scholarly journals A Universal Mathematical Methodology in Characterization of Materials for Tailored Design of Porous Surfaces

2021 ◽  
Vol 8 ◽  
Author(s):  
Muhammad Burhan ◽  
Faheem Hassan Akhtar ◽  
Qian Chen ◽  
Muhammad Wakil Shahzad ◽  
Doskhan Ybyraiymkul ◽  
...  
Keyword(s):  
Adsorption Isotherms ◽  
Adsorption Energy ◽  
Surface Characteristics ◽  
Material Structure ◽  
Heterogeneous Structure ◽  
Adsorbent Surface ◽  
Adsorption Processes ◽  
Characterization Of Materials ◽  
Directed Change ◽  
Adsorption Phenomena

Understanding adsorption phenomena is essential to optimize and customize the energy transformation in numerous industrial and environmental processes. The complex and heterogeneous structure of the adsorbent surface and the distinct interaction of adsorbent-adsorbate pairs are attributed to the diverse response of adsorption phenomena, measured by the state diagrams of adsorption uptake known as adsorption isotherms. To understand various forms of adsorption isotherms, the surface characteristics of the adsorbent surface with the heterogeneity of adsorption energy sites must be analyzed so that they can be modified for the tailored response of the material. Conventionally, such material synthesis is based on chemical recipes or post-treatment. However, if the adsorbent's surface characteristics and heterogeneity are known, then a directed change in the material structure can be planned for the desired results in the adsorption processes. In this paper, a theoretical and mathematical methodology is discussed to analyze the structure of various adsorbents in terms of the distribution of their adsorption energy sites. The change in their surface is then analyzed, which results in the tailored or customized response of the material.

Surface properties and adsorption characteristics to methylene blue and iodine of adsorbents from sludge

2010 ◽  
Vol 62 (8) ◽  
pp. 1705-1712 ◽  
Author(s):  
L. Y. Deng ◽  
G. R. Xu ◽  
G. B. Li
Keyword(s):  
Methylene Blue ◽  
Electrostatic Interactions ◽  
Active Sites ◽  
Pyrolysis Temperature ◽  
Weight Ratio ◽  
Surface Characteristics ◽  
Wastewater Sludge ◽  
X Ray ◽  
Adsorption Characteristics ◽  
Adsorbent Surface

Adsorbent materials created from wastewater sludge have unique surface characteristics and could be effective in adsorption applications. In this research, the sludge-adsorbents were generated by pyrolyzing mixtures of sewage sludge and H2SO4. Scanning electron microscope (SEM), thermal analysis, X-ray diffraction (XRD) and X-ray photoelectron spectroscope (XPS) were used to analyze the properties of sludge-adsorbent. XPS results show that the adsorbent surface functional groups with high contents of oxygen-containing groups serve as active sites for the adsorption and affect the surface characteristics; the adsorption mechanism of methylene blue (MB) is mainly Brönsted acid-base reaction between the adsorbent surface and MB; and iodine atoms are bonded to the surface of the adsorbent mainly by dispersive interactions rather than by electrostatic interactions. The results also show that H2SO4 level, pyrolysis temperature and sulfuric acid/sludge weight ratio actually affected the adsorption characteristics. Using the conditions (H2SO4 level of 1–18 M, pyrolysis temperature of 650°C, and weight ratio of 0.8), the adsorption capacities for MB and iodine were 74.7–62.3 mg g−1 and 169.5–209.3 mg g−1, respectively.

and Cyclic Hydrocarbons on y-Aluminium Oxide

1970 ◽  
Vol 25 (5) ◽  
pp. 688-692 ◽  
Author(s):  
Manlio Sanesi ◽  
Vittoriano Wagner
Keyword(s):  
Double Bond ◽  
Adsorption Energy ◽  
Surface Coverage ◽  
Aluminium Oxide ◽  
Unsaturated Hydrocarbons ◽  
Cyclic Hydrocarbons ◽  
Heats Of Adsorption ◽  
Adsorbent Surface ◽  
Acid Centers ◽  
Adsorption Heats

The heats of adsorption on weakly activated γ-Al2O3 of a number of linear 1-monoolefins (C4 to C9) and cyclic saturated and unsaturated hydrocarbons have been measured by gas-solid chromatography and extrapolated to zero surface coverage.The double bond contribution to the adsorption energy is shown by comparison of the adsorption heats with those of the corresponding saturated molecules and is related to the existence of Brensted acid centers on the adsorbent surface. The effect of cyclization is also shown.

Interaction of triton X-100 on silica: A relationship between surface characteristics and adsorption isotherms

1995 ◽  
Vol 63 (3) ◽  
pp. 249-256 ◽  
Author(s):  
Daniela M. Nevskaia ◽  
Maria Luisa Rojas Cervantes ◽  
Antonio Guerrero Ruíz ◽  
Juan de Dios López González
Keyword(s):  
Adsorption Isotherms ◽  
Surface Characteristics ◽  
Triton X

Reaction Of Diamond Surfaces With Halogen-Containing Species

1995 ◽  
Vol 416 ◽  
Author(s):  
K. Larsson
Keyword(s):  
Adsorption Energy ◽  
Growth Process ◽  
Initial Step ◽  
Quantum Mechanical ◽  
Structural Configuration ◽  
Structural Comparison ◽  
Diamond Surfaces ◽  
Mechanical Methods ◽  
Adsorption Processes ◽  
Adsorption Energies

ABSTRACTAn energetic and structural comparison has been made concerning adsorption processes on a diamond (111) surface from a hydrogen (H)-, halogen (X)- or H/X-carrying carbon precursors. The halogens X examined were F, Cl and Br. The quantum mechanical methods used in the investigation were the ab initio MO method as well as the LDA method. F, Cl, and H, were all shown to be able to sustain the sp3 structural configuration of the surface carbon atoms. For Br large sterical hindrances were induced and the diamond (111) surface could not be stabilized. The calculated adsorption energy of CF3 to a H-terminated diamond (111) surface was found to be numerically the largest one (489 kJ/mol on the MP2 level of theory) in comparison to the other adsorption processes studied in the present investigation. It was, in particular, much larger than the corresponding adsorption energy of CH3 (418 kJ/mol). The calculated adsorption energies do support the initial step in the growth process (adsorption) to be energetically more favourable for systems incorporating a mixture of halogen and hydrogen in the growth vapor than for corresponding systems involving unmixed halogen or hydrogen in the carbon containing precursor.

Surface behaviour of tetrapropylammonium cation at the mercury/solution interface measured by use of controlled convective adsorptive accumulation

1985 ◽  
Vol 50 (11) ◽  
pp. 2525-2534 ◽  
Author(s):  
Ladislav Novotný ◽  
Ivan Smoler
Keyword(s):  
Surface Tension ◽  
Adsorption Isotherms ◽  
Adsorption Energy ◽  
Surface Coverage ◽  
Adsorption Parameters ◽  
Surface Tension Data ◽  
Solution Interface ◽  
Constant Potential ◽  
Drop Time ◽  
Constant Charge

Using drop time technique with long drop times and a controlled convection of the solution the surface tension data of Hg with tetrapropylammonium perchlorate in 0.1 mol l-1 NaClO4 in the concentration range 4 . 10-6 - 3 . 10-3 mol l-1 have been obtained. The corresponding adsorption parameters have been evaluated from the Frumkin isotherm both at constant potential E and at constant charge q. Both E and q could be chosen as an independent electrical variable. The maximum free adsorption energy amounts to approx. -36.5 kJ mol-1. The congruence of adsorption isotherms with respect to E and with respect to q was very well fulfilled for the surface coverage Θ ⪬ 0.6-0.7.

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