support in the Ni–Co/γAl2O3. Though an addition of iron promoter improved catalyst distribution, the methane selectivity was lowered due to acceleration of both CO methanation and WGS reaction with the Ni–Fe/γAl2O3. Moreover, it was found that there was no synergetic effect from the binary Fe–Co promotors in the Ni–Fe–Co/γAl2O3 on catalytic activity for CO methanation.

Preparation and Characterization of Nanocomposite Calcium Doped Ceria Electrolyte With Alkali Carbonates (NK-CDC) for SOFC

2010 ◽  
Author(s):  
Ghazanfar Abbas ◽  
Rizwan Raza ◽  
Muhammad Ashraf Chaudhry ◽  
Bin Zhu
Keyword(s):  
Electron Microscopy ◽  
Fossil Fuels ◽  
Electrochemical Impedance ◽  
Renewable Energy Sources ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Doped Ceria ◽  
Alternative Source ◽  
Calcium Doped ◽  
Co Precipitation

The entire world’s challenge is to find out the renewable energy sources due to rapid depletion of fossil fuels because of their high consumption. Solid Oxide Fuel Cells (SOFCs) are believed to be the best alternative source which converts chemical energy into electricity without combustion. Nanostructured study is required to develop highly ionic conductive electrolyte for SOFCs. In this work, the calcium doped ceria (Ce0.8Ca0.2O1.9) coated with 20% molar ratio of two alkali carbonates (CDC-M: MCO3, where M = Na and K) electrolyte was prepared by co-precipitation method in this study. Ni based electrode was used to fabricate the cell by dry pressing technique. The crystal structure and surface morphology was characterized by X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM) and High Resolution Transmission Electron Microscopy (HRTEM). The particle size was calculated in the range of 10–20nm by Scherrer’s formula and compared with SEM and TEM results. The ionic conductivity was measured by using AC Electrochemical Impedance Spectroscopy (EIS) method. The activation energy was also evaluated. The performance of the cell was measured 0.567W/cm2 at temperature 550°C with hydrogen as a fuel.

Effect of the Synthesis Method on the Properties of Ultrafine YAG Powder

2018 ◽  
Vol 281 ◽  
pp. 40-45
Author(s):  
Jie Guang Song ◽  
Lin Chen ◽  
Cai Liang Pang ◽  
Jia Zhang ◽  
Xian Zhong Wang ◽  
...  
Keyword(s):  
Particle Size ◽  
Calcination Temperature ◽  
Hydrothermal Reaction ◽  
Synthesis Method ◽  
Particle Morphology ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Synthesis Process ◽  
Powder Materials ◽  
Co Precipitation

YAG materials has a number of unique properties, the application is very extensive. In this paper, the superfine YAG powder materials were prepared by co-precipitation method and hydrothermal precipitation method. The influence of synthesis process on the morphology of the powder was investigated. The results showed that the precursor powder prepared via the co-precipitation method is mainly from amorphous to crystalline transition with the increasing calcination temperature, the precursor agglomeration is more serious, In the process of increasing the calcination temperature, the dispersibility of the roasted powder is greatly improved, which is favorable for the growth of the crystal grains, so that the particle size of the powder is gradually increased, the YAG precursor prepared by the co-precipitation method is transformed into YAG crystals, the phase transition occurs mainly between 900 and 1100°C. When the molar ratio of salt to alkali is Y3+: OH-=1: 8 via the hydrothermal reaction, the YAG particles with homogeneous morphology can be obtained. When the molar ratio of salt and alkali is increased continuously, the morphology of YAG particles is not obviously changed. The co-precipitation method is easy to control the particle size, the hydrothermal method is easy to control the particle morphology.

Controlled Synthesis of Different Morphologies of SrWO4 Crystals via a Surfactant-Assisted Hydrothermal Precipitation Method

2013 ◽  
Vol 785-786 ◽  
pp. 449-454
Author(s):  
Yan Zhao ◽  
Chun Yan Wu ◽  
Dan Qin ◽  
Xin Lai ◽  
Si Wu ◽  
...  
Keyword(s):  
Ph Value ◽  
Precipitation Method ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Experimental Parameters ◽  
Infrared Spectrometer ◽  
Luminescent Spectra ◽  
Hydrothermal Precipitation ◽  
Surfactant Assisted

SrWO4 octahedrons, flowers, bundles, ellipsoids and dendrites had been successfully synthesized via surfactant-assisted method. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photo-luminescent spectra techniques (PL) and fourier transrform infrared spectrometer (FTIR). By through various comparison experiments, it can be found that some related experimental parameters including the reagent concentration, [Sr2+]/[WO42-] molar ratio (R), aging temperature and the pH value had great influences on morphology of the products.

Investigation on Synthesis Conditions of Silicon-Doped Hydrotalcite-Like Compounds

2013 ◽  
Vol 781-784 ◽  
pp. 239-242
Author(s):  
Lei Wang ◽  
Peng Xiao
Keyword(s):  
Silicon Content ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Accurate Data ◽  
Aged Condition ◽  
Synthesis Conditions ◽  
Silicon Doped ◽  
Major Factors ◽  
Co Precipitation ◽  
Research Analysis

In this paper, SiMgAl hydotalcite synthesis conditions were investigated using co-precipitation method, within a relatively stable pH environment of 8~9. Our research, analysis and discussion focused on the effects of major factors, such as material molar ratio ,silicon content and aged condition, on the structures of synthetic products. To achieve stable and accurate data, synthetic products were characterized by XRD and IR under the identical conditions. As shown in the results, it is suggested that the best Crystallization temperature is 70°C, molar ratio of Mg to Al is 3:1, and the best content of Silicon is 0.015mol/mol.

Sign in / Sign up

Export Citation Format

Share Document