Cr(VI) adsorption by a green adsorbent walnut shell: Adsorption studies, regeneration studies, scale-up design and economic feasibility

2018 ◽  
Vol 116 ◽  
pp. 693-702 ◽  
Author(s):  
Munmun Banerjee ◽  
Ranjan Kumar Basu ◽  
Sudip Kumar Das
2021 ◽  
pp. 131736
Author(s):  
Asma S. Al-Wasidi ◽  
Ibtisam I.S. AlZahrani ◽  
Hotoun I. Thawibaraka ◽  
Ahmed M. Naglah ◽  
Mohamed G. El-Desouky ◽  
...  

Processes ◽  
2018 ◽  
Vol 6 (9) ◽  
pp. 161 ◽  
Author(s):  
Maximilian Sixt ◽  
Axel Schmidt ◽  
Fabian Mestmäcker ◽  
Maximilian Huter ◽  
Lukas Uhlenbrock ◽  
...  

The article summarizes a systematic process design for the extraction and purification of artemisinin from annual mugwort (Artemisia annua L.). Artemisinin serves as an anti-malaria drug, therefore, resource-efficient and economic processes for its production are needed. The process design was based on lab-scale experiments and afterwards piloted on miniplant-scale at the institute. In this part of the article, a detailed economic feasibility studies including a reference process as a benchmark the lab-scale process and the pilot-scale process is given. Relevant differences between the different scales are discussed. The details of the respective unit operations (solid-liquid extraction, liquid-liquid extraction, chromatography and crystallization) are presented in dedicated articles. The study showed that even miniaturized lab-scale experiments are able to deliver data detailed enough for scale-up calculations on a theoretical basis. To our knowledge, a comparable systematic process design and piloting was never performed by academia before.


Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1503
Author(s):  
Luis Fernando Saldarriaga ◽  
Fernando Almenglo ◽  
Domingo Cantero ◽  
Martín Ramírez

Photosynthetic biogas upgrading using two-stage systems allows the absorption of carbon dioxide (CO2) in an absorption unit and its subsequent assimilation by microalgae. The production of microalgae requires large amounts of nutrients, thus making scale-up difficult and reducing economic feasibility. The photosynthetic process produces oxygen (O2) (1 mol per mol of CO2 consumed), which can be desorbed into purified biogas. Two-stage systems reduce its impact but do not eliminate it. In this study, we test the use of landfill leachate as a nutrient source and propose a viable and economical strategy for reducing the O2 concentration. First, the liquid/gas (L/G) ratio and flow mode of the absorber were optimized for 20% and 40% CO2 with COMBO medium, then landfill leachate was used as a nutrient source. Finally, the system was inoculated with nitrifying bacteria. Leachate was found to be suitable as a nutrient source and to result in a significant improvement in CO2 absorption, with outlet concentrations of 0.01% and 0.6% for 20% and 40% CO2, respectively, being obtained. The use of nitrifying bacteria allowed a reduction in dissolved oxygen (DO) concentration, although it also resulted in a lower pH, thus making CO2 uptake slightly more difficult.


Author(s):  
Mirka Deza ◽  
Francine Battaglia ◽  
Theodore J. Heindel

Fluidized beds are used to gasify materials such as coal or biomass in the production of producer gas. Modeling these reactors using computational fluid dynamics is advantageous when performing parametric studies for design and scale-up. While two-dimensional simulations are easier to perform than three-dimensional simulations, they may not capture the proper physics. This paper compares two- and three-dimensional simulations with experiments for a reactor geometry with side port air injection. The side port is located within the bed region so that the injected air can help promote mixing. Of interest in this study is validating the hydrodynamics of fluidizing biomass. Two operating conditions of the fluidized bed are studied for superficial gas velocities of 1.5Umf and 3.0Umf, where Umf is the minimum fluidization velocity. The material used to represent biomass is ground walnut shell because it tends to fluidize uniformly and falls within the Geldart type B classification. The simulations are compared to experimental data of time-averaged local gas holdup values using X-ray computed tomography. Results indicate that for the conditions of this study, two-dimensional simulations overpredict the gas holdup trends when compared to the experiments. However, the three-dimensional simulations compare exceptionally well with the experiments, thus predicting the fluidization hydrodynamics, irrespective of flowrate or complexity due to the side air port. Furthermore, the study demonstrates the importance of using a three-dimensional model for bubbling fluidized beds with complex physics.


Química Nova ◽  
2020 ◽  
Author(s):  
Elimar Vasconcellos ◽  
Priscila Souza ◽  
Marcella Franco ◽  
Vinícius Castro ◽  
Lorena Souza ◽  
...  

TECHNOLOGY SCALE UP: PROCESS DEVELOPMENT FROM THE LABORATORY TO PILOT SCALE CONNECTED TO MARKET (PART 1). In this article, it is described the main aspects to be considered during the process of scaling up hard sciences technologies developed in the Science and Technology Institutes aiming at industrial application. Based on the experience of our group in scaling up, pre-acceleration, and acceleration of different technologies, a methodology was developed and divided into four main stages: Step 1, which involves basic research, Step 2 with a focus on product development, and Step 3 with a focus on process development, all on the laboratory scale and the last one, Step 4 focused on pilot plant development. The most important aspect of this article is to show that many critical questions can be answered even in the laboratory phase. In this way, the risks of Step 4 are minimized. Step 4 is a complicated, lengthy, and expensive process of construction and operation of a pilot plant. Aspects such as proof of concept, technical and economic feasibility studies, minimum viable product, capital expenditures, and operating expenses of pilot plants are approached in a simplified way to serve as a basis for researchers who wants to know the long path to be followed by technology before reaching the industry, consequently the market.


Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8112
Author(s):  
Etiele G. Morais ◽  
Nathana L. Cristofoli ◽  
Inês B. Maia ◽  
Tânia Magina ◽  
Paulo R. Cerqueira ◽  
...  

Wastewater (WW) treatment using microalgae has become a growing trend due the economic and environmental benefits of the process. As microalgae need CO2, nitrogen, and phosphorus to grow, they remove these potential pollutants from wastewaters, making them able to replace energetically expensive treatment steps in conventional WW treatment. Unlike traditional sludge, biomass can be used to produce biofuels, biofertilizers, high value chemicals, and even next-generation growth media for “organically” grown microalgal biomass targeting zero-waste policies and contributing to a more sustainable circular bioeconomy. The main challenge in this technology is the techno-economic feasibility of the system. Alternatives such as the isolation of novel strains, the use of native consortia, and the design of new bioreactors have been studied to overcome this and aid the scale-up of microalgal systems. This review focuses on the treatment of urban, industrial, and agricultural wastewaters by microalgae and their ability to not only remove, but also promote the reuse, of those pollutants. Opportunities and future prospects are discussed, including the upgrading of the produced biomass into valuable compounds, mainly biofuels.


Antioxidants ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 462 ◽  
Author(s):  
Mauro ◽  
Fava ◽  
Spampinato ◽  
Aleo ◽  
Melilli ◽  
...  

The valorization of food wastes is a challenging opportunity for a green, sustainable, and competitive development of industry. Approximately 30 million m3 of olive mill wastewater (OMWW) are produced annually in the world as a by-product of the olive oil extraction process. In addition to being a serious environmental and economic issue because of their polluting load, OMWW can also represent a precious resource of high-added-value molecules such as polyphenols that show acclaimed antioxidant and anti-inflammatory activities and can find useful applications in the pharmaceutical industry. In particular, the possibility to develop novel nutraceutical ophthalmic formulations containing free radical scavengers would represent an important therapeutic opportunity for all inflammatory diseases of the ocular surface. In this work, different adsorbents were tested to selectively recover a fraction that is rich in polyphenols from OMWW. Afterward, cytotoxicity and antioxidant/anti-inflammatory activities of polyphenolic fraction were evaluated through in vitro tests. Our results showed that the fraction (0.01%) had no toxic effects and was able to protect cells against oxidant and inflammatory stimulus, reducing reactive oxygen species and TNF-α levels. Finally, a novel stable ophthalmic hydrogel containing a polyphenolic fraction (0.01%) was formulated and the technical and economic feasibility of the process at a pre-industrial level was investigated.


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