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• Diamine (DMAPA) and glycine (GLY) mixtures have high CO 2 loading capacity. • Ethanol was used to convert liquid absorbent and CO 2 into carbamates. • At low GLY-DMAPA concentration (0.1 mol/L) no product was formed. • Carbamates were generated at high concentration of GLY-DMAPA (0.5–2.0 mol/L). 3-dimethylaminopropylamine (DMAPA) and glycine (GLY) mixture was studied as a potential absorbent for carbon dioxide (CO 2) capture and utilization. The solubility of CO 2 in aqueous GLY-DMAPA solutions within the range of 0.1–2.0 mol/L (M) were measured experimentally using pressure differential technique. Utilization of CO 2 was also studied by mixing the CO 2 -saturated absorbent with ethanol. The final products obtained were characterized by using Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS). The solubility study revealed that the CO 2 loading capacity increased as pressure of CO 2 increased. In contrast, the loading capacity decreased when concentration of the absorbent and temperature in equilibrium cell increased. However, the total moles of CO 2 absorbed showed an opposite trend such that net CO 2 absorbed increased as concentration of absorbent increased. The chemical interactions between CO 2 and GLY-DMAPA molecules were studied by analyzing the changes of characteristic peaks observed form the FTIR spectra. For CO 2 utilization, the addition of ethanol as a reagent into 0.1 M CO 2 -saturated GLY-DMAPA solution did not produced any precipitate. Nonetheless, as the concentration of GLY-DMAPA increased from 0.5 M to 2.0 M, white precipitates were produced, indicated that the conversion of CO 2 into solid compounds occurred instantaneously after the CO 2 capture. The optimum concentration of GLY-DMAPA for CO 2 capture and utilization depends on the amount of solids generated and the CO 2 loading capacity of the absorbent. At 5 bar, the optimum concentration was found to be 1.0 M with 45 mg/g of solids recovered and CO 2 loading capacity of 1.6 mol CO 2 /mol absorbent. The final product was identified as carbamate salt based on the main characteristic peaks present on the FTIR and XPS spectra. [ABSTRACT FROM AUTHOR]

Risk assessment is the tool for maintaining perfect safety management systems and aiding sustainable process design, with hazard identification as the critical step. This step can be executed by past accidents analysis (PAA) to achieve the mentioned objectives. Despite of available analyses, the recurring of accidents identifies the shortcomings in PAA and requires a detailed examination as reported in this review. The intensified exploration of accident information will strengthen both the safety management system at existing facilities and process designing in terms of sustainability. Past accidents analysis is a significant method for the crtitical hazard identification step of risk assessment. The analyses reported in literature to determine the trends for process industry accidents for safety systems of existing process plants and sustainable process designing are critically reviewed. Future directions for accident analysis are highlighted. [ABSTRACT FROM AUTHOR]

[Display omitted] • We looked into the potential applications of hydrate-based desalination (HBD) • HBD process treats produced water with a concentration 2.8 wt% • CO 2 as guest gas produced a water recovery of 45.55% • The desalination efficiency is strongly dependent on the ionic radii and strength of the ionic charge. This paper emphasizes sustainable development goal 6 and accepts that social progress and economic prosperity depend on the appropriate management of produced water. Produced water being the largest source of wastewater, several conventional desalination methods (thermal, membrane and freeze–thaw), are applied to obtain treated water. Nevertheless, the methods are highly energy intensive. Prospective utilization of hydrate-based desalination was proposed with a novel filter-based apparatus design to separate hydrate crystals from residual water and enhance the gas–liquid contact with all the unit operations (hydrate formation, and dissociation) occurring inside a single reactor. Experimentations were implemented to obtain the optimum conditions for CO 2 hydrate formation and compared with pure water. CO 2 hydrate formation kinetics revealed induction time, moles consumed, water-to-hydrate conversion, and water recovery were 57 mins, 1.28 mol, 27.72 %, and 50.65 % at optimum conditions of 500 ml, 3.0 MPa, 450 rpm, and 275.15 K for purification of produced water. A desalination efficiency of 62–80 % is achieved with each of the metal ions in the sequence K+>Na+>Mg2+>Ca2+, and anions SO 4 2- > Cl- without any pre and post-treatment. Also, demonstrated that the ionic charge and size have a significant impact on the ion rejection mechanism. The findings disclosed that with an upsurge in the temperature to 277.15 K the desalination efficiency enhanced nevertheless the volume of formed hydrate is less resulting in less driving force. The total dissolved solids and electrical conductivity results indicate that the treated water meets Malaysia's water quality standards for irrigation purposes. This showcases the execution of the hydrate-based desalination process, investigating salt rejection and yield with our custom reactor design. The proposed reactor design may be utilized for the effective separation of hydrate and effectively desalinating waters of higher salinities. Hydrate-based desalination integrated with membrane reactors could lead to a sustainable source of clean water by treating produced water. [ABSTRACT FROM AUTHOR]

Over the years notable accidents have occurred in the chemical process industry thus creating a major concern for the safeness of its operation. The disasters led to the dire consequences that claimed human life and health as well as monetary losses. Inherently safer design is an effective solution to prevent accidents because it postulates that the best way to reduce risk is to avoid the hazard rather than control the hazard. Although the implementation of inherently safer design can give great advantages and cost optimal operation throughout process's life cycle, slow adoption of this principle into real design practice can be observed. This is partly because the inability to realise the benefits of inherent safety implementation among industrial practitioner. This paper presents a methodology for evaluating inherently safer design alternatives and identifying the benefits using an index-based approach at preliminary design stage. The proposed methodology is applied to ammonia storage with the objective of preventing and minimising toxic release. The results have shown that the new methodology can identify the best inherently safer design and the benefits where it is capable to reduce the severity of accident and the requirement to manage hazardous process. [ABSTRACT FROM AUTHOR]

• Interaction of cetylpyridinium bromide (CPB) with polyvinyl alcohol (PVA) was studied in aq. alcohols media. • Sharp increase of CMC values was observed with increase of temperature. • Negative Δ H m 0 v a l u e s showed that of CPB + PVA mixture aggregation is exothermic. • Interaction forces between CPB and PVA are electrostatic, hydrophobic and ion-dipole in nature. • Enthalpy-entropy compensation parameters were also assessed. The mixture of polymer and surfactant is extensively employed in numerous daily used products such as detergents, perfumes, cleaning agents, foodstuffs, oil recovery procedures, paints, as well as pharmaceutical formulations. Interaction of cetylpyridinium bromide (CPB) with polyvinyl alcohol (PVA) has been investigated in water and aqueous solution of different alcohols using the conductivity technique. The type and strength of interaction between CPB and PVA during assembly process have been assessed from different micellar parameters i.e., critical micelle concentration (CMC), extent of counterion dissociation (α), Gibbs free energy (Δ G m 0), enthalpy (Δ H m 0), entropy (Δ S m 0) of micellization etc. The CMC and α were determined from the specific conductivity vs [CPB] plots. The micellization of CPB was attained to be augmented in occurrence of PVA. The CMC values of CPB + PVA system were experienced to be increased through the elongation of chain length of carbon as well as increase of concentration of certain alcohol. The sharp increase of CMC values was also observed with the increase of temperature in a certain alcoholic medium. The values of degree of dissociation were undergone to be augmented by the increase of concentration of certain alcohol as well as the elongation of carbon chain length. The negative free energy of micellization (- Δ G m 0) values reveal that the CPB + PVA system undergoes aggregation spontaneously and spontaneity of micellization experienced a reduction with the elongation of carbon chain length. Values of enthalpy ( Δ H m 0) of micellization were negative i.e., aggregation of CPB + PVA system is an exothermic phenomenon. The Δ H m o and Δ S m o values disclose that the main interaction forces between CPB and PVA are electrostatic, hydrophobic, and ion–dipole interactions. The stability of the micelle formed was assessed from enthalpy-entropy compensation parameters. [ABSTRACT FROM AUTHOR]

Removal of CO2from natural gas using a membrane-based process has been adopted on an industrial scale, and about 200 membrane separation plants have been installed all over the world. In industry, inorganic membranes are preferred over the polymeric and mixed matrix membranes in CO2separation from natural gas because of their good chemical stability and high separation performance. Among all inorganic membranes, deca-dodecasil 3 rhombohedral zeolite (DDR) membrane exhibits the highest selectivity in CO2separation from natural gas. However, synthesis of DDR membranes requires a long duration, with a minimum of 25 days. Therefore, reduction of duration in the synthesis of the DDR membrane remains a challenging issue. In this review, separation performance of polymeric, mixed matrix and inorganic membranes are compared. Synthesis methods of DDR membranes and their performance in CO2separation reported by various researchers are discussed. The challenges and issues related to the formation of DDR membranes are also included. In conclusion, the future direction and perspective on the development of DDR membranes for CO2separation are summarized. [ABSTRACT FROM AUTHOR]

In this study, series of non-ionic surfactants from Span and Tween are evaluated for their ability to affect the viscosity profile of cyclopentane hydrate slurry. The surfactants; Span 20, Span 40, Span 80, Tween 20, Tween 40 and Tween 80 were selected and tested to provide different hydrophilic–hydrophobic balance values and allow evaluation their solubility impact on hydrate formation and growth time. The study was performed by using a HAAKE ViscotesterTM 500 at 2 °C and a surfactant concentration ranging from 0.1 wt%–1 wt%. The solubility characteristic of the non-ionic surfactants changed the hydrate slurry in different ways with surfactants type and varying concentration. The rheological measurement suggested that oil-soluble Span surfactants was generally inhibitive to hydrate formation by extending the hydrate induction time. However, an opposite effect was observed for the Tween surfactants. On the other hand, both Span and Tween demonstrated promoting effect to accelerate hydrate growth time of cyclopentane hydrate formation. The average hydrate crystallization growth time of the blank sample was reduced by 86% and 68% by Tween and Span surfactants at 1 wt%, respectively. The findings in this study are useful to understand the rheological behavior of surfactants in hydrate slurry. [ABSTRACT FROM AUTHOR]

Solvothermal synthesis is the most preferable preparation technique of metal–organic frameworks (MOFs) that consists of reactants mixing, ultrasonication, solvothermal reaction, product washing, and solvent evacuation. Owing to fast reaction kinetics in solvothermal reaction, this technique allows for production of uniform MOF particles with high crystallinity, high phase purity, and small particle sizes. However, it exhibits some difficulties of washing processes that may involve the blockage of pores due to incomplete removal of reactive medium from MOF products. The present study proposes an improvement of washing processes by introducing centrifugal separations with optimized parameters at two different stages: after reaction and after product washing. Nickel-based MOF-74 was synthesized as the experimental material for this purpose. The quality of the produced sample was evaluated by gas adsorption performance using CO2 at 1 bar and 25 °C. The final sample of the optimized synthesis routes was able to adsorb 5.80 mmol/g of CO2 uptake, which was competitive with literature data and significantly higher than the sample of the basic synthesis. Fourier-transform infrared spectroscopy (FTIR) and powder X-ray diffraction (PXRD) analysis revealed that the sample displayed much higher crystallinity structure and was clean from impurities after centrifugations. The outcome indicated the success of separation between MOF products and reactive medium during washing processes, leading to the effective pore activation of MOFs. [ABSTRACT FROM AUTHOR]