Preparation of a Sulfate-Based Complex Coagulant from Boiler Slag and its Application in Domestic Sewage Treatment

2010 ◽  
Vol 148-149 ◽  
pp. 259-266
Author(s):  
Jin Ping Li ◽  
Jin Hua Gan ◽  
Ying Ming Chen

This paper presents a new way of recycling aluminum and iron in boiler slag derived from coal combustion plants for the production of a sulfate-based complex coagulant containing ferric sulfate and aluminum sulfate. The boiler slag sample was determined for more complete characterization by means of scanning electron microscopy(SEM), X-ray diffraction(XRD), X-ray fluorescence(XRF) and other techniques. An analysis for the boiler slag sample collected from Baotou Steel Plant located in Inner Mongolia, PR China showed that the quantity of iron and aluminum oxides, in general, accounted for about 35% of the boiler slag. XRD analysis indicates that predominate minerals such as kaolinite, quartz, calcium silicide, hematate and metakoalin exist in this boiler slag. This boiler salg was evaluated to determine the efficiency of converting the iron and aluminum components of the material into a sulfate-based complex coagulant when heated with sulfuric acid at different temperatures and reaction times. The maximum concentrations of Fe3+ and Al3+ in the complex coagulant prepared from the boiler slag were obtained at 130 and after 3 h of reaction time. These concentrations were 0.04 M Fe3+ and 0.46 M Al3+, respectively. The corresponding conversion efficiencies of aluminum and iron were 66.2 and 95.0% in the boiler slag, respectively. Finally, the prepared sulfate-based complex coagulant proved to be an effective agent for reducing the turbidity and chemical oxygen demand(COD) of a typical domestic sewage sample.

2016 ◽  
Vol 74 (7) ◽  
pp. 1509-1517 ◽  
Author(s):  
Linan Zhu ◽  
Hailing He ◽  
Chunli Wang

The hybrid membrane bioreactor (HMBR) has been applied in ship domestic sewage treatment under high volumetric loading for ship space saving. The mechanism and influence factors on the efficiency, including hydraulic retention time (HRT), dissolved oxygen (DO) of chemical oxygen demand (COD) removal were investigated. The HMBR's average COD removal rate was up to 95.13% on volumetric loading of 2.4 kgCOD/(m3•d) and the COD concentration in the effluent was 48.5 mg/L, far below the International Maritime Organization (IMO) discharge standard of 125 mg/L. DO had a more remarkable effect on the COD removal efficiency than HRT. In addition, HMBR revealed an excellent capability of resisting organics loading impact. Within the range of volumetric loading of 0.72 to 4.8 kg COD/(m3•d), the effluent COD concentration satisfied the discharge requirement of IMO. It was found that the organics degradation in the aeration tank followed the first-order reaction, with obtained kinetic parameters of vmax (2.79 d−1) and Ks (395 mg/L). The original finding of this study had shown the effectiveness of HMBR in organic contaminant degradation at high substrate concentration, which can be used as guidance in the full scale of the design, operation and maintenance of ship domestic sewage treatment devices.


2014 ◽  
Vol 69 (7) ◽  
pp. 1410-1418 ◽  
Author(s):  
Weijie Guo ◽  
Zhu Li ◽  
Shuiping Cheng ◽  
Wei Liang ◽  
Feng He ◽  
...  

To examine the performance of a constructed wetland system on stormwater runoff and domestic sewage (SRS) treatment in central east China, two parallel pilot-scale integrated constructed wetland (ICW) systems were operated for one year. Each ICW consisted of a down-flow bed, an up-flow bed and a horizontal subsurface flow bed. The average removal rates of chemical oxygen demand (CODCr), total suspended solids (TSS), ammonia (NH4+-N), total nitrogen (TN) and total phosphorus (TP) were 63.6, 91.9, 38.7, 43.0 and 70.0%, respectively, and the corresponding amounts of pollutant retention were approximately 368.3, 284.9, 23.2, 44.6 and 5.9 g m−2 yr−1, respectively. High hydraulic loading rate (HLR) of 200 mm/d and low water temperatures (<15 °C) resulted in significant decrease in removals for TP and NH4+-N, but had no significant effects on removals of COD and TSS. These results indicated that the operation of this ICW at higher HLR (200 mm/d) might be effective and feasible for TSS and COD removal, but for acceptable removal efficiencies of nitrogen and phosphorus it should be operated at lower HLR (100 mm/d). This kind of ICW could be employed as an effective technique for SRS treatment.


2018 ◽  
Vol 42 (1) ◽  
pp. 7-12 ◽  
Author(s):  
Reza Teimuri-Mofrad ◽  
Somayeh Esmati ◽  
Masoumeh Rabiei ◽  
Mahdi Gholamhosseini-Nazari

A novel heterogeneous silica nanosphere-supported ferrocene-containing ionic liquid catalyst (SiO2@Imid-Cl@Fc) was designed and synthesised and was systematically characterised by Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) analysis. The catalytic activity of the SiO2@Imid-Cl@Fc catalyst was tested in a one-pot, three-component reaction of malononitrile and kojic acid with 15 aromatic aldehydes at room temperature under ultrasound irradiation. The products were pyrano[3,2-b]pyran derivatives, four of which are new. The catalyst exhibited good catalytic performance over short reaction times (15–20 min) and could be recycled at least five times without significant loss of activity.


Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1129
Author(s):  
Luyara de Almeida Cavalcante ◽  
Laís Sibaldo Ribeiro ◽  
Mitsuo Lopes Takeno ◽  
Pedro Tupa Pandava Aum ◽  
Yanne Katiussy Pereira Gurgel Aum ◽  
...  

The present work demonstrates the production of chlorapatite (ClAp) through thermal decomposition of chemically treated fish scales, originating from an Amazon fish species (Arapaima gigas). The scales were treated with hydrochloric acid (HCl) solution for deproteinization. Afterwards, the solution was neutralized by sodium hydroxide (NaOH) treatment to obtain an apatite-rich slurry. The heat treatment was carried out at different temperatures including 600 °C, 800 °C, and 1000 °C. The powders obtained were characterized through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM). The XRD analysis and FTIR spectra confirmed the incorporation of chlorine into the apatite structure. The FTIR results showed absorption bands relative to the OH–, PO43− functional groups which are a characteristic of chlorapatite. Moreover, the intensity of the OH–Cl elongation could be observed. Chlorapatite Ca5(PO4)3Cl, NaCl, and NaCaPO4 phases were identified, achieving up to 87.4 wt% for ClAp. The SEM observations show that with increasing temperature, the ClAp obtained consists of slightly larger, more crystalline grains. Furthermore, the grains ranged in size, between 1-5 μm and ClAp1000 sample recorded crystallinity of 84.27%. ClAp and NaCaPO4 can be used in electronics as phosphor materials due to their luminescence and biomedical applications.


2021 ◽  
Author(s):  
Shahryar Malekie ◽  
Hassan Shooli ◽  
Mohammad Amin Hosseini

Abstract This study aimed to introduce new composites, containing polyamide-6 (PA6) and lead monoxide (PbO), to protect against ionizing photon sources used for diagnostic and therapeutic purposes. Five composites, containing various weight percentages of PbO filler (0, 5, 10, 20, and 50%), were developed in this study. Initially, the numerical attenuation value was estimated using XMuDat program by calculating the mass attenuation coefficients at different energy levels. Next, the samples were synthesized based on the melt-mixing method in a laboratory mixing extruder, and their characteristics were determined by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Finally, experimental radiation attenuation tests were carried out. Based on the SEM results, the acceptable filler weight percentage was up to 20%; however, substantial aggregates formation was observed at the highest weight percentage. The results of XRD analysis showed a higher tendency for crystallization by decreasing the amorphous area, while increasing the filler weight percentage. Moreover, the amount of mass loss was monitored at different temperatures, revealing that the filler incorporation improved the thermal durability of the samples. According to the radiation results, a good agreement was observed between the experimental and computational data, except when aggregates formation was substantial. According to the experimental data, by increasing the lead weight percentage from 0% (crude PA6) to 50%, the half-value layer decreased from 3.13 to 0.17 cm at an energy level of 59 keV and from 7.28 to 4.97 cm at an energy level of 662 keV. Considering these promising results, the applicability of PA6/PbO composites for protection against low- and medium-energy ionizing photon sources must be investigated in future studies.


Author(s):  
Liliana Giraldo ◽  
Moreno-Piraján ◽  
John J. Hurtado

Abstract In this work, the catalytic activity was investigated in the hydrogenation of anthracene by BaSO3 and Cu(II), Zn(II) and Ni(II) complexes that contain the ligand bis(3,5-dimethyl-1-pyrazolyl) methane (L). The compounds were supported on activated carbon (AC) and studied as catalysts for the hydrogenation of anthracene over different temperatures and reaction times. The supported catalysts (Cat/AC) were prepared by direct impregnation on the support and characterized by surface area determination, FTIR spectroscopy, and X-ray powder diffraction and pore size distribution analysis. The results showed high conversions and selectivity toward hydrogenated products, where the highest value was obtained using LNiCl2/AC and the lowest with BaSO3/AC. It was established that the selectivity for Tetrahydroanthracene was more highest quantity as a product of hydrogenation using Cat/AC which is dependent of the temperature, reaching a peak at 450 °C. At this temperature and with very short reaction times, the catalytic activity is influenced mainly by the chemical characteristics of the metal in the complexes and the AC support.


2017 ◽  
Vol 64 (5) ◽  
pp. 508-514 ◽  
Author(s):  
M. Adam Khan ◽  
S. Sundarrajan ◽  
S. Natarajan

Purpose The aim of this paper is to study the hot corrosion behaviour of super 304H stainless steel for marine applications. Design/methodology/approach The investigation was carried out with three different combinations of salt mixture (Na2SO4, NaCl and V2O5) at two different temperatures (800 and 900°C). Findings The spalling and growth of oxide layer was observed more with the presence of V2O5 in the salt mixture at 900°C during experimentation than what was observed in 800°C. The mass change per unit area is calculated to study the corrosion kinetics and also the influence of salt mixture. Further, the samples are analysed through materials characterisation techniques using optical image, scanning electron microscope (SEM), energy dispersive X-ray (EDAX) and X-ray diffraction (XRD) analysis. The presence of V2O5 in the salt mixture was the most important influencing species for accelerating hot corrosion. Originality/value SEM, EDAX and XRD analysis confirmed the formation of Fe2O3 and Cr2O3 at 900°C showing contribution in corrosion protection.


2018 ◽  
Vol 276 ◽  
pp. 60-65
Author(s):  
Marcela Fridrichová ◽  
Dominik Gazdič ◽  
Jana Mokrá ◽  
Karel Dvořák

The stability of ettringite as high-watery mineral is highly dependent on the ambient temperature. Under standard laboratory conditions, onset of decomposition of this phase occurs at temperature of 80°C already and the theoretical temperature of the complete decomposition of ettringite is 180°C. Ettringite decomposition can occur at significantly different temperatures under humidity conditions other than the laboratory ones. Within the work verification of the possibility of synthetic preparation of ettringite by direct addition of aluminum sulfate, Al2(SO4)3·18H2O, and calcium hydroxide, Ca (OH)2, as an alternative method to the yeelimite hydration procedure was carried out. The stability of the resulting systems was examined in two different environments, namely in a laboratory environment and the environment of saturated water vapour. The phase composition of the samples was determined by X-ray diffraction (XRD) analysis, thermal analysis and scanning electron microscopy (SEM).


2015 ◽  
Vol 1087 ◽  
pp. 30-34 ◽  
Author(s):  
KANAGESWARY SOCKALINGAM ◽  
Mohd Azha Yahya ◽  
Hasan Zuhudi Abdullah

Hydroxyapatite (HAp), classified as bioceramic materials is the major mineral constituent of vertebrate bones and teeth. In this study, the effect of temperature on isolation and characterization of HAp from tilapia fish scales have been investigated. Scales were subjected to heat treatment at different temperatures (800°C and 1000°C) and microstructure of both raw and calcined scales were observed under Scanning Electron Microscopy (SEM). Thermo Gravimetric Analysis (TGA) and Energy Dispersive X-Ray Spectroscopy (EDX) results have revealed the best calcination temperature of tilapia scales to be 800°C due to the calculated calcium to phosphorous weight ratio (Ca/P). The Ca/P ratio for scales treated at 800°C and 1000°C were 1.598 and 1.939 respectively. The phase purity and crystallinity of produced HAp was further confirmed by X-Ray Diffraction (XRD) analysis. Based on the study, it can be concluded that tilapia fish scale is a good natural source of HAp with 800°C as the optimum calcination temperature in HAp production.


2021 ◽  
Author(s):  
G. Kavitha ◽  
K. Thanigai Arul ◽  
Manikandan Elayaperumal

Abstract The semiconductor-transition conducting metal oxides (p-type NiO: n-type ZnO) nanocomposites (NCs) called (NZO) are successfully prepared by a simple wet-chemical route followed by the systematic sintering at different temperatures such as 400°C, 500°C, 600°C, and 700 °C. The structure and morphology of the samples were characterized by X-ray diffraction (XRD), high-resolution scanning/transmission electron microscopy (HR-SEM/TEM), and energy-dispersive X-ray spectrometry (EDX) techniques. XRD analysis reveals that the average crystallite size of the NZO NCs was found to be in the range 16-18 nm. The synthesized sample discloses a ferromagnetic behavior. The photocatalytic degradation of rhodamine B in an aqueous solution was superior at the NZO NC at 600 °C in comparison with other samples. Here, the NZO NCs display to be good candidates for magnetic and photocatalytic application.


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