Hydrophobic Membrane Technology for Ammonia Extraction From Wastewaters

Kunz, Airton; Mukhtar, Saqib

doi:10.1590/1809-4430-eng.agric.v36n2p377-386/2016

Cited by 28 publications

(23 citation statements)

References 23 publications

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“…For this colorimetry methods was used (by the molybdovanadate method) with UV-VIS spectrophotometer model Cary50 (Agilent). Total ammoniacal nitrogen (TAN) was analyzed by colorimetric method (APHA, 2012) using a flow injection analysis system (FIAlab-2500, FIAlab), and the results were expressed as NH 3 -N. Free ammonia (FA) concentration was calculated according to Equation (1) (Kunz and Mukhtar, 2016).…”

Section: Methodsmentioning

confidence: 99%

Poultry Litter Solid State Anaerobic Digestion: Effect of Digestate Recirculation Intervals and Substrate/Inoculum Ratios on Process Efficiency

Marchioro

Steinmetz

Amaral

et al. 2018

Front. Sustain. Food Syst.

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This study evaluated the effect of the substrate:inoculum ratio and digestate recirculation conditions on the biogas and methane yield, free ammonia concentration and solid phase agronomic quality (after treatment) of poultry litter solid state anaerobic digestion (SSAD). Experimental tests were conducted using a central composite design (2²), with four trials at the factorial points and three at the central points, using poultry litter as substrate that was collected after 12 cycles of broiler production [TS 76% (w.w −1 )]. Three laboratory-scale reactors containing 3 kg of poultry litter each were operated at mesophilic conditions (37 • C) and seven experimental runs were performed at retention time of 30 days each. There were three substrate:inoculum ratios (1:1; 1:1.66, and 1:3) and three daily recirculation intervals (2, 3, and 4 times per day), and each recirculation event lasted 15 min. The highest biogas and methane yields were183 L Nbiogas .kg VSadd , respectively, and they were obtained at the substrate:inoculum ratio of 1:3 with a digestate recirculation frequency of four times a day. Digestate recirculation was the variable that influenced the concentration of free ammonia; the most frequently recirculated tests had lower concentrations (below 60 mgNH 3 .L −1 ). After the SSAD process, we identified a transfer of nutrients (N, P, K) from the solid phase to the liquid phase. The nutrient concentrations in the solid phase (N out = 11 g.kg −1 , K out = 5 g.kg −1 , and P out = 7 g.kg −1 ) indicated that the digested poultry litter still has potential for use in fertilization. In this study, it was estimated that 90 m 3 biogas .tons −1 poultrylitter was generated using SSAD. Whereas 100 tons of poultry litter are produced after 12 production cycles, the biogas generation capacity reaches 9,000 m 3 /year. In this scenario, farmers can use biogas from poultry litter SSAD as an additional source of energy.

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Section: Methodsmentioning

confidence: 99%

Poultry Litter Solid State Anaerobic Digestion: Effect of Digestate Recirculation Intervals and Substrate/Inoculum Ratios on Process Efficiency

Marchioro

Steinmetz

Amaral

et al. 2018

Front. Sustain. Food Syst.

Self Cite

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“…0.1 (pH < 10.1), which suggests that the solution contains ! 20 % [23] NH 4 + cations, and as ar esult ammonium ions,p layed as ignificant role in nucleation suppression in templated synthesis. [13] This finding explains the similarity of the results when H 2 SO 4 or (NH 4 ) 2 SO 4 is added to synthesis solutions.…”

Section: Angewandte Chemiementioning

confidence: 99%

“…[13] Ammonium sulfate is as alt of astrong acid (H 2 SO 4 )a nd weak base (NH 3 ), its solution is acidic and the NH 4 + /NH 3 equilibrium in liquid solution is pH dependent. [23] An alkaline medium will necessary shift the chemical equilibrium to the NH 3 side.Asaresult, in the pH range of 11.4-11.06, NH 4 + will exist in minimal concentration in synthesis solution (< 2.5 %), [23] suggesting that the suppression of nucleation in the bulk solution by ammonium sulfate addition is basically attributed to decreasing the pH value of the solution. In templated secondary growth, [13] ahighly b-oriented layer was obtained with NH 4 + /Si-source ratio !…”

Section: Angewandte Chemiementioning

confidence: 99%

Template‐Free Synthesis of Highly b‐Oriented MFI‐Type Zeolite Thin Films by Seeded Secondary Growth

et al. 2019

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Highly b-oriented, closely packed, MFI zeolitefilms are prepared on seeded stainless-steel plates using organic template-free,s econdary growth solutions,c ontaining aluminum sulfate as ac rystallization agent. The number of aoriented twin crystals is significantly reduced, and even eliminated, simply by restricting the pH value of the secondary growth solution to the narrowrange of 11.1-11.3. Values of pH can be adjusted through the controlled addition of (NH 4 ) 2 SO 4 or H 2 SO 4 to secondary growth solutions of the composition (1 SiO 2 :0.57 NaOH:137.5 H 2 O:0.0050 (Al 2 (SO 4 ) 3 ·18 H 2 O)) or by simply decreasing the molar composition of NaOH with no extra additives.MFI zeolite films are attractive for aw ide range of applications,i ncluding molecular sieve membranes,c atalytic membrane reactors,l ow-dielectric-constant materials,a nd corrosion-resistant coatings. [1] Both experimental data and simulation results [2] have suggested that the straight channel along the b-axis is the fastest diffusion pathway in MFI crystals and b-oriented zeolite films exhibit superior performance compared to randomly oriented ones. [3] At present, one of the most important applications of b-oriented MFI films is as membranes for separation of p-xylene from xylene isomers. [4] Therefore,s ynthesizing high-quality,b -oriented MFI zeolite films is of great interest from the viewpoint of both fundamental studies and practical applications.B-oriented MFI films have been grown on stainless-steel substrates through the accurate manipulation of synthesis solution composition [5] and kinetic parameters [6] for crystal nucleation and growth during in situ synthesis.Continuous boriented zeolite films and membranes were also successfully prepared on different supports with the secondary (seeded)growth method, taking advantage of ab-oriented zeolite seed layer deposited on the substrate prior to hydrothermal treatment. [7] Decoupling the nucleation and growth steps can significantly reduce the difficulty in manipulating the orientation of zeolite films,w hich in turn enhances the reproducibility and scalability of the zeolite layer synthesis.In the methods mentioned above for the synthesis of boriented MFI zeolite films,o rganic template (or structuredirecting agent, SDA) was necessary for the formation of zeolite crystals.T emplating agents are incorporated in zeolite pores during hydrothermal synthesis and acalcination step is necessary to follow the film/membrane synthesis process to remove the template and open the zeolite channels.D uring the calcination process,a na brupt shrinkage of the zeolite lattice,a nd differences in the thermal expansion characteristics of zeolite films and their supports yield substantial stresses that often result in microcracks in zeolite films. [8] These microcracks make zeolite films less effective in practical applications.Moreover,t he growth of a-oriented twin crystals is unavoidable when tetrapropylammonium hydroxide (TPAOH), the most common template,i su sed in the secondary growth method. [7...

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“…Ammonium sulfate is a salt of a strong acid (H 2 SO 4 ) and weak base (NH 3 ), its solution is acidic and the NH 4 + /NH 3 equilibrium in liquid solution is pH dependent . An alkaline medium will necessary shift the chemical equilibrium to the NH 3 side.…”

Section: Figurementioning

confidence: 99%

Template‐Free Synthesis of Highly b‐Oriented MFI‐Type Zeolite Thin Films by Seeded Secondary Growth

et al. 2019

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Hydrophobic Membrane Technology for Ammonia Extraction From Wastewaters

Cited by 28 publications

References 23 publications

Poultry Litter Solid State Anaerobic Digestion: Effect of Digestate Recirculation Intervals and Substrate/Inoculum Ratios on Process Efficiency

Poultry Litter Solid State Anaerobic Digestion: Effect of Digestate Recirculation Intervals and Substrate/Inoculum Ratios on Process Efficiency

Template‐Free Synthesis of Highly b‐Oriented MFI‐Type Zeolite Thin Films by Seeded Secondary Growth

Template‐Free Synthesis of Highly b‐Oriented MFI‐Type Zeolite Thin Films by Seeded Secondary Growth

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