Page 171 - CW E-Magazine (11-2-2025)

Special Report

A rapid wrap-up of what’s new in Operations,

Processes and Products

Separation Technology

reported for trans- to cis-azobenzene.
(Green Chem., 2024; DOI: 10.1039/
D4GC00736K).

Low-temperature desorption
in thermomorphic solvents for
CO capture: Systems with
2
N-methylcyclohexylamine
(MCA) and N,N-
dimethylcyclohexylamine
(DMCA)
[This column has covered several papers
on absorption and desorption in a variety
of amines and ways of reducing energy
consumption in desorption through
catalysis, ultrasonically, etc.]
CO removal heat duty. Mechanism is explained. (ACS J. Yuan and Y. Zhang have reported
2
Sustainable Chem. Eng., 2024; DOI:
2
Niobium-modified HZSM-5 10.1021/acssuschemeng.4C00200). highest absorption capacity of CO at
0.70 mol CO /mol amine. Thermophilic
2
zeolite catalyses low-energy Light-swing CO capture: solvents can be regenerated at even 60°C
2
regeneration of CO -captured Photoirradiation-based with a desorption efficiency of about
amine solution 2 chemical CO release based 83%. Extent of desorption increased
2
[This column has covered papers on on photoisomerisation of with temperature. The energy require-
catalysis of regeneration of loaded azobenzene-amine/guanidine ment was 0.342 GJ/t CO , which is
2
amines and this continues to attract derivatives 61% decrease compared to liquid-liquid
attention as energy consumption in phase change absorbents. [This system
regeneration is an important factor.] R. Murakami et al have come out with a merits consideration.] (Chem. Eng. Res.
new light-swing method that can poten- Des., 2024, 207, July, 373-379; DOI:
Y. Song et al have developed an efficient tially utilise a natural source of energy; 10.1016/j.cherd.2024.06.005).
solid catalyst, Nb-modified HZSM-5, to i.e., sunlight, as an alternative to tem-
facilitate CO desorption; 4% Nb has the perature - and pressure-swing methods. Novel tetramethylammonium
2
higher activity and stability. This strategy The key reaction is photoisomerisation cation-based ionic liquid
results in 61% increase in the desorp- of azobenzene-amine and guanidine solutions for highly efficient
tion rate and 37% reduction of relative derivatives. A plausible mechanism is CO absorption
2
[This column has covered many papers
on CO absorption/desorption in view
2
of its great importance with respect to
climate change.]

W. Liu et al have come out with a yet
another title absorbent, (N 1111 )(Py),
(N 1111 )(1,2,4-Tz) with aprotic hetero-
cyclic anion. Only 80% (N 1111 )(1,2,4-Tz)

Chemical Weekly February 11, 2025 171

Contents Index to Advertisers Index to Products Advertised