Kinetic studies of radiation induced grafting of N-vinylformamide onto polyethylene/polypropylene fibrous sheets and testing its hydrolysed copolymer for CO2 adsorption

CO2 adsorption and CO2/CH4 separation using fibrous amine-containing adsorbents: isothermal, kinetic, and thermodynamic behaviours

A series of fibrous aminated adsorbents for CO2 adsorption were prepared by covalent incorporation of poly (glycidyl methacrylate) (PGMA) by graft copolymerization of GMA onto electron beam (EB) irradiated polyethylenepolypropylene (PE/PP) fibrous sheets and subsequent amination with ethylenediamine (EDA), diethylenetriamine (DETA), or tetraethylenepentamine (TEPA). The physico-chemical properties of the adsorbents were evaluated using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric (TGA), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) analysis. All the adsorbents displayed typic primary and secondary amine features combined with a decrease in both of crystallinity and surface area of PE/PP, and such a decrease was higher in adsorbents with longer aliphatic chain of the amine. Of all adsorbents, TEPA-containing fibres showed the highest CO2 adsorption capacity and thus was further investigated for CO2 capture from CO2/CH4 mixtures of different gas ratios under various pressures and temperatures. The selectivity of CO2 over CH4 and equilibrium isotherms, kinetics, and thermodynamics of the adsorption on the fibrous aminated adsorbent were all investigated. The Sips model was found to best fit the isotherm of CO2 adsorption suggesting the presence of a combination of monolayer and multilayer adsorptions. The adsorption kinetic data was found to best fit Elovich model reflecting chemisorption. The ΔG°, ΔS°, and ΔH° showed positive values suggesting that the adsorption of CO2 on the present fibrous adsorbent was non-spontaneous with an increase in randomness implying that the process was endothermic. Overall, it can be suggested that PE/PP-g-PGMA/TEPA adsorbent has a strong potential for separation of CO2 from NG.

Effective CO2 capture by using poly (acrylonitrile) nanofibers based on the radiation grafting procedure in fixed-bed adsorption column

In this study, a new adsorbent was investigated for CO₂ adsorption in the fixed-bed column. Poly (acrylonitrile) nanofibers were prepared by electrospinning, then grafting under gamma irradiation with glycidyl methacrylate (GMA). Then, the nanofibers were modified with ethanolamine (EA), diethylamine (DEA) and triethylamine (TEA) to adsorb carbon dioxide molecules. Dynamic adsorption experiments were performed with a mixture of CH₄, CO₂ in a constant bed column at ambient pressure and temperature and CO₂ feed concentration (5%). The maximum adsorption capacity is 2.84 mmol/g for samples with 172.26% degree of grafting (DG) in 10 kGy. Also, the degree of amination with ethanolamine was achieved equal to 170.83%. In addition, the reduction of the regeneration temperature and the stability of this adsorbent after four cycles indicated the high performance of this adsorbent for CO₂ adsorption.

RAFT polymerisation of N-vinylformamide and the corresponding double hydrophilic block copolymers

Polyvinylamine-based double hydrophilic block copolymers are synthesised from RAFT polymerisation of N-vinylformamide.

Trimethylamine functionalized radiation-induced grafted polyamide 6 fibers for p-nitrophenol adsorption

The method of pre-irradiation grafting was used with the aid of electron beam (EB) accelerator to accomplish the grafting of polyamide 6 fibers (PA6) with glycidyl methacrylate (GMA). The extent to which GMA was grafted on PA6 was found to be markedly influenced by the absorbed dose of radiation and the reaction time of grafting. Trimethylamine (TMA) was afterwards employed for the functionalization of GMA-grafted fibers (PA6-g-GMA). A range of analyses (e.g., FTIR, FESEM, XRD, BET, and pHpzc) were carried out to determine the physiochemical and morphological properties of the fibrous adsorbent. p-Nitrophenol (PNP) adsorption from aqueous solution was conducted with the resulting TMA-(PA6-g-GMA) adsorbent. The adsorption behaviour of PNP on the fibrous adsorbent was clarified by investigating the adsorption kinetics and isotherm. According to the results, the adsorption of PNP on TMA-(PA6-g-GMA) reflected the pseudo-second order model. Meanwhile, the isotherm analysis revealed that the best description of the equilibrium data was provided by Redlich-Peterson model, followed closely by Langmuir isotherm model. The achieved adsorption capacity was highest at 176.036 mg/g. Moreover, the adsorption was indicated by the thermodynamic analysis to be spontaneous and exothermic. Regeneration and recycling of the adsorbent was possible for a minimum of five cycles with no reduction in adsorption capacity. It was concluded that the fibrous adsorbent could have applications for the removal of PNP at industrial pilot scale.