This paper investigates the selectivity of GMA-based-non-woven fabrics adsorbent towards copper ion (Cu) functionalized with several aliphatic amines. The aliphatic amines used in this study were ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetetramine (TETA), and tetraethylenepentamine (TEPA). The non-woven polyethylene/polypropylene fabrics (NWF) were grafted with glycidyl methacrylate (GMA) via pre-radiation grafting technique, followed by chemical functionalization with the aliphatic amine. To prepare the ion recognition polymer (IRP), the functionalized amine GMA-grafted-NWF sample was subjected to radiation crosslinking process along with the crosslinking agent, divinylbenzene (DVB), in the presence of Cu ion as a template in the matrix of the adsorbent. Functionalization with different aliphatic amine was carried out at different amine concentrations, grafting yield, reaction temperature, and reaction time to study the effect of different aliphatic amine onto amine density yield. At a concentration of 50% of amine and 50% of isopropanol, EDA, DETA, TETA, and TEPA had attained amine density around 5.12, 4.06, 3.04, and 2.56 mmol/g-ad, respectively. The amine density yield decreases further as the aliphatic amine chain grows longer. The experimental condition for amine functionalization process was fixed at 70% amine, 30% isopropanol, 60 °C for grafting temperature, and 2 h of grafting time for attaining 100% of grafting yield (Dg). The prepared adsorbents were characterized comprehensively in terms of structural and morphology with multiple analytical tools. An adsorptive removal and selectivity of Cu ion by the prepared adsorbent was investigated in a binary metal ion system. The IRP samples with a functional precursor of EDA, the smallest aliphatic amine had given the higher adsorption capacity and selectivity towards Cu ion. The selectivity of IRP samples reduces as the aliphatic amine chain grows longer, EDA to TEPA. However, IRP samples still exhibited remarkably higher selectivity in comparison to the amine immobilized GMA-g-NWF at similar adsorption experimental conditions. This observation indicates that IRP samples possess higher selectivity after incorporation of the ion recognition imprint technique via the radiation crosslinking process.
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.
The processing of rice (Oryza sativa L.) generates large quantities of lignocellulosic wastes termed rice husks (RH). Numerous researchers have proposed biomass gasification as the panacea to the waste disposal and management challenges posed by RH. However, a comprehensive analysis of RH gasification is required to examine the research landscape and future directions on the area. The research landscape and global developments on RH gasification from 1995 to 2019 are examined through bibliometric analysis of 228 publications extracted from the Web of Science. Bioresource Technology is considered the most influential journal on the topic, whereas China is the most productive nation due to government policies and research funding. The most productive organization is the Harbin Institute of Technology, which is due to the significant contributions of Zhao YiJun and co-workers. Keyword analysis revealed three crucial research themes: gasification, biomass, and rice husks. The literature revealed that the syngas yield, distribution, and performance of RH gasification are significantly influenced by temperature, equivalence ratio, selected reactor, and gasifying medium. The techno-economic analysis of RH gasification revealed that government interventions such as high sales rates and low investment costs could enhance the commercial viability of the technology. Furthermore, the integration of RH gasification with carbon capture utilization and storage could promote the decarbonization of power plants, negative emissions, and net-zero climate goals. Overall, the paper provides valuable information for future researchers to identify strategic collaborators, journal publications, and research frontiers yet unexplored.