Description of Carbon Dioxide Adsorption and Desorption onto Malaysian Coals under Subcritical Condition

AbstractCoal bed seams have been considered as promising sequestration reservoirs for CO2 disposal to mitigate the green house gas emissions. The CO2 adsorption and desorption attributes of CO2 on dry Malaysian coals (Sarawak, volatile bituminous) were performed using a sorptomat apparatus (ASAP 2010, Micromeritics, USA) and BELSORP-mini II machine (BEL Japan, Inc.) at 273K, 298K and pressure up to 1bar. The CO2 adsorption was favourable at low temperature and dry coal conditions. However, S3 and S4 coals have the highest adsorption capacity by 0.71 and 0.73 mmol/g respectively. According to IUPAC classification of adsorption isotherms, CO2 adsorption isotherm of all coal samples follow type I which most probably describe the adsorption limited to a few molecular layers (micropores). The results of adsorption and desorption isotherm demonstrate a positive hysteresis in all coal samples. The S1 coal and S2 coal have the highest hysteresis between adsorption and desorption isotherm compared to S3 coal and S4 coal. According to hysteresis classifications, the hysteresis during CO2 adsorption and desorption process for all coal samples follows type H3 which describes micropores and mesopores. The evaluation of the equilibrium adsorption data where fitted using by Langmuir, Freundlich, Redlich-Peterson, Koble-Corrigan, Toth and Sips models. Toth model provided the best fit for all adsorption experimental data that predicting all coals having heterogeneous surface properties

Effect of Liquid Flow Rate and Amine Concentration on CO 2 Removal from Natural Gas at High Pressure Operation in Packed Absorption Column

Abstract. Greenhouse gas (GHG) emissions such as carbon dioxide (CO 2 ) and methane (CH 4 ) from oil and natural gas operation at offshore platforms have significant contribution to global warming. The reduction of these GHG emissions is possible through CO 2 capture technology. This study reports the absorption performance of monoethanolamine (MEA) for the removal of CO 2 from natural gas (NG) at high pressure conditions. The absorption experiments were performed in an absorption column packed with Sulzer Metal Gauze Packing at 5.0 MPa operating pressure. The absorption performance was evaluated in terms of CO 2 removal (%) with liquid flow rate ranging from 1.81 to 4.51 m 3 /m 2 .h and MEA concentration of 1.0 -4.0 kmol/m 3 . It was found that CO 2 removal (%) had increased with increasing liquid flow rate and MEA concentration

Kinetic Assessment of Tetramethyl Ammonium Hydroxide (Ionic Liquid) for Carbon Dioxide, Methane and Binary Mix Gas Hydrates

This present work highlights the impact of ammonium-based ionic liquid tetramethylammonium hydroxide (TMAOH) on the formation kinetics of carbon dioxide (CO2), methane (CH4), and their binary mixed gas (50–50 mole%) hydrates. The TMAOH (IL) is applied in varying concentrations (0.5, 1, and 2 wt%) at different experimental temperatures, i.e., 1 and 4°C. The kinetic experiments are conducted in a high-pressure reactor equipped with two-bladed impeller, to provide sufficient agitation. The experimental pressures of CO2, CH4, and mixed 50% CO2 + 50% CH4 were 3.50, 8.0, and 6.50 MPa, respectively. Induction time, the initial apparent rate of formation and the total gas consumed are the kinetic parameters used to evaluate the performance of TMAOH as KHI. The results are further compared with commercial KHI (PVP), at higher subcooling condition of 1°C and 1 wt% of all the studied gaseous systems. Furthermore, the KHI performance of TMAOH is also evaluated via the relative inhibition performance (RIP) compared with other ILs for CO2 and CH4 hydrates. Results revealed that TMAOH delays the induction time for all the considered systems. The presence of TMAOH also reduced the total gas consumed and the initial rate of hydrate formation in most of the studied systems

Hydrothermal Synthesis and Characterization of One-dimensional Ceria Nanorod for Chromium Ion Removal from Wastewater

Remediation of wastewater contaminated with Cr(VI) species by ceria particles has received considerable attention in recent years. The main objectives of the present study were to investigate the adsorption of Cr(VI) species on the one-dimensional (1-D) ceria nanorod (CeNR). In where, CeNR has 20–40 nm in diameter and 200–300 nm in length, as confirmed through FE-SEM and TEM images. Higher surface area of CeNR is insisted to the remediation of Cr(VI)-contaminated wastewaters. This work exemplifies the utilization of XAS and BET to reveal the speciation of CeNR for further understands of the very complex adsorption process. It is also very clear that decontamination of Cr species in wastewater via the in-situ remediation with CeNR permeable reactive barriers would be environmentally attractive in the near future. Keywords: Cr(VI)-contaminant, One-dimensional Ceria, Wastewater treatment; XANES/EXAFS

Improved biological delignification of wood biomass via Ionic liquids pretreatment: A one step process

The enzymatic pretreatment of wood biomass for degrading lignin, a complex aromatic polymer, has received much attention as an environmentally safe or “green” process. However, this process for lignin degradation has been found to be very slow, even needed several months. To overcome this limitation, this study reports a new approach for enhanced enzymatic delignification of wood biomass using room temperature ionic liquids (RTILs)- a potentially attractive “green” and “designer” solvent- as (co)solvents or/and pretreated agents. The method comprised pretreatment of wood biomass prior to enzymatic delignification in ILs-aqueous systems with the aim of overcoming low delignification efficiency associated with the difficulties in enzyme accessibility to the solid substrate and the poor substrate and products solubility in aqueous system. The results showed that IL [emim] [OAc] (1-ethyl-3-methylimidazolium acetate) was better solvent for wood delignification than IL [bmim][Cl] (1-butyl-3-methylimidazolium chloride). The recovered cellulose rich materials obtained from combination effects of IL and biological pretreatment contained significantly lower amounts of lignin as compared to the amounts found when each method applied alone. The produced cellulose rich materials were characterized by acid hydrolysis, Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and X-ray diffractometry (XRD). SEM and XRD revealed considerable microstructural and crystallinity index changes in the pretreated cellulose rich materials.  We believe that this newly developed process will play a great role in converting cellulosic biomass- the most abundant renewable biomaterials in the world- to biomaterials, biopolymers, biofuels, bioplastics and hydrocarbons. Keywords: ionic liquids, wood biomass, cellulose, lignin, laccase, enzymatic delignification

Solubility of CO2 in Aqueous Solutions of 2-Amino-2-Methyl-1-Propanol at High Pressure

Carbon dioxide is one of the major green house gases. It is removed from different streams using amine absorption process. Sterically hindered amines are suggested as good CO2 absorbers. Solubility of carbon dioxide (CO2) was measured in aqueous solutions of 2-Amino-2-methyl-1-propanol (AMP) at temperatures 30 oC, 40 oC and 60 oC. The effect of pressure and temperature was studied over various concentrations of AMP. It has been found that pressure has positive effect on CO2 solubility where as solubility decreased with increasing temperature. Absorption performance of AMP increased with increasing pressure. Solubility of aqueous AMP was compared with mo-ethanolamine (MEA) and the absorption capacity of aqueous solutions of AMP was found to be better

Quantitative Estimation of Biocapped Surface Chemistry Driven Interparticle Interactions and Growth Kinetics of Gold Nanoparticles

In phytosynthesis of gold nanoparticles (AuNPs), biomolecules play a vital role in biocapping the surface of particles and generating the electrostatic repulsive forces to inhibit their growth kinetics. However, estimation of bioactive compounds influencing their surface characteristics through formation of electric repulsive forces (Velec\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$V_{elec}$$\end{document}), Van der Waals attraction forces (Vvdw\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$V_{vdw}$$\end{document}) and ultimately hindering their growth is still in the phase of obscurity. Current study, based on surface chemistry approach has been performed for identification of bioactive compounds in Elaeis guineensis leaves (EGL/OPL), acting as biocapping agents and directing the growth of AuNPs over a period of time. The quantitative estimation of interparticle interactions and modification in Ostwald ripening (MOR) model were also done to correlate the growth kinetic of AuNPs. The X-ray photoelectron spectroscopy (XPS) showed the major contribution of oxygen, carbon and nitrogen elements, corresponding to polyphenolic, carboxylic and amides, in biocapping the surface of AuNPs and directing their interparticle interactions associated with growth kinetics. The Velec\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$V_{elec}$$\end{document} forces were reduced with an enhancement in the Vvdw\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$V_{vdw}$$\end{document} forces, depicting their major role in impeding growth of AuNPs. The MOR model exhibited an excellent agreement of predicted growth with experimental size enlargements of AuNPs, having 4.8% average absolute relative percentage error

Quantitative and qualitative analyses of grafted okra for corrosion inhibition of mild steel in acidic medium

Introduction: Natural plant polymers demonstrate effective corrosion inhibition abilities, because of their numerous binding sites and excellent adsorption abilities.Methodology: In this study, the Box-Behnken method, gravimetric and electrochemical analyses were used to design and investigate the corrosion inhibition potential of a modified graft polymer of okra for mild steel in a 1M HCl medium. The influence of inhibitor concentration, temperature, and time were also investigated. Qualitatively, the Fourier Transform Infrared (FTIR) spectroscopy, Thermogravimetric Analysis (TGA), and Field emission scanning electron microscopy (FESEM) were used to characterize the extracts and evaluate the metal’s surface morphology.Results and discussion: The quantitative analyses showed that the modified natural polymer’s inhibition efficiency (IE) increased with concentration and reached 73.5% at 800 ppm, with a mixed-type mode of inhibition. From the response surface methodology, it was revealed that temperature influences the IE more than concentration and immersion time. The optimized IE using the desirability function showed the possibility of attaining 88.2% inhibition with inhibitor concentration at 142.3 ppm, temperature at 60.4°C, and an immersion time of 22.4 h. The new functional groups in the hybrid polymer revealed by FTIR analysis shows that grafting improved the inhibitor’s adsorption abilities. TGA analysis confirmed the extract’s high thermal stability, which highlights the inhibitor’s strong adsorption and efficiency for high temperatures. FESEM analysis indicated evidence of inhibitor adsorption onto the metal surface.Conclusion: These findings suggest that the grafting of okra with acrylamide enhances its inhibition properties and contributes to its functionality as a cost-effective plant-based alternative inhibitor against corrosion for mild steel facilities