Cleaner Chemical Engineering最新文献

Yeasts are used to produce several bioproducts, including functional bio-molecules, enzymes, biofuels, lipids, pigments, vitamins, organic acids, and other value-added bioproducts. When the production of the bioproduct occurs intracellularly, methods of disruption are traditionally used (mechanical and non-mechanical), which promote the release of bioproducts, but also the total degradation of the cell wall with consequent loss of yeast viability. As an alternative, cell permeabilization methods can be used through the use of external agents (chemical or physical), which form pores that increase the transfer of the product through the membrane, facilitating the separation of material, increasing the production of metabolites and also acting as an effective way of maintaining cellular viability - at least partially. In this review, we summarize the advances in yeast cell wall permeabilization compared to traditional methods of cell rupture. We also present the methods available for evaluating cell disruption and yeast permeabilization for yeast.

The recovery of palladium metal is essential in order to meet its growing global demand and also to address water pollution crisis. Herein, MIL-101(Cr)/ED was fabricated from waste polyethylene terephthalate (PET) bottles and modified using ethylenediamine (ED) to retrieve divalent palladium (Pd(II)) metal ions from aqueous environment. The successful grafting of ED moieties onto MIL-101(Cr) was established by the appearance of broad bands at around 2800–3300 cm⁻¹ on the Fourier transform infrared spectrum which was supported by the increase in binding energy using density functional theory. The adsorption experiments revealed that higher Pd(II) ion intake occurred using 30 mg of MIL-101(Cr)/ED in acidic media of pH = 3.0. The data fit better on the Langmuir isotherm with the correlation coefficient (R²) 0.9089. At 25 °C, the MIL-101(Cr)/ED achieved a substantial enhancement in the intake capacities of 454.2 mg.g⁻¹. Kinetics data demonstrated to comply with pseudo-second order, achieving a rapid rate of Pd(II) adsorption by the MIL-101(Cr)/ED in less than 3 min given by the rate constant k₂ = 0.02065 g.mg⁻¹.min⁻¹. The MIL-101(Cr)/ED has high affinity for Pd(II) ions as more than 80% removal was achieved even in presence of other ions. These observations revealed the potential utilization of MIL-101(Cr)/ED as an adsorbent to efficiently extract Pd(II) ions from wastewater.

Challenges in recycling heterogeneous waste remain untapped. Automotive shredder residue is one such heterogenous waste generated after processing End-of-Life Vehicles, making it difficult to process. There are two impediments to the recycling of ASR. One is the heterogeneity of the ASR (as received), and the other is not knowing what constituents to be extracted from the ASR. The ability of the thermochemical process to transform waste into beneficial products is well known. The objective of this work is based on a techno-economic evaluation of the recovery of energy and high-value metals from Automotive Shredder Residue. The equipment sizing and fabrication cost of each piece used in this process are calculated based on laboratory experiments. An integrated techno-economic study for processing heterogeneous waste ASR has not been studied in the literature previously. The economic evaluation was carried out assuming a plant life of 25 years. In addition, the plant's revenue was generated by the obtained products, and the payback period for energy and metal recovery was found to be 3 years respectively. The capital cost and operating cost for the ASR recycling plant with a combined approach of recovering energy and metals have been estimated from grass root stage. The outcome of this study confirms that ASR recycling has potential value for secondary resources and the process is economically viable. The resource recovery from ASR is an environmentally friendly technology where the maximum utilization rate is raised, along with energy saving and environmental protection by reduction of ASR waste in landfill.

Carbon dioxide emission has emerged as a major concern in the 21st century. The rising global average temperature and its impact on climate change has a major impact on the socioeconomic affairs of the world. This rise, directly causes the melting of the polar ice caps which in turn, brings about many other issues including extinction of polar animals, flooding of coastal regions, exposure to ancient microbial life and bacteria frozen in the snow which pose a risk of many more global pandemics and unseen diseases. An urgent need to control this carbon emission is required. The initial step in this process is to accurately identify the threat levels and milestones. Certain thresholds need to be mapped that express the most critical levels of CO₂ such as – the risk point, point of no return, etc. This is the main issue that this paper aims to address. The paper also aims to suggest some methodologies to deal with the same issue. The flow of the experiment and paper is described in the following lines. Historical data was used to make a prediction for the year in which the earth will hit a particular threshold for carbon dioxide concentration in the atmosphere. This level must not be breached and is essential in the fight against climate change. Next, analysis and data are used to calculate the reduction needed in the emission levels in order to bring back the CO₂ concentrations into a safer range. The study concludes that the critical level of CO₂ - 500 ppm, will be achieved by the year 2047. This level is considered a point of no return. A reduction rate of 6.37% and reversal rate of 23.38% is required to bring the emissions back to safe levels. The study also concluded that various socioeconomic factors such as population, greenhouse gasses, combustion industries contribute the most to these emissions. The authors recommend that further research be carried out on this problem to ascertain further predictions on the point of no return so that an action plan can be developed accordingly. The authors also recommend that a shift to renewable energy sources be undertaken speedily and that carbon neutrality be a crucial goal of every organization.

Biochemical routes have shown to be an interesting alternative for the reuse of glycerol, largely generated as a co-product in biodiesel production reaction. Previous works from the research group have demonstrated that glycerol can be efficiently assimilated by Yarrowia lipolytica to produce erythritol, mannitol, citric acid and bio-oil. To better understand the metabolic pathways involved, this work proposes a mathematical model to describe the observed phenomenon. This is the first computational work to model polyol's production and to address the simultaneous formation of four products by Yarrowia lipolytica. Particle Swarm Optimization and Interior Point Optimization were employed together to find the global optima. The developed model proved to be significantly promising and capable of satisfactorily predict the system's behavior in more than one experimental condition. Not only products’ concurrent formation was accurately described, but also polyols’ modeling was successfully performed, reaching R² values greater than 0.93.

Wood is one of the most abundant renewable resources in the world. However, large volumes of waste are generated in the losses and cuts of wood saws, being an important environmental problem. This work aims to evaluate the production of hydrochar from wood residues of Pinus caribaea combined with acid-base treatment for application as dyes Methylene Blue (MB) and Tartrazine Yellow (TAR). Hydrocarbonization was carried out at 200 or 240 ..C for 12 or 24 h, in acidic or basic medium. The pHZPC of the hydrocarbons obtained in acidic medium was between 2.66-4.12 and 4.46-5.76 for those processed in basic medium. The pseudo-secondorder model (PSO) better fitted the adsorption of MB and TAR on Pinus in natura and on hydrochar. In addition, the Sips model was considered the most suitable for MB (qmax= 132.1 mg g-1 for PIN and 149.0 mg g-1 for PIN-200-24-B) and Toth for TAR (qmax= 18.14 mg g-1 for PIN and 23.01 mg g-1 for PIN-200-24-B adsorption isotherms). Therefore, the hydrocarbonization of waste generated from the wood industry in acidic and basic environments has great potential for the treatment of materials such as biosorbents, thus promoting greater sustainability in this sector.

This work explains the production of isopropyl myristate (IPM), an ester formed from the esterification reaction of myristic acid and isopropyl alcohol in a reactive-distillation column. The design of the column has been done to achieve a dual process objective of achieving product purity of 99% and reactant conversion (99%) to produce 1000 kg/hr IPM at 30°C and about 1 bar pressure conditions existing within the column. The reboiler duty comes to be 190 kW against the condenser duty of 160 kW when an entrainer, cyclohexane at 1975 kg/hr is used, which can be reduced by employing two columns. The nonlinear quaternary system is solved using NRTL thermodynamic package, and the reactive distillation column is designed. The IMC-PID-based temperature controller has been designed for a closed-loop structure to achieve safe operation and desired dynamic control behavior and simulated by using MATLAB. The column has been stable under both steady-state and dynamic conditions by stabilizing the non-linear performance of the column by the controllers. The process integration of the reactor and separator into one column has minimized a process plant's operating and investment cost.

Microbial generation of coal bed methane (CBM) represents a significant source of natural gas on Earth. While biostimulation has been demonstrated in batch cultures, environmental parameters such as overburden pressure and formation water flow need to be tested at the laboratory scale to understand in situ potential. We designed and constructed a high-pressure (HP) flow-through reactor system that simulates in situ conditions of underground coal seams. Two stainless-steel columns contained coal from the Powder River Basin (PRB), USA, or a coal/sand mixture to represent the interface of coal seams with sandstone layers, which are hypothesized to exhibit higher methanogenesis rates in situ. The system was filled with CBM formation water, inoculated with a methanogenic enrichment from PRB coal beds, and stimulated with algal biomass as a nutrient. The reactors were incubated under pressure (5.4 atm) and flow of CBM water (0.01 mL/min), and control batch cultures were incubated at ambient pressure and without flow (± amendment). Dissolved and headspace methane concentrations were analyzed over time by gas chromatography for 75 days. The pressurized reactors exhibited longer latency periods than ambient pressure controls, but methane production did not reach a plateau phase, which might reflect the impact of scale on the inoculum. The coal/sand reactor exhibited higher methane production than the coal-only reactor, a pattern also observed in the corresponding controls, suggesting an interface effect on methanogenesis. This study indicates that the HP flow test system we designed is well suited for the study of methanogenesis and provides a successful demonstration of CBM generation from the PRB in field-relevant laboratory conditions as a precursor to meso‑scale demonstrations.

This work reports on a microwave-assisted solvothermal synthesis of CuS@In₂S₃ core-shell hybridized nanoparticles (Hy-NPs) at different weight ratios (wt%) of CuS to tune the heterojunction optoelectronic properties and evaluate the application for photocatalytic degradation of organic dyes. The photodegradation performance in terms of the efficiency and reaction kinetics shows that the 10 wt% CuS Hy-NPs presents the highest photoactivity in the degradation of two dye species, methylene blue (MB) and methyl orange (MO) when compared to 5 wt% CuS, 15% CuS Hy-NPs samples as well as the pristine CuS or In₂S₃ NPs. The structural and morphological studies combining the optical bandgap analysis suggest that the CuS amount used in the synthesis step plays an important role to forming the efficient heterojunction interfaces for charge carrier separation to inhibit the recombination of excited electron and hole pairs and the resultant apparent optical bandgap of the Hy-NPs. The 10 wt% CuS@In₂S₃ core-shell Hy-NPs demonstrate a lower optical band for a wide range visible light absorption and higher photocatalytic activity than that of the CuS NPs, In₂S₃ NPs, and the 5 wt% CuS, or 15 wt% CuS Hy-NPs. The findings in this work may offer an alternative simple and effective approach to designing and synthesizing metal chalcogenide heterojunctions for improving photocatalytic activity.

With realization that world's resources are limited, a number of initiatives in all global regions emerged to pursue a common goal of sustainable management of energy and material loops. The intensively researched topics are traditionally gathered under the roof of Sustainable Development of Energy, Water and Environmental Systems conferences (SDEWES), which in its 16^th edition saw a highly focused and impacting research contributions, tackling the cross-sectoral development and introduction of novel technologies and processes, all devoted to implementation and examination of possible solutions to contribute to Sustainable Development Goals (SDGs). The present paper is gathering and structuring these contributions, enriched with the outcomes of previous SDEWES conferences to enlighten the advances made in the fields of energy harvesting, circular economy and efficient energy use to put into context the role of cleaner chemical engineering. By this, it provides a basis and a guidance for future research on the axis of material-resource-energy nexus which is in the paper identified as an extensively interlinked research area, difficult to be tackled individually and still requiring an important effort to collectively address the cross-sectoral dimension of the challenge.