Removal of ammonium from rare-earth wastewater using natural brucite as a magnesium source of struvite precipitation

2011 ◽  
Vol 63 (3) ◽  
pp. 468-474 ◽  
Author(s):  
H. M. Huang ◽  
X. M. Xiao ◽  
L. P. Yang ◽  
B. Yan
Keyword(s):  
Rare Earth ◽  
Reaction Time ◽  
Experimental Results ◽  
Soluble Form ◽  
Ammonium Concentration ◽  
Ammonium Removal ◽  
Struvite Precipitation ◽  
Magnesium Source

This paper presents a study regarding ammonium removal from rare-earth wastewater by struvite precipitation with natural brucite mineral as a source of magnesium. Experimental results indicated that a pH ranging from 8.5 to 9.5 was the optimum for the removal of ammonium using the soluble form of brucite as a magnesium source. Additionally, when solid brucite was used as a magnesium source as well as an alkali reagent, the initial ammonium concentration of 4,535 mg/L decreased to 239–317 mg/L after an reaction time of 12 h in wastewater treated with the S/L (solid brucite/liquid wastewater) ratios ranging from 31.2 to 63.2 g/L. Furthermore, as some non-reacted brucite still remained in the precipitates obtained at the end of reaction, the precipitates were subjected to reuse. The reuse results demonstrated that the reuse of the precipitates obtained with 63.2 g/L was feasible, and almost half of the brucite dose could be saved.

Recovery of nitrogen from saponification wastewater by struvite precipitation

2010 ◽  
Vol 61 (11) ◽  
pp. 2741-2748 ◽  
Author(s):  
Haiming Huang ◽  
Xianming Xiao ◽  
Liping Yang ◽  
Bo Yan
Keyword(s):  
Grain Size ◽  
Rare Earth ◽  
Size Range ◽  
Separation Process ◽  
Ammonium Concentration ◽  
Subsequent Reaction ◽  
Ammonium Removal ◽  
Seeding Material ◽  
Series Of Experiments ◽  
Struvite Precipitation

In general, saponification wastewater produced from the separation process of rare-earth elements contains high ammonium concentration. In this study, a series of experiments were conducted to investigate the parameters to enhance the struvite precipitation potential for ammonium removal from the wastewater having an ammonium concentration of 4,100 mg/L. Experimental results showed that increasing the dose and grain size of pre-formed struvite, which was added as the seeding material in struvite reaction, could increase ammonium removal. The removal efficiency increased 7.6% when the dose of pre-formed struvite with crystal grain size range of 0.098–0.150 mm increased from 0 g/L to 60 g/L. Additionally, struvite precipitation was tested with the intermittent addition of magnesium and phosphate to utilize the struvite crystals formed during the reaction process as the seeding material for the subsequent reaction. The results revealed that intermittently adding magnesium 7 times effectively enhanced ammonium removal by around 8%, which was equivalent to that of using pre-formed struvite as the seeding material. Furthermore, the chemical composition of the struvite recovered with intermittent addition of magnesium was characterized, showing the struvite could be used as fertilizer. An economic evaluation indicated that intermittent addition of magnesium 7 times can save 13.4% cost for recovering per kg NH4+ compared to that of bulk addition.

Removal of ammonium from aqueous solutions using the residue obtained from struvite pyrogenation

2011 ◽  
Vol 64 (12) ◽  
pp. 2508-2514 ◽  
Author(s):  
Haiming Huang ◽  
Qianwu Song ◽  
Chunlian Xu
Keyword(s):  
Aqueous Solutions ◽  
Experimental Results ◽  
Synthetic Wastewater ◽  
Ammonium Concentration ◽  
Ammonium Removal ◽  
Optimum Ph ◽  
Series Of Experiments ◽  
Release Ratio ◽  
Phosphate Source ◽  
The Cost

This paper reports the results of laboratory studies on the removal of ammonium from aqueous solutions using struvite pyrogenation residues. A series of experiments were conducted to examine the effects of the pyrogenation temperature (90–210 °C) and time (0.5–4 h) on the ammonium release of struvite. In addition, the pyrolysate of struvite produced at different pyrogenation temperatures and times was recycled for ammonium removal from aqueous solutions. The experimental results indicated that the ammonium release ratio of struvite increased with an increase in the pyrogenation temperature and time, and the struvite pyrolysate used as magnesium and phosphate source for ammonium removal was produced at the optimal condition of pyrogenation temperature of 150 °C for 1 h. Furthermore, experimental results showed that the optimum pH and pyrolysate dosage for ammonium removal from 100 ml synthetic wastewater (1,350 mg ammonium/L) were at pH 9 and 2.4 g of struvite pyrolysate, respectively, and initial ammonium concentration played a significant role in the ammonium removal by the struvite pyrolysate. In order to further reduce the cost of struvite precipitation, the struvite pyrolysate was repeatedly used for four cycles. The results of economic analysis showed that recycling struvite for three process cycles should be reasonable for ammonium removal, with ammonium removal efficiencies of over 50% and a reduction of 40% in the removal cost per kg NH4+.

INFLUENCE OF STICKY RICE AND ANIONIC POLYACRYLAMIDE ON THE CRYSTALLIZATION OF CALCIUM CARBONATE IN CHINESE ORGANIC SANHETU

2015 ◽  
Vol 22 (06) ◽  
pp. 1550073 ◽  
Author(s):  
HUI LIU ◽  
CHANGSHENG PENG ◽  
MIN DAI ◽  
QINGBAO GU ◽  
SHAOXIAN SONG
Keyword(s):  
Reaction Time ◽  
Calcium Carbonate ◽  
Organic Material ◽  
Organic Materials ◽  
Experimental Results ◽  
Additive Concentration ◽  
Reactant Concentration ◽  
Natural Organic Material ◽  
Anionic Polyacrylamide

The crystallization of calcium carbonate ( CaCO 3) in soil controlled by natural organic material was considered a very important reason to enhance the property of ancient Chinese organic Sanhetu (COS), but how the organic material affected the crystallization of CaCO 3 in COS is still unclear. In this paper, a natural organic material (sticky rice, SR) and a synthetic organic material (anionic polyacrylamide, APAM) were selected as additives to investigate their effect on the crystallization of CaCO 3. The experimental results showed that the morphology and size of CaCO 3 crystals could be affected by the concentration of additives and reaction time, while only the size of CaCO 3 crystals could be affected by the concentration of reactant. Although the morphology and size of CaCO 3 crystals varied greatly with the variation of additive concentration, reactant concentration and reaction time, the polymorph of CaCO 3 crystals were always calcite, according to SEM/EDX, XRD and FTIR analyses. This study may help us to better understand the mechanism of the influence of organic materials on CaCO 3 crystallization and properties of COS.

scholarly journals Ammonium removal by a novel heterotrophic nitrifying and aerobic denitrifying bacterium Pseudomonas stutzeri KTB from wastewater

2015 ◽  
Vol 50 (3) ◽  
pp. 219-227 ◽  
Author(s):  
Maohong Zhou ◽  
Hairen Ye ◽  
Xiaowei Zhao
Keyword(s):  
Nitrogen Removal ◽  
Removal Rate ◽  
Pseudomonas Stutzeri ◽  
Culture Conditions ◽  
Aerobic Denitrification ◽  
Ammonium Concentration ◽  
Logarithmic Phase ◽  
Ammonium Removal ◽  
Removal Ratio ◽  
Initial Ph

The effects of culture conditions on a newly isolated Pseudomonas stutzeri KTB's ability to simultaneously perform heterotrophic nitrification and aerobic denitrification were investigated to determine its potential of application in nitrogen removal from wastewater. The results from experiments in the presence of 10 mmol/L of ammonium were as follows: succinate was the preferred carbon source, and the optimum C/N ratio, temperature, and initial pH were 10, 30 °C, and 7–8, respectively. Nitrogen removal took place not only in the logarithmic phase but also in the stationary phase. Under the optimum conditions, the nitrogen removal rate increased as the ammonium concentration elevated, until it was as high as 60 mmol/L. Meanwhile, the maximum specific growth rate decreased. The highest nitrogen removal rate of 0.977 mmol/L/h was observed at 60 mmol/L of ammonium and the maximum removal ratio of 85.6% at 40 mmol/L when the bacterial treatment for 48 h was completed. The strain was vulnerable to even higher ammonium loads. When incubated in anaerobically digested hennery wastewater containing 43.85 mmol/L of ammonium and 2.32 mmol/L of nitrate, the removal ratio and rate reached 82.4% and 0.397 mmol/L/h, respectively. The strain might be a great candidate for ammonium removal from wastewater.

scholarly journals STUDY ON THE REMOVAL OF AMMONIA IN WASTEWATER USING ADSORBENT PREPARED FROM RICE HULL WITH MAGNESIUM OXIDE MODIFICATION

2020 ◽  
Vol 58 (3A) ◽  
pp. 113
Author(s):  
Thuy Nguyen Thi ◽  
Van Tran Dang Lan ◽  
Hoan Nguyen Xuan ◽  
Son Le Thi Bich ◽  
Mai Tran Thi Ngoc ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Magnesium Oxide ◽  
Removal Efficiency ◽  
Magnesium Chloride ◽  
Domestic Wastewater ◽  
Adsorption Kinetic ◽  
Rice Hull ◽  
Ammonium Concentration ◽  
Chloride Salt ◽  
Ammonium Removal

This study is aimed to evaluate the ability of magnesium oxide-coated carbonized rice hull (MCRH) material for ammonium removal in synthetic and real domestic wastewater. The MCRH material was prepared using waste rice hull from a household rice-processing factory and magnesium chloride salt via a simple mixing and annealing method. The material was then characterized by scanning electron microscopy and energy-dispersive X-ray spectroscopy. The effects of magnesium chloride modification and environmental condition such as initial ammonium concentration (20 – 100 mg/L), amount of adsorbent (0.8 –2.0 g/L), and adsorption time (0 –32 h) on the ammonium removal efficiency and adsorption capacity were investigated. Adsorption kinetic and isotherms were also studied for MCRH material. Results showed that magnesium oxide was successfully coated on carbonized rice hull with Mg/C molar ratio of 0.22. Ammonium adsorption isotherm fitted well to Langmuir model with maximum adsorption capacity of 65.36 mg/g. The adsorption was physical process and adsorption kinetic was best described by intra-particle diffusion model with the correlation coefficients ranged from 0.942 – 0.979. Ammonium removal feasibility of MCRH was proved through the treatment of real domestic wastewater containing 80.7±1.6 mg/L initial ammonia concentration with removal efficiency reached 86.8% and the effluent concentration met the allowable value (10 mg/L) as given by QCVN 14 : 2008/BTNMT (column B) - National technical regulation on domestic wastewater. Hence MCRH is potential as a cheap and abundant material in Vietnam and the material after adsorption accumulated ammonium would be the source of fertilizer for soil quality improvement.

Phosphatization Coating-Forming Mechanism Based on Green Phosphating Accelerator Rare Earth Nitrate

2013 ◽  
Vol 838-841 ◽  
pp. 2806-2810
Author(s):  
Juch Kuang
Keyword(s):  
Rare Earth ◽  
Erosion Resistance ◽  
Film Formation ◽  
Substantial Reduction ◽  
Experimental Results ◽  
Forming Mechanism ◽  
Rare Earth Nitrate

Experimental results show that the samples gained in bath added Rare earth nitrate (REN), relative to the sample got in bath without REN, improve the anti-corrosion power of the coating because of increasing of covering rate of formless crystal Zn2Fe(PO4)2·4H2O (marked P) crystals and the ratio of P/(P+H) (H is the mark of Zn3(PO4)2 crystal) in the coating, combination of which with components parsing by EDS indicates that the sequence of contribution elements P and Zn to erosion resistance of coatings is P>Zn. And the correlative mechanism was discussed, which has it clear that RE is materially a catalyst holding excellent ability of carrying oxygen and cathode depolarization, its concentration gets so constant in certain range that it is much steadier and more efficient than the usual consumptive oxidants like nitrates. In a word, REN plays the role of surface regulator, accelerant and densification agent, which speeds up the phosphating, and bids it effective to enhance the anti-corrosion power of the coating. The addition of REN, not only promote the phosphating film formation and substantial reduction or exemption of nitrite. So, REN is green phosphating accelerator of live up to one's name.

Effect of Rare Earth Y2O3 Content on Microstructure of Gradient Bioceramic Composite Coating Produced by Wide-Band Laser Cladding

2005 ◽  
Vol 288-289 ◽  
pp. 351-354 ◽  
Author(s):  
Qi Bin Liu ◽  
Long Jiang Zou ◽  
Min Zheng ◽  
Chuang Dong
Keyword(s):  
Rare Earth ◽  
Composite Coating ◽  
Laser Cladding ◽  
Dominant Role ◽  
Monosodium Glutamate ◽  
Wide Band ◽  
Experimental Results ◽  
Ti Alloy ◽  
Y2o3 Content ◽  
Rare Earth Content

In the present paper, bioceramic coating with gradient compositional design was prepared on surface of Ti alloy by using wide-band laser cladding. Effect of rare earth Y2O3 content on gradient bioceramic composite coating was studied. The experimental results indicated that adding rare earth can refine grain. Different contents of rare earth affect formation of HA andβ-TCP in bioceramic coating. With increase of rare earth content, HA andβ-TCP were synthesized. When content of rare earth ranged from 0.4% to 0.6%, the active extent of rare earth in synthesizing HA andβ-TCP got best, which indicated that “monosodium glutamate” effect of rare earth played a dominant role. However, when rare earth content was up to 0.8%, the active extent of rare earth in synthesizing HA and β-TCP conversely went down, which demonstrated that rare earth gradually lost its catalysis in manufacturing HA andβ-TCP.

Eu and Yb Excitation Mechanisms in ZnS, CaS, SrS and InP

1993 ◽  
Vol 301 ◽  
Author(s):  
M. Godlewski ◽  
K. Światek ◽  
B. Monemar
Keyword(s):  
Energy Transfer ◽  
Rare Earth ◽  
Excited State ◽  
Exciton State ◽  
Experimental Results ◽  
Excitation Mechanism ◽  
Core State ◽  
Excitonic State ◽  
Excitation Mechanisms

ABSTRACTThe role of the excitonic excitation mechanism of the rare earth (RE) intra-shell emission is discussed. Two cases are analyzed. For Yb ion in InP 4f-4f emission of Yb3+ is induced by energy transfer from bound exciton state to the RE core state. For Eu in CaS and SrS RE emission is induced by carrier trapping directly to the excited state of Eu2+ ion. Also in this case the intermediate excitonic state may participate in RE excitation, as suggested by some experimental results.

Preparation of Copolymer Modified with Oxidized Starch and Dispersion Ability for Ferric Oxide

2014 ◽  
Vol 989-994 ◽  
pp. 156-159
Author(s):  
Ji Cheng Xu ◽  
Xin Shan Rong ◽  
Xiao Rui Guo ◽  
Feng Xian Qiu
Keyword(s):  
Reaction Time ◽  
Reaction Temperature ◽  
Uv Spectroscopy ◽  
Ammonium Persulfate ◽  
Experimental Results ◽  
Oxidized Starch ◽  
High Temperature Water ◽  
Mass Proportion ◽  
Single Factor Experiment ◽  
Temperature Water

A series of copolymers modified with oxidized starch containing maleic anhydride (MA), styrene sulfonic sodium (SSS) and oxidized starch (OS) were synthesized by the free-radical polymerization. The polymerization is initiated by ammonium persulfate. The effects of content of monomer and initiator, reaction time, reaction temperature on dispersion ability for Fe2O3 were investigated by single factor experiment. The dispersion ability for Fe2O3 measured through UV spectroscopy was studied. The experimental results show that the copolymer has good dispersion ability for Fe2O3 when the mass proportion of monomers is OS:SSS:MA = 1:3:1, the mass fraction of initiator in total monomers is 10 %, reaction time is 5 h, and the reaction temperature is 70 oC. The morphology of the copolymer was observed by scanning electron microscope (SEM). The experimental results indicate that the prepared copolymer modified with oxidized starch could be used in the corrosion inhibitor of high temperature water.

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