Tunnel structured manganese dioxides for the gaseous ammonia adsorption and its regeneration performance

The preparation of low-cost carbonaceous adsorbents for nitrogen recovery is of interest from agricultural and waste management perspectives. In this study, the gaseous ammonia (NH3) and aqueous ammonium (NH4+) sorption capacities have been measured for different types of carbonaceous chars produced under different conditions. The study includes a comparison of an oak-based hydrochar produced from hydrothermal carbonisation (HTC) at 250 °C with two biochars produced from slow pyrolysis at 450 °C and 650 °C, respectively. The chars were also chemically modified with H2SO4, H3PO4, H2O2, and KOH to investigate the potential for sorption enhancement. The highest sorption capacities for NH3 were observed for the hydrochars with typical uptake capacities ranging from 18–28 mg g−1 NH3. Sorption capacity for oak biochars is significantly lower and ranges from 4–8 mg g−1 for biochars produced at 450 °C and 650 °C, respectively. Hydrochar showed a substantially higher sorption capacity for NH3 despite its lower surface area. The CaCl2 extractable NH4+ following ammonia adsorption is incomplete. Typically, only 30–40% of the N is released upon washing with CaCl2 in form of NH4+. Post chemical modification of the chars resulted in only limited enhancement of char NH3 and NH4+ sorption. H3PO4 treatment showed the greatest potential for increasing NH3/NH4+ sorption in biochars, while KOH and H2O2 treatment increased NH3 sorption in the hydrochar. As only marginal increases to char surface area were observed following char treatment, these findings suggest that char surface functionality is more influential than surface area in terms of char NH3/NH4+ sorption.

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Treatment of Gaseous Ammonia Emissions Using Date Palm Pits Based Granular Activated Carbon

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph17051519 ◽

2020 ◽

Vol 17 (5) ◽

pp. 1519 ◽

Cited By ~ 2

Author(s):

Muhammad Vohra

Keyword(s):

Activated Carbon ◽

Functional Groups ◽

Gas Flow ◽

Date Palm ◽

Agricultural Waste ◽

Granular Activated Carbon ◽

Gaseous Ammonia ◽

Ammonia Adsorption ◽

Run Time ◽

Respective Surface

The present work investigated the application of granular activated carbon (GAC) derived from date palm pits (DPP) agricultural waste for treating gaseous ammonia. Respective findings indicate increased breakthrough time (run time at which 5% of influent ammonia is exiting with the effluent gas) with a decrease in influent ammonia and increase in GAC bed depth. At a gas flow rate of 1.1 L/min and GAC column length of 8 cm, the following breakthrough trend was noted: 1295 min (2.5 ppmv) > 712 min (5 ppmv) > 532 min (7.5 ppmv). A qualitatively similar trend was also noted for the exhaustion time results (run time at which 95% of influent ammonia is exiting with the effluent gas). The Fourier Transform Infrared Spectroscopy (FTIR) findings for the produced GAC indicated some salient functional groups at the produced GAC surface including O–H, C–H, C–O, and S=O groups. Ammonia adsorption was suggested to result from its interaction with the respective surface functional groups via different mechanisms. Comparison with a commercial GAC showed the date palm pits based GAC to be having slightly higher breakthrough and exhaustion capacity.

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Calorimetric study of the acidity of alumina-boria catalysts by gaseous ammonia adsorption

Journal of Thermal Analysis and Calorimetry ◽

10.1007/bf01979732 ◽

1992 ◽

Vol 38 (12) ◽

pp. 2565-2573 ◽

Cited By ~ 13

Author(s):

G. C. Colorio ◽

A. Auroux ◽

B. Bonnetot

Keyword(s):

Gaseous Ammonia ◽

Calorimetric Study ◽

Ammonia Adsorption

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Kinetics of the reaction between solid terephthalic acid and gaseous ammonia

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19733561 ◽

1973 ◽

Vol 38 (12) ◽

pp. 3561-3570 ◽

Cited By ~ 1

Author(s):

J. Smolík ◽

J. Vítovec

Keyword(s):

Terephthalic Acid ◽

Gaseous Ammonia ◽

Kinetics Of

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Tailoring Properties of Resol Resin-Derived Spherical Carbons for Adsorption of Phenol from Aqueous Solution

Molecules ◽

10.3390/molecules26061736 ◽

2021 ◽

Vol 26 (6) ◽

pp. 1736

Author(s):

Karol Sidor ◽

Tomasz Berniak ◽

Piotr Łątka ◽

Anna Rokicińska ◽

Marek Michalik ◽

...

Keyword(s):

Surface Composition ◽

Micropore Volume ◽

Gaseous Ammonia ◽

Poly Vinyl Alcohol ◽

Clear Correlation ◽

Hno3 Solution ◽

Synthesis Conditions ◽

Adsorption Of Nitrogen ◽

Oxygen Groups ◽

Size Of Particles

The polycondensation of resorcinol and formaldehyde in a water–ethanol mixture using the adapted Stöber method was used to obtain resol resins. An optimization of synthesis conditions and the use of an appropriate stabilizer (e.g., poly(vinyl alcohol)) resulted in spherical grains. The resins were carbonized in the temperature range of 600–1050 °C and then chemically activated in an aqueous HNO3 solution, gaseous ammonia, or by an oxidation–reduction cycle (soaking in a HNO3 solution followed by treatment with NH3). The obtained carbons were characterized by XRD, the low-temperature adsorption of nitrogen, SEM, TGA, and XPS in order to determine degree of graphitization, porosity, shape and size of particles, and surface composition, respectively. Finally, the materials were tested in phenol adsorption. The pseudo-second order model perfectly described the adsorption kinetics. A clear correlation between the micropore volume and the adsorption capacity was found. The content of graphite domains also had a positive effect on the adsorption properties. On the other hand, the presence of heteroatoms, especially oxygen groups, resulted in the clogging of the pores and a decrease in the amount of adsorbed phenol.

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