Academic Journal

A Scalable Functional Nanogel of Polyacrylamide-Piperazine-Copper Oxide Nanoparticles for Enhanced Biogas Purification.

Bibliographic Details
Title:	A Scalable Functional Nanogel of Polyacrylamide-Piperazine-Copper Oxide Nanoparticles for Enhanced Biogas Purification.
Authors:	Sahoo BB; School of Mechanical Engineering, Vellore Institute of Technology, Vellore 632014, India. Electronic address: bb.sahoo@vit.ac.in., Usama M; School of Mechanical Engineering, Vellore Institute of Technology, Vellore 632014, India. Electronic address: mohammedusam.m2024@vitstudent.ac.in., Vyas R; School of Chemical Engineering, Vellore Institute of Technology, Vellore 632014, India. Electronic address: rahulvyas0701@gmail.com., Bal DK; School of Chemical Engineering, Vellore Institute of Technology, Vellore 632014, India. Electronic address: dharmendrakumar.b@vit.ac.in.
Source:	Bioresource technology [Bioresour Technol] 2026 Jul; Vol. 451, pp. 134549. Date of Electronic Publication: 2026 Apr 01.
Publication Type:	Journal Article
Language:	English
Journal Info:	Publisher: Elsevier Applied Science Country of Publication: England NLM ID: 9889523 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1873-2976 (Electronic) Linking ISSN: 09608524 NLM ISO Abbreviation: Bioresour Technol Subsets: MEDLINE
Imprint Name(s):	Original Publication: Barking, Essex, England : New York, N.Y. : Elsevier Applied Science ; Elsevier Science Pub. Co., 1991-
MeSH Terms:	Acrylic Resins/chemistry , Copper/chemistry , Piperazines/chemistry , Polyethylene Glycols/chemistry , Polyethyleneimine/chemistry , Nanoparticles/chemistry , Biofuels*, Methane/isolation & purification ; Carbon Dioxide/isolation & purification ; Hydrogen Sulfide/isolation & purification ; Metal Nanoparticles/chemistry ; Polyacrylamides ; Adsorption ; Thermodynamics ; Nanogels
Abstract:	Efficient upgrading of biogas to bio-compressed natural gas (bio-CNG) quality requires the selective removal of carbon dioxide (CO2) and hydrogen sulfide (H2S) without compromising methane recovery or process economics. In this research, polyacrylamide-based nanogels were developed and evaluated as low-cost sorbents for biogas purification under continuous flow conditions. Dynamic sorption experiments were conducted using raw biogas, and the purification performance was assessed in terms of CO2 and H2S removal efficiency, methane enrichment, sorption capacity, selectivity and separation thermodynamics. The optimized nanogel achieved up to 95% CO2 removal, increasing the methane (CH4) concentration to more than 98% in the purified gas stream. Equilibrium analysis revealed high CH4/CO2 selectivity (32.75), accompanied by favorable equilibrium constants (32.74) and negative Gibbs free energy changes (-8640 J/mol), confirming the spontaneous nature of CO2 sorption. The CO2 removal capacity from raw biogas increased proportionally with gas flow rate, while equilibrium CO2 concentrations at the outlet decreased markedly for improved nanogel formulations, indicating strong sorbent-gas affinity. Breakthrough curve analysis demonstrated delayed CO2 breakthrough and sustained sorption performance. Adsorption isotherm modeling showed that the Freundlich model provided a superior fit compared to the Langmuir model, highlighting the heterogeneous and flexible nature of the nanogel adsorption sites and a predominantly physisorption-controlled mechanism. Overall, the results establish polyacrylamide nanogels as promising, regenerable, and energy-efficient sorbents for scalable biogas upgrading and bio-CNG production. (Copyright © 2026 Elsevier Ltd. All rights reserved.)
Competing Interests:	Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Contributed Indexing:	Keywords: Automobile; Bio-methane; Biogaspurification; Polyacrylamide gel; Sorption
Substance Nomenclature:	0 (Acrylic Resins) OP0UW79H66 (Methane) 9003-05-8 (Polyacrylamides) 0 (Biofuels) 142M471B3J (Carbon Dioxide) 789U1901C5 (Copper) 0 (Piperazines) T8BEA5064F (cuprous oxide) YY9FVM7NSN (Hydrogen Sulfide) 3WJQ0SDW1A (Polyethylene Glycols) 9002-98-6 (Polyethyleneimine) 0 (Nanogels) 0 (polyethylene glycol polyethyleneimine nanogel)
Entry Date(s):	Date Created: 20260403 Date Completed: 20260714 Latest Revision: 20260714
Update Code:	20260714
DOI:	10.1016/j.biortech.2026.134549
PMID:	41932517
Database:	MEDLINE

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