Chemisorption of Ammonia on Silica

1973 ◽  
Vol 51 (11) ◽  
pp. 1771-1781 ◽  
Author(s):  
G. A. Blomfield ◽  
L. H. Little
Keyword(s):  
Adsorption Process ◽  
Ammonia Adsorption ◽  
Adsorption Sites ◽  
Added Water ◽  
Adsorption Of Water ◽  
Amine Groups

The interaction of ammonia with silicas prepared by a variety of methods was studied to resolve conflicting reports of the mode of ammonia adsorption and to determine the role of chlorine impurities (present in the silica) in the adsorption process. Results for the adsorption of water on silica assisted in making band assignments and competition between ammonia and water for silica adsorption sites was observed. It was concluded that dehydroxylated silicas contain sites which dissociate ammonia to form Si—NH2 groups having infrared bands at 3540, 3450, and 1550 cm−1 (the surface amine groups are not displaced by added water). The presence of chlorine in the silica is not a prerequisite for chemisorption of ammonia.

scholarly journals Adsorption process and mechanism of heavy metal ions by different components of cells, using yeast (Pichia pastoris) and Cu2+ as biosorption models

RSC Advances ◽  
2021 ◽  
Vol 11 (28) ◽  
pp. 17080-17091
Author(s):  
Xinggang Chen ◽  
Zhuang Tian ◽  
Haina Cheng ◽  
Gang Xu ◽  
Hongbo Zhou
Keyword(s):  
Heavy Metal ◽  
Pichia Pastoris ◽  
Metal Ions ◽  
Cell Walls ◽  
Heavy Metal Ions ◽  
Adsorption Process ◽  
Yeast Pichia Pastoris ◽  
Adsorption Sites

The Cu2+ first bound to the outer mannan and finally entered the cytoplasm. During the whole adsorption process, the number of adsorption sites in the outer and middle cell walls was the largest, and then gradually decreased.

scholarly journals The Adsorption of Chloromethanes on KCl. The Role of the Surface Ions as Adsorption Sites

1983 ◽  
Vol 56 (7) ◽  
pp. 2086-2089 ◽  
Author(s):  
Masatoshi Chikazawa ◽  
Masatoshi Amada ◽  
Takafumi Kanazawa
Keyword(s):  
Adsorption Sites ◽  
As Adsorption

scholarly journals Synthesis of Zeolite from Carbothermal Reduction Electrolytic Manganese Residue for the Removal of Macrolide Antibiotics from Aqueous Solution

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2133 ◽  
Author(s):  
Xuli Li ◽  
Yue Zeng ◽  
Fangyuan Chen ◽  
Teng Wang ◽  
Yixin Li ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Carbothermal Reduction ◽  
Adsorption Process ◽  
Hydroxyl Group ◽  
Macrolide Antibiotics ◽  
Adsorption Sites ◽  
Electrolytic Manganese ◽  
Electrolytic Manganese Residue ◽  
Pseudo Second Order ◽  
The Fourier Transform

Zeolite analcime (EMANA) was synthesized through the hydrothermal method by using carbothermal reduction electrolytic manganese residue (CR-EMR). The structural properties of EMANA and CR-EMR were studied using various characterization techniques. After hydrothermal synthesis, the CR-EMR became super-microporous, and the surface area increased by 4.76 times than before. Among the various synthesized zeolites, 6 h-synthesized EMANA was selected as the best adsorbent for macrolide antibiotics in aqueous solution. The adsorption performance of EMANA on the adsorption capacity was examined by using various experimental parameters, such as contact time (0–24 h), initial concentration (50–300 mg/L), temperature (30–50 °C) and pH (3–13). The experimental results were also analyzed by the Langmuir and Freundlich adsorption models, with the latter obtaining better representation. The adsorption process could be described well by the pseudo-second-order model, even under a low concentration (50 mg/L). This result suggests that the adsorption process of macrolide antibiotics is due to chemisorption. According to the Fourier Transform infrared spectroscopy (FT-IR) results, the adsorption of zeolite was mainly due to its hydroxyl group, which played an important role during the adsorption process. Moreover, EMANA is more suitable for treatment of roxithromycin (ROX) than azithromycin (AZM), because ROX has more adsorption sites for the hydroxyl group.

A Study on Adsorption Ammonia Nitrogen of Diatomite Modified by Microwave

2012 ◽  
Vol 602-604 ◽  
pp. 1211-1214
Author(s):  
Zhi Wen Luo ◽  
Zhong Chen ◽  
Su Hong Liu
Keyword(s):  
Adsorption Process ◽  
Freundlich Isotherm ◽  
Nitrogen Adsorption ◽  
Microwave Treatment ◽  
Ammonia Nitrogen ◽  
Ammonia Adsorption ◽  
Freundlich Isotherms ◽  
Adsorption Capacities ◽  
The Impact ◽  
Modified Diatomite

Diatomite was modified by microwave treatment to increase their utilization value, using modified diatomite to treat ammonia-nitrogen wastewater. The experiment indicated that adsorption process of modification of the modified time by microwaves and microwave power is the impact of ammonia adsorption of the main factors. Through modification experiments by raising the capacity of diatomite adsorption ammonia nitrogen, adsorption of ammonia nitrogen increase over one time. Langmuir and Freundlich isotherms were used to fit and the experimental results show that the modified diatomite adsorption onto ammonia nitrogen accords with Langmuir and Freundlich isotherm. The maximum theoretical adsorption capacities are 5.81083mg/g.

scholarly journals STUDY OF THE FORMATION OF MESOPOROUS TiO2 USING ISOPROPOXIDE PRECURSORS UNDER LESS WATER CONDITIONS

2010 ◽  
Vol 5 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Indriana Kartini ◽  
Gao Qing Lu
Keyword(s):  
Self Assembly ◽  
Isopropyl Alcohol ◽  
Molar Ratio ◽  
Mesoporous Titania ◽  
Synthesis Parameters ◽  
Water Conditions ◽  
Evaporation Induced Self Assembly ◽  
Added Water ◽  
Templating Synthesis

The role of the synthesis parameters (the molar ratio of template, isopropyl alcohol, acetylacetone, and water with respect to titanium(IV) tetraisopropoxide) has been thoroughly investigated to understand their effects on the mesostructures and the formation of crystalline phases of mesoporous titania xerogels in less water condition (no added water) at 60 oC. The resultant mesoporous titania are more likely to have worm-hole like structure as the dominant stable structure. The template appears to play no significant role in structure directing at mesophase level. However, increasing the amount of the template delays the formation of anatase crystalline phase   Keywords: mesoporous titania, templating synthesis, anatase, evaporation-induced self-assembly

Role of Steps in the Dissociative Adsorption of Water on RutileTiO2(110)

2013 ◽  
Vol 110 (14) ◽  
Author(s):  
H. H. Kristoffersen ◽  
J. Ø. Hansen ◽  
U. Martinez ◽  
Y. Y. Wei ◽  
J. Matthiesen ◽  
...  
Keyword(s):  
Dissociative Adsorption ◽  
Adsorption Of Water

Cellulose-g-tetraethylenepentamine Dual-function Imprinted Polymers Selectively and Effectively Adsorb and Remove 4-Nitrophenol and Cr(VI)

2021 ◽  
Author(s):  
Daning Lang ◽  
Xia Xu ◽  
Ronglan Wu ◽  
WEI WANG ◽  
Ming Shi ◽  
...  
Keyword(s):  
Binary Systems ◽  
Competitive Adsorption ◽  
Dual Function ◽  
Imprint Polymer ◽  
Inorganic Contaminants ◽  
Cellulosic Material ◽  
Imprinted Polymer ◽  
Promising Candidate ◽  
Adsorption Sites ◽  
Amine Groups

Abstract A cellulosic material could efficiently and selectively adsorb organic and inorganic contaminants from aqueous solutions without interference from competing adsorption sites. In this study, cellulose-graft-tetraethylenepentamin molecular imprinted polymer (C-TEPA-MIP) was synthesized by using 4-nitrophenol (4-NP) as the template. The C-TEPA-MIP adsorbent could adsorb 4-NP and Cr(VI) simultaneously and selectively, without being affected by the competitive adsorption sites of each of these pollutants. The adsorption of 4-NP was predominantly due to the imprinted sites of 4-NP in C-TEPA-MIP that were located inside of the adsorbent, whereas that of Cr(VI) was primarily due to the amine groups of TEPA found on the surface of the adsorbent. Compared with the non-imprint polymer synthesized without the template, C-TEPA-MIP showed higher selectivity for both 4-NP and Cr(VI) in unitary and binary systems. In addition, C-TEPA-MIP exhibited good stability and recyclability for 4-NP, which makes it a promising candidate material for applications concerning wastewater treatment.

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